Part 4
My heartiest thanks for your letter of October 17th and for the copy of my first photograph by radio. I appreciate it more than I can easily say, and think it is a perfectly marvelous piece of work under the circumstances. Also it is more than pleasant to have it from you, in view of our long association, and so beautifully mounted.
With renewed appreciation, and heartiest thanks for all the trouble you took in getting it up.
Sincerely yours,
Gifford Pinchot
[Illustration: 1339–1351 DIVERSEY PARKWAY CHICAGO December 21, 1923. Mr. C. Francis Jenkins, Radio Pictures Corporation, Washington, D.C. Dear Mr. Jenkins: I was delighted to receive your letter of the 19th. Heartiest congratulations on making such wonderful progress with the Radio Pictures. I am sure that I am going to be one of those fellows who can proudly say “I knew him when—”. With all good wishes for a Merry Christmas and a Happy New Year, I am, Sincerely, Rothacker Film Mfg. Co. W. R. Rothacker WRR:GLD]
1339–1351 DIVERSEY PARKWAY
CHICAGO
December 21, 1923.
Mr. C. Francis Jenkins, Radio Pictures Corporation, Washington, D.C.
Dear Mr. Jenkins:
I was delighted to receive your letter of the 19th. Heartiest congratulations on making such wonderful progress with the Radio Pictures. I am sure that I am going to be one of those fellows who can proudly say “I knew him when—”.
With all good wishes for a Merry Christmas and a Happy New Year, I am,
Sincerely,
Rothacker Film Mfg. Co.
W. R. Rothacker
WRR:GLD
[Illustration: EASTMAN KODAK COMPANY ROCHESTER, N.Y. February 18, 1924. Mr. C. Francis Jenkins, Washington, D.C. Dear Mr. Jenkins: I am in receipt of your letter of February 6th enclosing the copies of photographs sent by radio. Your feat seems marvelous to me and I heartily congratulate you upon its accomplishment. With kindest regards, I am, Sincerely yours, Geo Eastman]
EASTMAN KODAK COMPANY
ROCHESTER, N.Y.
February 18, 1924.
Mr. C. Francis Jenkins, Washington, D.C.
Dear Mr. Jenkins:
I am in receipt of your letter of February 6th enclosing the copies of photographs sent by radio. Your feat seems marvelous to me and I heartily congratulate you upon its accomplishment.
With kindest regards, I am,
Sincerely yours,
Geo Eastman
[Illustration: 'WILLIAM]
W. J. Bryan'
WILLIAM JENNINGS BRYAN VILLA SERENA MIAMI, FLORIDA
July 29, 1924.
Mr. C. Francis Jenkins, 1519 Connecticut Avenue, Washington, D.C.
Dear Mr. Jenkins:
I thank you for the Radio Photograph—it is wonderful! What is there left to be discovered?
Appreciating your friendly interest, I am,
Very truly yours,
W. J. Bryan
[Illustration: Department of Commerce OFFICE OF THE SECRETARY WASHINGTON February 1, 1924. Mr. C. Francis Jenkins, 1519 Connecticut Avenue, Washington, D.C. Dear Mr. Jenkins: I wish to express my appreciation for the photograph which you so kindly sent me. It represents a very startling development in radio and sometime when I have some leisure I would be interested in discussing the method with you. Yours faithfully, Herbert Hoover]
Department of Commerce OFFICE OF THE SECRETARY WASHINGTON
February 1, 1924.
Mr. C. Francis Jenkins, 1519 Connecticut Avenue, Washington, D.C.
Dear Mr. Jenkins:
I wish to express my appreciation for the photograph which you so kindly sent me. It represents a very startling development in radio and sometime when I have some leisure I would be interested in discussing the method with you.
Yours faithfully,
Herbert Hoover
[Illustration: CARL AKELEY 77TH STREET AND CENTRAL PARK WEST NEW YORK CITY March 16, 1925. Dear Mr. Jenkins: You are perfectly welcome to publish anything I may have written you. I think few people realize or appreciate the practical possibilities of the transmission of radio photographs and the high development to which you have brought this art. I congratulate you on your success and wish a speedy realization of your dreams. Sincerely yours, Carl Akeley Mr. C. Francis Jenkins Jenkins Laboratories 1519 Connecticut Avenue, Washington D C]
CARL AKELEY 77TH STREET AND CENTRAL PARK WEST NEW YORK CITY
March 16, 1925.
