Papier mâché horse, 223 Parachute, 175 grenade, 31 search-light shell, 84 Paravanes, 288 Periscope, submarine, 244 trench, 11 Pill-boxes, 59 Pneumatic breakwater, 335 Pontoons, salvage, 320 Propeller, shooting through, 136 Radio, see Wireless Railroad, mine, 294 Railways, trench, 10 Range-finder, 170 Range, getting the, 169 Range of guns, increasing, 67 Range, torpedo, 213 Rats, freeing trenches of, 94 Rifle grenade, 28 safety device, 32 Rifle, machine, 55 Rifle stand, fixed, 14 Roads, camouflage, 225 Salvage, 310 diving, 324 ice-tongs, 334 lifting-magnets, 334 methods, 317 pneumatic, 319 pontoons, 320 shackles on ships, 333 submarine F-4, 321 submarine sphere, 332 Scouts, airplane, 128 Sea, deep, conditions, 312 Sea gulls finding submarines, 258 Sea lions locating submarines, 259 Sea tank, 299 Seaplane, 143 automatic, 145 submarine patrol, 259 torpedo, 145 towing-barges, 302 Search-light shell, 84 Shackles, salvage, 333 Shadowless buildings, 227 Shell, gas, 95 grapnel, 16 search-light, 84 shrapnel, 83 Stokes mortar, 39 Shield on wheels, 114 Ships, airplane, 304 Ships, blisters, 307 camouflage, 211 "clothes-line," 220 convoy, 267 hush, 304 making visible, 230 monitors, 306 mystery, 220 railroads on, 294 sunk by submarines, 310 Ships, see also Salvage Shrapnel shell, 83 Sled, submarine, 330 Smoke screen, 262 Sniper, locating, 13 Sniperscopes, 12 Sound, detecting submarines, 269 Sound detectors, mines, 18 Sound, spotting by, 181 Sphere, salvor's submarine, 332 Spotting by sound, 181 Spotting gun-fire, 177 Submarine, blindness, 244 chasers, 255 construction, 234 depth bombs, 265 egg-laying, 287 engines, 246 F-4, salving, 321 getting best of, 253 graveyard, 314 guns on, 249 history, 232 hydrophone, 270 mine-field, 290 mine-laying, 287 net, 290 oil-tank, 236 periscope, 244 reclaiming victims of, 310 rest chamber, 328 salvage vessel, 332 sea-gulls, 258 sea-lions, 259 seaplanes, 259 ships sunk, 310 sled, 330 steam-driven, 250 torch, 329 torpedo, 246 12-inch gun, 251 vs. submarine, 269 Super-guns, 62 Tank, 107 American, 122 flying, 139 French, 119 German, 120 one-man, 114 sea, 299 small, 121 Telegraphy, rapid, 199 Telephone, New York to San Francisco, 186 wireless, 178 _Titanic_, 314 TNT (trinitrotoluol), 18 Torch, submarine, 329 Torpedo, 299 boats, motor, 298 electrically steered, 308 construction, 246 getting range, 213 proof ships, 306 seaplane, 145 Towing-barge, seaplane, 302 Trajectory, 22 Trench, gas-lock, 97 Trench mortar, 36 pneumatic, 37 Stokes, 38 Trench railways, 10