PHOTOGRAPHS BY TELEGRAPHY 



339 



received image from being recognised. They were eventually 

 overcome by introducing counterbalancing oscillations, which 

 completely damped them. An adjustable back, E.M.F., with 

 variable capacity, enables the operator to counteract the line- 

 constants, with the result that crisply defined pictures are 

 being regularly received from Manchester at the London office 

 of the Daily Mirror at the present time. 



This method of photo-telegraphy is particularly adapted to 

 wireless transmissions, and I have arranged a satisfactory in- 

 stallation for experimental purposes in the following way. In 

 the diagram (fig. 6), d is the drum of the transmitter, and the 



Fig. 6 



intermittent currents from it are made to actuate the primary 

 p of the induction coil, a is the antenna and e the earth-plate 

 of the oscillating circuit, k the condenser battery, j the in- 

 ductance. In the receiver, the coherer c actuates the relay 

 through a small battery, and shunted to the decoherer is a 

 second relay z, through the local battery side of which the 

 current is passed into the receiver-drum x, to which is attached 

 the sensitive paper. Synchronisation is effected by a simple 

 arrangement, which I am not at liberty to enlarge on at the 

 moment, but the chief feature of the apparatus is the decohering 

 instrument, which after considerable experimental work I have 

 made to work exceedingly crisply, so that the effect is very 



