The bow of the vessel now rose upon the swell of the sea, and the instant that the index upon the scale reached the desired point, the Director-in-chief touched the button. There was no report, no smoke, no visible sign that the motor had left the cannon; but at that instant there appeared, to those who were on the lookout, from a fort about a mile away, a vast aperture in the waters of the bay, which was variously described as from one hundred yards to five hundred yards in diameter. At that same instant, in the neighbouring headlands and islands far up the shores of the bay, and in every street and building of the city, there was felt a sharp shock, as if the underlying rocks had been struck by a gigantic trip-hammer. At the same instant the sky above the spot where the motor had descended was darkened by a wide-spreading cloud. This was formed of that portion of the water of the bay which had been instantaneously raised to the height of about a thousand feet. The sudden appearance of this cloud was even more terrible than the yawning chasm in the waters of the bay or the startling shock; but it did not remain long in view. It had no sooner reached its highest elevation than it began to descend. There was a strong sea-breeze blowing, and in its descent this vast mass of water was impelled toward the land. It came down, not as rain, but as the waters of a vast cataract, as though a mountain lake, by an earthquake shock, had been precipitated in a body upon a valley. Only one edge of it reached the land, and here the seething flood tore away earth, trees, and rocks, leaving behind it great chasms and gullies as it descended to the sea. The bay itself, into which the vast body of the water fell, became a scene of surging madness. The towering walls of water which had stood up all around the suddenly created aperture hurled themselves back into the abyss, and down into the great chasm at the bottom of the bay, which had been made when the motor sent its shock along the great rock beds. Down upon, and into, this roaring, boiling tumult fell the tremendous cataract from above, and the harbour became one wild expanse of leaping maddened waves, hissing their whirling spray high into the air. During these few terrific moments other things happened which passed unnoticed in the general consternation. All along the shores of the bay and in front of the city the waters seemed to be sucked away, slowly returning as the sea forced them to their level, and at many points up and down the harbour there were submarine detonations and upheavals of the water. These were caused by the explosion, by concussion, of every torpedo and submarine battery in the harbour; and it was with this object in view that the instantaneous motor-bomb had been shot into the mouth of the bay.