Lee de Forest - We are SMPTE · Lee de Forest and the Invention of Sound Movies, 1918-1926 Mike Adams, Professor San Jose State University [email protected] Written for presentation

Lee de Forest

King of Radio, Television, and Film

By Mike Adams

San Jose State University

© 2012 SMPTE · The 2012 Annual Technical Conference & Exhibition · www.smpte2012.org

Lee de Forest

and the Invention of

Sound Movies,

1918-1930

- Biography

- The Vacuum Tube

- The Radio

- The Sound Film

Presented by Mike Adams, San Jose State University


Lee de Forest Bio - The Early Years

Born in Iowa, 1873

Raised in Alabama

Ph.D., 1899

Yale University The “Talking Arc” or Speaking Flame was de Forest’s Talisman

He turned to this at the beginning of each invention:

His “flame” detector

His vacuum tube “Audion” His arc transmitter for radio

His “flame” microphone

His sound-on-film process

His flat panel television

De Forest will enter the new

century with all the scientific

knowledge of the past


What de Forest Knew - the Science of the 19th Century

PHOTOGRAPHY & PHONOGRAPH & WRITING WITH LIGHT

Optics and chemistry for photos Sound vibration recording on wax cylinder Writing sound vibrations on film with light


The Science of the 19th Century

The

“Edison Effect”

Edison notices carbon

deposits inside his light bulb.

Adds a “plate” to “carry off”

electrons. Measures direction

of current flow. The principal

of Thermionic Emission (1880)

Fleming patents the diode

vacuum tube, using it as a detector

of wireless telegraph signals

(1905)

Fleming’s tube uses a

Galvanometer, a meter, to visually

indicate the presence of wireless

dots and dashes

Ambrose

Fleming’s

Valve Detector


From code to audio; science into art

Receiving Wireless:

the de Forest

Audion Detector, 1906

De Forest patents his diode

vacuum tube, also as a detector

of wireless telegraph signals

(1906)

De Forest’s tube uses

Headphones and a 2nd or “B”

battery allowing the dots and

dashes to be “heard” as sound.

This is significant for the future

new medium, the wireless

telephone. De Forest then added

the “grid” for greater

amplification. This was the

Audion Triode

De Forest’s improvements to the vacuum tube will lead to amplification for radio and film


Film begins as science and technology

Early Edison film device and Images, 1890


The language of film is slowly developed - the story

“Great Train Robbery,” 1903, Edison, Porter


Lee de Forest identifies the sound-on-film problems

Pre-de Forest sound films used the phonograph or a selenium cell and headphones

Edison and Dickson experiment

1894

Recording Sound Using Light

Selenium Cell

Bell and Ruhmer, arc and selenium cell




Eugene Lauste 1912

Edison’s final sound experiment

Edison synchronized film and phonograph, 1912


1918: Lee de Forest looks at the current recording and playback devices


The carbon telephone microphone for recording Headphones for listening


19th Century Devices


De Forest Combines his Amplifier and Oscillator for Sound-on-Film

Original notes Oct 1918

vacuum tube amplifier combined optics, chemistry, physics, acoustics


De Forest left hundreds of pages of lab notes and diary entries between

1918 & 1926. His Phonofilm experiments were conducted in his NY Lab

The diary and lab notes show

development in

amplifiers, microphones, loudspeakers,

along

with the device that records and

reproduces

the actual sound-on-film



De Forest collaborates with Theodore Case

Theodore Case

of Auburn NY

Above, the original Case laboratory preserved in Auburn NY

Case was a Fellow Yale Alum

Case and de Forest worked

together from 1920 to 1926


De Forest and Case: the relationship

Case supplied

the two most

important parts

of the de Forest

sound-

on-film system

Case and de Forest worked together from 1920 to 1926

Above, photocell (Thalofide) reads light

variations,

Below, tube (AEO light) converts sound to light


De Forest and Case: Who gets the credit? Why?

Case wanted credit for his contributions. De Forest received most of

it


De Forest Patented a Complete Phonofilm System Inside the Phonofilm

Studio a Condenser Mic?