Dear Mr. Jenkins:
You are perfectly welcome to publish anything I may have written you.
I think few people realize or appreciate the practical possibilities of the transmission of radio photographs and the high development to which you have brought this art. I congratulate you on your success and wish a speedy realization of your dreams.
Sincerely yours,
Carl Akeley
Mr. C. Francis Jenkins Jenkins Laboratories 1519 Connecticut Avenue, Washington D C
The First Radio Channel
While perhaps not singly applicable to the subject of pictures by radio, it is certain that without the discovery that signals could be transmitted through the air without wires, we should not now have either audible or visual radio.
While in 1832 Professor Joseph Henry discovered that electrical oscillations could be detected a considerable distance from the oscillator, it remained for a dentist, Dr. Mahlon Loomis, of Washington, D. C., to actually send the first radio messages. In 1865 he built an oscillating circuit, and connected it to a wire aerial supported in the air by a kite. One station was set up on the top of Bear Den Mountain, in Virginia, not very far from Washington; a duplicate station being set up on top of Catoctin Spur, some fifteen miles distant.
Messages were sent alternately from one station to the other station, by dot-and-dash interruption of a buzzer spark circuit; while reception was attained by deflecting a galvanometer needle at the station which was at the moment receiving.
In _Leslie’s Weekly_ (1868) Frank Leslie personally describes these “successful experiments in communication without the aid of wires.”
Later (1869) a bill was introduced in the U. S. Congress to incorporate the Loomis Aerial Telegraph Company (though nobody would buy the stock, and it remained for others, years later, to reap the reward of radio broadcasting).
In speaking on the bill, Senator Conger repeated, he said, the explanation that Dr. Loomis made to him, that—
[Illustration:
This Illustration of Dr. Mahlon Loomis’s Wireless Telegraph Set Was Made from His Original Drawings of His Invention Which Are on File in the United States Patent Office at Washington. ]
“The system consists of causing electrical vibrations, or waves (from the kite wire aerial) to pass around the world, as upon the surface of some quiet lake into which a stone is cast one wave circlet follows another from the point of disturbance to the remotest shores; so that from any other mountain top upon the globe another conductor which shall receive the impressed vibrations may be connected to an inductor which will mark the duration of such vibration, and indicate by an agreed system of notation, convertible into human language, the message of the operator at the point of first disturbance.”—_From Congressional Globe, Library of Congress._
Perhaps it may be a coincidence, or perhaps a blood strain of the pioneer, that the first radio school ever set up by a woman should have been founded by his granddaughter, Miss Mary Texanna Loomis, Washington, D. C.
[Illustration: [Photographs]]
Nipkow and Sutton
One of the most interesting examples of the attempts to see by radio was made the subject of a patent by Nipkow in 1884. The proposed transmitter consisted of a selenium cell and an objective lens, with a spirally perforated disc rotating between the cell and lens “to dissect the scene.”
The receiving device employed the polarizing light valve used by Major George O. Squire, and Professor A. C. Crehore, to measure the flight of gun shells at Fort Monroe, Virginia, in 1895.
The Nipkow scheme was preceded by Shelford Bidwell’s device for “the telegraphic transmission of pictures of natural objects,” described in _Telegraphic Journal_ 1881, Vol. 9, page 83; and later almost exactly duplicated by M. Henri Sutton, and rather fully described in _Lumiere Electrique_, Vol. 38, page 538, 1890.
[Illustration: [Machines]]
The Amstutz System
Of all the mechanisms which have been designed for the transmission of pictures electrically, that of N. S. Amstutz, of Valparaiso, Indiana, U. S. A., in the author’s opinion, stands out as the most conspicuous, not only for fine work, but for the cleverness of its accomplishment, the first successful picture being sent in May, 1891, over a 25-mile wire in eight minutes.
“Mr. Amstutz was not the first to send pictures over wire, but he was the first to send pictures with halftones, the others were simply line drawings. In this first method Mr. Amstutz used a relief photograph. The amount of relief was in direct proportion to the amount of light which had acted on the sensitive gelatine, resulting in an irregular surface, representing in elevation all the variations of light and shade in a regular picture.
