1897.1 HOUSTON, KEXNELLY — THE PATH OF A CURRENT. 169 



traveled so far as it went with the velocity of light in the ether of 

 gutta-percha, but the vanguard was completely dissipated and the 

 successive vanguards were attenuated with complete dissipation for 

 a comparatively long time before the distant end could be reached. 

 It is only on long circuits, such as are afforded by telegraph and 

 telephone wires or submarine cables, that the phenomena of electric 

 transmission with their attendant distortion and attenuation are 

 most clearly evidenced. In the comparatively short circuits em- 

 ployed for transmission of electric light and power, the phenomena 

 of distortion and attenuation of electric and magnetic flux are of 

 little practical importance. Fig. 40, represents the signals sent over 



T r an s m i tte d 



Fig. 40. — Distortion of Signals Received Over Last- Laid Atlantic Submarine Cable. 



the last laid Atlantic cable and the corresponding signals which were 

 received at the distant end. The two should be exact facsimiles 

 and should, therefore, be capable of actual superposition if no dis- 

 tortion occurred in the electric impulses. jN'ot only the delay or 

 retardation in the received signals, but also the great distortion 

 which is noticeable, are due entirely to the fact that there is very 

 little leakage in the insulator, while there is very appreciable resist- 

 ance in the conductor. This cable, laid in 1894, has a published 

 length of 1847.5 nautical miles. The copper conductor offers a 

 resistance of 1.68, or about if, ohms per nautical mile, while the 

 insulator has a resistance of 85,000,000,000 ohms in each nautical 

 mile. This cable has a working speed of over forty-five words per 

 minute, which is much faster than any other previously laid Atlan- 

 tic cable, owing to the greater conductance of the circuit. This 

 cable possesses, of course, enormous distortion, although such dis- 

 tortion does not prevent signals being read until a speed of over 225 

 letters per minute is attained. If, however, the insulation, instead 

 of being 85,000,000,000 ohms in each nautical mile, were reduced 

 to about 500 ohms in the nautical mile, the leakage tailings would 