The Camera is a Modified

Bell & Howell


Lee de Forest and Theodore Case make films

Both de Forest, and later Case, made films to promote their process


Lee de Forest Presents to the SMPE, 1923

De Forest gave credit to those

scientists of the past whose work

led to his sound-on-film success


Audion Amplifier + Audion Oscillion = Sound-On-Film

“It was not difficult to construct a gas-filled tube giving such a light

when excited by a high frequency current from a small

radiotelephone transmitter.” SMPE Paper, 1923



Lee de Forest Presents to the SMPE, 1923


Who really received the credit for the Talkies?

“Don Juan,” 1926 - music and SFX Sync using

Disc

1927s “The Jazz Singer” was a “transitional” sound

picture with mostly traditional intertitles and very

little synchronized dialogue


De Forest and Case: The End It ended in court

Both de Forest and

Case

presented exhibits that

proved that they

received

their ideas from

19th Century scientists

Bell and Ruhmer


Importance of the “Language of Film”

De Forest Sound Film


Vitaphone Sound

Film

Importance of the “Language of

Film”


The de Forest Film Legacy

De Forest received this OSCAR in 1960

Lee de Forest

King of Radio, Television, and Film

By Mike Adams


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Lee de Forest and the Invention of Sound Movies, 1918-1926

Mike Adams, Professor


[email protected]

Written for presentation at the

Los Angeles 2012 Conference

Abstract. Lee de Forest received his Ph D in physics and electricity from Yale in 1899 and entered the 20th Century into a world of silence – the silent film of Edison and the quiet key clicks of the dots and dashes of Marconi‟s wireless telegraph. By 1906 he had patented his signature invention, the three-element vacuum tube he called the “Audion.” Beginning in 1918 he developed and patented a system of writing sound on motion picture film for synchronized talking pictures. Between 1920 and 1926 he worked with fellow inventor Theodore Case to develop the Phonofilm system of variable density recording. De Forest and Case ended up in court, with neither the winner. But for all subsequent systems of sound for motion pictures, the de Forest tube was the key as it allowed amplification of audio using loudspeakers which made it possible for audiences to experience talking pictures. In 1960 de Forest received an Oscar for his sound-on-film contributions.

Keywords. sound-on-film, variable density, Lee de Forest, vacuum tube, Audion, arc, selenium cell, Theodore Case, Lauste, Bell, Edison, Fleming, Ruhmer, Vitaphone, Phonofilm, Dickson, Fox, SMPE, Oscar

Introduction

Thank you. Today I am going to reintroduce you to a time when we were known as the SMPE, there was no television, radio was only a few years old, and movies were silent. The subject of my research and writing, Lee de Forest, had a great deal to do with all popular forms of media, and he first introduced his version of sound-on-film to the SMPE in May, 1923. (1)

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Figure 1. Lee de Forest holding his Photion Tube and posing with a Bell & Howell camera, modified to record sound-on-film, about 1923, colorized by author.

Closing the Circle

So I am here 90 years later, to close the circle, to talk about de Forest‟s work and how your organization knew about it first. As a scientist, de Forest was aware of all the knowledge that came before, and he did credit his predecessors: “Contrary to the popular idea, the history of attempts to record sound vibrations photographically is not new.” (2) Between 1920 and 1927, there were only four sound-on-film presentations before this organization and de Forest was responsible for three of them. (3)

Today I will re-introduce you to Lee de Forest and how he improved upon the science of the 19th Century to help create the entertainment media of the 20th Century. And what was de Forest‟s major accomplishment? It was the development of his vacuum tube as an amplifier of sound, allowing the audience experience for the first time, expanding the audio experience from hobbyists with headphones to the public through loudspeakers in the home and theatre. In this paper I‟ll concentrate on de Forest‟s work leading to one of the earliest successful sound-on-film systems.

