534 



Popular Science Monthly 



conduit line ten ducts wide and seven 

 ducts high. 



The work was carried on in the heart 

 of a great city, and also in the midst of 

 the added confusion of tearing down old 

 and erecting new buildings. 



In the transfer of cables from the old 

 ducts to the new, the fact that this could 

 be done without splicing and consequent 

 interruption of service was particularly 

 important. The long distance cables, 

 moreover, were composited for the simul- 

 taneous working of telephone and tele- 



Laying the cables into split ducts without 

 cutting or drawing through conduits as 

 usual. The ducts used were the usual 

 vitrified clay, but before baking they 

 were scored inside and out, and easily split 

 open by the brick-layer 



The cables are in the ducts and the con- 

 crete which will seal them is about to be 

 applied. The split conduit was a new idea, 

 but it allowed for the "laying" of the cables 

 instead of drawing them through the pipes 



The only cable cut. It 

 was necessary to do this 

 to get around an obstruc- 

 tion. There were 800 

 wires to be cut and spliced 

 individually 



graph, or else carried 

 additional phantom 

 telephone circuits su- 

 ])erimposecl upon the 

 l)hysical circuits. The 

 cutting of these cables, 

 which was the usual 

 thing to do, would 

 have entailed not only 

 expense, but interrup- 

 tions more serious than 

 on the local serA'ice. 



