ARY
NE. 1916 ; 'Z- 10 CENTS
+ LARGEST CIRCULATION OF ANY, ELECTRICAL PUBLICATION
|
— i — ! — ; ! — - — ! Two People Shouting the same words in the same tone of voice can make the sound carry farther than if both shouted in different tones. In the same way, wireless receivers have a greatly increased range if both of them are exactly matched in tone. You have less trouble getting "in tune" with the sender and you get the signals much clearer. The long distance records >2Mfefc. made under these conditions are surprising. That is Iff |B gr^ the way Brandes Wireless Head Sets are made — both »i iff If ^B^. ifflr \ vi receivers closely matched. In addition, they are easily If Jl fl 1| ^ J 1 adjustable and yet so rigid, when once adjusted to your flf \ JjU comfort, that they never slip nor irritate. IIBl /^rv\ 0*tJ*k There are types of Brandes Receivers for different if Hit Vv^'* yf / JjJr purposes. Learn about them by sending for our Cata- log! ^"-S^A mm£T log E. It also contains valuable radio information \_/y Jf that will help you get better results. Send 4 cents in "Superior" Type Brandes Head Set, C. BRANDES, Inc. Complete With Headband, $5. .... , _ . _ ... _ «..««...■■'« », „ , ., ,. Wireless Receiver Specialists. Room 814, 32 Union Square, New York, N. Y. Brandes Wireless Head Sets |
|
|
' • : 1 '■:■>,; , : .'..:,:.,>■■,,:.!, i !\. , I'M 'J'I!M|«I t V0i 1 ' |
|
|
&el~3ladion 1 Permanent, instantaneous, ^^^J^fe||B^. No lost messages constant - ;^ No static interference 1 No batteries needed No delays or interruptions No operating expense "^^^ ^(^^ Always reliable and | No set screws or fine ad- ^\^J^^^^ efficient justments It never fails you I ' HE only wireless detector that has been found to be absolutely permanent and needing no adjustment at any time. After severest tests found to be the only permanent wireless detector that upheld its advertiser's claims. You can jar and kick the Tel-Radion, but you cannot knock it out of adjustment nor destroy its sensitiveness. Don't be misled into buying a so-called "permanent" detector whose only attraction is its low price. For a few pennies you can construct the same type yourself. Seal up a piece of crystal after locating a sensitive spot on its surface. He is a novice who doesn't know the secret. Every operator knows how unsatisfactory it is in operation. We will welcome a comparative test with any detector on the market by an expert, and we challenge anyone to disprove any of our claims. The Tel-Radion has been tested and approved by the experts of some of the largest commercial wireless stations in America. Especially recommended for shipboard and field work or any location subject to jars and vibrations. Don t throw your money away on toys. Convince yourself at our expense. We pledge ourselves to refund the purchase price of the Tel-Radion if not satisfactory. The Tel-Radion is the best permanent detector on the market. The Tel-Radion permanent wireless de- ft* f\f\ tector is enclosed in a highly polished mahogany cabinet. Size 412x41ix3 inches, equipped with a duplex JKi^ UlJ rotary switch, all metal parts silver plated. Prepaid to any part of the United States. Price NOTE OUR GUARANTEE We guarantee the Tel-Radion to be superior to any other detector advertised as "permanent" or will refund your money. Equip your station with a Tel-Radion and lift it out of the amateur class. Send for descriptive literature. TEL-RADION CO. 32 Union Sq., New York City |
|
|
You benefit by mentioning "The Electrical Experimenter" when writing to advertisers. |
June, 1916
THE ELECTRICAL EXPERIMENTER
73
DUCK'S
ftie William B. Duck Co.
320-PAGE ELECTRICAL and WIRELESS CATALOG
MORE THAN EVER JUSTIFIES YOUR VERDICT THAT IT IS THE ONE CATALOG WORTH WHILE
3 k 5""33
15,000 of our catalogs ready for delivery to eager electrical and wireless enthusiasts in all parts of the world. One of ten consecutive ship- ments of catalogs to our patrons during last [November.
ELECTRICAL SUPPLIES
the WI LL I AM B. DUCK co.
150 pp. Wireless struments.
In-
170 pp. Electrical Sup- plies.
Over 40 pp. of Wireless Instruments.
Only 8c. in stamps will bring this unri- valled catalog to your home. The great cost of catalog and the ex- ceptionally low prices (oftentimes fully 25% below usual retail price)
I prohibits its distribu- tion otherwise. You
You
may deduct the 8c. on first $1.00 purchase.
WHAT OUR BIG CATALOG CONTAINS
150 pp. Wireless Instruments, magnet wire of all kinds, raw material, storage batteries, telegraph instruments, battery motors, commercial motors and gen- erators, sewing machine motors, telephones, step-down transformers, massage vibrators, bells, push buttons, auto accessories, flash lights, hand lanterns, auto and miniature lamps, Xmas tree outfits, voltmeters, ammeters, lighting plants, Victrolas, air rifles, electric aeroplanes, model builders, electric railways, elec- trical and mechanical books and general electrical supplies.
The William B. Duck Co.,
230-232 SUPERIOR ST. TOLEDO, OHIO
—TRY CRYSTAL'
10 days subject to trial and our Money Back guarantee
QRYSTALOI is the ideal summer detector because the peculiar arrangement of mineral and finely divided alloy renders it remarkably free from static and gives it a proven range of over 5000 miles.
TYPE AA. SUPER-SENSITIVE Price, $6. MaiingWt., 2 Pounds
CRYSTALOI— Type 0— $3.50 Postage, 10 cents
"The Crystaloi detector won a signal victory Dec. 31, when the New Year's message of Oswald Becker, President National Rotary Clubs, was correctly handled in our station and a verbatim copy handed to the President of the Wichita Rotary Club. In competition with all types of detectors, it remained for the Crystaloi, with a 4-wire aerial, to deliver the goods."
{Signed) Wichita Telegraph College
(W. S. Ezell, Manager) Wichita, Kans.
JTT Crystaloi is the most efficient and economical wireless detector ever produced. ^JJ It is extremely well made and simple in construction — there is nothing to get out of order — will not burn out. Every message comes in clear as a bell.
Send 5 c in stamps for Catalog "C" fully describing Crystaloi and all of our other High Class receiving apparatus.
Eugene T. Turney Company, Inc., NEW YORK CITY
You benefit by mentioning "The Electrical Experimenter" when writing to advertisers.
74
THE ELECTRICAL EXPERIMENTER
June, 1916
PRECISION VARNTUNERS
PRECISION VARICOUPLER TYPE AML
This instrument combines great range with won- derful accuracy and handsome appearance. Highly efficient on undamped waves. Will re- ceive amateur, ship, navy and long wave trans- atlantic stations with our loading coils below. Range — 2,000 meters, size 7" x 7" x 23", finish Mission oak, hard rubber, silver finished coils. Price $20.00
PRECISION VARIOMETER TYPE M
Embodies a new idea in variometers. Extremely accurate adjustment, high efficiency, appearance to match all other Precision instruments. Three times the range of any other variometer. Finish Mission oak, genuine hard rubber trimmings and panel, silver finished coils. Size 7" x 7" x 23". Price $8.00
PRECISION VARICOUPLER TYPE AMS
This instrument is similar in size and range to our Type AMM but is designed with a view to making a Precision Varicoupler of wide range and great efficiency as well as handsome appear- ance at a very low price. This instrument will do extremely fine work and presents a fine ap- pearance on the instrument table. Size 7" x 7" x 23", finish Mission oak, hard rubber, silk cov- ered wire. Range 100 to 600 meters. Price $14.00
ALL Precision apparatus here shown gives you ab- solutely accurate adjustment without the use of switches or sliders. Precision Varicouplers have no "dead ends," no taps, and can be used without vari- able condensers. They have a remarkable beauty which ap- peals to you on sight, and pre- sent a fine appearance on your instrument table. Acknowl- edged by all experts to be the superior tuners.
Important Notice
These prices are good for 30 days only; our former prices have been reduced, in order to universally in- troduce the present Precision pro- ducts, as illustrated on this page, within the shortest possible time.
PRECISION VARICOUPLER TYPE AMM
This tuner is similar to our type AMR but the secondary is not detachable from the primary. Range 100 to 600 meters, designed especially for amateur, commercial and navy work. Finish Mission oak, hard rubber panel and trimmings, silver finished coils, metal parts heavy nickel plate on brass. This instrument is a highly efficient and handsome Precision Varicoupler at a moderate price. Size 7" x 7" x 23".
Price $16.00
PRECISION VARICOUPLER TYPE AMR
Specially designed for long wave amateur re- ception on oscillating audion circuits. Extremely loose coupling, wonderfully accurate adjustment high efficiency, handsome appearance. Range 100 to 600 meters. Finish, Mission oak, hard rub- ber, silver finished coils. With this tuner you can pick up amateurs hundreds of miles away. Size 7" x 7" x 13" closed.
Price $20.00
PRECISION VARIOMETER TYPE S
Same design and range as our Type M, finish Mission oak, hard rubber, silver finished coils. Has greater range than any other variometer at the extremely low price of $6.00
PRECISION LOADING COILS
Designed especially for reception from long wave undamjed and damped stations. Wound with silk covered copper wire on spe- cially treated tube, genuine turned oak base and top, seven sections with nickel plated binding posts and flexible connecting cord with hard rubber handled plug. May be used with any of our vari- couplers.
No. 941 for primary $6.00
No. 942 for secondary $0.40
Size 36" x 434"
USE THIS SLIP NOW
You may intend to use it before the 10 days are up and forget.
Precision Radio Equipment Co. 868 Putnam Ave., Brooklyn, N. Y.
Gentlemen:
Ship immediatly express collect one Precision Varicoupler, Type N, at your 10-day price of $3.50 for which I enclose money order. If I de- cide to get one of your de luxe Varicouplers wit hin three months you hereby agree to accept the one ordered now as part payment to the ex- tent of $3.50.
Name
Address
City and State
EXTRAORDINARY ANNOUNCEMENT
TYPE N - FTER months of experiment we
have at last succeeded in develop- ing a Precision Varicoupler at such a low price that even the amateur who now wishes to make only a very small investment may secure one of our re- markable instruments. This instru- ment has a range equal to our type AMM and has primary and secondary adjustment without sliders or switches; has no dead ends or taps, and conse- quently has wonderful efficiency. The tubes are specially treated, all the wire used is genuine silk covered copper wire, all metal parts are heavily nickel-plated and the woodwork is mahogany finish. Adjustments are provided with hard rubber handles and the instrument is securely made and well finished. A remarkable instrument at an unheard of price. Size 13"x 5"x 5" $3.50 for 10 days only.
PRECISION RADIO EQUIPMENT CO., Inc.
General Office: 868 Putnam Avenue - - BROOKLYN, N. Y.
You benefit by mentioning "The Electrical Experimenter" when writing to advertisers.
The Electrical Experimenter
233 Fulton Street, New York.
Published by Experimenter Publishing Company, Inc. (H. Gernsback, President; S. Gernsback, Treasurer; M. Hymes, Secretary), 233 Fulton Street, New York.
Vol. IV Whole No. 38
CONTENTS FOR JUNE, 1916
No. 2
FRONT COVER— "ELECTRIC BOMB FIRER."
From a Painting by George Wall.
AN AUXILIARY PERISCOPE FOR SUBMARINES 77
ELECTRICITY AND THE WEATHER MAN. By Samuel Cohen 79 WHEN NEW YORK CITY TURNS ON THE "JUICE." By H.
Winfield Secor 80
ELECTRICITY AND WIRELESS SOLVE SECRET SERVICE
PROBLEMS 81
WIRELESS MUSIC WITH YOUR MEALS 84
DROPPING BOMBS THRU A CONE OF LIGHT 86
TESLA'S EARLY WORK WITH RADIO CONTROLLED VESSELS. 88-89 WHEN ELECTRICITY ENTERED THE HOME. Bv Thomas Reed 90 THE WIRELESS "WIZ" PLAYS WAR LORD. By Thomas Benson 91 BARON MUNCHHAUSEN'S NEW SCIENTIFIC ADVENTURES.
By Hugo Gernsback 92-93
MIMIC ATOMS AND THEIR EXPERIMENTAL FORMATION
By Eric R. Lyon, A.B 94 95
MARVELS OF MODERN PHYSICS. By Rogers D. Rusk 96
RADIO LEAGUE OF AMERICA NEWS 97
RADIO DEPARTMENT 98
A PRACTICAL PORTABLE WIRELESS SET. By Milton B.
Sleeper 102-103
HOW-TO-MAKE-IT DEPARTMENT 107
EXPERIMENTAL CHEMISTRY. By Albert W. Wilsdon 110
WITH THE AMATEURS (Prize Station Contest) 111-112
UNITED STATES GOVERNMENT LIST OF NEWLY LICENSED
RADIO AMATEURS H3
LATEST PATENT DIGEST U4
QUESTION BOX 116
FISH swimming in the water, his natural element, is not conscious of the fact that he lives in any particular medium. Before you were six years old you did not realize that you lived in a similar medium, the same as does a fish. In this case, however, the me- dium is air instead of water. Having been born sur- rounded by air and having lived in air for several years, you never were conscious of the fact that you were walking daily in a gaseous, tho invisible fluid, compressing you with a force of 14.7 pounds on every square inch of your body. Just as the fish does not "feel" the water in which he swims, so we in turn do not realize at once that we are living in a comparatively dense medium also.
Let us remove the water from the lake in which the fish swims. What takes the place of the water? The air, of course. Now let us take away the air, too. What remains? A vacuum, the layman will say. But what is in the vacuum? A void? Nothing?
Here the scientist steps in and speaks an emphatic "No."
There can be no such thing as a void. The vacuum is only a vacuum as far as the air is concerned, but the space which contained the air before and which we prefer calling a vacuum is entirely filled with ether.
It is true that we have no sense by which we can detect the presence of the ether, but we know today that it must exist. Nor are proofs lacking. We know that energy cannot be transmitted from one point to another without a medium to conduct it. Thus for ex- ample if we place an electric bell under a glass jar we can hear it ring through the glass. If we pump out the air from the glass jar we can no longer hear the bell, for we have taken away the medium — in this case the air — which sound requires to travel thru from one point to another.
Similarly, lig point to anothe?
cannot be air, fors^4n^c^WT'6HcTi nary incandescent lightbulb In wf vacuum. If light were dependent on air, you could manifestly not look thru the bulb, ergo the medium is not the air, it must be something else. The medium is the ether, properly called the luminiferous ether. It is an indefinable "fluid," so fine and so impalpable, that our most ingenious instruments have never been able to detect it directly. It fills every inch throughout the universe, it fills the interplanetary space as well as it fills your body. Briefly the ether fills and permeates everything ; the same as water fills the interstices be- tween the individual grains of a handful of sand. There is this difference however : the water does not fill all of the interior of the sand grains, while the ether does.
We know that ether has no weight, on the other hand we know that it has a certain amount of inertia because time is required for the propagation of its waves — the ether waves traveling at the rate of 186,000 miles per second.
Ether is the modern magic wand of the scientist. By its means our most inexplicable phenomena become at least plausible and can be understood. Thus we know that if we take a minute piece of matter — an atom — and vibrate it rapidly, the ether, which is a sort of weightless jelly, produces certain waves. If we vibrate the atom rapidly enough we produce light. A variation in the speed of the vibrations of a given atom will pro- duce all sorts of manifestations, be they heat waves, light waves or electromagnetic (wireless) waves.
All of these waves are fundamentally one and the same thing; they only appear different due to their atoms vibrating either slower or faster.
It is with these ether vibrations that our scientists will be concerned in the future.
H. Gernsback.
THE ELECTRICAL EXPERIMENTER is published on the 15th of each month at 233 Fulton Street, New York. There are 12 numbers per year. Sub- scription price is $1.00 a year in U. S. and possessions. Canada and foreign countries, $1.50 a year. U. S. coin as well as U. S. stamps accepted (no foreign coins or stamps). Sinele copies, 10 cents each. A sample copy will be sent gratis on request. Checks and money orders should be drawn to order of THE EXPERIMENTER PUB- LISHING CO., INC. If you change your address notify us promptly, in order that copies are not miscarried or lost. A green wrapper indicates expiration. No copies sent after expiration.
All communications and contributions to this journal should be addressed to: Editor, THE ELECTRICAL EXPERIMENTER, 233 Fulton Street, New York. Unaccepted contributions cannot be returned unless full return postage
75
has been included. ALL accepted contributions are paid for on publication. A special rate is paid for novel experiments; good photographs accompanying them are highly desirable.
THE ELECTRICAL EXPERIMENTER. Monthly. Entered as second- class matter at the New York Post Office, under Act of Congress of March 3, 1879. Title registered U. S. Patent Office. Copyright, 1916, bv E. P. Co., Inc., New York. The contents of this magazine are copyrighted and must not be reproduced without giving full credit to the publication.
THE ELECTRICAL EXPERIMENTER is for sale at all news stands in the United States and Canada; also at Brentano's, 37 Avenue de l'Opera, Paris. West- ern Advertising Office, 58 E. Washington St., Chicago, 111.
June, 1916
The Blitzen Rotary
variable condenser has a glass case because we're proud to show its high grade material and workmanship. _ You'll only need one glance to see its 43 aluminum plates, accurately ma- chined brass separators and substantial bear- ings.
Price $4.00
Others are transmitting
500 to 600 miles with the "Hytone" Rotary Quenched Spark Set. It is the only high grade transmitter and the only quenched spark gap which will operate satisfactorily on 60 cycle current.
Price Complete $175.00
TO HIM
Who seeks "Something for Noth- ing" is usually given "Nothing for Something."
TO YOU
Who seek quality Who demand results Who crave satisfaction Who enjoy fair dealing Who will send 6c. postage
TO US
Will be sent two catalogs of wire- less and electrical apparatus de- scribing products recognized as standard for ten years of continu- ous manufacture.
CLAPP-EASTHAM CO.
141 Main Street, Cambridge, Mass.
Charge Storage Batteries
from alternating current at home, garage, or workshop with our Electrolytic Rectifiers. Safe, clean, economical.
Price $7.50 and up
The Blitzen Wave Meter
is an accurate instrument for rapidly ascertain- ing the wave length not only of your own transmitter but also of all signals received at your wireless station. Beautifully mounted in a mahogany case with curve sheets and full directions.
Prices $6.00 to $17.00
THE DE FOREST AUDION
"There is only one Audion — the De Forest"
MOST SENSITIVE
The Bulletin of the U. S. Bureau of Stand- ards states that the De Forest Audion is fully 50 per cent, more sensitive than any other known form of detector (Vol. 6, No. 4, page 540).
7
THE GENUINE DE FOREST TUBULAR AUDION
Is sold separately to any ama- teur who prefers to build his
DTttct? Price $5.50
Adapter 40 cents extra. Get the Bulletin ( AT6)
MOST RELIABLE
It is not affected by mechanical vibration nor burned out by static or the transmitting spark. It never fails at the critical moment.
The detector is the heart of the receiving set. Why waste valuable time on an in- sensitive, unreliable .detector?
The genuine De Forest Audion is now with- in the means of every operator.
THE TYPE R59 DE FOREST AUDION DETECTOR
Incorporates the Audion Bulb and the genuine De Forest patented circuits with the most approved accessories needed tc form a complete detector. The most popular Audion Detector ever offered.
Price $14.00
Gel the Bulletin (M16)
SEND FOR BULLETINS XU6 AND Mil 6 DESCRIBING AUDION Detectors, Audion Amplifiers and Audion Receiving Cabinets
DE FOREST RADIO TELEPHONE & TELEGRAPH C0o
101 PARK AVENUE -:- NEW YORK, N. Y.
You benefit by mentioning "The Electrical Experimenter" when writing to advertisers.
THE- ELECTRICAL EXPERIMENTER
H. GERN5B&CK editpr
H. W. 5EZVR rt55DCI&TE EDITOR
Vol. IV. Whole No. 38
JUNE, 1916
Number 2
An Auxiliary Periscope for Submarines
THE most vulnerable part of the pres- ent submarine is its periscope. When running submerged with the periscope below the surface of the water, the submarine is "blind," in other words its commander does not know what goes on above the wa- ter. If he is not very cautious he runs two separate risks when rising to the surface. One is that the periscope im- mediately be- comes the tar- get for the enemy's shell fire, if his ves- sels are near the spot where the submarine rose. The other is that frequently the periscope col- lides with the hull of another vessel, either enemy or friendly. In both cases the result is disas- trous, for, as far as its utility is concerned a "blind" subma- rine though otherwise in- tact, ceases to exist for the enemy. Of course, the sub- mersible could scuttle away under the wa- ter, without coming to the surface even though its peri- scope had been shot away. This is known as running it blind. How- ever, the diffi- culty is not that it cannot get away in the manner de- scribed, but usually, and possibly in most all cases, there is considerable damage ef-
fected aside from that to the periscope.
