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Telegraph and Telephone Wire

These wires, when made from the ordinary bronzes, were found to be insufficiently conductive. A silicon-bronze has now been substituted, which is equal in strength to the best phosphor-bronze, much superior as a conductor of electricity, and much lighter. The alloy, when produced from the prepared compound, contains, in telephone wire, copper 99.94, tin 0.03, silicon 0.02. For telegraph wire, copper 97.12, tin 1.14, silicon 0.05, zinc 1.62, with iron a trace in each. The compound which forms the base for this mixture is obtained by fusing the copper in a lead crucible with carbonate of soda, fluorsilicate of potassium, chloride of soda, chloride of calcium, and glass. The oxides are by this means absorbed by the acid flux of the silica. Silicon-bronze thus obtained has about 70 per cent of the electrical conductivity of copper, while phosphor-bronze has but 30, and steel something over 10.