“The picture received is actually a phonographic spiral around the receiving drum carrying the celluloid sheet. When finished it is removed from the cylinder and flattened out and a stereotype or electrotype made from it for relief printing; or the engraved celluloid sheet can be inked and printed immediately on the intaglio press.” (_From exhibit in U. S. National Museum._)
[Illustration: THIS PICTURE WAS TAKEN FROM THE RECEIVING MACHINE AFTER HAVING BEEN TRANSMITTED EIGHT HUNDRED MILES OVER A TELEGRAPH WIRE. THE INTERNATIONAL ELECTRO-GRAPH CO. NOV. 1ST, 1900. CLEVELAND, O.]
THIS PICTURE WAS TAKEN FROM THE RECEIVING MACHINE AFTER HAVING BEEN TRANSMITTED EIGHT HUNDRED MILES OVER A TELEGRAPH WIRE.
THE INTERNATIONAL ELECTRO-GRAPH CO.
NOV. 1ST, 1900. CLEVELAND, O.
The Electrograph
From the accompanying illustration and title it will readily be seen that rather good pictures were reproduced with pen and ink method in 1890.
The original of this picture was given the author by Mr. T. A. Witherspoon, who at the time of the experiment (1900) was a principal examiner in the U. S. Patent Office, and detailed in charge of the Patent Office Exhibit at the Buffalo Exposition, where, also, these machines were on exhibition.
It may be a coincidence of passing interest that from Cleveland twenty-four years later the American Telephone and Telegraph Company sent their first wire pictures.
[Illustration: 1910.—Baker. 1. PHOTOGRAPH WIRED FROM PARIS TO LONDON]
The Baker Machine
The machine of the opposite illustration, “the telestereograph,” is the invention of T. Thorn Baker, Esq., of England, and “was used by the _London Daily Mirror_ in July, 1909, and was worked by wire rather regularly between London and Paris, and London and Manchester.” The picture to be sent was “a halftone photograph printed in fish glue on lead foil, and wrapped on a sending cylinder, rotating once every two seconds with a metal point riding on it.”
The receiving cylinder carried “an absorbent paper impregnated with a colorless solution which turns black or brown when decomposed by the incoming electric current.”
What electrolytic solution was employed is not stated in the report, but was probably sodium iodide or potassium bromide judging from the description of its color and behavior.
To synchronize, the receiving drum turns faster than the sending drum, and is caught each revolution until the other catches up. (_Smithsonian Report_, 1910.)
[Illustration: 2. FASHION PLATE TRANSMITTED BY PROFESSOR KORN’S TELAUTOGRAPH.]
2. FASHION PLATE TRANSMITTED BY PROFESSOR KORN’S TELAUTOGRAPH.
The Dr. Korn Machine
The accompanying illustration shows the work of a machine developed by Dr. Korn, of Germany, and first used by the Daily Mirror between London and Paris in 1907. “On a revolving glass cylinder” a transparent picture was put. He used a Nernst lamp and “selenium cells on opposite sides of a Wheatstone bridge” to overcome the inherent lag of the selenium cell.
Signals were sent over a wire and received on photographic film on a cylinder, using “two fine silver strings free to move laterally in a strong magnetic field.” A light was focused on the obstructing “silver strings,” which the incoming electric signals, passing through the “strings,” separated to a greater or lesser degree “to widen or thin the photographed line.”
“When the film is developed it is laid out flat, and the spiral line becomes resolved into so many parallel lines.” The sending and the receiving machines were synchronized by “well calibrated clocks which released the cylinders at end of every five seconds.” (_Mr. Baker in Smithsonian Report_, 1910.)
[Illustration: [Machines]]
Rignoux and Fournier Scheme
One of the early suggestions had for its fundamental principle a surface studded with thousands of “selenium cells” each a part of an individual circuit, and upon which a picture was projected. The idea was that the different cells would transmit a different value of current with each different intensity of light which made up the picture.
At the distant station a given surface had a corresponding number of tiny lamps, each attached to its respective cell at the sending station, and being lighted thereby the ensemble would reproduce the distant picture.