In other words, it is not the loss of the periscope that endangers the under-sea boat as much as it is the probable damage to
Gernsback Auxiliary Periscope for Submarine Use in Reconnoitering. The Image
Glass Window in the Shell of the Submersible.
the thin steel hull. An extra periscope is undoubtedly available for such contingen- cies on most foreign submarines. But this is of no avail if the vessel becomes leaky.
With this and other objects in mind Mr. H. Gernsback, of New York City, has devised a separate, aux- iliary periscope for the use of submarine war- craft. The il- 1 11 s t ration brings out the idea in detail. There is pro- vided a float- ing air tank of circular form, on which is mounted a coni- cal mirror. This mirror re- flects an image of the entire horizon down- ward through the water on a second (flat) mirror located within the sub- marine as the illustrat ion clearly shows. In this way no danger from shell-fire is in- curred, as far as the hull of the craft is concerned. If the auxiliary periscope is de- stroyed by the enemy, the sub- marine may be navigated s u fa- merged or it may remain in the location, venturing up- ward cautiously after an hour or so, and the usual periscope now comes into play. It is pos- sible also to equip each sub- ma r i n e with this apparatus designed by Mr. Gernsback. The s u b m a r i ne's chances of foil- ing the enemy are increased a hund red-fold.
Is Reflected Downward Thru a
78
THE ELECTRICAL EXPERIMENTER
June, 1916
We may now consider the details of the auxiliary periscope, as proposed. To be- gin with the floating tank carrying the conical mirror can be submerged, like the submarine itself. This is accomplished by the electric control of a sea-valve in- stalled on the under side of the floating chamber. When opened, it floods a sep- arate compartment with water, causing the device to sink. To make it rise an elec- trically operated pump, mounted within the buoyancy chamber, is started up. The sea- valve now being closed, the water in the submerging tank is soon pumped out. A check valve in the efflux pipe from the pump prevents the sea-water from backing up into the apparatus.
Attached to the floating mirror pontoon are two wire cables, which may be wound up on suitable drums, driven by electric motors within the submarine hull. These motors operate the cable winding drums through bevel gears; the shafts of the mo- tors passing - through water-tight stuffing boxes. To compensate for the rise and fall of the floating pontoon, if so we may term it, owing to a choppy sea, there are provided two automatic cable take-up reels, se- cured to the upper end of each wind- ing cable. These reels act in a simi- lar manner to those used on trolley cars for automatically taking up the slack in the trolley rope.
In order to haul in or lower the aux- iliary periscope to its resting place es- pecially provided at the top of the sub- marine, the sea- valve, regulated by an electromagnet, is opened to admit water to the sub- merging chamber, and by operating the electric motors con- nected to the wire cables the device is pulled downward in- to its proper place. To release it, the pump motor is started, which, emp- tying the water tank, renders the
pontoon buoyant again. The cable motors are released to permit the auxiliary sight- ing device to float upward by its own buoyancy.
The circular form of the pontoon and its central orifice tend to give reasonable steadiness unless the sea happened to be very choppy. By squirting oil on the sea the waves may be made to subside appre- ciably. Most important of all, it does hot matter if the float and its conical reflector do bob around slightly, as the : sighting accomplished by its aid is only intended for general reconnoissance and not for de- termining the exact range of an enemy ves- sel so as to torpedo her. Its primary pur- pose is, therefore, to render an inspection of the sea above the submarine a safer operation than where the usual periscope
is utilized for the purpose, as if this hap- pened to be shot away bv a nearby war- ship the chances are that part of the hull plates would be damaged also, and the unlucky crew sent to their eternal resting place — Davy Jones' locker.
RADIO CONTROLLED TORPEDO IN THE MOVIES.
WHAT would we do to-day if a for- eign country invaded this land? Our army and navy at present are not very suitable for defensive and of- fensive work, and the quantity of ammuni- tion which we have to-day is perhaps not sufficient for carrying on actual warfare for any appreciable period. The only way the invader can be checked from entering the country is by employing some defen- sive means that does not require a large number of trained men. For example the utilization of projectiles that can be fired and controlled at a considerable distance. It is possible to control a torpedo of either the aerial or water type by wireless, but
Fig. 1. How the Inventor in the "Movies" Develops a Radio-Controlled Torpedo. Fig/2. One of the Aerial Torpedoes Ready for Launching. Fig. 3. Interior of Control Station. Fig. 4. TheRadio Tor- pedo Destroying the Enemy.
although enormous sums of money have been expended by various inventors in an effort to develop a satisfactory radio-con- trolled torpedo, totally satisfactory results have not been obtained up to this time. In spite of the fact that, although the invent- ors were not successful in perfecting such a torpedo, a "movie" concern has already produced an elaborate and realistic film showing real aerial torpedoes controlled by wireless. This exciting film, "The Fly- ing Torpedo," was produced by the Triangle Film Corporation. The picture is supposed to illustrate events in 1921, when the Uni- ted States Government learns of a secret coalition of foreign powers against it. A technical advi6ory board, composed of the leading American scientists, is organized for the defense of the country. They en-
courage the invention ot contrivances ior destruction and defense and offer prizes for the best death-dealing machines de- veloped.
Winthrop Clavering, an alert and in- genious writer of detective stories, reads of the offer and calls the attention of his friend, Bartholomew Thomson, an inventor, to the item. Thomson has previously com- pleted a wireless control mechanism with the financial assistance of Clavering. One of the needs suggested by the board is a guided aerial torpedo. Clavering urges Thomson to invent the desired torpedo and provides the necessary funds. Immedi- ately experiments are started by Thomson and William Haverman, his assistant.
After spending a considerable amount of time and money the first experimental tor- pedo is built and made ready for a trial. It is assembled out in a secret place and the parts are all properly tuned up. Fig. 1 shows the testing arrangement. (In the movies they do it !) Later the United States is invaded by the foreign hordes, who effect a landing in Southern Califor- nia. The valiant de- fense by the navy with the submarine torpedoes controlled by wireless keeps the enemy from our coast on both the Atlantic and Pacific. The invasion of California, however, sets the country in a panic. Clavering and the young inventor lose no time. They co-operate with the Government experts for the manufacture of great quantities of aerial torpedoes provided with wire-, less control. In a short time they are transported to Cal- ifornia, and sta- tioned out of range of the enemy's guns. Naval and land bat- tles have been lost repeatedly by the insufficient American forces. Fortresses are demolished and great stretches of territory speedily occupied by the ene- my. At a critical moment the new torpedoes are launched by the young inventor and his assistant. Fig. 2 shows a group of soldiers holding the radio-controlled torpedo ready for launch- ing. When the propeller is released by a signal from the inventor (suitably pro- tected at the radio control station. See Fig. 3), the missile darts towards the en- emy. An ingenious device is employed in observing the course of the missiles. It is an electric periscope, supported by kites, from which connections are brought to an observation apparatus in the operating room. In the illustration at Fig. 3 the operators are using this periscope. In Fig. 4 one of the radio-controlled torpedoes is seen darting downward on the enemy.
According to the pictures, these torpedoes saved the country from the enemy.
DATE OF ISSUE. — As -many of our readers have recently become unduly agitated as to when they could obtain The Electrical Experimenter, we wish to state that the newsstands have the journal on sale between the fifteenth and the eighteenth of the month in the eastern part of the United States and about the twentieth of the month west of _ the Mississippi River. Our subscribers should be in possession of their copies at these dates. Kindly bear in mind, however, that publications are not handled with the same dispatch by the Post Office as a letter. For this reason delays are frequent, therefore kindly be patient and do not send us complaints as to non-arrival of your copy before the twenty-fifth of the month.
*
June, 1916
THE ELECTRICAL EXPERIMENTER
79
Electricity and the Weather Man
w
HAT will be the weather to-mor- row ?" is the continuous question asked by millions of people all over the country, and this is most accu- rately answered by the Government weather forecaster.
One can not imagine offhand perhaps the important role electricity plays in operat-
Fig. I (Top):— At the Extreme Left are the Dry and Wet Bulb Thermometers for Finding the Humidity of the Air. Because of Varying Rates of Evaporation of Moisture from the Wet Bulb Thermometer with Consequent False Readings, the Instruments are Whirled Rapidly when the Record is Taken. Next Comes the Sunshine Gauge Which Records in the Office Below, Exactly the Duration of Sunshine. Next is the Minimum (top) and Maximum (bottom) Thermometers, That Give the Lowest and Highest Temperature Each Day. Below is a Kite Meteorograph Used for Recording Conditions of the Upper Atmosphere, When it is Sent Up on a Kite. Next to the Right is the Anemometer or Wind Gauge. At the Extreme Right is Shown the Barograph Which Records the Continuous Barometric Pressure.
Fig. 2 (below): — The Instrument at the Left Gives a Continuous Record of the Weighing Rain and Snow Gauge. Next is the Triple Register or Station Meteorograph, Which Records the Action of the Wind Vane, the Anemometer (wind velocity), the Sunshine Gauge, and the Rainfall as Told by the Tipping Bucket Gauge, All of Which Instruments are on the Roof Above.
ing the various delicate weather recording instruments. However, it would be nearly impossible for the Weather Bureau to op- erate successfully the different sub-stations if electricity was not employed. Practi- cally every conceivable instrument used by the bureau is operated by electricity.
Some of the most important weather forecasting instruments are shown in Fig. 1, These are placed outdoors (on the roof) and the electrical connections of each- are brought separately to the recording in- struments, which are shown in Fig. 2. Coming back to the outdoor instruments, at the extreme left of the photo are dry and wet bulb thermometers used for determin- ing the humidity or the amount of mois- ture in the air. Because of the varying rates of evaporation of moisture from the wet bulb thermometer, which would tend to give a false reading, the instruments are whirled rapidly when the record is taken, so that the evaporation is always at the
By Samuel Cohen
fastest rate possible.
The glass tube, set at an angle, next to the humidity instruments is a sunshine gauge, an ingenious instrument that re- cords exactly the duration of sunshine. This apparatus consists of two tubes, one of which is placed inside the other. The outer tube is partly exhausted. The inner one is made similar to a dumb-bell, but instead of having globes on the end, it has cylinders. The lower one is coated with lamp black to absorb the sun's heat. The lower tube is Idled with mercury to about three-eights its capacity, while the upper one con- tains alcohol used for lubri- cating this mercury. The center portion of the tube contains two.sealed-in plati- num wires, which are con- nected to the recording in- strument. Now it is evident that whenever the sun shines on the sooted portion of the tube the absorbed heat will expand the air in the bulb and thus cause the mercury to rise. As soon as it rises to a certain height it will short-circuit the two sealeJ-in platinum wires and thus complete the re- cording circuit.
The two thermometers on the stand at the cen- ter comprise a minimum (top) and a maximum (bot- tom) thermometer, which indicate the lowest and highest temperature each day. Underneath is a kite meteorograph, used for re- cording conditions of the upper atmosphere. The ve- locity of the wind is meas- ured by an anemometer ; this is perceived standing at the right of the kite me- teorograph. It consists of four aluminum buckets set at right angles to each other and supported by a suitable frame. The cups when re- volved by the wind cause the rod, which is enclosed in the tubular upright, to op- erate a gear arrangement placed in the lower portion of the instrument. The gear is so made that when- ever the buckets revolve at a speed of 500 times per minute a centrifugal device makes contact with an electric terminal which is connected to the recording instrument. It is, there-
of the wind. The greater the velocity of the wind, the more times the recording circuit will be made and thus in turn the recorder will make its record faster.
At the extreme right is shown the baro- graph, an instrument which records the continuous barometric pressure.
The rain and snow gauges are not shown in the illustrations but are also important instruments to the weather man, as they determine the amount of rain and snow that fall during a certain period of the day. The rain gauge consists of a circular cham- ber, covered with a funnel which leads to a double bucket, delicately supported. A spring contact is so placed underneath the bucket that whatever bucket falls, it will depress this spring which touches another electric terminal connected to the record- ing instrument. The buckets are so ad- justed that one-hundredth of an inch of rain will upset the equilibrium of the buck- et, thus causing it to fall and in so doing complete the recording circuit. It is thus quite clear how the weather man is enabled to determine exactly the amount of rain that falls each day.
In determining the amount of snow that falls during a certain period, a unique ma- chine is used which consists of a copper pan placed upon a special scale. The scale- is so adjusted that one-hundredth of an inch of snow will upset it and in so doing causes two terminals to touch, which are connected to the recording instrument. An arrangement is placed on the scale whereby the balance is set to the zero position when additional snow falls into the copper pan. This consists of a weight placed on the scale lever which is automatically shifted on the scale lever by a ratchet operated by an electromagnet when the depression of the pan closes the circuit. Thus an accu- rate reading can be obtained by the use of this snow recording instrument.
The recording instruments (Fig. 2) are placed indoors. The instrument at the left gives a continuous record of the rain and snow gauge. Next is the triple register or station meteorograph which records the action of the wind vane, the anemometer (wind velocity), the sunshine gauge and the tipping bucket gauge. The recorder it- self consists of a drum carrying a paper chart upon which different records are made. The drum is revolved by a spring motor. Ink pens, controlled by electro- magnets, are actuated by the various out- door instruments. A portion of an actual record taken by the triple register or sta- tion meteorograph is given in Fig. 3. The record of the wind direction appears at aa. The velocity of the wind is shown by the lateral deflection of the velocity record at b. Each ten miles is marked by a relatively broad deflection. Duration of sunshine is recorded by the zigzag trace at c ; rain- fall, by the line d. The line e indicates
Wind direction
Sun
Fig.5
i4
Imi/e wind re/oaf y wind ye/ocify
fain
Typical Weather Chart as Automatically Registered on Apparatus Shown at Fig. 2.
Wind, Direction and Velocity, Rain, and Sunshine.
It Registers
fore, obvious that the number of turns of the cups per minute determine the velocity
cloudiness or the absence of either rain- fall or sunshine.
8o
THE ELECTRICAL EXPERIMENTER
June, 1916
When New York City Turns On the "Juice"
WHEN the average New Yorker turns on his electric lights or power mo- tor, he possibly does not stop to think once in a thousand times as to what effect this small quota of electrical energy has on the gross amount used in the entire city of Greater New York with a population of over 5,000,000 people. Again it is just as possible that he does not stop to think once in ten thousand times as to the effect of turning on the electric lights at any cer- tain time of the day or night. The graphic curve, as it is termed among engineers and illustrated herewith, shows how the de- mand for electrical energy both for illu- mination and power consumption varies during the complete cycle of twenty-four hours, starting in this particular instance at midnight of Sunday, December twelfth, and ending at midnight Monday, December thirteenth. This curve covers the combined total daily output of both the New York
255000
By H. Winfield Secor.
rapid increase of energy consumption from this point on to seven o'clock is due to the great demand for electric lights during the breakfast period.
A great many of the large manufacturing establishments and factories start work at 7 a.m. or at least by 8 a.m., and the load curve goes shooting skyward at a rapid rate as the illustration depicts. Now the thousands of office employees are arriving and the elevators in the towering skyscra- pers of the greatest city in the world are taxed to capacity. These require a larger amount of energy than is popularly imag- ined and consume no small part of the total load component for the day.
The central and sub-stations scattered about the city have been the scene of great activity during these hours of increasing demand for current in one form or another, and dynamo after dynamo has had to be switched on to the city's feeder lines in
240.000
225000
.210000
This Graphic Curve Shows in a Remarkable Manner How the Demand for Electricity in Twenty-four Hours. First the Factories, Then the Theatre Matinees, Business Offic
Restaurants Help to Boom the Demand for "More Juice
Edison Company and the United Electric Light & Power Company. The two cor- porations supply all of the electrical load for the metropolis exclusive of subway, surface and elevated train requirements which are cared for by private central sta- tions owned by the companies operating these traction systems.
Starting at midnight, as indicated by the point on the curve at the extreme left, we see that the total motor and illumination load of the entire city was about 65,000 K.W. (kilowatt equivalent to H.P.). As the wee small hours of the morning pro- gress, the demand falls off until it reaches the lowest point of the whole cycle of twenty-four hours with a kilowattage of 37,000. This ebb tide point starts to move upward, as observed, after four in the morning, or about the time the milkman begins to make his rounds and when a considerable portion of the city's working people have risen, and for the time _ of year here under consideration the fairly
order to care for the enormous demand now created. Just before the noon hour ar- rives, the maximum peak for the morning load has occurred. The maximum total out- put at this period of the day has reached 166,000 K.W. The curve starts to fall away at this period just before reaching twelve, presumably due to the fact that the many thousands of factory employees have start- ed to wash their hands preparatory to as- similating their noon repast, and directly af- ter twelve the curve makes a decided drop of 33,000 K.W. in thirty minutes.
As many of the manufacturing establish- ments have from one-half to three-quarters of an hour nooning, the load curve begins to crawl skyward again and shortly after 1 p.m. it has attained the same value as that existing before the noon drop.
As perceived the afternoon load reaches a much higher value than the maximum de- mand during the morning hours. Now the theatres have started to open their doors and contrary to the olden days in the great-
est theater city on earth, most of the playhouses now run matinees owing to the great spread of the moving picture craze. The theaters are one of the greatest con- sumers of electrical power, both directly and indirectly, in Greater New York. The afternoon section of the curve fluctuates through a value of about 10,000 K.W. until at 4 p.m. it starts on its last steady rise.
Considering the time of year this rapid increase of the curve is to be looked for, as the afternoon and early evening are quite dark. Now all the various manufacturing establishments, stores and restaurants are in full swing together and the final "peak" of the twenty-four hours' load is reached at 5 p.m. This is the most critical moment of the whole day's performance at the central and subsidiary stations ; every dynamo is humming to full capacity and every con- ceivable form of activity is going on in the city. The office and factory workers are homeward bound, the thousands of eleva- tors in public and private buildings are scuttling earthward with their human freight. The restaur- ants are full to over- flowing with dinner crowds and not to mention the thousands of electric lights be- ing switched on in private residences and apartment houses throughout the me- tropolis.
The maximum peak of the load carries it- self well for about one-half hour, when it begins to take a de- cided slump. In one hour's time there has been a decrease in the maximum demand for electrical energy of 30,000 K.W. As may be imagined this has required some very clever maneuver- ing on the part of central station opera- tives and those in charge. As the load falls off, some of the dynamos are shut down and the sky- rocketing load curve has started on its last downward path, never to reach the peak value of 235,500 K.W. again until the mor- row.
There continues a brisk demand for elec- tric current, as witnessed by the appear- ance of the curve, and it hangs grimly in its slow but sure downward movement. At night time is when the 5,000,000 New Yorkers . enjoy themselves. Generally a large majority, of course, visit the theaters. These, as_ well as the hotels, are the leading factors in the evening load component. Broadway's millions of scintillating lights and its thousands of huge signs atop the buildings also consume a respectable amount of current. Even after 10 p.m. the curve drops very doggedly and keeps up a fairly decent appearance up to its starting point, or midnight.
New York is probably the gayest city in the world, not even excluding Paris, and the after-theater supper crowd manages to keep the central stations busy by their de- mand for illumination in the restaurants (Continued on page 142)
New York City Varies During the ffices, Elevators, Electric Signs and
June, 1916
THE ELECTRICAL EXPERIMENTER
Electricity and Wireless Solve Secret Service Problems
THE illustrations herewith give sev- eral views of a Western Secret Serv- ice Bureau. This bureau has been extraordinarily active in quickly adapting the latest advances in electricity and wire- less to their various needs and require- ments. They handle a great many differ- ent cases, including murder, arson, bur-
not be able to do much aside from sitting down again, as the various cabinets, bril- liant flashing, buzzing and spitting from the numerous electrical appliances in the rooms create an atmosphere of mysticism and un- certainty that will work pretty definitely on the mind of an individual who has trans- gressed the law and who is aware of the
that makes a permanent record of all speech taking place on all incoming or outgoing telephone messages, and also verbal con- versations that occur in any of the offices. It is claimed that it does almost everything but think. Besides there is a special pho- tographic apparatus mounted in one of the cabinets which will snap a man's physi-
glary and robbery and, therefore, have every opportunity to make use of any sci- entific aids which may be available.
The exact degree to which an individual may jolt up against the air of mystery that pervades the Bureau's offices may be best described in showing what a suspect would encounter were he taken to the rooms by an officer.
With the door opened half way he is startled by a hissing flash, partly concealed and' he does not realize the fact that his photo is being taken. After this he is seated in another office and his photo taken front and profile, his finger marks recorded, ev- ery word he says recorded automatically without his knowing it, and his very foot- steps on the rug are made part of another record. If he grows fussy over some- thing and attempts to escape he will find every avenue for escape cut off and he will
fact that every move he makes, every word he says, the exact shading of his voice, the peculiar nervousness he manifests, the char- acter of his walk, and all other personal characteristics are becoming part of a per- manent filing system that will check him up anywhere in the country.
In the general private 'phone system, which has recorders and transmitters so delicate that one does not have to employ the usual ear trumpets or the like, the office has already been connected up with a num- ber of institutions necessary and the service is in perfect working order.
