IX GETTING THE RANGE 169 X TALKING IN THE SKY 184 XI WARRIORS OF THE PAINT-BRUSH 209 XII SUBMARINES 232 XIII GETTING THE BEST OF THE U-BOAT 253 XIV "DEVIL'S EGGS" 276 XV SURFACE BOATS 298 XVI RECLAIMING THE VICTIMS OF THE SUBMARINES 310 INDEX 339 LIST OF ILLUSTRATIONS Oil-tempering the lining of a big gun _Frontispiece_ FACING PAGE Lines of zig-zag trenches as viewed from an aëroplane 8 French sappers using stethoscopes to detect the mining operations of the enemy 9 A 3-inch Stokes mortar and two of its shells 36 Dropping a shell into a 6-inch trench mortar 36 The Maxim machine-gun operated by the energy of the recoil 37 Colt machine-gun partly broken away to show the operating mechanism 37 The Lewis gun which produces its own cooling current 44 The Benèt-Mercié gun operated by gas 44 Browning machine-gun, weighing 34-1/2 pounds 45 Browning machine-rifle, weight only 15 pounds 45 Lewis machine-guns in action at the front 52 An elaborate German machine-gun fort 53 Comparative diagram of the path of a projectile from the German super-gun 60 One of our 16-inch coast defence guns on a disappearing mount 61 Height of gun as compared with the New York City Hall 61 The 121-mile gun designed by American ordnance officer 68 American 16-inch rifle on a railway mount 69 A long-distance sub-calibered French gun on a railway mount 76 Inside of a shrapnel shell and details of the fuse cap 77 Search-light shell and one of its candles 77 Putting on the gas-masks to meet a gas cloud attack 84 Even the horses had to be masked 85 Portable flame-throwing apparatus 85 Liquid fire streaming from fixed flame-throwing apparatus 92 Cleaning up a dugout with the "fire-broom" 93 British tank climbing out of a trench at Cambrai 112 Even trees were no barrier to the British tank 113 The German tank was very heavy and cumbersome 113