"A novel and curious instrument. 
The Telectroscope", 
Vol. XL, n°10, New York, 8 March 1879.


Nous reproduisons cet article d'après la citation qui en est faite par Constantin Senlecq dans sa brochure Le télectroscope, Saint-Omer, 1881.

Senlecq signale également sa parution dans The Electrician, n°14, vol. XI, London, 1 February 1879 et dans d'autres journaux scientifiques anglais et américains.

A novel and curious instrument. The Telectroscope

    - M. Senlecq of Ardres, has recently submitted to the examination of MM. du Moncel and Halley d'Arros a plan of an apparatus intended to reproduce telegraphically at a distance the images obtained in the camera obscura. - This apparatus will be based on the property posseded by selenium of offering a variable and very sensitive electrical resistance according to the different gradations of light. - The apparatus will consist of an ordinary camera containing at the focus an unpolished glass and any system of autographic telegraphic transmission ; the tracing point of the transmitter intended to traverse the surface of the unpolished glass whill [sic] be formed of a small piece of selenium hold by two springs acting as pincers, insulated and connected, one with a pile, the other with a line. - The point of selenium will form the circuit. - In gliding over the surface, more or less lightened up, of the unpolished glass, this point will communicate, in different degrees and with great sensitiveness, the vibrations of the light.

    The receiver will also be a tracing point of blacklead or pencil for drawing very finely, connected with a very thin plate of soft iron, held almost as in the Bell Telephone, and vibrating before an electro-magnet, governed by the irregular current emitted in the line. This pencil, supporting a sheet of paper arranged so as to receive the impression of the image produced in the camera obscura, will translate the vibrations of the metallic plate by a more or less pronounced pressure on that sheet of paper.

    Should the selenium tracing-poing run over a light surface the current will increase in intensity, the electro-magnet of the receiver will attract to it with greater force the vibrating plate, and the pencil will exert less pressure on the paper.

    The line thus formed will be scarcely, if at all visible ; the contrary will be the case if the surface be obscure, for the resistance of the current increasing, the attraction of the magnet will diminish, and the pencil, pressing more on the paper, will leave upon in a darker line. - M. Senlecq thinks he will succeed in simplifying this apparatus by suppressing the electro-magnet and collecting directly on the paper by means of a particular composition the different gradations of tints proportional to the intensity of the electric current.


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