■92 



Professor J. A. Fleming 



[March 27, 



of ordinary deep-sea cable, and I have the ends of the sections 

 brought out so that I can attach a receiver to any point on the Hne. 



I shall apply to this artificial cable a periodic or alternating 

 electromotive force, the wave form of which is very irregular. This 

 •can be produced by a suitable alternator and transformer, by means 



SENDING END 



.^-^ 20 MILES 



Fig. 2. — Two Examples of the Distortion of an Electric 

 Wave in travelling along a Cable. 



Capacity of cable 

 Resistance of cable 



0-3018 mfds. per mile. 

 7 • 235 ohms per mile. 



of which an alternating current of the required irregular wave form 

 can be created. 



We shall then employ a Duddell oscillograph to throw upon the 

 screen a representation, in the form of a line of light, of the wave 

 form of this electromotive force. The oscillograph contains two 

 wires, and one of these is employed as above to depict the wave form 