Referring to the illustrations, Fig. 1 de- picts the wireless "Revelarophone" switch- board and this is so constructed that with the few switches shown it is possible to op- erate over ten distinct apparata. Fig. 2 shows the secretary's office in which is in- stalled the "Revelarograph," an instrument
ognomy in three different positions without any attention whatsoever. By means of the lately perfected and marvelously sensitive detectaphones here used it is possible for a person standing in the secretary's office to hear everything going on in any of the other offices, without the use of a receiver or without straining one's ears to catch even a whisper, the reproduced voice emanating loud and clear from the receiver of the in- strument. The apparatus may be adjusted to any degree of sensitivity. The chief electrician, Mr. L. S. May, of the Bureau's scientific staff, has also evolved an elec- trically operated Bertillon photographic ap- paratus and a wireless telephone of the portable type, which may be carried about in a suitcase. The inventor is observed busily engaged in his private laboratory at Fig. 3. Thus does science slowly reduce the activities and artifices of the underworld.
ELECTRIC CLOCK RESEMBLES LOCOMOTIVE.
A Kansas mechanic has constructed an electric clock in the shape of a locomotive. It is 30 inches long, 13 inches high and 8 inches wide, weighing 9 pounds and 11 ounces. It required nearly eight months to
Unique Electric Clock in Form of Locomotive.
complete this unique model, including the work of wiring and mounting of the thir- teen electric lamps. A manual switch con- trols the wiring system in twelve different ways and combinations. The clock auto-
matically turns on the current at six o'clock in the evening and turns it off twelve hours later. Separate circuits are arranged for the headlight, lamps on the face of the clock and those in the cab. The various lights are flashed on about every fifteen seconds for a duration of three seconds. The dial is of imitation ebony and is stud- ded with tiny ruby and green incandescent lamps. This clock is of the eight-day type and strikes on the hour and half hour by ringing the engine bell. When this is done the driving wheels rotate. Contributed by H. E. ZIMMERMAN.
ELECTRIC SIREN HEARD FOR MILES.
The motor-driven siren of extra large size here illustrated was used as an at- traction and also for fog signal work dur- ing the recent Panama-Pacific Exposition at San Francisco, Cal. The motor is of the alternating current induction type. The siren or sound producer is direct coupled through an offset crank or coupling. It is said that the one shown here is the largest motor-operated siren ever constructed. It was installed on the roof of one of the
Exposition buildings. The piercing and extremely powerful note emitted by this noise producer could be heard ten miles out at sea. This form of electrically operated sound generating device is also available in small and medium sizes which have proven
Electric Siren Which Can Be Heard Ten Miles.
of extreme efficiency for many different re- quirements such as fog signaling, factory alarms and time signals and the like.
82
THE ELECTRICAL EXPERIMENTER
June, 1916
WHEN EDISON
TAKES LUNCHEON.
The general public is always more or less interested, to an unimaginable degree, in the daily habits and hobbies of those whom the gods have chosen as their most fa- mous sons. The il- lustration herewith depicts the well- known inventor, Mr. Thomas A. Edison, just finishing lunch- eon at his home in Llewellyn Park, Orange, N.J. Mr. Edison is a light eat- er always, but he be- lieves in the best of everything and three meals a day, except when engaged in some lengthy experiments, in which event he frequently forgets to eat for many hours at a stretch.
Talking about hab- its of "the powers that be," an interest- ing anecdote is related about Mr. Edison and a box of those justly famous, or rather "in- famous," Perfectos with which our wives and sweethearts are wont to bombard us at the Yuletide season.
One of his particular friends presented him with a box of what was supposed to be pure Havanas, but which on their first labora- tory test" proved somewhat otherwise. It
A MOTOR-DRIVEN RIDDLE FOR FOUNDRIES.
A motor-driven gyratory riddle for use in foundries is one of the latest devices de- signed for boosting efficiency in the great
is said that the cigars were placed on a shelf out of the way, presumably for pres- entation to some of the many unwanted visitors to the laboratory. Directly, how- ever, the great inventor became so en-
Photo Copyright by Janet M. Cui
Thomas A. Edison, the Veteran Inventor Taking Luncheon at His Home in Llewellyn Park, N. J
grossed in deep research work on which he was engaged, that he managed to dispose of every one of those Perfectos. Absent- mindedness is one of the attributes of all the great men it seems, but if some of us didn't concentrate our minds the patent of- fice would go bankrupt.
A MOTROLA FOR
YOUR VICTROLA.
The Motrola, as it is called by its spon- sors, is nothing more nor less than a very neatly contrived electric motor and driving gear attachable to any type of talking ma- chine for either disc or cylinder records. On the axle of the motor is a worm-gear that operates a wheel and this latter in turn is fastened to the winding rod of the talking machine mech- anism.
When connected with the electric cur- rent by virtue of the attachment plug sup- plied with same and inserted in any lamp socket, the Motrola winds up the talking machine to about three-quarters of the capacity of the spring, then the current is automatically cut off. When the machine runs down to about one-half the spring's resistance capacity, the current is auto- matically turned on again. Thus it is claimed that this de- vice tends to keep the spring of the machine motor constantly wound between one-half and three-quarters of its full strength — which is the strength required to give even time and true tones. One particularly good feature about this attachment is that should the electric cur- rent fail at any time, the device may be
that this machine will sift more sand in a day than 10 men. This riddle not only sifts the sand, but mixes it as well, thus saying one turning of the sand. Evenly mixed and tempered sand not only reduces the time of making the mold, but insures a much better mold, necessitating fewer patches after the pattern is made, thus in- creasing the output of each foundryman, besides making the casting truer to the pattern.
The device as here observed may be run about the foundry on a trolley cable. Its motor, being of a small size, may have its service connection plug inserted in any near-by lamp socket. The motor develops 1/6 h.p., and hence is very economical in the use of current. The sieve is 20 inches in diameter, and is held in place by an im- proved clamping device, which enables the operator to remove the sieve, dump and replace it in less time than it takes to tell about it. The design is very simple indeed, and no gears or other complicated or dan- gerous moving parts are incorporated. Moreover, there are but three bearings to be oiled and cared for. All parts are made of metal, thus insuring the longest life pos- sible to the device.
New Motor Driven Riddle for Foundry Work, a Great lime Saver.
iron and steel plants. It is said that this machine will sift sand faster than one man can shovel it in, and moreover it sifts it better and more thoroughly than can be done by manual labor. Again it is stated
NAVY RADIO BRINGS WIFE MONEY FROM HUBBY.
A. new application of wireless has been found by the Navy Department. When Mrs. Nellie G. Shippee complained that she was in want, a message was sent from the Brooklyn Navy Yard to the battleship "Wyoming," at target practice off Guan- tanamo, Cuba, telling Earl W. Shippee,1 chief electrician, that he must send money to her. Shippee sent his wife a money order.
The "Motrola" Electric Motor Drive for Talking Machines.
removed very quickly and the winding crank for the spring motor reattached.
June, 19 16
THE ELECTRICAL EXPERIMENTER
83
Bronze Tablets Mark the Birth place of the Telephone
March thirteenth last was a red-letter day tion speech by Courtenay Guild of the Bos- in the annals of the city of Boston, when toman Society and also briefly acknowl-
UNVEILING OF THE TABLET ON 5 EXETER PLACE, BOSTON. In the Foreground are the Following: Vice-president E. K. Hall of the New England Telephone and Telegraph Co., Professor Alexander Graham Bell, Mrs. Bell, Vice-president W. T. A .Fitz- gerald of the Boston City Club.
CHARLES AUGUSTIN COULOMB.
June, 1916, Marks His 180th Birthday. Born, June 14, 1736 — Died Aug. 23, 1806.
CHARLES AUGUSTIN COULOMB was born at Angouleme, France, June 14, 1736, and died at Paris, August 23, 1806. Coulomb belonged to a noble family of Montpelier. He chose the profession of military engineering. In 1773 he gained great distinction by his statistical problems applied to architecture, which he presented to the Academy of Science in 1778. He shared with Van Swinden the prize for im- provements in the construction of com- passes. In 1771 he was stationed perma- nently at Paris, and was appointed inspec- tor of public instruction in 1802, but he was not strong enough for the work and four years later he died. He had the rank of lieutenant colonel of engineers. His fame rests chiefly on his most elaborate and important investigations in electricity and magnetism, and on his invention of the torsion balance in 1777. This instrument is still used universally in all elaborate re- search work, particularly in measurements of electrical and magnetic actions. Cou- lomb proved by a series of extensive ex- periments, that, contrary to the general ac- cepted theories of Cavendish, electro-static electricity, like gravity, varies inversely as the square of the distance. Adopting the two-fluid hypothesis, Coulomb investigated the distribution of electricity on the surface of bodies. His experiments on the dissipa- tion of electricity are of considerable value. He found that a thread of gum-lac was the most perfect of all insulators ; it was ten times better an insulator than a dry silk thread. He ascertained that a silk thread covered with fine sealing wax insulated as effectually as gum-lac, when it had four times its length. Considerable study on his part proved that the dissipation of elec- tricity along insulators was chiefly due to adhering moisture, but in some measure also to a slight conducting power. His writings were collected by the Societe de Physique, and a great part of the matter was obtained thru the courtesy of Mon- sieur Potier from his volume 1 of the "Memoirs Relating to Physics."
The Paris Electrical Congress of 1881 adopted the name of Coulomb as the prac- tical unit of electrical quantity. The cou- lomb is equal to 10-1 of the C.G.S. unit of quantity.
WIRELESS AIDS RAISING OF FUNDS FOR BOYS' CLUBHOUSE.
While a campaign was being recently carried on to raise $125,000 for the erec- tion of a clubhouse, in Charlestown, Mass., wireless played an important role. On Sunday, March nineteenth last, at 2 p.m., a radiogram asking help from all amateurs was sent out from the powerful radio sta- tion at Tufts College. As a result many amateurs and Boy Scout organizations ap- peared with contributions which they had collected. The $125,000 was collected- in ten days and the club-house will be under con- struction in a few months. The new club, when completed, will have classes of in- struction in wireless telegraphy, wire teleg- raphy, electricity, engineering, mechanical drawing and many other trades. There will also be a first-class radio sending and re- ceiving station. This organization has twice outgrown its quarters and is forced by lack of space to move to a larger building. At the present time there is a class in wireless telegraphy. Out of twelve boys, eight have passed the Government examination and obtained their license. They all have send- ing and receiving stations.
he fortieth birthday of the telephone was celebrated by the Bostonian Society, the Boston City Club and the Telephone Com- pany, assisted by the inventor, Mr. Alex- ander Graham Bell. Professor Bell was the guest, during his stay in Boston, of the Boston City Club and, accompanied by Mrs. Bell, participated in the unveiling of two bronze tablets placed by the Bostonian Society and the Telephone Company upon the two sites made memorable in the first experiments of Professor Bell.
On a column of a porch of the building, 109 Court Street (now known as the Palace Theater), where, on the top floor, Thomas A. Watson heard the first sound ever sent over a telephone wire, the permanent rec- ord "Here the telephone was born June 2, 1875," was placed in bronze. Until Pro- fessor Bell unveiled the bronze tablet it was draped and obscured by an American flag.
Professor Bell spoke of his regret over the absence of Mr. Watson (who was in Florida) in his response to the presenta-
ELECTRICITY SAVES "BUBBLES" IN BOTTLING CHAMPAGNES.
In the aging and clearing of wines elec- tricity plays a most important part. As may not be generally known, considerable sediment forms in the process of aging wines made from the grape.
In the case of still wines the process can be carried on in casks and the clear wine decanted off, but in the sparkling wines the treatment must be done in bottles. This involved not only considerable skill in han- dling, but there was often loss of "bub- bles."
This is now all changed. The bottles are placed in racks neck down and, at vari- ous stages of aging, they are transferred to electrical refrigerating machines, which freeze the dense liquid next to the cork. This is then scraped out and the cork re- placed. A better product at far less cost is thus secured.
edged the honor of being present on these auspicious occasions.
A short time elapsed between that un- veiling and the arrival of the official party at No. 5 Exeter Place, where, on the wall of the building now occupying the site where Mr. Watson heard the first con- nected speech over a telephone wire (Pro- fessor Bell's "Mr. Watson, Mr. Watson, I want you. Come here"), a bronze tablet was placed, reading "Here Alexander Gra- ham Bell transmitted to Thomas Augustus Watson the first complete and intelligent sentence by telephone, March 10, 1876."
The Bronze Tablet, Commemorating the Birth- place of the Telephone. Erected at 109 Court St.? Boston.
Professor Bell, himself, removed the American flag from that tablet, completing the recording of those two historic events.
AMONG the hundreds of new devices and appliances published monthly in The Electrical Experimenter, there are several, as a rule, which interest you. Full information on these subjects, as well as the name of the manufacturer, will be gladly furnished to you, free of charge, by addressing our Technical Information Bureau,
84
THE ELECTRICAL EXPERIMENTER
June, 1916
Wireless Music With Your Meals
There is a new "fad" in Southern Cali- fornia, the place where novelties grow over night like the proverbial mushroom. This time the "something new" comes in the form of phonograph concerts by wireless. Sometimes they come in at the noon hour, at others while dinner is being served and again perhaps in the quiet of the evening, while the family is gathered around the hearth. However, when they do occur they do so un- announced, this fact making them all the more^ welcome. This "music by wireless" idea is one of the most recent electrical inventions of Earl C. Hanson, a young California radio expert. In a word this new "fad" consists of phono- graph music being transmitted by wire- less from the home of the inventor to the dwellings of a number of friends and neighbors resid- ing within a mile or so of the Han- s o n residence. This music is $ent to all of the homes simultane- ously and with no effort on the part of those at the receiving ends of the "line." To show that his in- vention was a "workable" one young Hanson gave a series of concerts recently and the work
of the system was pronounced wonder- ful.
During the past several years Mr. Hanson has been working on a new type of wireless telephone and it is with the assistance of this apparatus which he has recently perfected to a high de- gree that these wireless concerts are made possible. The telephone shown in
By ALBERT MARPLE
one of the illustrations accompanying this story is used as a central station, being lo- cated in the experimenting room of the Hanson residence. Upon the roof of his home this inventor has erected an elabo-
Left Hand Photo Shows Radiophone Loud Speak- ing Receptor on Dining Table. Lower Picture Depicts Loud Talking 'Phone on Table.
rate aerial and this was used for trans- mitting, while the receiving stations are located, some within and some outside the homes selected for the concerts. At the central station an ordinary horn- less phonograph is placed upon a table along with the wireless telephone ap- paratus. The shutters at the front of the phonograph are removed and with- in the "horn" section one or more ordi- nary microphones are placed, these being connected by wire with a pair of binding posts on the telephone. A cable connects the telephone with the aerial upon the roof. When the phono- graph is started the music is caught by the microphones and carried by wire to the wireless telephone instrument, which, after serving as an amplifier (continues it on its way to the aerial. After leaving the aer- ial the sound is caught by the various radio receiving s t a - tion apparatus, which latter are connected by wire with ordi- nary telephone .receivers, these heing equipped with small meg-
t . t , apho'nes, the
Top View: Wireless Tele- _i „£ ,.4,:„U phone Enthusiast, Mr. work °f which Earl C. Hanson. Right IS to assist m in- Hand Photo: Victrola, creasing the Vol- Microphones and Radio- ? j
phone Transmitting Ap= "me ot S O U n d.
paratus. A n important
feature about this wireless music trans- mission is that so far as can be ascer- tained the music heard at the receiving stations is equally as loud as is that fur- nished by the phonograph. The central operator has absolute control over the volume of sound furnished by this de- vice, this depending entirely upon the amount of electrical energy employed.
WHAT MAKES THE MATCHES GO AROUND?
A very clever electrical window attraction is shown in the accompanying illustration and is known as the "Mysterious Match Box." The device is much in demand by all merchants, both large and small, having show window space as it can be operated on batteries and does not necessarily re- quire electric light current.
It has been widely used by retail drug Stores and has proven very satisfactory as
The Matches Rise, Rotate Then Collapse, Repeatedly.
a business "booster." In operation the matches lie down on the upper plate and at certain moments rise and start to ro- tate. Directly, however, they collapse again and the action repeats itself peri- odically, much to the amusement of the
wondering public. Any one of a thousand different objects can be made to operate on the piece of glass which forms the top of the cabinet, thereby giving the pub- lic something different to think about as frequently as the merchant may desire. A cigar placed flat on top of the glass will rise, whirl in a circle for an instant and return to its original position, repeating this movement continuously.
Possibly the greatest features of all the moving attractions which may be worked with this invention is a display card car- rying advertising matter on both sides. When placed flat upon the glass top, it will rise, turn around and then fall back upon the glass again. This operation is kept up continuously in the same way that the matches behaved.
In Zurich, Switzerland, street cars are run by liquid air.
A NOVEL ELECTRIC RUBBING AND POLISHING MACHINE.
In the accompanying illustration is per- ceived one of the latest electrically operated grinding, sanding, rubbing and polishing ma- chines adaptable for manufacturing require- ments where furniture, stone work and the Hike are to be dressed, surfaced and polished. The machine operates at very high efficiency and thus costs but a very small amount per hour for its operation. It may be con- nected up with any lamp socket. The pol-
ishing element of the device is driven by a small but sturdy motor, especially designed for the work. The whole device measures 16 inches long, 5J/2 inches wide and 12 inches high, and weighs 25 pounds. The two felt pads mounted on the face or under- side of the machine, each of which measures 5y2 by 41/- inches, shift about in an oscil- latory fashion over 400 times per minute. A switch is mounted conveniently on the
Unique Electric Polishing Machine.
base of the device to control the motor cir- cuit. Black fiber handles are provided, which eliminate any possibility of the op- erator receiving a shock.
June, 1916
THE ELECTRICAL EXPERIMENTER
85
MOTORCYCLE HELPS LIGHT A TOWN.
When the town of St. Charles, Mo., was left in darkness a short time ago by the breaking of the high-powered transmission cable from the great Keokuk dam on the Mississippi, a motorcycle helped to save the
ELECTRIC ENGINES PROVE STRONGER THAN STEAM TYPE.
On the Pacific slope of the Rocky Moun- tains, in sight of Butte, Mont., electricity recently won a decisive victory over steam power. The test was a haul of freight trains up the Continental divide and is said to have been the first prac- tical pulling contest ever ar- ranged to determine the ad- vantage of one power over the other.
One of the trains in the competition weighed 2,200 tons and was drawn by three steam locomotives. The other weighed 3,000 tons and was pulled by a two-unit electric engine. At the time set an electric engine started up the 2 per cent grade, rounded the big curve and sped on at a uni- form pace and without ap- parent effort. A few min- trtes later the three loco- motives came chugging and laboring up the same hill hauling their lighter load. The contest determined A Motorcycle Used to Drive'the Exciter for the Large Dynamos Here the use of electric engines Shown Prevented St. Charles, Mo., from Being in Darkness. over the 440 miles of main
line from Avery, Idaho, to
situation in a unique manner and keep the town lighted. Before the town secured cur- rent from the Keokuk dam it was illumi- nated by a steam power plant which drove a 150-kilowatt generator. When the en- gineers came to hook up the abandoned steam plant they found it possible to get up steam and run the big generator, but discovered at the same time that a very important auxiliary, the kiltie exciter gen- erator, which is run in conjunction with the big machine to excite the fields of same, was out of commission. The sub- station of the Keokuk plant, however, is of the same general type, except that the generators there are driven by motors which take current from the transmission line. The exciter at the sub-station was available, and if power could be obtained to run jt the current could be transmitted to the old steam plant and by a combina- tion of the two units the town would be lighted. About that time it occurred to E.. F. Wayee, electrician and trouble man em- ployed by the Electric Co. of Missouri, that there was power enough in the engine of his Indian motorcycle if it could be har- nessed.
No sooner said than done. He set his motorcycle on the stand, took off the tire, slipped on a belt from the rear wheel to the pulley of the little exciter and started his gasolene engine. For an hour and a half he pulled the exciter and furnished the city with light for that period of time, while the wires to the Keokuk dam were repaired. The motor was run on wide- open throttle the entire length of time emergency service was required.
Harlowton 113 miles of which have already been electrified.
PLANS WIRELESS SERVICE IN MISSISSIPPI.
Frederick de Lamorton who is a wireless operator from the Pacific Coast, whose base of operation has extended as far north as Alaska, and as far south as the Panama Canal, recently spent a few days at his father's home in Laine, Miss., prospective of establishing a wireless station at the port of Pascagoula or Moss Point, for the benefit of the lumber and general shipping interests of that port and the Mississippi Gulf Coast.
The station which is being planned for establishment is to have a radius of '2,500 to 3,000 miles.
HOW LONG DOES RADIUM LAST?
In determining the life of radium, or, in other words, the total time period of de- terioration of this remarkable element, it would be quite a simple matter to arrive at the conclusion if radium were formed di- rectly from uranium, thus making it easily possible to separate the radium from a quantity of mineral containing a known amount of radium. The uranium could then be purified so as to be free from ?dl trace of the radium and to allow it to remain until a measurable amount of radium had been pro- duced within it, then to compare the radium so formed from the uranium with the radium present initially in the mineral.
