STEADILY ALTERNATING CURRENT ON A LONG LINE. 339 



six times (5.691) the initial sending-end current. This represents 

 a series of regular initiating a.-c. wave transients. 



The e,- curve starts about half an alternation behind the es and is 

 curves, since 4.3 milliseconds are required to transmit the wave 

 along the artificial line, and an alternation at 60.6 '—' lasts 8.25 milli- 

 seconds. It then develops into a sinusoidal wave with an amplitude 

 that steadily increases, owing to increments reflected from the send- 

 ing end. The steady state is, however, very nearly reached by the 

 end of the oscillogram. The ratio of the final to the initial crest 

 value is 5.627. As has been already mentioned, the line happens 

 to be nearly quarter-wave length for the impressed frequency 

 (60.6 -'). 



The growth of the is curve and especially of the Cr curve, has 

 been found to be in substantial agreement with the theory of initiat- 

 ing regular transients over the corresponding smooth line, as will 

 shortly be detailed. This means that in spite of the lumpiness of 

 the artificial line, the transient stages of voltage and current de- 

 velopment into the a.-c. steady state, are presented substantially as 

 they might be expected over the corresponding smooth line, pro- 

 vided that the voltage application is made at an instant of zero e.m.f. 



Splash and Lumpiness Transients Mingled with Regular Initiat- 

 ing Transient. — In Fig. 10 (Film no), the same artificial line, 



Fig. 10. Example of Splash, Lumpiness and Regular Transients. 



freed at the far end, is closed on the same generator at the same 

 frequency. The switch is closed, however, at or near a crest value 

 of impressed e.m.f. eg. The entering current is, instead of rising 

 smoothly, as in Fig. 9, jumps up rapidly to crest value, with an 



