THE ELECTRIC TELEGRAPH. 



It may be necessary to state here that it is customary to call 

 the wire which proceeds to the chief terminal station of a line the 

 up wire, and that which proceeds to the secondary terminal station 

 the down wire. Thus, if a line of telegraph be extended between 



Up. Line 





London and Dover, the wire which would connect London with any 

 intermediate station would at that station be the up wire, and 

 180 



