1910] on the Telegraphy of Photographs, Wireless and by Wire. 851 



almost entirely avoided, as if an arc be formed the current is inter- 

 rupted an instant later and the arcing ceases in consequence. 



The receiving apparatus is very simple, and depends, for short- 

 distance work, upon a coherer cymoscope, the decohering apparatus 

 being of a particular character. Every time an oscillation passes to 

 the antenna, the coherer becomes conductive in the ordinary way, 

 and a relay is actuated ; this relay is usually made to start a hammer 

 vibrating, the hammer hitting the coherer, and thus causing it to 

 loose its conductive power. But a vibrating hammer is useless for 

 the photo-telegraphic receiver, and it is essential to have one strike 

 only on the coherer for each signal detected. 



The form of apparatus I have employed for this purpose is seen 

 diagrammatically in the next lantern-slide (Fig. 8). E E is the 

 magnet which is actuated by the relay R. It then attracts an 



armature M N, which moves towards the magnet poles and brings 

 a f resilient hammer H, fitted with a platinum contact p, against the 

 coherer. The coherer A B is also fitted with a collar F and contact 

 pin, so that in the act of striking the coherer the hammer closes a 

 local circuit, and so causes a black mark to appear on the chemical 

 paper. Successive distinct marks can be obtained in '017 second in 

 this way, which is considerably more rapid, I believe, than a de- 

 coherer was given credit for. 



There is not sufficient time to show an actual transmission by 

 wireless, and I should to make it clear that only sketches of the 

 simplest character are at present being transmitted. But as you will 

 see from the result now thrown on the screen — a simple portrait of 

 his Majesty the King — the images are recognisable, and merely 

 require slightly more detail to make them quite comparable with the 

 early results in line obtained by Professor Korn's tel-autograph. 



Another result shows a plan transmitted by wireless : here an 