B. B. Boltwood mentions in Science that this was attempted, but it was found that radium was produced too slowly to be de- termined with y accuracy and was far less than was to be ex- pected from theoretical deduc- tion. At any rate, the writer states that this obstacle was overcome in 1907, when he was able to separate from uranium minerals a previously unidenti- fied radio-element which was in- termediate between uranium and radium in the series of atomic transformations, and which by its own disintegration produced radium in readily measurable quantities. The name "Ionium" was given to this element. Thus it became possible to separate the ionium element from a min- eral containing a known amount of radium and to determine the rate of growth of radium in this ionium. This is a measure of the rate of production of ra- dium in the mineral and there- fore a measure of the rate of disintegration of the radium.
The two diagrams (Figs. 1 and 2) will perhaps be useful in making the general conditions and method of procedure more easily understood to those without a tech- nical knowledge of the subject. In the first
(Fig. 1) the amount of uranium changing per year relative to the total amount present is shown by two cubes whose volumes are proportional to the number of atoms in- volved in the transformation. In the second diagram (Fig. 2) the first cube on the left is supposed to be of the same size as the smaller cube in the first figure. Since the constant change of ionium is as yet unde- termined, it has been assumed for con- venience to be approximately the same as that of radium, and the amount of ionium in the mineral is therefore indicated as of the same order as the amount of radium. With this limitation, and omitting the slight complications involved by the existence of branch products, like actinium, and prod- ucts of a rapid rate of change, like the emanation and radium-A, the diagrams rep- resent the general conditions and changes to be found in an old uranium mineral.
The chief relation of interest shown by the diagram is that since the radium chang- ing to radio-lead cannot be determined ex- perimentally with sufficient exactness, it is equally satisfactory and very much simpler to determine the ionium changing to radium and compare its quantity with the total amount of radium in the mineral. As a matter of fact, the actual amounts of ra- dium involved in these two quantities need not be known, it is only their relative values which are required, since the value of the disintegration constant is determined by the ratio of one of these to the other. In this respect the method is independent of any standard of purity of radium preparations, an advantage which is not possessed by other methods which have been used for attacking the problem. Thus, for example, the estimate of the half-value period of radium made by Rutherford and Geiger as a result of their experiments in 1908 had to be altered from 1,760 years to 1.699 years when, in 1912, the present international ra- dium standard was adopted.
In some thorough and interesting re- search work carried on by Miss Gleditsch,
- Total of Doo'- -aibei onthis- -edge.
Uranium
JOtol or isoo cubes gnttiis edqe
Radium ^&^^r
Radium hdio-lead ftftrnv chaitg'uig dunging ctoq/ia toftaJjQ- tafobintmi toUnmo-
Ionium chong/hg ro Radium.
Diagrammatic Representation of Change in Uranium per Year. Also Successive Disintegration of Uranium.
and cited by Mr. Boltwood, there were de- termined some valuable figures on the prob- able disintegration period of radium. In four results of experiments carefully con- ducted the following half-value periods of radium were found, viz., 1,836 years, 1,780 years, 1,640 years, 1.670 years.
86
THE ELECTRICAL EXPERIMENTER
June, 1916
Dropping Aerial Bombs Thru a Cone of Light
BOMBS-
A NOVEL bomb-dropping scheme is de- picted in the painting reproduced on our front cover. This scheme is intended for use in conjunction with Bat- tleplanes, the aerial bombs being dropped through a cone of light. This powerful illuminant is composed of a ring of high candlepower electric lights. Each lamp is supported in a separate reflector under the hood of the bomb-dropper as shown in the accompanying illustration. The various light beams from each lamp cross the other beams and in this manner a concentrated cone of light is produced as is evident. The lamps themselves may be the new in- candescent arc units recently developed and perfected by the Ediswan Company of England. This unit has the appearance of a high candlepower tungsten bulb, but in- stead of heating a fine wire filament in the usual manner, an arc between tungsten or other high fusing al- loys is made the source of light.
These incandescent arc lamp units can readily be constructed to yield as high as 3,000 CP. If then, we should use, say, 20 such lamps (the ef- fiency being 2 CP. per watt of electrical energy), there would be required 30 K.W. or 40 H.P. with total resultant CP. of 60,- 000. The present tend- ency in building Bat- tleplanes is toward massive proportions, involving engines de- veloping several hun- d r e d horsepower. Therefore the energy required for the bomb-dropper illumi- nant is not unreason- able, and besides it can be built in smaller sizes than here sug- gested. The energy necessary for operat- ing the electro-mag- nets which release the bombs one after another (independent- ly but consecutively) is slight and could be supplied by a small storage battery. A dynamo direct-con- nected to the main
engines would probably be found best for the source of current for the high candlepower lamps. Furthermore, there might also be used a form of cold light, which, it has been said, a French scientist has quite recently invented.
Reports state that the French war office experts are now experimenting with this new type of searchlight proposed by the French professor, Dussaud, which will throw a blinding beam to unheard of al- titudes and betray the Zeppelins to the French batteries and aeroplanes.
Professor Dussaud's cold light is gen- erated by utilizing nearly 100 per cent, of the electric current for illuminating in- stead of losing 70 or 90 per cent, of the power in generating useless heat, as in the
ordinary electric lighting system at present.
Hopes are entertained that this system will produce a searchlight five times stronger than the old types, with over 100,- 000 candle power. These new lights will absolutely blind everything in their path it is said and will bore a luminous hole through the heaviest cloud strata.
At any rate there are a number of pow- erful electric lamps available for this pur- pose and by means of a switch .on the aeroplane the illumination can be instantly cut off as desired. The bomb-dropper with its ring of lamps is suspended at the lower
LAMPS
REFLECTOR
Details of electrically controlled Bomb-Dropper depicted in action on the front cover. A set of electromagnets release each Aerial Bomb at the touch of a button at battleplane commander's side.
end of a flexible steel cable and the wires controlling the whole outfit follow this cable also. When necessary the suspension cable is wound up by a power-driven winch and the bomb-dropper can thus be raised right up into the 'plane through a suitable opening in the floor of the machine. It is proposed that the bombs be put up in magazine holders, each of which may con- tain eight to twelve bombs. It will then be a simple matter to reload the bomb- dropper by inserting one of these prepared magazines, just before the device is again lowered to the proper level.
Referring to the sectional view of the bomb-releasing mechanism, it will be ob- served that each bomb is retained nor- mally in the vertical magazine tube by a
pair of electro-magnets provided with slid- ing cores. The two cores engage, when projecting within the tube, an annular groove turned in the wall of the bomb. Each pair of magnet coils, corresponding, of course, to a certain bomb, is connected to its own individual push button on a control switchboard aboard the Battle- plane. Hence by pressing buttons marked No. 1, No. 2, No. 3, etc., consecutively, the death-dealing missiles will be dis- patched earthward with scientific precision and without, moreover, endangering the life of a bomb-dropping expert suspended in a basket at the end of the cable, a scheme said to be employed by the German Zep- pelins.
In reloading the bomb - dropper the magnetically operated retaining rods are re- leased by simply pull- ing upward on the locking pins, which are spring actuated as the illustration clear- ly shows. When the magnet core is pulled inward by exciting, the winding with cur- rent from the 'plane above, the locking pin drops into a notch in the core. It cannot move outward again to obstruct the path of the remaining mis- siles, until the en- t i r e mechanism is hauled aboard again. The locking pins can then be manually re- leased, when the bombs are in position, and the springs be- hind each core will force them outward for the purpose set forth.
This scheme has several distinctive fea- tures. For one thing, the dropping of the bomb through a circle of light is bound to increase the accuracy of the marksman, as this arrangement cor- responds to a flash- light-pistol which has been proven to possess a deadly accurate fire. Once the target lies in the center of the circle of light, a misSed shot becomes a rarity in- deed. Identically the same efficiency holds here, modified naturally to some extent, by the movement of the Battleplane in its flight, which makes the work of the aerial gunner considerably more difficult. Should the enemy start shelling the bomb-dropper illuminant, the lamps can be instantly ex- tinguished. Then the armored Battleplane can rise quickly and speed away in safety before the hostile searchlight beams man- age to locate it.
By the construction of a dam below Niagara Falls, it is planned to raise the water 90 feet, thus tripling the power now being derived from this great source. This can be done without diverting any water from the crest, which would be likely to mar its beauty.
June, 1916
THE ELECTRICAL EXPERIMENTER
87
NEW EDGEWISE ILLUMINATED ELECTRIC SIGN.
What is known as the Polaralitc electric sign is shown in the illustration produced herewith. Unique indeed is the method by which the passer-by is attracted by this display. We are all more or less familiar with electric signs, to be sure, where the
the Two Bottles as Well as the Center Plate Light Up In This Sign.
The Two Glass Signs Here Portrayed Are Illuminated by Reflecting Light Through Them Edgewise.
illumination is concentrated either at one or several points. These signs, which, 'by the way, are works of art, have no highly intrinsic point of illumination perceptible. Instead, the whole sign, which is made of fairly thick glass, is illuminated by a special long tubular incandescent bulb contained in the base of the structure. The light is allowed to filter through the lower edge of the upright glass containing the advertise- ment. In this way, by having the light rays shoot upward through the glass, a very beautiful and engaging effect is pro- duced. In the sign here illustrated, contain- ing the two bottles at either end, the bottles are illuminated as the sign lights up. In some signs the illumination flashes on or off, but in other cases the light is left on steadily. In either event the effect is beauti- ful and out of the ordinary.
STOCKHOLM WIRELESS CAN REACH U. S. NOW.
Wireless messages can now be sent from Stockholm to the United States by way of Nauen, Germany, to Sayville, it was announced recently. The messages must be in English and not longer than 25 words, and are sent at the sender's risk.
A FARMER'S AUTOMATIC TELE- PHONE. By Frank C. Perkins.
The accompanying illustration shows a farmer's automatic telephone which is utilized at Aberdeen, S. D., by the Farm- ers' Automatic Telephone Co. and which, it is claimed, makes possible a simple, prac- tical and economical selective ringing, anti- "rubbering" lockout service for party lines.
It is pointed out that this mechanism is installed in an ordinary telephone cabinet in place of the magneto generator and con- sists of a "selector" with numbered dial and an "impulse" mechanism. Twenty-five of these telephones can be on the line and each one can selectively call and be called by any other.
The method of operation is unique. When the line is not in use all the dials stand at zero and receiver hooks are all locked down. When a subscriber desires to call another he first connects his instrument to the line. This is done by insert- ing the pin in the pin-hole op- posite his own number and then bringing it around to the top. When the dial stops moving his bell rings ; he now removes the receiver and the hook goes up, making the connection with the line. He then takes the pin and inserts it in the pin-hole op- posite the number he wishes to call and brings it to the top. When the dials stop with the selected number at the top the bell of the instrument called rings and its receiver hook un- locks.
It will be seen that the two people may then carry on a con- versation without fear of any- one "listening in." If, however, a third party shoul 1 desire to come in while the line is in use he can do so by bringing his number to the top, ringing his bell and unlocking his receiver hook ; but when doing this the two persons already on the line will notice the movement of their dials, and when it stops will know who has come in.
This is preferable to an abso- lute lockout system which pre- vents a third party coming in at all, or at the will of a central operator. A central operator cannot always exercise good judgment in handling a line of telephone users of various whims and dispositions. The farmers' automatic set relieves the central operator of this disagreeable duty. Any system which allows a central or the subscribers to absolutely lock out a third party must meet with many seri- ous objections.
It is held that this instrument particu- larly meets the wants and demands of the farmers for better telephone service.
POLISHING TILE FLOORS BY MOTOR.
Ordinarily tile floors are invariably put down by artisans skilled in this work, and the paper on which the small pieces of tile
A Powerful Motor=Driven Polisher for Tile Floors.
are pasted is simply washed off. However, when it comes to smoothing and polishing several thousand square feet of such floor surface, it is a man's size job, and the trusty electric motor has been brought into play once more for this particular work. The illustration herewith produced through the courtesy of the New York Edison Co. shows a powerful motor-driven tile floor polishing machine being operated in the new Municipal building in New York City.
The motor on these machines develops 13 h.p. The complete outfit weighs 1% tons. The motor operates the brush secured to the lower end of the motor shaft at 220 r.p.m. What one of these machines really is capable of accomplishing in a working day is astonishing. That it should work ten times faster than hand operation is not surprising, but, however, what is a more telling fact is that one of these monster polishers does well over 500 square feet per day. For border work a machine of 1-6 h.p. is made use of. Thanks to electrical operation, the contractor with an average force of 75 men was able to accomplish his share of the city's work in a little less than nine months.
A Selective Calling Automatic Telephone for Farmers' Lines.
The cost of instruments is but little more than that of other telephones, and the cost of maintenance of the line is increased only by the expense of a line battery, or similar means for giving current to the line. The cost of line upkeep is equal to that of a
ILLINOIS MAY HAVE STATE WIRELESS STATION.
Governor Dunne is considering a plan, it became known recently, to have a pow- erful wireless apparatus , installed at the State House at Springfield, III, as a part of the military equipment of the State.
As suggested to the Governor, the plan calls for antenna? reaching from the dome of the State House, 360 feet high, to the roof of the State power plant smokestacK, which when completed will be 200 feet high.
telegraph line of the sa-ie length under similar conditions.
THE ELECTRICAL EXPERIMENTER
June, 1916
Tesla's Early Work With Radio Controlled Vessels
ALTHOUGH present day inventors are prone to shout loudly about their marvelous schemes for controlling torpedoes, boats or other mobile bodies by wireless, it is interesting at this time to take note of the fact that a very complete patent on an ingenious radio control sys- tem for torpedoes, etc., was issued to Nikola Tesla in the year 1898, or over eighteen years ago. At that time the science of ra- dio telegraphy was barely on the threshold of possibilities and how far ahead of his time this great scientist is will be the more evident after perusing the following para- graphs :
The illustrations herewith are photo- graphs of the early models constructed by Dr. Tesla and which were actually tried out with entire success. The diagrammatic il- lustrations will help to explain the work-
the coherer circuit, it causes the relay a and the de-cohering device f to function, and simultaneously a commutator device j' and j" to rotate a quarter of a revolution for
step desired to be put in action at the re- ceiving device in this case.
The coherer of this early vintage is ver-y interesting and comprises a metal cylinder
Early Model of Radio=Controlled Vessel Designed by Nikola Tesla.
Model Shown at Fig. 1.
It Antedates the
Fig. 1. Tesla's Radio-Controlled Boat Model, Which Was Built Over Eighteen Years Ago.
ing parts of the telemechanical models as sponding outlined in his patent. Fig. 1 shows a mod- lengths or at el vessel corresponding to that shown in least a har- the sectional views, while Fig. 2 represents monk of same, a model constructed at an earlier date. He also men- Referring to diagrams 3, 4, 5 and 6 re- tions that it spectively, we have in general a radio is possible (al- wave sensitive device resembling the well- though not known coherer at c. This is supported in a considered in special movable holder on the de-cohering the present elis- or resetting mechanism a and f. The ra- cussion) to dio receptor circuit connected with the co- control as herer c leads to a grounded connection at many . as fifty B' (see Fig. 4), and an elevated aerial or or a hundred antenna system E'. A radio transmitting circuits, each station on shore utilizes a spark gap S, with tuned to a dis- an elevated aerial and ground circuit tinct and differ- hooked-up in the usual manner. A source ent transmit- of high potential current at T is provided to ting wave charge the spark gap, thus sending out peri- length. Of odically radio waves of a given frequency. course a dif- A control switch is mounted on the end of ferent trans- the cabinet at T, and this passes over four mitting wave points T, T', U, U'. This part of the radio length would control arrangement will be referred to later. be sent out for When an incoming wave passes through each control
each incoming wave impulse. As will be perceived by referring to Fig. 6, it is thus possible to cause two major control relays K' and K", to be closed alternately or again they both may be left open-circuited, and in consequence their local or armature circuits 18 and 19 will be left open. These relays control a reversible motor, F, which op- erates through a worm gear drive to turn from "port" to "starboard," or vice versa, a rudder F'. Referring to Fig. 3, the worm gear for motor F moves the rudder F' through a gear H", as becomes evident; also and simultaneously the movable sleeve b, with its attached insulated disk U moves about the fixed vertical rod H. As per- ceived from the various diagrams and sec- tional views, this disk L' when rotated through the agency of the steering motor F, will cause a series of metal seg- ments 9, 10, 11, etc., to pass un- der a set of spring metal brush- es 1, 2, 3, 4, etc., which are se- cured to the fixed insulating member L. The movement of this connector disk controls the circuit of the propelling motor D, connected through a shaft in the usual manner to a screw-pro- peller C (see Fig. 3) The ener- gy for operating the motor, etc., is obtainable from the storage or other batteries E, carried in the moving vessel.
Tesla in his early patent men- tions specifically that the trans- mitting and receiving radio cir- cuits should be tuned to corre- wave
c (detail in Fig. 5), with insulating heads c', through which passes a central metallic rod c". A small quantity of grains d, of conducting material (such as an oxidized metal) is placed in the cylinder. A metallic strip d', secured to an insulated post d", bears against the side of the metal cylin- der c, forming one part of the circuit. The central rod c" is connected to the frame of the instrument and so to the other part of the circuit, through the forked metal arm e, the ends of which are fast- ened with two nuts to the projecting ends of the rod, by which means the cylinder c is supported.
In order to interrupt the flow of battery current, which is started through the action of the sensitive coherer, special means are provided, which are as follows : The arma- ture e' of the relay magnets a, when at- tracted by the latter, closes a circuit con- taining a battery b' and magnet f. The ar- mature-lever f of this magnet is fixed to a rocker-shaft f", to which is secured an an- chor-escapement g. This controls the movements of a spindle g', driven by a clock-train K. The spindle g' has fixed to it a disk g" provided with four pins b"; hence for each oscillation of the escape- ment g, the spindle g' is turned through. one-quarter of a revolution. One of the spindles in the clock-train, as h, is geared so as to make one-half of a revolution for each quarter-revolution of spindle g'. The end of the former spindle extends through the side of the frame and carries an ec- centric cylinder h', which passes through a slot in a lever h", pivoted to the side of
|
' Y |
||||
|
1 '" |
Fig. 3. Sectional View of Telemechanical Vessel Illustrated at Fig. 1.
June, 1916
THE ELECTRICAL EXPERIMENTER
89
the frame. The forked arm e, which sup- ports the cylinder c, is pivoted to the end of eccentric h', and the eccentric and said arm are connected by a spiral spring i. Two pins i'i' extend out from the lever h", and one of these is always in the path of a projection on arm e. They operate to prevent the turning of cylinder c with the spindle h and the eccentric.
It will be evident that a half-revolution of the spindle h will wind up the spring i and at the same time raise or lower the lever h", and these parts, are so arranged that just before the half-revolution of the spindle is completed the pin i', in engage- ment with projection or stop-pin p, is with- drawn from its path, and the cylinder c, obeying the force of the pring i, is sud- denly turned end for end, its motion being checked by the other pin i'. The adjust- ment relatively to armature f of magnet f is furthermore so made that the pin i' is withdrawn at the moment when the arma- ture has nearly reached its extreme posi- tion in its approach toward the magnet — that is, when the lever 1, which carries the armature f, almost touches the lower one of the two stops s s (Fig. 5), which limits its motion in both directions.
The normal position of the cylinder c is vertical, and when turned in the manner de- scribed, the grains in it are simply shifted from one end to the other ; but inasmuch as they always fall through the same space
the consequent operation of the electro- magnet f, as above described, are utilized to control the operation of the propelling- engine and the steering apparatus in the
respectively; or both relays will be inac- tive while the brush J' bears upon an in- sulating-space between the plates j' and j". While one relay, as K', is energized
Plan View of Radio-Controlled Boat and Shore Wireless Station.
Details of Clever Coherer, De-coherer and Double Relay Scheme.
and are subjected to the same agitation they are caused, after each operation of the re- lay, to offer precisely the same resistance to the flow of the battery current, until another radio impulse from afar reaches the receiving-circuit.
The relay-magnet a should be of such character as to respond to a very weak current and yet be positive in its action. To insure the retraction of its armature e' after the current has been established through the magnet f and interrupted by the inversion of the sensitive device c, a light rod k is supported in guides on the frame, in position to be lifted by an ex- tension k' of the armature-lever 1, and to raise slightly the armature e'. As a feeble current may normally flow through the sensitive device and the relay-magnet a, which would be sufficient to hold though not draw the armature down, it is well to observe this precaution.
The operation of the relay-magnet a, and
one end each of the re- lay-coils, the opposite ter- minal to the brush J', and the opposite ends of the re- lay-coils to the brush J and to the frame of the instrument, (r es'p eotively. As a conse- quence of this a r r a n gement either the relay K' or K"will be energized, as the brush J' bears upon the plate ]' or j",
following manner : On the spin- dle g', which carries the escape- ment-disk g" (Figs. 4 and 6), is a cylinder j of insulating mate- rial, with a conducting plate or head at each end. From these two heads, respectively, contact plates or segments, j' j" extend on diametrically opposite sides of the cylinder. The plate j" is in electrical connection with the frame of the instrument through the head from which it extends, while insulated strips J J' bear upon the free end or head of the cylinder and the periphery of the same, respectively. Three terminals are thus provided ; one always in connection with plate j', the other always in con- nection with the plate j", and the third adapted to rest on the strips j' and j" in succession, or upon the immediate insulating- spaces, according to which of the four distinct positions the com- mutator is brought to by the clock-train and the anchor-es- capement.
