654 PROCEEDINGS OF SECTION J. 



all the rest of the world. The network of wires in the streets 

 became a serious matter, and several municipalities passed rules 

 requiring Electrical Companies to place their wires underground. 

 This of course stimulated invention, and hundreds of difierent 

 systems have been devised, and many of the most promising of 

 them tried and abandoned. 



In 1885 the Franklin Institute in America issued reports on 

 underground conduits, and in them (published in the Proceedings 

 of the Institute for the Year) may be seen a large number of 

 systems fully described and reported on ; not one of them being 

 recommended as having been proved successful, or free from 

 serious objections. I would recommend all persons interested to 

 I'ead these reports. It would seem as if every possible plan to 

 place wires underground has been tried in America. The ingenuity 

 shown is remarkable, and the description of the different systems 

 is extremely interesting and instructive ; as well as the methods 

 used by the Committee of the Institute to test the various sections 

 submitted to them. 



The proverbial inventive genius of our American friends is 

 plainly shown, but in spite of that inventive genius, and the 

 persistence with which the underground wire question has been 

 experimented with, it is still only in the experimental stage. 



In the early months of the present year a number of papers 

 upon the undergrounding of wires (as it is termed in America) 

 were read before the National Electric Light Association at 

 Pittsburgh. From these I find that the question is looked upon 

 as being in an unsatisfactory and unsettled state. 



Professor Thomson, in his address said, that it was generally 

 agreed, that except for expense and the difficulty of insulation 

 and making satisfactory connections from mains to houses, under- 

 ground wires were preferable. If a difference of potential of 

 only one hundred to two hundred volts existed, it was not difficult 

 to insulate, but where the difference amounted to two or three 

 thousand volts very great difficulty existed ; and the problem was 

 not only to secure an insulating covering which would adapt wires 

 to the use of high potentials without leakage, but to find an insu- 

 lation which was of indefinite durability where exposed to weather, 

 great toughness and power to resist abrasion, and at not too high a 

 cost. 



Mr. Leggett said that with underground wires, both telegraph 

 and telephone, the difficulty was much the same. Moisture must 

 be excluded. Insulation must be good and induction reduced to a 

 minimum. Then as regarded electric light wires, the Board of 

 Commissioners of Electric Subways instituted a thorough investiga- 

 tion, and reported in 1887. The Board said : — With regard to 

 electric light conductors, this Board has found no device which 

 would with certainty, in its opinion, enable the wires carrying arc 

 light currents to be safely and successfully operated in the same 



