8 PHOTO-TELEGRAPHY 



matician, and photo -telegraphy is one instance 

 where somewhat abstruse calculations on paper 

 turned out to be in perfect harmony with practical 

 work. 



In referring to the methods of Amstutz, I will 

 quote from an interesting article by Mr. William 

 Gamble, that appeared twelve years ago in the first 

 number of Penrose's Pictorial Annual, of which he 

 is the editor. Briefly, he says, the process is this : 

 A photograph in relief (prepared in gelatine) is 

 fixed to something akin to a phonograph cylinder, 

 so that a stylus travels over its surface, rising and 

 falling as the picture passes beneath it. Instead 

 of producing sound, like the phonograph, it is made 

 to vary the strength of an electric current, which 

 passes over a telegraph wire and actuates a similar 

 stylus at the other end, which, bearing on a plate 

 bent round a revolving cylinder, cuts a reproduc- 

 tion of the original, but in a series of parallel lines 

 (the successive " turns " of the cylinders) which 

 gives the effect of a half-tone block. The stylus is 

 sharpened like a graving tool, V-shaped, so that 

 as it cuts deeper it cuts wider, and in printing 

 produces darker or wider lines, 



Amstutz, in a lengthy letter which the editor of 

 the Annual publishes, describes a method in which 

 a photographic print is made on a metallic sheet, 

 the half-tone of the photograph being broken up 

 into parallel lines, " the photo -message being re- 