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Biography and Background

Lee de Forest graduated with honors from Yale University, earning his Ph D in physics and electricity in 1899. In an 1897 Yale notebook, de Forest drew a schematic diagram of an arc modulated by a telephone microphone, and next to it wrote: “Talking Ark, like „speaking flame.‟ It gives a fine reproduction of any sound at microphone.” (4) As an inventor he will begin each project with this “speaking flame,” using it as a talisman. It will be his inspiration for his first wireless detector, his vacuum tube, his radiotelephone transmitter, his flame microphone, and his method of writing sound on film.

Figure 2. De Forest draws this schematic during one of his Yale lectures, 1897, History San Jose de Forest papers.

De Forest enters the Twentieth Century with a complete understanding of the science of the Nineteenth Century. He understands the limitations of wet plate photography, the phonograph of Edison, and the Photophone of Bell. (5) He reads about Edison and his collaboration with Eastman for a flexible film base for moving pictures. He understands the limitations of acoustical recording on cylinder and disc, and he reads about the Photographophone of Ruhmer. (6)

The Importance of the Audion

The best example of how de Forest the inventor works is found in the creation of his signature invention, the three element vacuum tube he called the Audion. His tube can be traced back to Edison and his 1880 patent called the “Edison Effect.” (7) Edison‟s light bulb had one annoying drawback. As the bulb burned and aged, its filament would add a black carbon deposit to the

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inside of the bulb, gradually reducing its light output. He experimented with the addition of a plate to “carry off” what he believed were the offending electrons. He measured the direction of the current flow, seeing it move from filament to plate. He had created a “rectifier” but seeing no commercial value he put it aside. Ambrose Fleming knew about the Edison Effect, and by 1905 had received a patent for a vacuum tube diode detector. (8) Fleming believed he had found a better detector of wireless dots and dashes. Using his diode, he had placed a galvanometer between the plate and filament to indicate the presence of code. It was a visual detector.

Figure 3. early de Forest Audion triode, author photograph from the Stewart Oliver collection.

But in one of the most significant events in the invention of electronic media, Lee de Forest looks at the Fleming patent and makes one very important change, one that will reverberate for decades. In his 1906 Patent, “Oscillation Responsive Device,” (9) de Forest cleverly substituted a second battery, called a “B” battery, and earphones in place of the meter. And while he positions his version of the Fleming diode as a device for listening to code, he has just opened the door to audio. A year later he adds to his tube the third element, the grid, and now his device is poised to be a receiver of voice over radio, and an amplifier which will later allow radios to speak loudly for family consumption. Of major importance, a tube that amplifies sound will add the missing link to several decades of unsuccessful experimentation of all versions of talking pictures, both sound-on-film and disc.

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Sound Film Sputters and Dies

The years between 1890 and 1915 were the formative ones for the silent film. An industry emerged as technical experimentation gave way to art, and by 1915 film would find its language as it moved from the experimental recording of events to actual storytelling using the shot, camera movement, and editing. As the public embraced the new media, the simple films of Edison and Porter gave way to the more expressive work of directors like D.W. Griffith. The motion picture began as 19th century science and became the first 20th century art form. (10)

Some believed that the addition of synchronized dialogue would make the film more real. And it could be done as Edison employee WKL Dickson proved in 1894 in a 13 second film of a man playing a violin into a large phonograph horn accompanied by Edison employees dancing. (11) It showed that picture and sound could be synchronized, but it would be labor intensive in the theatre playback. Another problem with film-phono sync sound was the length of recording time. With the cylinder and disc, there was a maximum plying time of 3-5 minutes, but even the shortest film was 10-12 minutes.

In the 1886 Photophone patent of Bell and Tainter, they wrote “This invention relates to a new method of and apparatus for producing a photographic record of such vibrations.” (12) This is probably the first known system of writing with light on photographic media. A few years later German inventor Ernst Ruhmer developed a complete system for writing what appears to be a variable density sound track on 35 mm film using an arc modulated by a telephone microphone. For playback a selenium cell and earphone was used. His device was the Photographophone. (13)

By 1912 Eugene Lauste had developed a system for sound-on-film using a variation of a variable area recording system. (14) The Lauste invention used the insensitive selenium cell and earphone for reproduction. Even Edison tried one more time in 1912 to present his version of a talkie using his phonograph. Apparently the phonograph was behind the screen, and a long cable connected it to the projector motor. Again, it was an imperfect method of synchronization.

