KENNELLY. — BUILDING UP VOLTAGE AND CURRENT. 715 



pedance at a point, sets up a pair of secondary waves ; namely, those 

 that go on through the impedance, and those that go back reflected. 

 The final steady state is the harmonic variation of a vector sum at 

 each point, due to all the primary, secondary, tertiary, etc., ^Yaves, 

 summed to infinity. In many cases this vector sum may be very 

 simply expressed in hyperbolic functions ; but if these functions are 

 not made use of, there is a fearful and wonderful summation. 



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