W.E. Sawyer critique la proposition de George R. Carey
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Un inventeur concurrent d'Edison
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W.E. Sawyer est resté dans l'histoire de l'électricité comme un des inventeurs de la lampe à incandescence, invention pour laquelle il porta plainte contre Edison pour interférence de brevet.
Avant son invention de la lampe à incandescence, Sawyer s'était intéressé à la transmission des images fixes et avait inventé un obtenu un brevet pour un télégraphe à facsimile (autographic telegraph). Il avait créé The United States Postal Telegraph C° pour exploiter ce système. Edison, qui lui même travaillait sur un projet de télégraphe autographe. Edison nourissait pour Sawyer un profond mépris. Dans une lettre à Frederick Royce (16 May 1876) il écrivait : "Regarding that despicable Sawyer, I never believed a word he ever said. Hes nothing but a bay of miasma under pressure. He's got his two Autographic machines placed on a table and connected together by a rod and bevel gear under the table, to obtain synchronisation. So I am told."
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Une réponse à George R. Carey
Le texte de Sawyer "Seeing by electricity" est publié par Scientific American le 12 juin 1880, soit à peine une semaine après l'article du même titre, également publié par Scientific American, le 5 juin 1880, mais aussi par The Operator dès le 1er juin 1880, et présentant la caméra électrique au sélénium de George R.Carey. Cette réaction extrêmement rapide laisse supposer que Sawyer avait été informé de la proposition de Carey avant même sa publication. La chose n'est pas impossible car dans une lettre du 7 janvier 1879, A.C. Carey, le père de George R., lui propose de rencontrer Sawyer à New York.
La contribution de Sawyer nous apprend deux choses : d'une part il évoque une curieuse démonstration de transmission d'images qui aurait eu lieu à Cordlandt Street, n°52, à New York, à l'automne 1877. On ne connaît pas d'autre témoignage relatif à cette démonstration, par ailleurs bien improbable.
Par ailleurs, Sawyer évoque ses propres travaux sur la transmission d'iamges à distance en recourant aux propriétés photosensibles du sélénium, mais dresse d'emblée un diagnostic d'échec de toutes les tentatives qui pourraient être menées et ce pour trois raisons :
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la réactivité du sélénium à la lumière est très lente,
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la transmission d'une image précise d'une surface de un pouce carré demanderait plus de 10 000 connections !
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un appareil ne pourrait transmettre de manière assez sensible les modifications de réaction du sélénium sur un seul point,
Avec l'appareil proposé par Carey, il n'est pas possible d'obtenir le synchronisme souhaitable entre l'émetteur et le récepteur.
Pour pallier à ce défaut de l'appareil de Carey, Sawyer propose un système dans lequel le transmetteur serait constitué par une spirale de sélénium, placée dans une chambre noire d'environ 3 pouces de diamètres et sur laquelle l'image serait projetée, par l'intermédiaire d'un tube de petit diamètre, animé d'un mouvement de rotation rapide. La lumière émanant de l'image impressionnerait la spirale de sélénium aux différents points de la spirale. Le récepteur comporterait une spirale animée à la même vitesse que celle du récepteur.
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Le télégraphe à facsmimile (autographic telegraph) de Sawyer (1876).
W.E.SAWYER, "Seeing by Electricity", Scientific American, June 12 1880.
On trouvera une traduction en français du texte de Sawyer dans l'article de Th. du MONCEL, "Le Téléphote et le Diaphote", La Lumière électrique, Paris, 1er juillet 1880.
Graphique du dispositif de Sawyer propose par P. Hémardinquier, dans son ouvrage Histoire des techniques de télévision, Dunod, Paris, 1933.
Une mort tragique
Pour la petite histoire, signalons que Sawyer mourrut des suites d'une rixe avec un certain Dr. Steel. Voici sa notice nécrologique parue dans Electrical World, Vol 1, May 19, 1883, pg 309.
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Death of an American Electrician
"Mr. William E. Sawyer, a well known electrician and electric light engineer, died at his residence in this city on the 15th inst. Mr. Sawyer will be remembered as one of the pioneers in the field of electric lighting in America. His career as an electrician was begun under very favorable auspices, and it is a pity that it should have proven but a record of neglected opportunities. Unfortunately for Mr. Sawyer, his nature combined discordant elements of character; his disposition was governed by traits at once uncongenial and incompatible with each other. He was not lacking in the essential qualities of ability and genius. On the contrary, he possessed undoubted talent as an electrician. But his character was not possessed of that fixedness and stability which command success. His erratic and careless habits were perpetually at war with his talents, and led him continually into difficulty.
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"He achieved fame and fortune at an early date. It is said that his inventions formed the basis of the first electric light company in America—the United States Electric Light Company—who retained his services on a contract of several years, at a munificent salary. Mr. Sawyer only remained a few weeks, however, and then threw up his contract. It is said that the $50,000 which he received for his inventions soon disappeared. He then gave his attention anew to electric lighting, and a new company, the Sawyer-Mann Electric Light Company, was formed to operate his incandescent system. It appears that he was at work on an incandescent system much sooner than Edison or Maxim, and that he was successful in contests with them for priority in the Patent Office.
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"A difficulty arose between Mr. Sawyer and a Dr. Steele, who boarded at the same place where he lived, which culminated , on the 5th of May, 1880, in an altercation, in which Mr. Sawyer shot Dr. Steele. Mr. Sawyer was arrested, and when the trial took place in March, 1881, he was convicted and sentenced to four years' imprisonment at hard labor. An appeal was made, and as his health was poor, he was permitted to remain at his home pending the appeal. The Court of Appeals affirmed the decision of the Court of General Sessions, and Mr. Sawyer then sought pardon from the governor. As his health was such that his removal was considered dangerous, he was permitted to remain at his house. The District Attorney consented to delay in moving for sentence in one month, which expired May 16, but before the time had expired he received official notice of the death of Mr. Sawyer.
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"In the beginning of 1881 Mr. Sawyer published a book on "Electric Lighting by Incandescence," which, for a time, was the best work on the subject. The Sawyer-Mann Company did not live long, and Mr. Sawyer started one or two other companies, which shared the same fate. He then turned his attention to the electric railroad, and managed to produce a sensation once more. He had lately given considerable attention to perfecting his electric railroad. At the time of his death it is said that he had several applications for patents in course of preparation, to cover distinctive features of his inventions.
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"As an electrician, Mr. Sawyer belonged to the practical school rather than to the scientific. His inventions are not so remarkable for originality of conception as for ingenuity of application. In a word, his genius was constructive rather than creative. His inventions were bright innovations of old ideas, rather than departures toward new principles."
Bibliographie
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POPE, F.L.., Evolution of the Electric Incandescent Lamp, 1894
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André Lange; 11 mars 2003 / Révision décembre 2017
SAWYER, W.E., "Seeing by Electricity", Scientific American, 42, 12 June 1880, p.373. (Reproduit in "Mining and Scientific Press", 9 October 1880, p.227)