American telegraphy and encyclopedia of the telegraph; systems, apparatus, operation (1909)
Maver, William, jr. [from old catalog] · New York, Maver publishing company · leaf 641
object in using several layers of gutta-percha, in the construction ofthe cable, is that, in the process of covering the wire with that material, air holes areliable to occur. If but one layer were used it is evident that the de /elopment of anair-hole into a fault would speedily follow the… … gutta-percha, and, over the hemp, a number of twisted galvanized iion wires, formingthe armor, is finally placed. For crossing rivers and bays in this country, cables containing from i to 7, ormore, conductors are employed. The insulation employed is mainly India rubber orgutta-percha, while, for…
Telegraph
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