Every torpedo-boat was now ordered to the front, and in a long line, almost abreast of each other, these swift vessels--the light-infantry of the sea--advanced upon the solitary and distant foe. If one torpedo could but reach her hull, the Vice-Admiral, in spite of seven disabled ironclads and a captured gun-boat, might yet gaze proudly at his floating flag, even if his own ship should be drifting broadside to the sea. The line of torpedo-boats, slightly curving inward, had advanced about a mile, when Repeller No. 11 awoke from her seeming sleep, and began to act. The two great guns at her bow were trained upward, so that a bomb discharged from them would fall into the sea a mile and a half ahead. Slowly turning her bow from side to side, so that the guns would cover a range of nearly half a circle, the instantaneous motor-bombs of the repeller were discharged, one every half minute. One of the most appalling characteristics of the motor-bombs was the silence which accompanied their discharge and action. No noise was heard, except the flash of sound occasioned by the removal of the particles of the object aimed at, and the subsequent roar of wind or fall of water. As each motor-bomb dropped into the channel, a dense cloud appeared high in the air, above a roaring, seething cauldron, hollowed out of the waters and out of the very bottom of the channel. Into this chasm the cloud quickly came down, condensed into a vast body of water, which fell, with the roar of a cyclone, into the dreadful abyss from which it had been torn, before the hissing walls of the great hollow had half filled it with their sweeping surges. The piled-up mass of the redundant water was still sending its maddened billows tossing and writhing in every direction toward their normal level, when another bomb was discharged; another surging abyss appeared, another roar of wind and water was heard, and another mountain of furious billows uplifted itself in a storm of spray and foam, raging that it had found its place usurped. Slowly turning, the repeller discharged bomb after bomb, building up out of the very sea itself a barrier against its enemies. Under these thundering cataracts, born in an instant, and coming down all at once in a plunging storm; into these abysses, with walls of water and floors of cleft and shivered rocks; through this wide belt of raging turmoil, thrown into new frenzy after the discharge of every bomb,--no vessel, no torpedo, could pass.