During the nineteen days mentioned above, no incident of any kind happened to signalise our voyage. I saw little of the Captain; he was at work. In the library I often found his books left open, especially those on natural history. My work on submarine depths, conned over by him, was covered with marginal notes, often contradicting my theories and systems; but the Captain contented himself with thus purging my work; it was very rare for him to discuss it with me. Sometimes I heard the melancholy tones of his organ; but only at night, in the midst of the deepest obscurity, when the _Nautilus_ slept upon the deserted ocean. During this part of our voyage we sailed whole days on the surface of the waves. The sea seemed abandoned. A few sailing-vessels, on the road to India, were making for the Cape of Good Hope. One day we were followed by the boats of a whaler, who, no doubt, took us for some enormous whale of great price; but Captain Nemo did not wish the worthy fellows to lose their time and trouble, so ended the chase by plunging under the water. Our navigation continued until the 13th of March; that day the _Nautilus_ was employed in taking soundings, which greatly interested me. We had then made about 13,000 leagues since our departure from the high seas of the Pacific. The bearings gave us 45° 37′ S. lat., and 37° 53′ W. long. It was the same water in which Captain Denham of the Herald sounded 7,000 fathoms without finding the bottom. There, too, Lieutenant Parker, of the American frigate Congress, could not touch the bottom with 15,140 fathoms. Captain Nemo intended seeking the bottom of the ocean by a diagonal sufficiently lengthened by means of lateral planes placed at an angle of 45° with the water-line of the _Nautilus_. Then the screw set to work at its maximum speed, its four blades beating the waves with in describable force. Under this powerful pressure, the hull of the _Nautilus_ quivered like a sonorous chord and sank regularly under the water. At 7,000 fathoms I saw some blackish tops rising from the midst of the waters; but these summits might belong to high mountains like the Himalayas or Mont Blanc, even higher; and the depth of the abyss remained incalculable. The _Nautilus_ descended still lower, in spite of the great pressure. I felt the steel plates tremble at the fastenings of the bolts; its bars bent, its partitions groaned; the windows of the saloon seemed to curve under the pressure of the waters. And this firm structure would doubtless have yielded, if, as its Captain had said, it had not been capable of resistance like a solid block. We had attained a depth of 16,000 yards (four leagues), and the sides of the _Nautilus_ then bore a pressure of 1,600 atmospheres, that is to say, 3,200 lbs. to each square two-fifths of an inch of its surface.