206 



ANNUAL EEPOET SMITHSONIAN INSTITUTION, 1908. 



style which a spring F presses upon the plate. As this plate is com- 

 posed of a series of points more and more extended as it is desired 

 to represent a black more and more intense, when the style passes 

 over these points it closes the line through a battery during a greater 

 or less period according to the length of contact touched on the 

 plate and the transmitted signals therefore consist of a series of 

 currents of the same intensity but of varying duration. 



A somewhat similar apparatus serves as the receiver. The cylin- 

 der D is covered with a sensitive film and before an opening into 

 its dark chamber is placed a lamp. An electro-magnet placed in the 

 line circuit carries a shutter stopping or allowing the light to fall 

 upon the film; the half tones are due to the length of the x^oints 

 traced by the luminous pencil. 



APPARATUS OF CARBONELLE. 



This system recalls the telegraph of Caselli in its use for the trans- 

 mitter of a design traced with greasy ink upon a metallic sheet. His 



receiver, however, 

 is wholly different. 

 It consists of a 

 telephone the mem- 

 brane of which car- 

 ries a style which 

 engraves in the wax 

 or lead with which 

 the receiving cyl- 

 inder is covered. 

 For transmitting 

 photographs or 

 drawings in half 

 tones, Carbonelle suggests the employment of hatched photographs 

 as was done by Berjonneau. 



In the trials between Brussels and Antwerp, Carbonelle sent a pic- 

 ture, 13 by 18 centimeters, in eighty seconds. 



APPARATUS or SENLECQ-TIVAL. 



Pio. 9. — Apparatus of Senlocq-Tival. 



We will say a few words in closing about an apparatus which has 

 been announced but does not appear to have been tried. In the device 

 of Senlecq-Tival, the photograph to be sent is made by the carbon 

 process, using in the place of carbon a conducting poAvder, and the 

 prepared plate is rolled upon the metallic cylinder A of the trans- 

 mitter (fig. 9). A style S closes across this film, a circuit con- 

 sisting of a battery, the electro-magnet B and the cylinder A. Each 

 13oint of the film has a conductivity proportional to the opacity of 