The scheme is possible but hardly practical, for if only fifty lines per inch each way were sufficient on a picture but one foot square, there would have to be three hundred and sixty thousand cells at the sending end, and a like number of lamps at the receiving end, each but one-fiftieth of an inch in diameter. Such a problem would seem to present difficulties, though the author himself in the bravery of ignorance suggested this very scheme in the _Electrical Engineer_, of July 25, 1894. (_Illustration by courtesy of Science and Invention._)
[Illustration: [Machines]]
The Belin Machine
The “Belinograph” is the invention of Edouard Belin, of Paris. With these machines “the first step in transmitting a picture is to convert the latter into a bas-relief. Or a drawing can be made in a special ink, which, when dry, leaves the lines in relief. The picture when ready for transmission has an uneven surface, the irregularities of which correspond with the pictorial details. The transmitter resembles the cylinder of a phonograph. The picture is wrapped around this metal cylinder, and a style presses down on the picture cylinder as it is rotated by clockwork. As the style moves up and down over the irregularities of the picture, a microphone varies the strength of an electric transmitting current.
“At the receiving end another cylinder in a light-tight box carries a sensitized paper upon which a point of light is reflected from the mirror of a galvanometer actuated by the incoming current from the distant station.”
Two very accurately regulated chronometers are employed to keep the machines in synchronism, one chronometer for the sending machine and one for the distant receiving machine. (_From Review of Reviews_, 1922.)
[Illustration: [Photographs]]
American Telephone & Telegraph Company Machine
The picture opposite is one of those sent by the A. T. & T. Company on May 20, 1924, by wire from Cleveland to New York. Some of the pictures sent were from photographs taken earlier, and some were taken only a few minutes before being transmitted.
In the sending machine, “the film picture is inserted in the machine simply by rolling it up in a cylindrical form and slipped into the drum. During operation a very small and intense beam of light shines through the film upon a photo-electric cell within.”
In the receiving machine, “the sensitive film is put on a rotating cylinder and turns like the cylinder record on a phonograph. On this film falls a point of intense white light varied constantly.”
For synchronizing “two separate currents were sent over the wires, one is called the picture channel, the other the synchronizing channel.”
“Forty-four minutes elapsed from the time the picture was taken in Cleveland until it was reproduced in New York.” (_New York Times, May 20, 1924._)
It seems unlikely that returns from the daily wire transmission of pictures can equal the day-by-day revenue from the wires used for the transmission of speech when balanced up for the principal circuit, phantom circuits, and carrier circuits.
[Illustration: [Photographs]]
Radio Corporation Machine
The accompanying “photoradiogram” is a development by the Radio Corporation of America, and was transmitted from London to New York on November 30, 1924.
“The transparent picture film is placed on a glass cylinder. An incandescent lamp inside the cylinder is focused in a minute beam onto the film as the cylinder rotates, and this transfers the light values of the picture into electrical impulses, in a General Electric Company photo-electric cell.
“The receiving cylinder has white paper placed thereon, and the incoming dots-and-dashes, amplified in passing through a bank of vacuum tubes, are recorded in ink on this paper with a special vibrating fountain pen, drawn down by magnet coils to record the picture much in the style of an artistic stippled engraving.” The cylinders of both the sending and the receiving machines are “rotated back and forth, the electric camera itself advancing down the length of the picture one notch at a time.”
“The necessary synchronism of the two machines is maintained by the use of special driving motors, and a special controlling mechanism based on the constant pitch of a tuning fork.” (_See Radio News, February, 1925._)
[Illustration:
By courtesy of “The World,” New York.
A RADIO CODED PHOTOGRAPH.
How the picture looked after being sent from Rome by radio and decoded on Professor Korn’s machine. ]
The above is an example of one of the rather odd methods of “sending pictures by radio.” The picture to be sent is divided into many small squares with varying values of dark in the squares. Seventeen different grades of light in these squares are translated into seventeen letters printed on a tape.
This coded picture is transmitted to a distant place and there decoded into dots of sizes corresponding to the seventeen values, and each dot placed in its corresponding square on a white paper. The collection of large dots builds up the dark areas; a similar collection of smaller dots makes up the halftones; and still other collections of very minute dots make up the light areas. (_From the New York World._)
[Illustration: [Photographs]]
A telegraphic code scheme in which points in a picture are determined by the crossing of straight lines, ordinates and abscissas, and in which the shades of light, of gray, and of black which make up the picture are also indicated by letters.
This coded information is telegraphed to the distant stations where the receiving artist determines the location of these points and shades by (1) a similar pair of crossed straight lines, and (2) letters indicating the light values to be washed in on paper.