At K' and K" (Figs. 4 and 6) are two relay-magnets conveni- ently placed in the rear of the propelling-engine. One terminal of a battery k" is connected to
of
its armature closes a circuit through the motor F, which is rotated in a direction to throw the rudder to port. On the oth- er hand, when relay K" is active another circuit through the motor F is closed, which reverses its direction of rotation and shifts the rudder to starboard.
A small auxiliary motor, m, may be em- ployed to control signaling lights erected on masts above the deck of the vessel, so that the operator on shore can tell in the dark just how and in what direction the telemechanical vessel is progressing through the water. This signaling motor arrange- ment is connected in series with the arma- ture of the steering motor F, so that when- ever either one of the circuits of the latter is closed through relay K' or K", the mo- tor m is likewise rotated, but in any case in the same direction. The signal lamps may be colored to facilitate matters. By this mechanism it is also possible, by send- ing out a predetermined series of electric wave impulses, to cause its spring repelled switch arm m" to come in contact finally with switch point n', thus closing a cir- cuit through a special device o, which might, for instance, be the detonating cap of an explosive chamber in the case of a radio-controlled torpedo.
With regard to the method of handling the entire outfit, we may now have refer- ence to Fig's. 4 and 6. Here S designates {Continued on page 136)
Circuits of Model Vessel, Including Radio Apparatus.
go
THE ELECTRICAL EXPERIMENTER
June, 1916
When Electricity Entered the Home
PICKING up a magazine, to while the time away as I listen through the re- ceiver for flurries in the wireless world, my eye lights on a double-page ad- vertisement headed "Electricity in the Home," and showing pictures of a hundred fascinating rinktums through which every- thing in the home can be done for you by the busy and accommodating little ions, ex- cept washing the dog and getting Johnny in at supper-time. And as I pore over them, I look back to the old, old days when the only application of Electricity in the Home was the Electric Belt.
The electric belt held the place of honor in the advertising-columns of every paper, from the Farm and Poul- try Oracle to Godey's Lady's Book. Sometimes it was pictured in its habitat around a man's waist (nev- er a lady's ; it wasn't con- sidered well-bred then for a lady to appear in the pub- lic prints clad only in — er — ■ under-necessaries of any sort) ; but most often the belt was suspended in air so you could look at the back of it and see the ring of high-tension sparks ex- uding from each of the cop- per and zinc discs hidden somewhere inside. It was only in the advertisement that it was so energetic; when you got it home its voltage had dropped per- ceptibly— dropped so far, in fact, that it could be handled with practically no danger of electrocution.
How slowly new inven- tions make their way ! Vol- ta discovered that zinc-cop- per-saline-solution thing way back in 1800 ; and you'd expect him to get a little simple thing like a belt on the market in quite a lot less than seventy years, now wouldn't you? Why, the G. E. Co. would have had one in the 1801 spring cata- logue at the latest. But it wasn't till after 1870 that the belt idea really struck in; and then, of course, as usual, the patent had ex- p i r e d, and Volta, too. Regular inventor's luck !
It had to wait for the de- velopment of advertising "with a punch" ; and the puncl^n this case was the catcP0Brase "Electricity is Life."* That was the stuff; what more could you claim for a curative agent and still be conservative ? Peoplewere getting tired, anyway, of the old-fashioned remedies, like pulverized toads, and then, too, they cost so much ; you had to keep buying them and buying them. But this belt was a thing that went right on curing after the first outlay with no expense whatever. Practically one to a family was enough, or even one to a neighborhood, provided the neighborhood was small and conscientious about the weekly bath. It was a great "talking point" in the hard times.
My father used to buy these belts for their curative properties. There was noth- ing really the matter with father, except that elusive disease known as "what-ails- you," so the belts did him a world of good.
The minute you put one on, he said, you
By Thomas Reed.
could feel the warmth generated by the powerful currents of electricity, as they forced their way through the high resist- ance of the "organs," on the well-known principle of C-equals-E-over-R. Also, there was a distinct tickling sensation caused by the electricity hunting around over the skin to find the pores. (The belt had four thicknesses of red flannel ; but that had practically no influence on its electrical out- put.)
. Father always had two belts on hand — one for a "spare," in case of a break- down. I cut the "spare" open once to get a diagram of the hook-up. I was disap- pointed there, because the only hook-up I
" . . . .In sewing father's electric belt up again, I accidentally left a needle in it, Perhaps you think he was annoyed? On the contrary . ... he said it was an unusually powerful belt; best one he ever had."
could find was the strap-and-buckle in the front. The metal discs were sewed to the flannel an inch or so apart (to avoid short- circuiting, I suppose) and that was about all.
In sewing the belt up again, I accident- ally left a needle in it. When it went in- to commission, the needle and father met, and the rendezvous was right over his liver. Perhaps you think he was annoyed? On the contrary, he was immensely pleased. He said it was an unusually powerful belt, best one he ever had. He reckoned that an especially active disc had got mingled with the others. It cured him completely of his liver-trouble and by rotating the belt a little every day, he finally had a completely-cured ring all around him. It did so well that he had a small belt built to treat him for rheumatism in his knee,
but that one didn't do him any good. Its wave-length, or decrement, or something, wasn't right; anyhow, it never had the power the needle-belt had.
Electrical apparatus has changed a lot since father's day. Now you can laugh all you want to, but if he could come back I don't believe he would care for the mod- ern rinktums in this advertisement — things that buzz, or boil; or kick when you hitch them to a socket. They can only do one trick per rinktum, and at the end of the month there's a kilowatt-bill staring you in the face. Not like his good old belt, full of discs and mystery and all kinds of pow- erful "properties" that worked while you slept and didn't dole their benefits out by meter. The world has grown better, of course, but prosy — awful prosy.
"Imagination had some play In the days of old."
JOVIANS AND SOCIE- TY FOR ELECTRICAL DEVELOPMENT CO- OPERATE.
To effect even closer co- operation between the Jov- ian Order and the Society for Electrical Development, reigning Jupiter — Thomas A. Wynne, has appointed James M. Wakeman, Gen- eral Manager ; Harry W. Alexander, Director of Pub- licity, and George W. Hill, of the Field Co-operation staff, as Statesmen-at-Large in the Jovian Order.
The Jovian Order, with its nearly 20,000 members, has substantially the same object as The Society for Electrical Development, but the functions are different. The recent appointment will effect better co-operation which will consistently com- plement the work of both organizations, such as the founding and fostering of local Jovian Leagues, and the harmonizing of relations between local electrical in- terests.
The Jovian Order is an effective generator of the personal side of better busi- ness conditions in the indus- try, while the Society will represent, as it does now, more largely the definite business co-operation ex- pressed in a corporate form. The Jovian Order accepts only personal membership while the ' So- ciety memh rship is made up exclusively of firms or businesses.
During the "America's Electrical Week" campaign this fall, it is expected that the Jovians will exert great force in the handl- ing of local sales committee work and cele- brations. The Society will, however, con- duct the national campaign as it. did Elec- trical Prosperity Week.
Both the Society and the Jovian Order are growing in membership and the new plans for even more effective co-operation will' undoubtedly be great boosts for both organizations.
These societies have done much valuable work in the extension of electric lighting and power service. Both the central sta- tions and the customers have been bene- fited by their efforts.
June, 1916
THE ELECTRICAL EXPERIMENTER
9i
The Wireless Wiz Plays War Lord
PERHAPS others may have noticed that an expression will linger in the sub- conscious mind and any series of sounds will act as a sort of music set to the words. The Wizard's remark to the ef- fect that those who laugh last are not al- ways Englishmen was no exception to this rule.
By Thomas Benson
wave, wonder what he has to shoot !" put in some one.
In silence we copied his stuff and looked at each other in amazement. No one want- ed to show his "copy," thinking they would be laughed at for mistaking the signals, but an armistice was declared and comparing notes evolved this message :
Further details are expected sliortlv.
(Signed) N. A. A.
that
spoke,
"Arlington with half aloud, as the note had not the clear high pitcli that usually identified that sta- tion. Still they may have tuned coarse and slowed up their gap so that every station would hear it without fail. The puzzle
. 'Look!' one of the boys gasped, 'there is one of the raiders now.' We rushed to the windows and there, silhouetted against the dark sky,
was a massive airship."
The words kept turning over in my mind and every trolley car, even the water drop- ping from a faulty faucet kept time to the words. Under such conditions a surprise would not be surprising, or putting it the other way, I was expecting the unexpected and naturally he went thru my guard and had his laugh.
The ether had been filled for some time with war talk, the President's lat- est note, submarine outrages and what not. They had be- come more than common and no self-respecting ama- teur would copy the stuff.
Three of the fel- lows were listening in on my set one evening when we were suddenly elec- trified so to speak by an extremely loud station sending "Q.S.T." or general call to all stations.
"Some hog on the ether," I muttered, trying to get his ex- act tune, but his
wave was as broad as a housetop without a trace of a peak. "Coming in like a tidal
Q.S.T. — Official reports have it that an air raid is planned on the United States by a foreign nation. The in- formation was obtained by foreign representatives and it is believed that it is too late to prevent the attack. Citizens are advised to remain perfectly
remained unsolved for we could not doubt that the country was in danger of attack despite the arguments of Pacifists to the contrary. That we might ultimately have to fight to hold the money obtained from the nations' cutting each other's throats was an accepted fact but such attacks would sure- ly not be made until the main conflict was settled.
/Length of gos p/pe for cannon /-Dummy o/rsh/p
\ Revers/ngsw. <§o- \ 6 v. mo/or,
Schematic Arrangement of the Wiz's "Zeppelin" Surprise and How It Worked
calm should their city be attacked and the seek shelter at the first sign of danger.
At the next club meeting we men- tioned the matter and strange to say no others had cop- ied the signals ! The mystery was getting deeper. The penal- ty for false mes- sages made a trick too dangerous. We were prepared to swear to message and the signature.
At first we were met with incredulity, but our very insist- ence demanded re- spect. Our story was told over and over and they had to believe, for even as there is honor among thieves so is there honor among much maligned radio amateurs. (Continued on page 140)
92
THE ELECTRICAL EXPERIMENTER
June, 1916
Baron Miinchhausen's New Scientific Adventures
By Hugo Gernsback
PROMPTLY as usual, on the second of 11 p.m., his Excel- lency "called." Perhaps it would be more correct if I had said hol- lered, instead of "called." For I have become mighty tired of wearing those Wire- less head receivers all of the time, that make you look like a horse with blinkers over his head. A few days ago I installed my new Audi- Amplif one , and, in "Bug" language, it is "some peach." Why, if a half-dead wireless waif wave has strayed anywhere within a thousand miles of my station, I will hear it over my Audi-Ampli- fone as loud as a young brass band in a cemetery at 2 a.m.
I can now sit twenty- five feet away from the horn of the A u d i- A m p 1 ifone and hear the s 1 i gh t e s t "rustling" in the ether p e r f e ctly plain. No matter how emaciated or how con- s u m p t i v e that wavelet is, I will hear it. It's great, you "B u g s," or my name isn't I. M. Alier!
(P.S.— If the Editor of this sheet wasn't such an insuffer- able crank, I would tell you right here howl c o nstructed that Audi- A m plifone. Simplicity it- self. First, take an old shoe - horn. Then bor- row your father's safety razor. Next we need the wheel of a discarded wheelbar- row. Now, try and in- duce your local boiler f a c t o ry to loan you a medium-size boiler, about 16 feet high and 9 feet in diameter, which we will need for the horn. After you have soldered the shoe-horn to one of the spokes of the wheelbarrow and riveted the safety razor blade to the closed end of the boiler, we are ready to mount the wheel with the shoe-horn ....
Note. — We contracted with Mr. I. M. Alier to furnish us one Miinchhausen story
Martian Amusements
a month. So far he has broken his contract twice. We, therefore, cannot allow him, in fairness to other contributors, to run" How- to-Makc-lt" articles in this department ; furthermore our space is limited. — Editor.
(Didn't I tell you that Editor of yours is an unappreciative, soulless old "crab"? —I. M. Alier.)
Well, anyway, Miinchhausen was talking. His dear, croaking, sepulchral voice seemed to fill my wireless laboratory, and I shiv- ered when I tried to realize that his voice had originated sixty million miles away
Before we could find time to th beam,
ink, a peculiar feeling of lightness had permeatedus, as if we had been so many dust particles floating in a
from earth, and here I heard it as plain as if the dear old soul had been sitting five feet away from me instead of talking to me from the Planet Mars.
"My dear Alier," he began, "you are the only human being to whom I can rave about our Martian wonders, and I assure you it is a great relief to do so. It does Copyright. 1916, by H. Gemsback. All rights reserved.
not help much to voice my constant astonishments to Flitternix, for his brain is in a whirl much the same as mine all of the time. But it is a relief to pour out one's heart to someone who is not fortunate enough to have been trans- ported into a civilization hundreds of thou- sands of years ahead of yours. But alas, I am raving again and you want to hear facts.
"Well, after our host had shown us a close view of the Earth and the planets by means of his extraordinary amplifying 'telescope,' he took us to an after-dinner 'show.' You see certain habits and customs are, after all, much the same on the two
planets. Only the 'show' was a bit different than the ones we are accustomed to on earth !
"In one of the superb flyers of the Ruler we fl e w over the magnifi- cently illum- inated city and after a few minutes d e s c e nded on an im- m e n s e , s 1 i g h t. 1 y curved dome, form- ing the top of a build- ing. This dome must have meas- ured at least 2,000 feet across and it was con- structed out of a single- piece of transpare n t Tos. The dome itself must have been fully 400 feet above the ground. We walked to- wards the edge of the dome, where at one point a powerful yellow ray was playing at the arena below. Ar- riving at the source of the ray we peered down into the house, and we involuntarily caught our breaths. What a sight ! There must have been at least 200,000 Martians below. And there was no noise, no talk, no sound of any kind ! For the Martians do not talk aloud, all conver- sation being carried on by thought trans- ference. It was uncanny to look at all these thousands of "speechless" Martians.
we were wafted down the yellow sun ray.
June, 1916
THE ELECTRICAL EXPERIMENTER
93
"The house was entirely circular, built in the form of an ancient Roman amphi- theatre, in other words like a circus. There were twenty distinct tiers, one above the other, with comfortable seats abounding. The arena seemed to be constructed entirely of
transparent Tos as far as
I could ascertain from the great height at which we were stationed at the time. While we were still marveling, our host had stepped between us and had walked us di- rectly into the yellow ray. Before we could find time to think, a peculiar feeling of light- ness had permeated us and we were wafted down the yellow beam, ^^^^^^^ as if we had been so many dust particles float- ing in a sun ray. Down, down we went at a fair rate of speed, like angels floating in space,' 500 or 600 feet, I don't know exactly how much, till we landed on a brilliantly il- luminated platform. The second we touched it, the yellow ray was turned off and our original weight was restortd to us. He then mounted a few steps and took seats in the luxuriously appointed "box" of the Ruler of the Planet Mars. The seats as well as the upholstery were white and soft, silk- like transparent Tos. The box itself was about forty feet above the arena, and was so placed that we could see nearly every one of the 200,000 Martians assembled in the House. No sooner had the Ruler sat down than every Martian saluted their chief, which they did by merely raising their left hand straight up, pointing it sky- ward. The hands were kept in this posi- tion for a few seconds. The Ruler re- turned the salute in a like manner for about five seconds. The salutation over, the show began instantly.
"The house was plunged into darkness, when suddenly an immense, dazzlingly illuminated ball appeared over the center of the arena, about twenty feet above the ground, where it hung suspended in space. In a few seconds another, very much smaller, brown ball appeared as if from nowhere. It was some fifty feet distant from the illuminated globe, and it was lighted upon its face by the latter. An- other ball, slightly larger than the former, then appeared about twenty feet away from the second globe. Next, still another globe, a little larger than the preceding one, ap- peared, but this one had a tiny globe of its own accompanying it, but a foot or so distant from the parent one. Suddenly, we understood. This was a mimic world. The large illuminated ball represented the Sun. The first small ball was the planet Mercury, the second ball Venus, the third the Earth with its moon.
"In quick succession 'Mars,' with its two tiny moons ; then the myriad of small asteroids appeared, followed by a much larger ball — Jupiter, which was larger than all the planets combined, not counting in its many moons. Next came Saturn, with its rings and its moons ; then Uranus, and finally Neptune. No sooner had the last planet appeared than all of the planets began to rotate around their 'sun,' a most magnificent spectacle. After revolving for a few minutes, several of the planets slowed down, and finally all stood still.
"Our host explained to us (by thought transference) that these positions of the planets were absolutely accurate for the present time of the year, and that every Martian show opens with the mimic world exhibition, so that all Martians are kept informed of the relative positions of the
planets and their respective distances from each other.
"What interested us most, however, was the fact that this mimic world was exactly proportioned, and that the distances be-
"\7"OU are pretty well convinced that intelligent living beings exist on other worlds outside of our earth. It has been accepted for some time that intelligent living beings exist on Mars, that mysterious planet. If intelligent beings they are, what are their habits, how do they think, what are their sorrows, what their pleasures? Are certain human traits only to be found on earth, or has Nature's almighty wisdom seen to it that they prevail throughout the Universe?
Read this interesting instalment, .brim full with new ideas; it opens up new possibilities of the capacity of the human mind.
tween the mimic planets and their sun was also in proportion. By means of anti- gravitational means below the arena, as well as beneath the Tos dome, all exterior attractions and outside planetary gravita- tional effects were done away with, with the result that the globes hung suspended in space with nothing to make them fall down, exactly as our planetary system, which hangs freely suspended in space.
"Nor was the revolving of the mimic planets around their 'sun' accomplished by artificial means. It is true they were
BE SURE TO READ THE JULY NUMBER The July number of The Electri- cal Experimenter will be brimming over with good things. Several of the papers previously announced have had to be held over, due to lack of space, but the next issue will make tip for the deficiency. Don't miss the July number; here are the rea- sons:
"Harnessing the Atmosphere's Nit- rogen Electrically." By Samuel Cohen.
"The Gyroscope — Jts Great Utility." By E~. J. Christie, M.Sc.
"Water Wheel Drives For Private Lightin Plants — How to Build Them." By H. Wiuficld Secor.
"Baron Miinchhauscn's New Scien- tific Adventures." By H. Gems- back.
New Tungsten — Molybdenum Alloy
Substitute for Platinum. "The Construction and Use of the
Gold Leaf Electroscope." By E. H.
Johnson.
"The Mimic Atom"— Part II. By
Eric R. Lyon, A. B. "The Electric Furnace."
mond Francis Yates. Making Selenium Cells. Popular Misconceptions
tism (Including the
nation of Watches). Electric Shocks and How to Avoid
Them.
By Ray-
of Magne- Demagneti-
started revolving artificially, by invisible rays, directed from behind the scenes. But once started they kept on their elliptical courses, exactly as the real planets do, in strict accordance with the motion of all bodies suspended in free space. After the mimic planets had reached the desired posi- tions (which their real brothers occupy in space), they were stopped by means of the same invisible rays which started them originally.
"The next act was a beautifully rendered concert by some fifty young male Mar- tians. It was a 'vocal' concert, no instru- ments being used. Nor did they open their mouths! Still they sang — by thought trans- ference! This, of course, ^ _ sounds violently impos-
sible. Just the same, I
assure you it was the best 'singing' I ever had the pleasure to 'hear.'
"I am equally certain that our lack of experi- ence and training caused us to miss most of the beauty of the concert, for our mental capacity of receiving all of the impulses is of necessity much lower than that of a Martian. • "We probably heard
the concert in the same manner as an intelligent monkey hears a Beethoven Symphony. He hears it perfectly — as perfectly as a human being— but he cannot understand its full meaning, because his mind cannot grasp it. Exactly so with us. Our minds were filled with the beautiful music, and while we caught much of the rhythm, the full mean- ing was necessarily lost upon us.
"The next act was almost entirely lost upon us. From what I could grasp from our host, it was a wonderful symphony of odors. It is well known to you that every smell or odor or scent causes a certain mind reflex or association; thus you are aware of the fact that certain perfumes or scents produce certain emotions upon our nerve centers. Certain scents will imme- diately conjecture a definite trend of thought upon you, all depending upon the intensity of your feelings. In the present day humans, this faculty of correctly asso- ciating thoughts with certain scents is as yet but little developed. With the Martian, it seems very highly developed; each scent, every moderation of scent has a certain well defined meaning.
