(> i Mr. 0. Heaviside on. the 



the resistance of the latter ; and with a, fault in tlie middle of 

 infinitely small resistance, the maximum is reached in 6\5a, 

 as shown by curve 3, fig. 2. It cannot be reached sooner 

 with a single fault. 



4. In condenser working, the working current is the current 

 entering the receiving condenser — that is, the rate of increase 

 of its charge, and therefore proportional to the rate of increase 

 of the potential at the insulated receiving end when terminal 

 resistances and capacities are neglected. The arrival-curve of 

 the current when there is no fault is shown in fig. 3, curve 1. 

 This curve was given by Sir W. Thomson in 1854, not how- 

 ever in connexion with condenser working (for that method 

 was not then invented), but as showing the current at the dis- 

 tant end produced by an infinitely short contact with an infi- 

 nitely powerful battery at the beginning, both ends being kept 

 to earth. The current reaches a sensible proportion of its 

 maximum much more rapidly than without condensers. It 

 reaches its maximum in 3*93«, and then decreases. 



With a fault of infinitely small resistance in the middle of 

 the line, other things being the same, the arrival- curve of the 

 current is shown by 3, fig. 3. It reaches *0081 of its maxi- 

 mum in "8a, *0523 in la, and its maximum in 2'6a nearly. 

 It then falls to zero, which it reaches in 6'5a, and becomes 

 negative, as the electricity runs back to escape through the 

 fault to earth. 



Curve 2, fig. 3, is similar. It corresponds to the fault in 

 the middle having one fourth the cable's resistance. The 

 maximum is reached in 3'45a, and zero in 103a. 



Fipr. 3. 



