G. Galvanometer, astatic, 87 ----, detector, 88 ----, differential, 88 ----, tables, Siemens' universal, 287 ----, thermo, 89 ----, Thomson's reflecting, 87 ----, three coil, 88 ----, universal, Siemens', 89 Generating electricity, methods of, 269 German torpedo vessel _Uhlan_, the, 158 Gun, the Nordenfelt torpedo, 257 ----, Hotchkiss torpedo, 259 Gun-cotton, 212 Gunpowder, 208 Guns, torpedo, 257 Gutta-percha as a dielectric, 38 H. Harbours by booms, defence of, 110 Harpoon torpedoes, Fulton's, 5 Harvey's towing torpedo, 119 ---- ----, brakes for, 123 ---- ----, buoys for, 122 ---- ----, for defensive purposes, 129 ---- ----, launching, 123 ---- ----, methods of attack with, 127 ---- ----, mode of firing, 121 ---- ----, tactics with, 127 ---- ----, the value of, 129 Helmet for divers, 260 Herreshoff's torpedo boats, 178 High tension fuzes, 102 Hooper's electric cables, 41 ---- material, 39 Horsley's powder, 216 Hotchkiss torpedo gun, the, 259 I. Ignition, Bushnell's mode of, 2 ---- of Whitehead's fish torpedo, mode of, 135 Illustrated torpedo explosions, 218 Improved form of Lay's torpedo, an, 153 India rubber tube joint, the, 45 Inertia circuit closer, Mathieson's, 61 ---- ----, improvements in, 63 Instrument and observing telescope, shutter, 84 Instruments used in testing, 85 Insulated electric cables, 38 ---- joints, electrical test of, 104 Insulation, sea cell tests for, 106 ---- test for electric cables, 102 Insulators, 268 Intensity of a current, measuring the, 95 Internal resistance, Voltaic battery test for, 104 Intersectional arcs, firing by, 71 Invention and adoption of the fish torpedo, the, 131 Italian torpedo launches, Thornycroft's, 168 J. Jacobi's fuze, improved form of, 24 Jar, the Leyden, 279 Jointing electric cables, 44 Joints, Beardslee's, 46 ----, electrical test of insulated, 104 ----, india rubber tube, 45 ----, Mathieson's, 45 ----, McEvoy's, 46 ----, Nicholl's metallic, 45 ----, rules to be observed in forming, 51 ----, Siemens' permanent, 47 _Jones_, the loss of the _Commodore_, 189 Junction boxes, 51 ---- ---- for multiple cables, 52 ---- ---- single cored cables, 52 ---- ----, T, 53 K. Keys, firing, 80 ---- ----, description of a series of, 81 ---- ----, Morse, 81 Kiel, torpedo experiments at, 222 Knowledge, theoretical, 8