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.
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