Lee de Forest clearly understood the problems of inventing a system of synchronized sound for motion pictures. He looked at the current technology of the microphone, still the carbon telephone transmitter of 19th Century Bell design. It would never be sensitive enough to record sound, and as a practical matter the performers would have to be just inches away from this microphone. De Forest also understood the synchronization and length of disc problems of a phonograph-based system. He also was aware that the playback technology of the selenium cell used by Bell, Ruhmer and Lauste was barely loud enough to power earphones.

De Forest Defines the Talkies

De Forest believed that he possessed and understood the one important piece of technology that would gradually lead to a successful sound-on-film process, and that was his Audion vacuum tube. On a single piece of paper dated October 1918, de Forest described his version of a variable density recording and playback process for talking motion pictures. (15) He titled these notes, “3 methods for photographing sound waves on film for talking motion pictures.” (16) Not surprising, his first method was “use the „speaking flame.” His second method, “a very short, fine filament incandescent lamp – superimpose voice currents on the d.c. lighting current,” and his third, “use „glow tube light‟ – glass bulb filled with gas. Electrodes of plate excited by high-frequency currents modulated by voice, exactly as in radiotelephony.” (17) He would use these latter two methods to begin his experiments. The most significant part of this one page

description was his use of his triode vacuum tube to amplify the microphone well enough to record a sound track through a “fine slit onto moving film.” (18)

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Figure 4. De Forest‟s 1918 lab notes, “3 methods for photographing sound waves on film for talking motion pictures.” This was followed a year later by a complete patent. History San Jose

de Forest papers.

Less than a year later his notes become the basis of a patent filed on September, 1919 called “Means for recording and reproducing sound.” (19) In this patent de Forest is able to combine his knowledge of his Audion tube as an amplifier of audio and as an oscillator/transmitter for practical radio, and directly apply both toward sound-on-film. This marks a major difference

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between the earlier Bell-Ruhmer-Lauste experiments and a system that will be good enough to gain public audiences. In this filing he has explained in detail an entire system, “to reproduce talking moving pictures from a single roll of film.” (20) This is the first practical explanation of how successful talkies might work. He begins with the incandescent lamp, “the light emanating from the lamp is recorded on the film, preferably in the nature of a minute ray obtained through a pin point aperture or focused by a point by a lens.” (21) He finds that system unsatisfactory due to thermal lag, as the tungsten filament brightens and dims. Within a year he puts all his energy into what he termed “method 3,” “high frequency currents modulated by voice.” (22) For reproduction, de Forest writes, “I have found that the best results when using a photoelectric cell of the Kuntz variety.” (23) He writes in his diary: “On this day I made a photographic voice record on film with „talking flame‟ – which actually spoke to me words which I had forgotten were there, „one – two, three - - -nine, ten. August the twenty third.” (24)

This begins an almost decade-long period of time when de Forest and others developed his and other versions of sound-on-film, but whether the industry would settle on variable density, variable area, or disc, it was de Forest and amplification that would allow it to happen.

Figure 5. How Phonofilm variable density recording works. The top tube is a speech amplifier, coupled to the bottom tube, an oscillator. Like an AM transmitter, the audio frequencies are

superimposed on the high frequency carrier of the oscillator. It is coupled to the lamp which is focused through a slit and is written on the film.

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De Forest and Case Collaborate

De Forest learned about the work of the young scientist and fellow Yale Alumnus Theodore Case right before his 1920 breakthrough, and made this inquiry by mail: “Gentlemen, Professor R.W. Wood has informed me that you are producing a very sensitive photo electric cell (Thalofide).” (25) Case‟s background was in the development of photocells for clandestine infrared signaling during the just-concluded war. The six year de Forest-Case collaboration was largely a scientific one, each developing very small pieces of the system that would be known as Phonofilm. And while de Forest had the early ideas for recording sound-on-film, he needed Case. Hundreds of letters were exchanged between the two scientists between 1920 and 1926, the great majority scientific discussions. (26)

Figure 6. de Forest holds a Case AEO (alkaline, earth, oxide) lamp used to write the sound on the film. Author photos and compilation.

