National Telegraphic Union · New York : N.T.U. · leaf 12
rown earthenware. In the only American insu-lator on exhibition two different materials, each possessing obtained by coating the bolt or supporting pin with vul-canized rubber. The rim of the outer cup is rounded offinside, for the purpose of preventing the sprinkling of theinterior with rain-water… … Fig. 2
Telegraph
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