"This is how the 'symphony of scents' was enacted. Perforated pipes were placed on top of the railing of all the tiers. This piping ran continuous through the entire house, while large supply mains led to a mix- ing and generating plant behind the scenes. The scents and perfumes were led in large mixing chambers, here to be blended scien- tifically by accomplished artists performing the 'symphony.' By means of pumps the scents were driven into the perforated pipes, but a few feet away from the audience, who thus simultaneously was enveloped into clouds of invisible scents and perfumes. The 'clouds' came at times in puffs, at times they were sustained, sometimes they were long drawn-out, changing from one scent into another. We could detect a certain rhythm throughout, and from the ecstatic expressions on the Martian's faces we un- derstood how deep their feelings were dur- ing the performance, which lasted well over half an hour.
"Upon us the full meaning was, of course, lost, for we did not understand it all, but just the same our sensations were delight- ful in the extreme, and exceedingly pleas- ant. Just exactly what the feelings of the Martians were, and just what mental pic- tures or emotions the various scents pro- duced upon their nerve centers, we have, of course, no means of knowing, but we knew that their systems responded very power- fully to the performance.
"The next act was a dazzling acrobatic performance of several Martians, going through marvelous evolutions in free space with no visible means of supporting their bodies. It seems that they were kept float- ( Continued on page I??)
94
THE ELECTRICAL EXPERIMENTER
June, 1916
Mimic Atoms and Their Experimental Formation
By Eric R. Lyon, A. B.
[The editors are pleased to state that the subject matter of the original experiments constituting this paper have been discussed before the Physics Club of Chicago University ; further that it won a fel- lowship for its author in the Rice Institute of Houston, Texas; that it was the sub- ject of congratulation to Mr. Lyon upon the part of Dr. A. C. Crehorc, of Columbia University, who has, with Sir J. I. Thomson, performed extensive and valuable work toward the establishment of the equilibrium- group-figure theory of the atom. Also commendatory notice was sent the author by Sir J. J. Thomson himself, through the courtesy of the assistant professor of physics in Rice Institute, who met the famous scien- tist during a visit to England and Cambridge University.]*
Part I. — Experiments.
FORTY years ago saw the real nucleation of a the- ory which is destined to become one of the greatest contributions ever made to hu- man knowledge. This is the electron theory which sweeps forward to the explanation of matter and to the solution of that question which foreshad- ows a new age and a marvel era in human progress — the question : "How' can we release the almost unthinkably vast energy which is locked up in the atoms?"
Forty years ago on the east- ern side of the Atlantic, at- tention was first being actively directed toward finding out the nature of cathode rays. There were some who thought these rays were ether waves, similar to radiant light, and others who believed them to be small par- ticles of matter or corpuscles. We all know that the latter were right and that the cathode rays have since been proved to be little flying mites of matter, the electrons, which are at once mites of matter and at the same time extremely mi- nute charges of negative electricity.
Forty years ago on the western side of the Atlantic a work was being done which could not at that time have been seen to have had even the remotest bearing- on
but in its crystalline forms as composed of atoms. Prof. Alfred Marshall Mayer of the Stevens Institute of Technology at Hobo- ken, N.J., was investigating the elasticity
Showing the Various Stages Gone Thru in Winding the Submersible Magnet Coil.
cathode rays, or upon the only dimly fore- shadowed electrons ; much less upon the then undreamed of problem of the elec- tronic constitution of the atoms of mat- ter. However, the work was upon the constitution of matter, not in its atoms,
How the Coil, Which Is to Be Submerged in a Tank of Water, is wrapped With Tape and Cord.
of metals. This investigation led him into the study of crystals, because the elasticity of metals is due to their crystalline com- position. His study of crystals led him to inquire why the atoms in a crystal (for example, the. cube of common salt) should arrange themselves in a regular order or "space-lattice," such that in each group of neighboring atoms the form of the com- pleted crystal may be seen, and such that the latter completed crystal is built up from an original simple group of the type de- scribed— wherein an atom occupies and de- fines each of the several corners or vertices of the crystalline form — simply by the addi- tion of successive parallel layers of atoms to the original crystal faces.
To answer that question Prof. Mayer magnetized a number of sewing-needles, thrust them through corks, and floated them upon a basin of water so that all of their North magnetic poles pointed upward and so that all of their South poles pointed downivard. Having all of their like poles together, the little floating magnets hasten- ed to magnetically push away from one another and to seek the farthest distance apart, which was at the wall of the basin. To counteract this expansion of the group, due to the mutual repulsions of the float- ing magnets, he held vertically a short dis- tance above the center of the basin a large bar magnet with its south pole down. The south pole of the bar magnet attracted the north poles of the floating magnets so that the group was made more compact and so that the floating magnets were so close to one another that their mutual repulsive
_ * Adapted from the author's rjaper, "An Exten- sion of Professor Mayer's Experiment YVith Float- ing Magnets," published in the "Physical Review," issue of March, 1914. Specially prepared by the author for The Electrical Experimenter.
June, 1916
forces exactly balanced the attraction of the bar magnet. When this had occurred Professor Mayer observed that the floating magnets always arranged themselves geo- metrically and in concentric rings about a central member, which might consist of one magnet at the center and inside of the in- nermost ring; or of two magnets, one on
THE ELECTRICAL EXPERIMENTER
95
Part II,) were periodic in structure; i.e., that a certain form of strcture, say the triangular structure having a small equi- lateral triangle at the center of the rings' system, would repeat itself after an inter- val of other kinds of structure, and would be again repeated after another interval of other kinds of structure; each repetition
possible with it. The construction details may be varied to suit the experimenter's convenience. They are such as were actu- ally followed by the author in making the apparatus described. The materials to be purchased are :
2 dry cells, <a< 35c cost, 70c.
1 roll. ->4 in., electrician's black fric- tion tape cost,' 25c.
1 lb No. 26 D. C.C. mag- net wire cost, 70c.
1 small horseshoe magnet (at a 5 and 10c. Store) . .cost, 10c.
2 packages No. 10 sewing- needles ("Sharps"), @ 5c cost, 10c.
1 doz. fine grade smooth
white, 1 in. corks cost, 5c.
1 box "Parowax" paraffin cost, 10c.
2 balls, 1/16 in. wrapping cord or marline, (§> 5c. cost, 10c.
1 stick of sealing wax cost, 5c.
1 magazine-pencil of the kind consisting of a short brass tube having a removable stub-pencil inserted in one end and a pen and eraser in the other cost, 5c.
fig. a
Fig 15
4
Construction of Cork Disc Cutter and Method of Magnetizing Steel Sewing Needles.
either side of that center and equally dis- tant from it; or of three magnets forming a little triangle around the center ; or of four magnets forming a little square around that center. The groupings so obtained are practically the same as those shown in Fig. 17 (Part II of this paper). Professor Mayer regarded them as crystals in which the floating magnets take the place of atoms ; the mutual magnetic re- pulsions, of atomic mutual repulsions, or reboundings due to heat quiverings ; and the centrally attracting bar magnet takes the place of the force of cohesion which holds the crystal together.
We will not further concern ourselves with this theory of crystallization except to note that the "space-lattice" system of atomic arrangement in a crystal which Mayer sought to explain, has since been proved in form, although not yet explained, by the experiments which have very re- cently been carried out in I'.ie reflection of X-rays from crystal faces.
In the development of the electron the- ory there was to come the application of Professor Mayer's experiment to the ex- planation of a much more minute and much more wonderful crystal than Professor Mayer had anticipated. Sir J. J. Thomson in a paper published in the Philosophical Magazine, 1904, and in his "Corpuscular Theory of Matter" was the first to give definite statement to this new electronic crystallography of the atom and to employ Mayer's experiment in explanation of an arrangement of the electrons within an atom which must give to the latter the periodic character of its properties and especially of its valencies. It was ob- served that Mayer's groups (See Fig. 17,
embodying essentially the preceding exam- ple of the particular structure, but with the addition of another ring. As we said, periodicity in properties is an extremely important feature in the family of atoms and so Mayer's experiment has come to have a most" peculiar significance in the atom theory.
We will now take up the construction of a form of Mayer's apparatus, which is an improvement on the original form, permit- ting the experimenter to obtain much larger and more beautiful groups than was possible with the use of a suspended bar magnet. Any one will be able to construct this simple apparatus and to actually make for himself the experiments which are
Totol approx. cost $2.20
Tools and utensils required, but which are kept in any house and kitchen, are a pair of pli- ers, a screw driver, a stove po- ker, a good fire of coals in which to heat the poker, a kit- chen range or gas stove, a flat file and a triangular file, a safe- ty-razor blade of the "Ever- Ready" type, an ordinary tin (iron) wash basin, a tin (iron) dishpan about 13 in. bottom di- ameter, 4 fruit jar covers, a bread pan, size, too 10^2 in. by 6l/2 in., depth, 3'/2 in.; an 8 quart (preferably aluminum) preserving kettle, top diameter, 1154 in., depth, 6 in.; some cotton cloth or "domestic" to be torn in strips; and some heavy thread, No. 30 linen, or twine.
Fig. 1. Carefully wrap three lengths of tape, b, c, and d, side by side parallel to the top and around the kettle as shown. Strip off the middle length c. Cut twelve pieces of twine, each two feet in length. Arrange these, a, over the top of the ket- tle so that the ends hang evenly to about six inches down the side of the kettle and so that they are equally spaced around the kettle. Where the twine ends pass over b and d, press them against the sticky sur- face of b; allow a little slack to fit in c, and press against d. The coil of No. 26 wire will be wound in c and the pieces of twine will be used in binding the coil. Tie heavy wrapping cords around the kettle (Continued on page 138)
Co/A Water t/ne^ D/shpon]
Dry ce/ts Fruit jor cover Fig. 16 Hooting magnets
Appearance of Magnet Coil in Tank, Also Batteries and Floating Magnetized Needles.
96
th£ electrical experimenter
The Marvels of Modern Physics
June, 1916
By Rogers D. Rusk Assistant Instructor in Physics, Ohio Wesleyan University
Important Electric Phenomena.
THE simplest electrical phenomena are often the most difficult to explain, and we are apt to take the more com- mon-place of them for granted, without seeking an explanation. For instance we
though existing together, they are distinct and at right angles to each other.
This immediately suggests the close re- lationship existing between electricity and magnetism, and leads us to conclude that even the electric unit — the electron — may
o.o.P,o.o.o.Q:o
A j oppo: p.oop y 00000000
Arrangement of Free Electrons in a Conductor.
are as familiar with electricity flowing in a wire as we are with water in a pipe, but are we as familiar with the exact nature of the current? Although the latter is often used to explain the former, in so doing we only draw an analogy whici. aids us in vis- ualizing the action, and which adds nothing to our knowledge of its nature. In seek- ing the true solutions of such problems- we are brought to a realization of the close re- lationship existing between different nat- ural phenomena, and we recognize more clearly the fundamental character of elec- tricity.
Electrical phenomena are those occur- rences which are caused or brought about by electricity. Of such there are many and their range is indefinite, extending from magnetism and ionization even to that nat- ural phenomena of the polar skies, the au- rora.
A battery or dynamo acts as a force pump in forcing an electric current along a con- ductor. According to the latest theories there may be a number of free electrons in a conductor (Fig. 1), at any given in- staiit, due to the fact that electrons fre- quently gather sufficient kinetic energy to enable them to break away from their re- spective molecules. It is a stream of these free electrons that constitutes a current, and we may consider electrical resistance to be due to the friction opposing the motion of these particles. In this theory the exist- ence of the free electrons has been assumed, but their presence can be proved in any metal by heating, and subjection to ultra- violet light. The only drawback is that one is likely to imagine the current as something quite material within the wire. In reality it is more as Steinmetz once said to a sur- prised newspaper reporter "not in the wire itself but in the ether about it." This is truer than at first seems, for the energy of the current resides in the field of strain about it, and it is this moving field which constitutes the current.
Every moving charge of electricity car-
How Electrolysis Is Possible by the Migration of Minute Electric Charges Between Two Electrodes.
ries with it a double field, as shown in Fig. 2. The straight radial lines represent the electrostatic field, while the concentric circles represent the magnetic field. Al-
produce a magnetic field when in motion. Langevin and Weiss have developed such a theory, which makes every molecule a magnet due to the polarity given it by its rotating electrons. Such an elemental mag- net is shown in Fig. 3. In soft iron these elemental magnets are in neutral groups, but when magnetized they arrange themselves with like poles pointing in one direction. In non-magnetic materials, the polarity of the molecules has either been destroyed by opposing electrons or the neutral groups can not be broken up. The fact that the necessary elements are present is proved
*-----i-i-p^:-r-
\ sv/ 1 y
v /■>..• 1 --' ^
V / 1 .- *
Lines of Force About a Moving Electric Charge.
by the well known Heusler alloys which are magnetic alloys formed by the combi- nation of non-magnetic materials.
The passage of a current through a con- ducting liquid is attended with results quite different than in a solid conductor. In the
a - Wave by Elecfron slowly moved b ■ Wave by Electron suddenly moved 0
Showing Difference between Propagation of Electro Magnetic Wave, by Moving Electron Slowly and Quickly.
first place, a conducting liquid has striking characteristics of its own. It is ionized; that is, its molecules have divided into charged particles or ions, and these, though neutralizing each other, are free to move about. In the second place an imposed cur- rent causes a separation of these charges. Thus, as in the case of sulphuric acid (IFSCM the ionsH2 and SO* are formed in solution, which are positive and negative respectively. The current causes a motion of these particles as seen in Fig. 4, and so hydrogen is carried to one pole while the sulphate particles are drawn to the other. The fact that these quantities do not appear except at the electrodes suggests that they onlv exist as true H and SO* after having given up their respective charges to the elec- trodes. This same phenomena of ioniza- tion is seen in gases, and thus in matter in all its forms we see evidences of the forces of electricity. In the case of ionization, such a division of the molecules into charged particles has led scientists to believe
that electricity is the connecting link be- tween the atoms. This explanation of chemical affinity was proposed some time ago by Davy and Berzelius. A chemical combination occurs only be-
Illustrating an Elemental Magnet.
tween two atoms each of which contains an unbalanced electron. When the union takes place the excess charge of one fills up the deficiency of the other and a complete neu- tral molecule is formed. Recently it has been thought that not only those inter- atomic, or chemical forces, but also the inter-molecular forces of cohesion and ad- hesion may be explained in a similar way. The force of adhesion which makes glue stick to wood, or the force of cohesion which makes the particles of glue stick to each other, are likely an interaction be- tween pairs of electric charges acting through distances which are extremely mi- nute, and depending to a degree on the geo- metric arrangements of the atoms. A com- plete theory must wait until our knowledge of the atom is more definite.
More interesting than this to the wire- less experimenter is the origin of the elec- tric ether wave. Doubtless many who are familiar with all the apparatus extant have never stopped to think just how these waves are generated. Our present conceptions of light and Hertzian waves are largely due to J. Clerk Maxwell, the mathematical phys- icist, who suggested that these waves were electro-magnetic disturbances. In order to understand this, let us remember that the moving electric charge carries a double field with it. In the case of an alternating cur- rent, the electron moves first in one direc- tion and then in the other, or it oscillates back and forth, and the coincident motion of its electric and magnetic fields produces a disturbance of electro-magnetic nature in the ether. This is an electro-magnetic wave. How this wave is propagated may better be shown by taking the example of a single electron and considering only a sin- gle line of force. Now if the electron is moved a little to one side as indicated in Fig. 5, the whole line will not all move at
Lines of Force About a Radio Antenna.
once, owing to the inertia it possesses. The part nearest the electron will move first and (Continued on page 130)
June, 1916
THE ELECTRICAL EXPERIMENTER
97
™* RADIO LEAGUE
•/AMERICA
HONORARY MEMBERS CAPT. WH.G. BU1LARD. U S.N. NIKOLA TESLA PROF. REGINALD FESSENDEN. DR. LEE DE FOREST.
Manager, H. Gcrnsback
Radio League of America News
AS evidence of the steady growth of the Radio League of America, the following letter from Captain W. H. G. Bullard, U.S.N., is reproduced, in which
erintendent of Radio Service and has created a profound impression on the of- ficers in charge. Let some of our Radio Club members write also, explaining the
The Rholphakapa Radio Club of East Liberty, Ohio
acknowledgment is given of the receipt of 596 names of radio amateurs, forwarded by Mr. H. Gernsback, manager of the R. L. of A. In this way the Government authorities in charge of the United States Radio Service are put in touch with all bona fide experimental wireless stations throughout the land. This is of para- mount importance in the event of war as many of these amateur stations are cap- able of handling official radiograms very ex- peditiously. This fact was forcibly brought out by the admirable work accomplished in relaying a radio message clear across the continent through a chain of amateur stations on the night of February twenty- first last. This remarkable feat was de- scribed with photos of the relay stations, in the May number of The Electrical Ex- perimenter.
A great many radio amateurs are under the impression that if the location of their station is once known to Uncle Sam, they are then in a position to be called on for military service if war should come. Such is not the case, however, and although during a state of military rule any ama- teur station may be confiscated by the Gov- ernment, the owner thereof is not com- pelled to operate the station unless he desires to do so. It is gratifying to learn that a large number of those joining the ranks of the Radio League of America fraternity are also signifying their will- ingness to serve their country in time of national peril, by signing the blanks dis- tributed by the R.L. of A. or by the sup- erintendent of Radio Service, Radio, Va.
The letter cited below is worthy of a second reading by all patriotic and law- abiding amateurs. It was sent to the sup-
scope and facilities of their organizations to Captain Bullard. Following is the At- lanta Radio Club letter. Note the spirit of cooperation manifested therein :
suggesting any improvements he thinks necessary.
We decided that the objects of our club should be to promote interest in radio communication and to increase knowledge and operating efficiency. To promote these objects, we have decided to rate each member according to the percentage he makes on competitive examinations to be held every three months. These examinations will be very similar to the Government examinations as given to op- erators. They will consist of questions on the radio laws and regulations, questions on the theory and operation of the apparatus, and an operating speed test. We believe that by creating a spirit of rivalry among the members the interest will be stimulated and operating efficiency increased.
We want you to understand that Atlanta is as alive "wirelessly" as she is in other respects. Dur- ing "electrical prosperity week" last December we were invited to enter an exhibit in the electrical show. We realized that this was beyond the scope of the average wireless club, and quite an under- taking for so young an organization. However, after discussing the matter we decided that it would be beneficial both to ourselves and to the public at large. Luckily we were allotted a space right beneath a skylight. Some of our energetic and enterprising members obtained permission, and erected an aerial on top of the 17-story building, on the ground floor of which the show was held. Thus it was that we were able to have a station in actual operation in the exhibit. Several of the boys were always present to explain the mysteries of wireless to the eager spectators. Taken alto- gether, the venture was a glorious success. The Atlanta newspapers all gave us good writeups and we secured many new members.
The probable reason for the late start of wire- less in this vicinity is that there are no Govern- ment or commercial stations within 250 miles of Atlanta. In order to hear anything at all the first amateurs had to have comparatively large aerials and very sensitive instruments. Until recently these instruments were beyond the reach of all but the wealthy experimenters. (It is a curious fact that I have noticed that rich amateurs are few and far between.)
As we are so far beyond the zone of interfer- ence, most of us use transmitting waves somewhat over the limit prescribed by the Government. We do this knowingly, but we feel that we are still
College Park, Ga.
Dear Sir: I would like to give you a few facts about the Atlanta amateurs. As president of the At- lanta Radio Club, it is my duty to see that you do not get a mistaken impression of us.
I have one of the oldest stations in this section and have watched with much interest the increase of the number during the last two years. At first I could hear only one or two amateurs. The number commenced to grow, and soon in- terference became a problem. By this time most of us knew each other and, being congenial, we de- cided to band together and discuss our problems.
There were about 10 of us to start with. We secured the use of one of the small anterooms of the Carnegie Library Building and there held our first few meetings. The club grew rapidly. The small room was soon so crowded that we had to seek larger quarters. Several of our number who were members of the local Y.M.C.A. obtained per mission to use a large room on the third floor of the 10-storv building. We have held our meetings there on alternate Saturday nights since last summer. A temporary aerial has been erected on top of the build ing and we use it for receiving tests
After our constitution was drafted we proceeded to draw up a set of operating rules. These rules con sisted of the Government Radio Service regulations and a few which dealt with the local conditions. In addition to the usual club officers we elected a club radio inspector, whose duty it is to enforce these regulations. It is also his duty to visit each station once every 60 days for the purpose of
u. s.
NAVY DEPARTMENT.
NAVAL RADIO SERVICE,
Radio. Va..
April 21. 1916,
Mr. H. Gernsba^k. Manager. -
Hsdlo League of Amerloa,
231 Pulton street,
flew York. H. Y.
Uy dear Sir: —
I have the pleasure to acknowledge your letter of. April 20, 1916, In which you advise ttiat you are sending under separate cover 696 application clanks of members who have Deen enrolled In the "Radio League of Amerloa" since you last wrote on this same subject.
I now have the pleasure of acknowledging receipt of these applications and of thanking you most heartily for them. They will be very valuable In the organization of amateurs In our various alstrlots for Government purposes. Independent of the organization of the Radio League and the privileges tney have thereunder. ■ _
I congratulate you on the growth of the League whlcn Is shown by the very. great enlargement of its membership, and I assure you your co-operation In this matter is heartily appre- ciated. I am sure, further, that the Government can rind very useful work ror these amateurs to do at such times as their ser- vices may be needed.