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As an example, in 1922 there was a rather long letter about how to eliminate a scratching sound on the track. Wrote de Forest: “This noise is due to grainess (sic) of the emulsion and I am taking the matter up with Dr. Mees of the Eastman Kodak Company to see if he can produce an emulsion which contains only very fine silver bromide agglomerations.” (27) Another letter from Case: “I am sending down to you by the porter on tonight‟s sleeper the newest light which is very excellent. It may not look very bright to you but it is extremely rich in the violet. I think once you get this light right up to your slit you will have no trouble in getting pictures” (28)

There were also personal and business issues between de Forest and Case, one of these familiar to all who knew de Forest: sloppy business practices. In the very beginning Case contracted with de Forest on a lease arrangement for his cells, but de Forest and his company apparently could not pay on time or even keep accurate track of what was owed. The other issue that really bothered Case was that he was always in de Forest‟s shadow, publicity-wise. Case wanted his name on the marquee of the theatres showing these films. In this 1924 letter from Hugo Riesenfeld who was the director of the New York theatre showing the de Forest films, he wrote in response to a Case-credit-query, “You surely understand that all our publicity has been exclusively de Forest which we consider a valuable asset on account of the great popularity of radio.” (29)

These two issues, lack of timely payment for his cells and lack of proper credit for his contributions, would eventually drive Case to work on his own version of Phonofilm, and by 1924 he began to file patents for his improvements to the de Forest system. The other avenue for Case was a legal one, and he sought advice on how to collect money owed, how to change the contractual arrangement with the de Forest Company for his cells, and ultimately how to sever the relationship. But in the beginning, the de Forest-Case relationship was mostly one of science, and at the New York offices of the newly created “De Forest Phonofilm Company,” science was applied to art as short films were being made, and theatres were being contracted with and equipped with Phonofilm technology. (30)

Promoting Phonofilm

Always the promoter, de Forest wrote in science magazines, gave speeches before professional organizations, and unlike many scientists of the era, he was willing to sit down with members of the press. One week before his première at the New York Rivoli Theatre, he appeared before the New York Electrical Society to talk about Phonofilm and show the reel he had prepared for the premiere: “He admitted that the technique of building a talking drama for motion picture audiences was something which would require a long time to perfect and predicted that the silent drama would never be transformed in to a talking machine drama merely by superimposing dialogue on the present type of photoplay.” (31) He tries to convince the attendees that he doesn‟t want to replace the silent film, but rather he is producing and showing “short subjects” of musical and vaudeville acts, prologue-like films that will go into theatres to screen before the main silent feature attraction. The press reaction to his Rivoli première was mixed: “New talking picture shown, but what of it? The invention, which is called the Phonofilm and which has been perfected by Dr. Lee de Forest, does all that is claimed for it. The action and the sounds synchronize perfectly – but what of it?” (32)

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Figure 7. two frames from a 1924 Phonofilm of President Calvin Coolidge. Some Phonofilms were restored in the 1980s by Maurice Zouary and Ray Pointer.

The Importance of the SMPE

For his film industry technical audience de Forest arranges to present to the Society of Motion Picture Engineers, the SMPE. He believes that in order for Phonofilm to be successful he has to convince the film industry technical fraternity. De Forest wrote and presented three Phonofilm papers between 1923 and 1926 for the SMPE Transactions. In this he was practically alone, as in the first half of the 1920s it is mostly de Forest who presents about sound for the movies. He is the first to describe before an audience of motion picture technical professionals “variable density” sound-on-film recording.

