S/X WILLIAM 67A.J/A.Y.S, l-.R.S. i;i 



The system of suspended line-wire now generally in use is open 

 to many grave objections. Atmospheric electricity frequently 

 causes such disturbances as to interrupt the working of long lines 

 for hours at a time, and the most perfect lightning dischargers do 

 not always prevent damage to the working instruments, when 

 atmospheric discharges of electricity into the line-wire take place. 

 Again, the mutual induction between parallel line-wires and the 

 leakage from one wire to another through the supporting poles are 

 a permanent source of trouble in working telegraph instruments, 

 and this difficulty increases as we advance from the simple needle 

 or recording instrument to the more refined duplex or quadruplex 

 system, to the mechanical transmitter or the telephone. 



Again, it happens that not unfrequently suspended line-wires 

 are thrown down, causing the almost entire cessation of tele- 

 graphic communication for days in the event of a great gale or 

 snowstorm, interruptions which are quite incompatible with the 

 idea that the electric telegraph has become a great public 

 institution. 



The remedy for these interruptions is undoubtedly the under- 

 ground line-wire system. This was first tried in Germany upon 

 an extended scale in 1848 49, but was given up in favour of the 

 suspended line in consequence of the want of experience in manu- 

 facture and imperfect protection afforded to the gutta-percha 

 covered copper wire. Since then it has been largely used in this 

 country for underground communication in cities, also for aerial 

 lines, by suspending a bunch of the insulated conductors by steel 

 wires in the air, as we see them supported on the house-tops of 

 this metropolis. The German Telegraph Administration, under 

 the able direction of Dr. Stephan, has within the last year or two 

 again resorted to the application of the underground conductor 

 for long lines. A representative cable of what it was intended to 

 lay was put down in 1876 between Berlin and Halle, a distance of 

 120 English statute miles. The success of this line induced his 

 Government to lay down last year multiple cables between Berlin 

 and Cologne, and Berlin, Hamburg, and Kiel, an aggregate 

 distance of 600 miles, and further extensions are in course of 

 execution. These cables consist of seven separate conductors, each 

 insulated with gutta-percha, surrounded with a complete iron 

 sheathing and a double outer covering consisting of hemp steeped 



