The second familiar means of defence was the gun. Here again there was a temptation to despair. The secondary armament of any battle-ship or cruiser was fairly certain to make short work of a torpedo-boat, or of a submarine visible upon the surface. But no living gunner had ever fired at the periscope of a submarine--a mark only two feet, at most, out of the water, and only four inches in diameter. To see such an object at, say, 1,000 yards, was difficult; to hit it might well seem impossible. Yet 1,000 yards was but one-tenth of the possible range at which a modern submarine might fire its torpedo. Nevertheless the use of the gun was not discarded; and two important discoveries were made in consequence. The first of these was that gunfire may be distant, wild, or even unaimed, and yet have an excellent effect. The existence of a submarine is so precarious--its chance of surviving a single direct hit is so slight--that the mere sound of a gun will almost always be enough to make it submerge completely--unless it can engage the enemy, with superior gun-power, at a range of its own choosing. When Captain Weddigen had already hit the _Aboukir_, the _Hogue_, and the _Cressy_, and all three were sinking, the sound of the _Cressy’s_ guns was enough to cause his disappearance, though it is very improbable that the shooting was really dangerous; for the listing of the ship was rapid, and according to eye-witnesses, the gallant gunners were soon firing in the air. Since then, the same thing has been repeatedly observed; and some brilliant successes by our patrol-boats and trawlers have shown that the U-boat has every right to be nervous when it hears even a 6-pounder talking English. The other discovery is a much more recent one. As soon as it was once recognised that a torpedo is just as innocuous when deflected, as when stopped or evaded, the idea was sure to strike the handiest gunners in the world that they might use their weapons to disturb the straightforwardness of the fish’s onset. Even thirty knots is nothing to the velocity of a modern shell, and without hoping for a direct hit on an object from six to twenty-two feet under water, it was thought possible to give a twist to the torpedo’s nose sufficient to make a potential hit into a miss or a glancing shot. This feat was actually performed by the gunners of the _Justitia_, who, with splendid coolness, shot at torpedoes as sportsmen used to shoot at oncoming tigers, and succeeded in killing or diverting several, only to fall at last before the rush of numbers. [Illustration: ‘She had gone full speed for the enemy, and rammed him.’]