In this more technical revealing of how it works, he explains how it could not have been possible without his Audion both as an amplifier of weak signals, but also as an oscillator connected to the Photion tube to vary the intensity of the light. He compares his film recording system to a radio transmitter: “This oscillator is a form of the radiotelephone with which you are all more or less familiar. Connected to this high frequency output circuit is a gas-filled tube which I have called the „Photion.‟ This tube glows at all times with a violet light which is highly actinic in quality. The intensity of this light increases around its normal brilliance in exact correspondence with the modulated high frequency energy of the oscillator. The light from the end of this tube is focused by means of a lens upon the very fine slit directly upon the emulsion side of the film.” (33)

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Figure 8. A partial page from SMPE Transactions, No. 16, May 1923. This is what Lee de Forest was showing and telling the Society about his Phonofilm, variable density process.

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And in actual production? “For example, everyone must work in absolute silence, except the actors or musicians who are being actually recorded. This involves, of course, studios particularly designed for this work with every precaution taken against extraneous noises and interior echoes. The usual hammering, pounding and general bedlam which has heretofore distinguished the moving picture studio must be completely eliminated during a „take.‟ A new type of moving picture director must be evolved, or if the old type is continued he must be thoroughly gagged, and learn to direct by signal and gesture only.” (34) What he is doing, perhaps unknowingly, is threatening the familiar way of life of thousands of motion picture employees, not to mention making obsolete all the studios and equipment used in the very successful production of silent motion pictures. As a member of the Society of Motion Picture Engineers you would have to seriously consider all of this and what it might mean to your livelihood.

Case and the Courtroom

The year 1926 will be the beginning of the end for the De Forest Phonofilm Company. The first Vitaphone release, “Don Juan” with John Barrymore featured sound effects and music synchronized using the formerly discredited phonograph record. It is a hit and Lee de Forest becomes ill when he learns the news: “Last week the flashing posters of Vitaphone gave me first a shock, like a blow. Why and how have we wasted the last two years? (35) One year later “The Jazz Singer” would be released, and this would be the starting gun for the wholesale conversion from silent to sound. (36)

Meanwhile, Theodore Case is tired of living in the inventing and publicity shadow of de Forest. Beginning in 1924 he begins to make films and create what he believes is a better version of the Phonofilm technology. Believing that the most important parts of the system are his, the Thalofide cell for playback and his AEO lamp to write on the film, he sells his process and patents to William Fox. De Forest sues and sides are taken, exhibits and evidence are presented. The big sound-on-film case of 1926 is “de Forest v. Fox-Case.” The preparation of this case will take several years during which time the Hollywood film community will make sound pictures, apparently oblivious to what is happening in the offices of the New York lawyers of de Forest and Case.

What both parties in this suit really ending up presenting to the court can be summed up in this letter from Case to his attorney: “The idea of photographic sound-on-film and reproducing it electrically had its inception long before Dr. de Forest entered the field. The idea first developed in this country in 1880 – 46 years ago. Since those early trials it has become more a question of producing suitable tools in the form of photo-electric cells, taking lights and reproducing apparatus to accomplish the results desired by the pioneers in the field” (37) De Forest submitted several books of evidence, also showing that the roots of sound-on-film could be traced back to Bell and Ruhmer. (38) After three years both sides agreed to a draw. In 1929, Fox settled with de Forest for $60,000 and de Forest agreed to drop the suit. This settlement went largely unnoticed by a movie industry rushing to convert their entire operation from silent to sound.

Perhaps one reason that Phonofilm failed to attract the attention of Hollywood was that de Forest the scientist was not de Forest the film maker. The silent film of the mid-1920s was a highly developed art that used the then mature language of film of the shot, camera movement and editing. A de Forest Phonofilm was typically a single establishing shot with no camera movement or editing. (39)

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Oscar in the End

De Forest called the 1920s his lost decade, a ten year period in which he combined the best of 19th Century technology and the lessons learned from his vacuum tube into what he believed would be his major accomplishment – the talkies. By 1930 he had sold the Phonofilm company and he would spend the remainder of his long life, until 1961, trying to secure his legacy, telling his story to anyone who would listen, attempting to reap the rewards of a long and important career. In April, 1960 he was awarded an honorary Oscar: “Academy Honorary Award to Lee de Forest for his pioneering inventions which brought sound to the motion picture.” (40)

Figure 9. Lee de Forest remembered. This honorary Oscar was presented to him in April, 1960, the inscription reads: “Honorary Oscar presented to Lee de Forest for his pioneering inventions

that brought sound to the motion pictures.” History San Jose.