Very truly yours
Captaln.U.S.Havy Superintendent naval Radio Ser- vice.
obeying the spirit of the law, which is to prevent interference with Government and commercial sta- tions. If we had the faintest idea that we were {Continued on page 132)
THE ELECTRICAL EXPERIMENTER
June, 1916
United States Signal Corps Use Radio In Mexico
THE accompanying illustrations depict the excellent portable Radio sets in use by the United States Army Signal Corps during the expeditionary campaign n Mexico. The particular apparatus is that in use at Casas Grandes, Mexico '(right hand photo). The Radio operator 5s receiving Radio messages from the Mex- can border line. Many important mili- tary despatches are sent back and forth from the expeditionary forces and the ar- my headquarters located on the border.
Owing to the unreliability of the courier and telegraph service, the Radio has proven of wonderful help in maneuvering the various bodies of troops quickly and accurately. Wireless telegraphy has changed to a very large extent the strat- egy used in the conduct of warfare, both on land and on sea. It is now possible to send a radio call for re- inforcements, and to have them on the spot within a few hours in a great many
outfit is mounted on a large automobile truck and is of sufficient power to serve the army headquarters' staff, even though mes- sages are to be transmitted several hun- dred miles. The demountable aerial mast rises above the arid, desert-like country to a height of 85 feet. So expert are the sig- nal corps members in unpacking and set- ting up this apparatus that the whole opera- tion requires but a few minutes.
Most of these radio sets for portable
Above: U. S. Radio Operator on Duty at Casas Grandes, Mexico.
Left: Radio Truck and 85 ft. Mast at Columbus, N. M. Note the Sandy Na= ture of the Coun- try.
instances, whereas in previous wars it very often required one-half a day or a whole day, and even more, to get a message through.
The illustration at the left portrays the powerful' Radio station in use by the United States troops at Columbus, N.M. This
work utilize a gasoline or kerosene oil en- gine which drives a 500 cycle A. C. Gen- erator. This gives a high pitched spark note which is heard the best in the receiv- ers, especially under tropical and heavy static conditions.
PHONOGRAPH CODE-PRACTICE RECORDS THE LATEST,
Wireless telegraphy, especially in Eng- land, has become such an important con- sideration that the British Marconi Com- pany has developed a complete set of records, corresponding to those used on the regular disc type talking machines, each record containing an excellent assort- ment of code practice in dots and dashes. They were recorded by having an expert operator transmit signals on the specially
devised apparatus, while the talking machine was in operation. The present set of records comprise six double-sided disc records, containing instructions for both the beginner and the advanced stud- ent. Each side gives from 3 to 4 minutes instruction at the usual speed at which the record is run; the complete set thus giv- ing up to three-quarters of an hour of first- class receiving practice. This scheme pos- sesses many important advantages over others now in use, and any part of the
record is available for instant reproduc- tion, whenever the operator or student may so desire. Moreover, the speed at which the record is run can be controlled to suit any student.
The first record, intended especially for beginners in the art, contains on one side the complete Morse code with all standard abbreviations and punctuation sig'ns. On the reverse side of this record difficult letters such as C, Q, Y, etc., are picked out, and they occur several times in succession; then there follows a sentence very slowly and deliberately, containing several letters of the alphabet. The second disc contains on one side numbers, at a speed in the neighborhood of about ten words per minute, and on the other side, similar matter which has been transmitted at a speed approximately fifty per cent, faster. Owing to the possible regulation of the speed in any standard talking machine, a record whose normal velocity yields 10 words per minute, may be adjusted as to speed so as to give any reproduction at a speed of from 8 to 12 or 13 words per minute.
Both sides of the third record contain dummy messages properly numbered, timed and counted exactly similar to those sent between government or commercial stations and to ships at sea.
Record No. 4 contains stock exchange terms, fractions, etc. On the reverse side of this record is found code words, ci- phers, etc., normal transmission being at the rate of 20 words per minute.
The fifth record contains a collection of messages of varied degrees of difficulty, such as are encountered in the course of an ordinary day's work, and, correspond- ingly, the speed at which these are trans- mitted is 25 words per minute. The re- verse side of this record contains a mis- cellaneous assortment of French, Spanish and Italian messages in code, at a rate of 25 words per minute.
The sixth record is perhaps the most in- teresting of the whole series and without doubt the most valuable. This remarkable record contains signals sent out by two distinctly different transmitters on slightly different notes. The home student who has not had access to a wireless installa- tion will now be in a position to hear just what signals sound like "when "jammed" and will at the same time be given ex- ceedingly favorable preparatory instruc- tions for the time when he takes up his duties on board ship. This "jamming" record contains on one side "press," trans- mitted at a normal speed of 25 words per minute, and "jammed" or interfered with by similar matter transmitted at a slightly lower speed. On the reverse side there is given mixed messages at the rate of 25 words per minute, also "jammed." A student can gain a large amount of practice with this one record, as it often becomes necessary for an operator to read a note through considerable interference of static and one or more neighboring sta- tions which endeavor to deluge him with a multifarious accumulation of dots and dashes, with a few splashes of static thrown in for good measure.
June, 1916
THE ELECTRICAL EXPERIMENTER
High Speed Radio Telegraphy
99
THE first attempt toward perfecting a rapid transmission system for radio telegraphy was that made by the Poulsen Wireless Telephone and Telegraph
'W
Transm/fter Fig.t
drc.
DC
dutomofjc fronsmt/ler
Relay hey
Automatic Transmitter for Undamped Wave Station.
Company of San Francisco, California. In June, 1910, the company erected two ex- perimental stations, one at Sacramento and the other at Stockton. These stations were erected for both radio telephone and tele- graph work and were especially located at these points so that atmospheric interfer- ence would be minimized so far as possible.
The initial- high speed radio telegraphic system was installed and supervised by Mr. Schow of Copenhagen, Denmark, with Mr. V. Poulsen as chief engineer. The stations were in charge of Mr. Albertus and Mr: Jensen, both of Denmark.
The first system tried out employed a tape transmitter, as shown in Fig. 1. The tape consisted of a perforated sheet of pa- per containing the (code) message and this was passed between two contacts, one of which was a roller, as perceived. The tape and the two contacts operated a relay, which in turn controlled the antenna wavelength. At the other end the receptor consisted of a standard form of circuit, in which the telephone circuit was linked to a fine gold wire A-B, Fig. 2. This was about four inches long and had a resistance of about 360 ohms. The wire was placed between the poles of a powerful electro-magnet NS, which were excited by 110 volts D.C. A condensing lens P was placed on one side of the gold wire, while in front of it was mounted a Nernst lamp L. The light de- veloped by this lamp was focused on the wire. The light passing through the micro- scope indicated was caused to fall upon a moving photo film, as depicted at the right. It is then obvious that if the gold wire is made to vibrate it will cause the continuous ray of light to oscillate and thus a wavy image or line will be photographed on the film. The film, which moves continuously, passes through a developing and fixing chamber.
A great deal of experimental work has been conducted on this system, but it finally proved unsuccessful. The first defect that had to be eliminated was that of the break- ing of the fine_ gold wire and the second was that the signals were not clearly re- corded on the moving film. This latter was overcome by placing a small slit about l/32"xy2" before the film, so that the light received by it would be equally distributed. The other defect which had to be remedied was that of the detector. The first detector utilized was that having graphite in contact with galena. It is obvious from this de- scription that any direct current impulse through the crystal detector would cause the gold wire to be attracted by the electro- magnet poles.
After extensive trials and research along this line, the experiments proved total fail-
By C. V. Logwood ,
ures, but the object was not entirely aban- doned. Mr. Christensen of Copenhagen, noting the difficulties which were observed in the previous experiments, began to work on the problem, but after trying for a year without results, he decided to give some other engineer a chance to develop a high speed telegraphic instrument and finally Mr. Elwell, Chief Engineer, assigned the author the task of solving this interesting problem.
Complete installations were made at Los Angeles and San Francisco, using the last improved type of rapid transmitters and receivers. After six weeks of constant, la- borious work it was demonstrated that the system was a complete failure.
The author had previously made some promising experiments with the telegra- phone and microphonic relay, which had all the "ear-marks" of a new system. The fol- lowing scheme was installed by Dr. De For- est and myself. At first a Wheatstone transmitter was employed for translating the perforated paper strip containing the (code) message into dots and dashes. It
Photographic Scheme of Recording Radio Mes- sages.
consisted of a circular, toothed metallic wheel, as perceived at W, Fig. 3, which re-
' Transmitter rig 5
I/O V AC OR DC
DC
II
□ _ □
-Arc.
Perforated Paper Tape Used for Rapid Trans- mission of Radio Arc Signals.
volved by means of a motor. Upon the surface of the wheel was placed a strip of paper. A fine brush contact B was then placed on top of the paper strip so that it made contact with the metallic wheel W, when a punched mark in the paper was un- der the brush contact B. The Wheatstone transmitter was connected to the relay, as indicated. Now it is quite evident that whenever the strip of paper traveled across the wheel that it would automatically op- erate the relay. The first problem encoun- tered in this work was that of finding a proper telegraph relay, which would han- dle heavy currents at high speed. At last this was overcome by making a powerful, stocky key; one which would act instantly and at the same time withstand heavy am- perages.
When the transmitter was finally per-
fected our minds turned to the development of a receiver which would record the high speed "incoming" signals. The problem was eventually solved by employing a tikker of my rotary type, to break up the sus- tained waves and then lead them to a three- step audion amplifier; a two-step one of the same type is depicted at Fig. 4. The highly amplified signals were then brought to a single sensitive receiver R. This was ar- ranged against a microphonic transmitter M, the diafram of which was tuned to the receiver's diafram, and thus the greatest amount of sensitiveness was obtained. The microphone was connected in series with a battery and a small telephone induction coil C, Fig. 4, the secondary of which was linked to a telegraphone.
Owing to the coarse sounds produced by the tikker, it was impossible to receive sig- nals having a speed greater than seventy- five words per minute. This was due to the following reasons : the signals coming in at seventy-five words per minute could be readily recorded on the moving steel wire of the telegraphone, but in order to repro- duce them at normal (thirty or thirty-five words per minute) speed, it was necessary to run the steel wire slowly and in doing so the tone of the signals was not very clear. This resulted from the harsh sounds de- veloped in the telegraphone receiver due to the slow speed of the moving steel wire. However, this was readily eliminated by employing a higher pitch than the tikker's "paper-tearing" note. The Federal Tele- graph Company has operated successfully with this system for a whole season, but sig- nals were transmitted at somewhat slower speed than seventy-five words per minute. Finally it was abandoned as this company installed several duplicate stations.
Apparatus for use in rapid radio trans- mitters and receivers are still in their in- fancy and there is a wide field of research for those who are interested in the commer- cial end of radio telegraphy, as it is patent that a great deal of money can be saved if an all around, thoroughly reliable system can be evolved.
WIRELESS GIVES BEARINGS.
A Bellini Tosi direction finder has been installed at the naval radio station at North Truro on Cape Cod. With it the bearings of a ship from the station can be ascer- tained by the radio waves and the direc- tion can be found, affording a new aid to navigators in determining their position. In tests the direction finder has been found correct within about two degrees.
All merchant ships with wireless are re- quested by the Government to aid in the experiments whenever within range of the station by requesting their bearings from
Reproducing coils n - re/egrophone ffecorgmg com* fig 4
W
®
Hook-up for Audion Amplifier and Telegraphone Recorder
the station and stating how such bearings check with the ship's observation.
IOO
THE ELECTRICAL EXPERIMENTER
June, 1916
HOOK-UP FOR UNDAMPED AND DAMPED OSCILLATIONS.
With this hook-up the writer has been able to copy Germany, and Honolulu, using an antenna of two wires 165 feet long and 50 feet high. "
All contacts for plugs are spaced three inches apart except 1 and 2, which are spaced two inches from each other in order that the variometer may be either cut out of the circuit or left in (for the short wave lengths). The inductance coil L-10 is 28 inches long and 5$4 inches in diameter, wound with No. 28 S.C.C. wire. The coil L-9 is 5^2 inches in di- ameter and 7 inches long, wound with No. 24 S.C.C. wire. The coil L-8 is also 7 inches long and 5 inches in diameter. It is wound with the same wire as coil L-9. Coil L-7
is 29 inches long by |Hook-Up for Rece
5^4 inches in diam- eter, wound with No. 28 S.C.C. wire.
The primary winding of L-3 is 6 inches in diameter and 14 inches long, wound with No. 24 S.C.C. wire, and the secondary L-4 is 16 inches long by 5 inches in diameter
and wound with No. 28 S.C.C. wire.
When switch No. 1 is thrown to the left and coils L-7 and L-10 cut out of circuit, amateur signals are picked up immediately. It is quite simple with this hook-up to
/lud/on
Short wore /nduct/ve coup/ed tuner /soo meters
iving Either Damped or Undamped Waves with
change from the short to the long wave lengths, and moreover, but one audion de- tector is necessary to gain all the results here enumerated.
Contributed by HARRY Y. HIGGS, R.E.
Our navy needs wireless operators and electricians. The advancement is rapid. All men who enlist for this work are sent to the navy school for six months and are paid while under instruction.
POCKET RADIO RECEPTOR WITH 60 MILE RANGE.
This is a real pocket receiving set ; one that actually "receives." Using a 50-foot aerial, stations 60 miles distant have been
A GOOD EMERGENCY AERIAL.
During a recent storm my aerial blew down and on account of the condition of the weather it was impqssible for me to go up on the roof and repair it. So I de- vised the following antenna and was agreeably surprised at the good results obtained.
I had in my cel- lar four feet of cardboard tubing measuring about four inches in diameter. I wound this with No. 18 bare copper wire (in the same man- ner as you wind an ordinary tuning coil). Having fin- ished -this I lined the bottom with the remains of an old hot water bag. The bottom was lined with the rubber so as not to be ground- ed when it was in- serted over the top of the iron waste pipe, but with a lit- tle care this may be a Single Audion. dispensed with. Af-
ter exploring the roof for a suitable place I espied an old waste pipe. After placing the coil over it I connected it to my lead-in and was astonished to hear "Arlington" (NAA) as well as with my regular aerial which was one hundred and ten feet long. Contributed by
ANDREW W. J. GALLAGHER.
EMERGENCY TELEPHONE HEAD- BAND.
This headband, while easily made, is as serviceable as those which are more elab- orate. It is very easy to adjust and can be used in an emergency to good advantage.
A and A' are 12-inch Meccano strips, B and B' are 2%-inch strips and C and C are 6-inch ones. Bolts and nuts D, E and F are the regular Meccano bolts.
First bend the pieces A and A' as shown. Then bend C and C, also B and B', about % inch from the end. Put the pieces to- gether as shown in the illustration. At D and F place a few small washers and clamp two nuts together so as to make these points readily movable. E and E are small bolts filed down to fit the recess in the re- ceiver shell. The whole band may be en- ameled black or covered with leather after the adjustments have been made to give it
|
'Meccano' |
|
|
/*/? |
|
|
It f |
|
|
1 1 f / 0 ^ |
|
|
1/ ' B |
|
|
C5^ PI |
|
|
® |
A "Meccano" Headband for Your Receivers.
a good appearance. To adjust, change the position of F. This headband is of the usual standard tvoe. Contributed bv
CECIL H. OSTERMERER.
Diagram for Pocket Radio Set.
heard, while by using gas pipes, beds, etc., amateurs within two and three miles are easily read.
The set consists of loose coupler with taps, condenser, detector and 'phones. The tuning system is all attached inside and outside of an empty wireless receiver from which the magnets have been removed. The loose coupler consists of a primary coil (staggered winding) of 150 turns of No. 30 copper wire wound so as to fit tightly inside the empty receiver. Five taps of 30 turns each are taken off and brought to the midget switch points on the back of , the 'phone case. The secondary contains 50 turns of No. 30 wire, with no taps, and fits inside the primary. The condenser fits inside the case also and consists of 36 square inches of tinfoil separated by paper and folded to fit the 'phone.
The detector is novel and consists of a fixed silicon element. That is, a piece of silicon about V± inch in diameter is ground flat on two opposite sides and clamped be- tween two rods held by two binding posts. Over the crystal and the rods is placed a cardboard tube. See illustration. Con- trary to general opinion, silicon is sensitive and used in this manner is permanent.
Through the two holes in the side of the 'phone two conductor cords are brought. One twin cord connects to the aerial and ground and the other to a head 'phone.
LONG WAVES WITHOUT A LOADING COIL.
Any one possessing a loose-coupler may hear stations whose wave lengths are be- yond the normal range of his tuner by connecting the primary and the secondary of the loose-coupler in series, leaving the closed circuit connections unchanged. Of course a certain amount of selectivity is sacrificed by this arrangement, but a loose- coupler connected in this way is more select- ive than a long wave tuning coil and cheap- er than a receiving transformer plus a loading coil. With this connection the writer has been able to bring Wellfleet in very loudlv on his receiving transformer.
Contributed by THOMAS T. HOOPER.
Thus the complete set consists of two 'phones, one containing the tuning appa- ratus and the other being used over the ear in the usual manner.
First connect all the leads of the coils, taps and condenser. Then put the coils in
I
®
Extremely Compact Pocket Radio Receptor.
place and, lastly, the condenser. Screw the cap and diaphragm on to hold the "in- nards" in place. Wire as per hook-up and connect cords as indicated.
Contributed by EARL H. SWANSON.
June, 1916
THE ELECTRICAL EXPERIMENTER
101
A GOOD "TAP" SWITCH ARRANGEMENT.
One of the principal difficulties in con- structing a good tuner, switch panel or
Pone/)
Groove - Spring-
lo f it groove /n rod
Efficient Design of Loose Coupler Switch.
other piece of electrical apparatus requir- ing a multiple point switch is to mount the knob on the shaft, and the shaft on the panel in a satisfactory manner. The shaft should be rigid and true, and yet turn freely.
The accompanying illustration shows the method evolved by the writer after consid- erable experiment, and adopted as the most satisfactory, and at the same time exceed- ingly simple to construct.
The knob shown at C is best made of Bakelite, hard rubber or black fiber. A hole is drilled nearly through from the under side with a one-quarter inch tap drill, and then tapped as deep as a plug or bottoming tap will go. A thin lock nut is made, as shown at B. A 'piece of one-quarter inch brass rod is threaded, as indicated, and cut off to the right length, which is determined by the size of the instrument and the taste of the builder. Close to the lower end a groove is turned or filed around the rod for the spring to fit in. This rod is held on the panel by means of the tube A. This may be a piece of three-eighths brass or fiber tubing with a quarter-inch hole, or may be a piece of the same size material with the hole drilled. This tube should be a tight fit for the hole in the panel, and the inside of the hole in the panel should be well soaked with glue before driving in the tube.
The spring, as shown in the insert, has a fork formed on one end to fit the slot, and is bent to pull in on the rod. The spring is fastened to the inside of the panel by screws, as shown, and the con- necting wire is best soldered to it.
Contributed by C. S. ROBINSON.
IMPROVING THE SINGLE WIRE AERIAL.
I have found that when using a single wire aerial about two or three hundred feet long, the sending range is increased by sus- pending as many wires as possible from the single horizontal wire. These vertical
mproving the Single Wire Antenna.
wires may be slid along the .horizontal wire by attaching small weights to the ends as shown in the sketch.
Contributed by J. W. HALLIGAN.
A HIGH-VOLTAGE BATTERY FOR AUDIONS.
The average high-voltage battery for the audion detector or amplifier consists of either flashlight batteries or dry cells.
The battery here described is a good deal cheaper than either of the above and, what is more, most any experimenter can readily make one.
First buy enough raw copper and zinc (any gauge will do) to make between 25 and 60 pieces of both copper and zinc, each \y2 inches by Y<\ inch. The same number of sheets of the same size should be made out of common white blot- ting paper. The base should now be made of fiber, and fiber blocks should be made (B-l and B-2), so that when fastened with screws near the top of the bare the copper, blotter and zinc couples will just fit in be- tween them. The tighter they are the bet- ter. The galvanic couples should now be put in place in this order : zinc, blotter, cop- per ; zinc, blotter, copper, and so on until they are all fitted in place. Each couple yields about one volt. The voltage control knob should be mounted at the bottom of the base and a narrow, tapering, knife- edge switch blade attached to same. Five cents' worth of 10 per cent, solution of sul- phuric acid should be obtained and applied to the blotters with a medicine dropper. The switch blade should only touch one element at a time.
An interesting experiment may be made by getting your friend to put the wires
be done away with by having the contacts immersed in oil (paraffin or transit oil). 1 hope this may help some amateurs who
Copper-zinc High Voltage Battery for Audions.
from the two binding posts on ms tongue and then quickly turning the control switch on. He won't get hurt, but he will be con- siderably surprised. Contributed by FRANCIS R. PRAY.
HOW TO FILE COPPER.
