New Developments in Science 



587 



Keystone View Company. 



A TELEPHOTOGRAPH SENDING APPARATUS 



Notice the revolving cylinder at the right with the picture fastened to it. The light 



bulb and the lens focus a beam of light on one part of the picture after another. 



The photoelectric cell, to which the light is reflected from the surface of the picture, 



is located in the metal box at the left. 



reflected from the surface of the picture to the photoelectric cell. 

 Since more light is reflected from the light parts of the picture than 

 from the dark parts, the amount of reflected light constantly 

 varies and this causes variations in the strength of the electric 

 current flowing through the cell. The varying electric current, 

 greatly amplified by a series of vacuum tubes, is either sent by 

 telegraph to the receiving apparatus or else flows through the 

 aerial wires of a radio sending set and creates corresponding radio 

 waves in the ether. 



The receiving apparatus in telephotography is much like the 

 sending apparatus. The varying electric current from the sending 

 set, greatly amplified by a series of vacuum tubes, operates a 

 special lamp filled with neon gas. As the current increases and 

 decreases in strength, the neon lamp glows with a corresponding 



