Hoopers patent submarine telegraph cables, 1862. Mr. Hoopers cable is composed of the usual copper or other conductor insulated with indiarubber, which is now generally admitted to be by far the best material on account of its high insulating quality, its low inductive capacity, and its being unaffected by the heat of tropical climates...inclosing the indiarubber insulated wire within a jacket or coating of vulcanite or vulcanised indiarubber...decomposition [is prevented], as the indiarubber...becomes firmer by time...Another feature...is the protection of the wires used for tensile strength from corrosion or oxydation...Mr. Hooper either imbeds these wires in the vulcanite or vulcanised indiarubber jacket, or he covers them separately with either of these materials, and thus perfectly protects them from corrosion or decay. Figs. 1 and 2 show longitudinal sections of two forms of cable. Fig. 1: a, conductor; b, indiarubber insulator; c, separator; D, vulcanite or vulcanised indiarubber; e, f, wires for tensile strength imbedded in vulcanite or vulcanised indiarubber. Fig. 2 : a, conductor ; b, indiarubber insulator; c, wires or cords for tensile strength; d, protector of vulcanite or vulcanised indiarubber. From "Illustrated London News", 1862.