CAPACITY OF TWO-PHASE AND THREE-PHASE LINES 95 



Adding together and dividing by 3, we obtain the ap- 

 proximate average value per mile, 



that is, E a 



where s 



Similarly, E b 



2 TTJ 



27T 



and 3. = *(// -/a') a log.* 



2 7T/ \ / p 