The process depends for its success largely on the skill and cleverness of the receiving artist, and is hardly more than a “filler-in” pending the adaption of the directly photographic process. (_Courtesy Science and Invention._)
[Illustration: [Schematic]]
The Braun Tube Receiver
One of the theoretically attractive forms of receivers is the Braun oscillograph tube, for it is so very easy to wobble the cathode ray spot about over the fluorescent screen, to form figures. It has an imponderable pencil of light which can be moved over the picture screen with very little electrical energy. Its use has been proposed by many.
But the feature of the system which is most often overlooked in this scheme is the necessity for an analytical picture machine at the sending station, and no such device in satisfactory workable form has yet been suggested.
The Braun tube system awaits, therefore, the attention of the practical-application engineer before it can compete with other forms of receivers.
[Illustration: [Photographs]]
Pictures by Radio in Natural Colors
It is well known that pictures in color are in common use in magazine printing, in window transparencies, decorations, etc. The process consisting in making three negatives, one through a red screen, a second through a green screen, and a third through a blue screen. When transparencies from these three negatives, each stained in its complementary color, red, green and blue, are superimposed and viewed by transmitted light, the resultant picture is seen in its natural colors.
With this process generally well known, it is obvious that three such negatives transmitted by radio or wire could be colored and combined to make a “picture sent by radio in natural colors.” Of course, the picture is not sent in color at all, and the author hesitates to claim for such a feat more than that the resultant picture proves the excellence of the synchronism of the machines employed in the transmission of the three successive pictures which after their reception are to be colored and combined into one.
[Illustration: [Photographs]]
Prismatic Disc Machines
These machines are principally used in radio transmission of photographs; employ four overlapping prismatic discs or “rings” in both the sending and the receiving machines. Either a transparent or an opaque picture is used in the sending instrument; and in the receiving camera a filament lamp, modulated by the incoming radio signals, recorded on a photographic negative plate.
In the sending machine (first illustration) the picture is projected with a magic lantern (1) through four overlapping prismatic rings, (2) two of which in rotation sweep the picture vertically across the light sensitive cell, at the same time the image is moved laterally by the other pair of prisms. The different light values of the picture are changed into electric values in light cell 4, and broadcast. A rotating perforated disc, (3) interposed between the lens and light cell, produces a pulsating direct current which can immediately be amplified through the usual radio transformers, on its way to the broadcasting set.
In the radio camera (second illustration) a photographic negative (1) is used and a pencil of light from lamp 2. The rotating plates (3) draw the lines and the radio signals vary the light intensities of the lamp to give gradations of exposure on the negative plate. (See next page.)
[Illustration: [Photographs]]
[Illustration: [Photographs]]
The Jenkins Prismatic Ring
The prismatic ring or plate is a new contribution to optical science, and was designed for use in a machine for the transmission of radio pictures from a flat surface, and for recording them on a flat surface, the only way in which radio vision and radio movies will ever be produced; and a method which permits of the reception of portraits having true photographic value, without lines, and having tone and shading unequaled by any other known process to date.
The prismatic ring section is ground into the face of a glass disc, and from one end to a point half around it has its base outward, and from this midway point around to the other end having its base inward. The warp from one end to the other is gradual.
A beam of light passing through this ring, in rotation, is caused to oscillate, having its hinged action fulcrumed in the plane of rotation of the prism ring. The oscillation is always in the plane of the diameter of the disc from the point where the light passes through the prismatic ring section.
The plates (made with the initial grinding machine) may have one, two, or four prismatic sections to the ring, and may be made right or left hand, and in 10 inch and in 7 inch sizes, and also in disc ring (first illustration) or band ring form (second illustration).
[Illustration: [Photographs]]
[Illustration: [Photographs]]
Jenkins Synchronizing Forks
The accompanying photographs show a vibrating-fork-control employed to keep distantly separated motors in synchronism. This is the motor control employed in the system developed by the author for the sending and receiving of photographs and photograms, by radio and by wire.
The control unit is surprisingly simple and dependable, and is believed might be found useful for many other purposes where it is desired to keep motors in step with each other which are separated by long distances, the control signals being sent by wire or by radio, and from fixed or moveable stations, on land, on water, or in the air.
The fork illustrated is about fifteen inches long, mounted on a cast brass frame with a bakelite cover plate upon which the fork, motor coil, and binding posts are mounted. A single cell of dry battery keeps the fork in vibration.