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Conclusion

Lee de Forest will be remembered for his signature invention of the vacuum tube, which allowed amplification for practical radio, television, and sound film. Nevertheless, for inventor de Forest, the years between 1918 and 1930, were those in which he labored to create his system of talking pictures, but instead he saw fortune appear and then disappear, heard applause rise and then fall, finally mired in court battles, some won, some lost, but most just faded to black.

End Notes

1. Lee de Forest, SMPE Transactions, No. 16, May 1923

2. ibid

3. SMPE Index; no. 16, May 1923; no. 20, Sep 1924; no. 27, Oct 1926

4. Lee de Forest, Yale notebook, 1897, de Forest papers, History San Jose State (HSJ)

5. Lee de Forest, papers, his collections of articles and patents, HSJ

6. ibid, Seaver Center Los Angeles Natural History Museum

7. Thomas Edison, U.S. Patent 307,031, 1880

8. J.A. Fleming, “Instrument for converting alternating electric currents into continuous currents, U.S. Patent 803,684, Nov 7, 1905

9. Lee de Forest, U.S. Patent 836,070, Nov 13, 1906

10. restored films, 1890-1915, Treasures for the American Film Archives, San Francisco, Edison Films, Library of Congress

11. Edison experimental sound film, W.K.L.Dickson, 1894, restored by the Library of Congress

12. A.G. and C.A Bell, Tainter, U. S. Patent 341,213, May, 1886

13. Ernst Ruhmer, Wireless Telephony, Crosby, Lockwood and Son, London, 1908

14. Edward Kellogg, “History of Sound Motion Pictures, part 1,” SMPTE Journal, June 1955

15. Lee de Forest, papers, Oct, 1918, HSJ

16. ibid.

17. ibid.

18. ibid.

19. Lee de Forest U.S. Patent 1,446,246, filed Sept. 18, 1919, granted Feb 20, 1923

20. ibid.

21. ibid.

22. Lee de Forest, papers, Oct, 1918, HSJ

23. Lee de Forest U.S. Patent 1,446,246, filed Sept. 18, 1919, granted Feb 20, 1923

24. Lee de Forest diary, Aug 23, 1920, de Forest papers, HSJ

25. Letter, de Forest to Case, August, 1920, Case Papers, Auburn NY

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26. for a complete explanation of the significance of all the de Forest primary source documents and papers, see Mike Adams, Lee de Forest, King of Radio, Television, and Film, Springer Science, NY, 2012

27. letter, November 23, 1922, de Forest to case, Case papers, NY

28. letter, Dec 22, 1922, Case to de Forest, Case papers, NY

29. letter from Riesenfeld to Phonofilm company manager Waddell, Feb 13, 1924, Case papers, NY

30. Phonofilm Company, stock certificate, patent and photo of playback adapter for the Simplex projector, Case papers, NY

31. New York Times, April 5, 1923

32. Cleveland Plain Dealer, April 22, 1923

33. Lee de Forest, “The Phonofilm,” SMPE Transactions, No. 16, May 1923

34. ibid.

35. Lee de Forest, diary, July 25, 1926, de Forest papers, HSJ

36. for a complete explanation of the significance of all the de Forest primary source documents and papers, see Mike Adams, Lee de Forest, King of Radio, Television, and Film, Springer Science, NY, 2012

37. Case statement, re: suit by de Forest, Aug 6, 1926, Case Papers, NY

38. From the two-volume de Forest court exhibit for his suit, de Forest Phonofilm Corporation v. Fox Case Corporation, 1929, a copy of which is in the Case Papers, NY

39. films, a comparison of two mid-1920s music shorts, the first de Forest, followed by one by Vitaphone

40. This Oscar is part of the Perham de Forest papers, History San Jose

Documents

Lee de Forest - We are SMPTE · Lee de Forest and the Invention of Sound Movies, 1918-1926 Mike Adams, Professor San Jose State University [email protected] Written for presentation