wires across the field are much finer ones, at intervals of about 

 3oft. making a complete network above the ground. To allow 

 of carting to be carried on after the wires are put up, they are 

 generally placed at a height of about I5ft. above the ground. The 

 moment the coil is excited the overhead system becomes charged 

 at a very high pressure, and the electric discharge imme- 

 diately commences. 



