MIRACLES OF SCIENCE 



that the picture is removed from the cylinder and 

 laid flat, appear as parallel lines drawn across the 

 picture. It is obvious that the closeness of the spiral 

 will determine the degree of accuracy with which the 

 tones of the original are reproduced. 



Although this system of tarnsmitting pictures 

 proved a commercial practicality, it early occurred to 

 Professor Korn that he could improve upon it for 

 commercial purposes by a method which retained the 

 cylinders, but operated otherwise in a quite different 

 manner. The new method utilizes an apparatus which 

 Professor Korn calls a telautograph. It was further 

 improved by Mr. T. Thorne Baker of London, whose 

 perfected instrument is called a telectograph. This 

 instrument makes no use of selenium, and the 

 principle upon which it works is not that of a fluctuat- 

 ing but of an interrupted current. 



The picture to be transmitted must now be com- 

 posed of lines, like a pen drawing, or of dots, as in 

 case of a half tone. The picture is printed with some 

 non-conducting substance such as fish-glue on a thin 

 sheet of lead, and this is wrapped about a cylinder 

 as in the other apparatus. A point of metal connected 

 with the transmitting electric wire is arranged to 

 touch the cylinder and traverse it in a spiral as the 

 cylinder revolves, precisely as the needle of the Edi- 

 son phonograph traverses the cylindrical record. As 

 the metallic point passes over dots or lines on the 

 picture, the current is interrupted; but contrariwise 

 the -current is transmitted when the point comes in 

 contact with the lead surface, which represents the 

 high lights of the picture. 



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