Mechanics are frequently called upon to file copper connections, in wiring switch- boards particularly. When using a file on copper the teeth easily become filled or choked, making the file ineffective in a short time. There are two ways of pre- venting this, says Robert Oster in Elec. Re- view and Western Electrician. One is by using a little chalk on the file teeth ; this prevents the copper filings from adhering and choking up the t:eth. Another method is to use backward strokes of the file for the finishing touches.
If you expect to keep the wire on your tuning coil tight, place it away from the radiators. Heat stretches the wire.
AN OIL-BREAK KEY.
Herewith is an illustration of a key that is very useful for wireless work, and one that can be used with sets of one kilowatt capacity. When the common wireless key gets red hot at the contact points this can
Oil-break Radio Key.
are having trouble in keeping good con- tacts on thei keys.
Contributed by JAMES R. ALLEN.
WHAT A SPIRAL AERIAL CAN DO.
Regarding spiral inside aerials, I am sure there are quite a few amateurs who would like to own a receiving set, but hesitate be- cause they do not like to erect an outside aerial, and I am certain that if the follow- ing directions are carried out successful reception will be accomplished :
The aerial is composed of about two pounds of No. 14 "Antenium" or other wire stretched along a piece of rope in a coil about 14 inches in diameter and the turns spaced about 3y2 or 4 inches apart. The rope is insulated at each end with a porcelain cleat and also supported in the center in the same way.
It can be located in the garret of any wood or brick dwelling, provided the roof is not tin and the lead-in wire runs on porcelain knobs to any part of the house; of course running this wire in as straight a line as possible.
The antenna should be at least 25 feet high and 50 feet long. All dimensions given herewith are the same as those used by the author, and with a three slide tuning coil 3,000-ohm head, set, fixed condenser, vari- able condenser, galena detector, and load- ing coil Arlington can be copied every night during the favorable months of the year, as well as all the commercial and amateur stations in and about Detroit at all times.
Contributed by H. P. HARDESTY.
VARIABLE INDUCTANCE FOR TRANSFORMERS.
The drawing herewith and the descrip- tion which follows is of a variable induct- ance to be used in transformer circuits, etc. Wind around a 1-inch square brass tube, 6 inches long, about 100 turns of No. 14 D. C. C. wire. Fasten this to a wood base and then construct a laminated sheet iron core that will slide in and out of the brass tube. The iron laminations may be riveted to form a compact core.
Finely Adjustable "Choker" for Transformer.
This can be done by hand or by means of a screw for fine regulation. Contributed by
CHASE HUTCHINSON.
102
THE ELECTRICAL EXPERIMENTER
June, 1916
m Q2N5TRUQT2R
A Practical Portable Wireless Set
NOW that summer is in sight, the pro- gressive radio amateur is making ready for experiments with portable eauipment. Unfortunately, too many sets are made of extra, or discarded instru- ments. For this reason, the results which
Fig. I, Appearance of Completed Radio Sending and Receiving Set. Sending Range i to 5 Miles. Has Received 300 Miles and is Capable of Much Finer Work.
many experimenters have obtained were far from satisfactory. Although it is possible to receive a considerable distance with sim- ply a pair of receivers and a detector, with a large aerial, practical work with portable apparatus requires a set of high efficiency. At the same time, the outfit must be simple, to be compact and easily carried. _ The set described in this article was designed for use with a single wire aerial, 150 to 200 feet long, 20 feet high at each end. This aerial will not emit a wave of 200 meters, but the spark-coil is so small that it will comply with the law. The complete ap- paratus, including the battery and carrying- case, weighs only fourteen pounds.
Sending Set. The general dimensions of the carrying case may vary slightly, but this set is designed for a standard size suit case, the cost of which is only $3.00. Fig. 1 gives a general idea of the appearance of the completed outfit. On the panel at the right are mounted the controls for the re- ceiving instrument and the sending key. In Fig. 2, A is a galena detector ; B, B the primary switches ; C, the secondary switch ; D, the buzzer-test switch ; E, the variable condenser, and F, F, the binding posts for two pairs of receivers. As will be explained later, no coupling variation is
By Milton B. Sleeper
needed. A buzzer and battery are mounted beneath the panel, Fig. 2. A fixed con- denser is fastened inside at the back.
The left hand panel c rries the spark- gap, G, primary circuit ammeter, H, change-over switch, I, antenna and ground connections, J, while the vibra- tor of the spark coil, K, pro- trudes into the compartment allowed for the phones. In the case are the batteries and sending condenser. If it is de- sired, an auxiliary battery may be connected to the binding- posts L.
The wooden frame upon which the panels are fastened, is made of pine or white wood. When this set was built the pieces were cut from one long strip, 4 inches wide and ^-inch thick. Fig. 2 gives the length of the pieces.
Although binding-posts are provided at the left of the sending panel, Fig. 1, for the connection of an extra battery, a space is provided in the case sufficient for holding 6 flash- light batterys of 4J/2 volts each. These when connected in paral- lel have sufficient power to op- erate the spark-coil for a con- siderable length of time. It is more satisfactory, however, to carry a separate battery box holding 6 large-size dry cells. The ammeter is to register the current supply in the primary circuit and is always connected in series with the battery and coil. For convenience, the send- ing key is mounted at the right. It may be necessary to shorten the lever, but this really im- proves the action of the key.
A code chart, list of abbreviations, or any necessary information can be fastened to the cover. There is room enough to lay a pad of paper on the top when the case is closed.
In communicating up to one mile, a half- inch coil is large enough. The coil used with this set is of the Bull Dog type. This is most convenient, as the tube enclosing the coil can be inserted through a hole in the wooden case. This leaves the vibrator screw where it can be easily adjusted.
A plate-glass condenser, C, connected in shunt to the coil, Fig. 3, greatly increases the sending range. Four glass plates, 5x3^2 inches are needed. The three tin-foil plates are 4x2^ inches. Small wooden strips, V\y^A inches hold the condenser in place. It improves the insulating qualities to coat the complete condenser with wax.
The spark-gap, G, is of the conventional type. A thread. in the front binding-post makes the adjustment finer than when the movable electrode simply slides in and out. Ordinarily, the gap is not more than 1/32 inch long, as the condenser and the con- nection of the aerial and ground greatly reduce the usual 34-rnch spark developed by the coil.
All wiring, both for the sending and re- ceiving instruments must be of rubber-cov- ered, high-tension cable, to prevent any sparking, due to the small spacing between the wires in the case. A relay, in series with the battery circuit can be used to dis- connect the receiving instruments while sending. This requires an anchor gap in the ground lead. A double-pole, double- throw switch, Fig. 1, is more satisfactory, however. A hard rubber auxiliary base was used with this set, although it is not necessary.
Receiving Set. The most unusual part of the receiving apparatus is the loose-coup- ler. No variation in the coupling is pro- vided. The tuning, however, is extremely
Layout of Sending and Receiving Apparatus to Fit Into Small Suit Case.
June, 1916
THE ELECTRICAL EXPERIMENTER
sharp, while the signals are much louder than with an ordinary receiving transform- er. Unlike most loose-couplers, the prim- ary coil is on the inside. This is composed of a single layer of No. 26 single cotton- covered wire, wound on a tube 5 inches long by 3 inches in diameter. Fourteen taps are taken off, beginning at the left, every fourteen turns. Then seven taps are taken every two turns. All wires go to the inside of the coil, through small holes in the tube. Antenna and ground connections are made to the switch blades.
easily adjusted, and does not jar out quick- ly- Some form of fixed condenser, fastened inside the case, must be connected across the receiver binding posts. Connections are provided for two pairs of phones. For only one pair, connections are made to the out- side posts.
Fig. 5 shows the buzzer test. A flash- light battery, held by two screws under the spring contacts, supplies current for the buz- zer. A high pitch is most easily obtained by gluing a sliver of wood under the con-
Wiring Diagram and Buzzer Test Arrangement in Portable Radio Set
A layer of writing paper or empire cloth, over the primary winding, separates it from the secondary. The same size wire is used for both coils. This may seem unadvis- able, if the two circuits are to be brought to resonance. As a matter of fact, the var- iable condenser in shunt with the secondary makes up for the capacity added to the primary by the antenna. Only five taps are taken from the outer coil; sharp tuning is made possible by the variable capacity. A layer of heavy empire cloth over the coil protects the wire from rubbing against the connections and carrying-case. _ In the photograph, the upper left-hand switches are for the primary, while the right-hand switch is for the secondary.
Fig. 4 shows a new method of fastening the wires in a simple way, to prevent the connections from being twisted off by the constant turning of the handles. The wire is formed into a loop to fit around tLe shaft. Over this a piece of spring brass, bent in the shape of a bow, is placed. This spring serves the purpose of holding the contact against the switch points, and of protecting the connection. Two washers, under the nuts, make the action smoother. Fig. 2 gives the dimensions for the switches.
A rotary variable, condenser gives the close tuning adjustment of the secondary circuit. This is an ordinary 43 plate type, with the case removed. A hole in the hard rubber panel admits the plates ; the instru- ment is held by machine screws from be- neath. The tuning is so sharp that a slight variation of the capacity will bring a sta- tion in or out.
The detector used with this set is ex- tremely simple, although a..j type can be used. It consists only of an adjusting handle, held in a binding post. At the end of the shaft a fine piece of phosphor bronze wire is clamped by two nuts. The detector cup, holding a piece of ''Radiocite" rotates in a trough-shaped slide. This detector is
tact of the armature The two-point switch controls the buzzer-operation.
OPERATION.
If a battery is put in the case, it is only necessary to carry, exclusive of the set, two hundred feet of aerial wire and some form of ground connection. An excellent coun- terpoise consists of ten wires, twenty feet long, fastened together so that they can be extended radially. The ground connection is taken from the center. If the set is used on moist earth, however, an iron rod, driven three feet into the ground, will be satis- factory. A reel can be used to hold the two hundred feet of aerial wire and the counterpoise. If possible, the aerial should be stretched between trees ; poles are awk- ward to carry. With a two hundred foot aerial, twenty feet high, the government sta- tion at Radia, Va., was easily copied from New York City, a distance of 275 miles. Longer distances, however, can be covered. The one-half inch • rk coil is large enough to send two miles, or even five to ten miles if an audion detector is used at the other station. The weight of the set, fourteen pounds, makes the set extremely portable. The cost of the entire outfit was only fifteen dollars, low enough to bring it within the reach of every wireless club and Boy Scout troop. Even though the set requires a little careful workmanship, it is far more prac- tical than the little pocket sets, of which ex- perimenters are so fond.
[Editor's Note : We will be glad to fur- nish any experimenters or wireless clubs unth the names of the manufacturers of the individual or complete apparatus.]
divided by resistance (R) equals current in amperes (7) ; electromotive force divided by current gives the resistance, and resist- ance multiplied by current shows the elec- tromotive force traversing a circuit. So simple, says R. M. Telschow, in Telegraph and Telephone Age, yet so elusive to all students. Science is built around exact for- mulas and processes, and you can scarcely hope to lay the foundation of a successful career by haphazard methods. So you start all over again, and deepen the furrows made in your fertile brain area by previous efforts.
It may be that the writer is a natural dul- lard, for these initial principles proved very elusive. Finally, however, the unwilling factors were successfully harnessed, and the trite word "Erie" proved the happy medium.
Henceforth E-r-R=I, -E+I=R and Ry_I=E was simply a matter of men- tally looking at the magic word "ERIE." Reading it E-i-R=I gave me formula num- ber one; backwards, E-^-I—R; and for- ever unforgettable was the multiplication of the central letters R and / whose prod- uct was the E on either side of the multi- plied factors. Thus, doubt departed for- ever with the introduction of the "Erie" short cut. Truly a case of "multum in parvo."
EXPERIMENTAL CHEMISTRY.
(Continued from page no)
THE METRIC SYSTEM.
How the table is made up:
Divide a meter into ten equal parts. One of these parts is a DECIMETER.
If a decimeter is divided into ten equal parts, each one of these parts is one CENTIMETER.
If a centimeter is divided into ten equal parts, each one of these parts will represent one MILLIMETER.
Ten METERS make one DEKAMETER.
Ten DEKAMETERS make one HECTOMETER.
Ten HECTOMETERS make one KILOMETER.
Ten KILOMETERS make one MYRIAMETER. TABLE
10 Millimeters 10 Milligrams 10 Milliliters 10 Centimeters 10 Centigrams 10 Centiliters 10 Decimeters 10 Decigrams 10 Deciliters 10 Meters 10 Grams 10 Liters 10 Dekameters 10 Dekagrams 10 Dekaliters 10 Hektometers 10 Hektograms 10 Hektoliters 10 Kilometers 10 Kilograms 10 Kiloliters
USEFUL METRIC TABLES 1 inch equals 1 Centimeter
|
(m.m.) (surface) 1 |
Centimeter |
(c. m.) |
|
|
(m. g.) (weight) 1 |
Centigram |
(c. g.) |
|
|
(m. 1.) (liquid) |
1 |
Centiliter |
(c 1.) |
|
(c. m.) |
1 |
Decimeter |
(d. m.) |
|
(c. g.) |
1 |
Decigram |
(d. g.) |
|
(c. 1.) |
1 |
Deciliter |
(d. 1.) |
|
(d. m.) |
1 |
Meter |
(M) |
|
(d. g.) |
1 |
Gram |
(G) |
|
(d. 1.) |
1 |
Liter |
(L) |
|
(M) |
1 |
Dekameter |
(D.m.) |
|
(G) |
1 |
Dekagram |
<D. g.) |
|
(L) |
1 |
Dekaliter |
(D. 1.) |
|
(D.m.) |
1 |
Hektometer |
(H.m.) |
|
(D. g.) |
1 |
Hektogram |
CH. g.) |
|
(D. 1.) |
1 |
Hektoliter |
(H. 1.) |
|
(H.m.) |
1 |
Kilometer |
(K.m ) |
|
(H. g.) |
1 |
Kilogram |
(K. g.) |
|
(H. 1.) |
1 |
Kiloliter |
(K. 1.) |
|
(Km.) |
1 |
Myriameter (M.m.) |
|
|
(K. g.) |
1 |
Myriagram |
(M. g.) |
|
(K. 1.) |
1 |
Myrialiter |
(M. 1.) |
If you have made any really new appa- ratus, photograph it and send us a descrip- tion. It will pay you.
HOW TO REMEMBER OHM'S LAW.
Textbooks state that electromotive force (or volts) designated by the symbol E,
2.54 centimeters
(Approx. 2.5 cm.) 0.3937 inch
(Approx. 0.4 inch) 1.000 cubic centimeters 0.2642 gallon 1.057 quarts 0.473 liter 0.946 liter
29.57 cubic centimeters 3.7 cubic centimeters
cubic centimeter of water
0.035 ounces
(Avoirdupois) 15.43 grains 28.35 grams 1.000 grains 2.2 pounds 1,000 kilograms 2.205 pounds
In our July issue Mr. IVilsdon will give us chemical definitions and he will show us hoiv to perform simple chemical experi- ments.— Editor.
1 liter
1 liter
1 liter
1 pint
1 quart
1 fluid ounce
1 fluid dram
The gram is the unit of 1 at 4 degrees Centigrade. 1 gram enuals
1 gram 1 ounce 1 kilogram 1 kilogram 1 Metric ton 1 Metric ton
104
THE ELECTRICAL EXPERIMENTER
June, 1916
AN ELECTRIC PUP THAT HEEDS YOUR CALL.
Here is an electric pup that will surely interest every electrical experimenter, not to mention his small brother or sister, as well as the rest of the family. All you have to do to call out his "reverence, the pup" from his kennel is to speak to him or blow a whistle. Electricity serves as the modus operandi. The pup himself is
This Electric "Pup" Comes Forth at Your Call.
about 4 to 5 inches long and about 3 inches high, being cut from wood on somewhat of a Cubist pattern. This wooden dog is made so as to slide along the floor of the kennel and out of the opening in the front of same.
The electrical apparatus operating this remarkable "hound" is perceived at A, B, C and D (Fig 1). A is a small electro- magnet about the size of an ordinary 75- ohm telephone receiver spool and wound Jull of No. 26 insulated copper magnet wire. This is secured to the back of the coop by means of a screw fitted into the iron yoke of same, as indicated more in detail at Fig. 3. A rather stiff iron or soft steel spring B is supported on the tapered wooden block D. The position of this spring when not held down by the electro-magnet A is shown at Fig. 5, and, as becomes evident, if released quickly so as to assume the
Magnet co/t
Details of Electrical Apparatus Actuating the Electric "Pup" Outfit.
position there depicted it will propel the pup forward and out of the kennel.
Below the block D is mounted a small tin can, such as those used for shoe polish. A hole is cut through the top to permit
the entrance of a steel wire I. This wire does not touch the tin box C at the low- er extremity J, Fig. 4, where a small graphite bob serves to hold it in very close proximity to the diaphragm K, which is at the same time the top of the box. A spring M helps to release the iron armature B. In the operation of the apparatus all of the parts must be adjusted carefully, so that the armature will just hold against the electro- magnet faces at A. A brass rivet mounted in the center of the disc B helps to render the magnet quick releasing.
A small flashlight battery placed within the miniature dog- house operates the device in good fashion. Its action depends upon the fact that when a certain whistled note or voice sound im- pinges against the diaphragm K of the tin box C it causes same to vibrate; in so doing it makes and breaks the electric circuit as outlined at Fig. 5. The slight- est variation in the strength of the circuit causes the electro- magnet to release the spring B which must be reset by hand. The whole arrangement will now be thoroughly understood. It is best to have the diaphragm K tuned to some certain note and use a whistle or pitch pipe of this same note to call forth the pup from his domicile. In most cases clapping the hands once will bring him forth in a jiffy.
This "Wireless Pup" is now regularly manufactured by an Eastern manufacturer. A sample in possession of the editor works so well that the pup will jump from the kennel if a whistle is blown 15 feet away from the pup.
A SMALL LEAD
STORAGE BATTERY.
A small lead storage battery can be made by putting two sheets of ordinary lead in a glass battery jar containing a dilute so- lution of sulphuric acid. To charge this battery connect the lead plates in series with an ammeter and a dry battery of four cells, giving about six volts pres- sure. While the current is passing, bubbles of gases will rise from each plate. After a few minutes, if the circuit is discon- nected and the two wires attached to the lead plates are touched to a voltmeter, the meter will show a pressure of about two volts. If these wires are then connected in series with the ammeter and a small electric bell, the bell will ring, and the de- flection of the ammeter needle will show the current to be passing in opposite di- rection to that used in charging the bat- tery. When lifted out of the solution after charging the positive plate will be found to be colored brown, due to a coating of lead peroxide, while the negative plate will retain its usual gray color.
DEMONSTRATING EFFECT OF HEAT ON MAGNETISM.
A paper presented before the Societe de Physique recently by M. Cotton cited the rapid disappearance of the magnetism of iron at a red heat, and he illustrated this action by an experiment in which the effect was readily seen. A long aluminum tube is arranged so as to swing freely from a pivot support at the top end, and means are provided to limit the swing by a stop piece. At the lower end of the tube h a ■curved platinum wire carrying a sheet-iron plate at one end. The device is placed near the poles of a strong magnet, so that the tube or pendulum swings toward the
magnet, owing to the attraction exerted on the iron plate, and the pendulum is thus drawn to the limit of its swing. The flame of a large Bunsen burner, or other source of heat, is placed so as to entirely sur-
Assembly of the Electric "Pup" in His Kennel.
round the iron plate when in this position, and when the latter reaches a red heat it loses its magnetic properties and ceases to be attracted, so that the pendulum now falls down to the zero position.
When the iron plate cools down it re- sumes its magnetic properties and is agaia attracted by the magnet, so that the plate enters the flame and becomes heated, and so on. In this way the pendulum is made to keep up a constant swing. On this prin- ciple the loss of magnetism by heat can be made the basis of a device which furnishes motive power, though in a small amount in the present case. It is an interesting ex- periment and upon such apparently non- important physical effects our whole elec- trical industry and science is based.
Stop
ii
K
sP/VOt
Magnet
tleot
Bunsen burner — -
Demonstrating the Effect of Heat on Magnet ized Iron.
An electric light is now made small enough to be attached to the ordinary dry battery cell. It will give a strong beam of light for several hours.
June, 1916
THE ELECTRICAL EXPERIMENTER
MAKING A MOVING COIL RELAY.
Many experimenters are in need of a very sensitive relay; one that is more re- sponsive than the polarized type. The com- mercial instrument is beyond the means of
Sensitive Relay Constructed from Moving Coil Type Measuring Instrument.
the average experimenter, financially and mechanically.
Anyone having a moving coil type of Weston voltmeter or ammeter can make a very sensitive instrument. This instrument compares very favorably with high-resist- ance telephone receivers for detecting small currents.
The instrument shown in the picture gave a large deflection on .2 milliamperes. An old dry cell whose E.M.F. was about 1 volt (as it was polarized), operated the relay through more than 5,000 ohms resistance.
The case and scale should be removed from the meter and a suitable hardwood base prepared, with holes bored to corre-
fig!
Det0//orcaw/er\
fig. 2
Details of Moving