Nothing, of course, was visible through the downpour; but they were startled at hearing fearful cries issuing out of the darkness. The rural parts of the city, filled with gardens and villas, lay round within a quarter of a mile of the ark, and the sound, accelerated by the water-charged atmosphere, struck upon their ears with terrible distinctness. Sometimes, when a gust of wind blew the rain into their faces, the sound deepened into a long, despairing wail, which seemed to be borne from afar off, mingled with the roar of the descending torrent--the death-cry of the vast metropolis! "Merciful Heaven, I cannot endure this!" cried Professor Moses. "Go to my cabin," Cosmo yelled in his ear, "and take the others with you. I will join you there in a little while. I wish to measure the rate of rise of the water." They gladly left him, and fled into the interior of the ark. Cosmo procured an electric lamp; and the moment its light streamed out he perceived that the water had already submerged the great cradle in which the ark rested, and was beginning to creep up the metallic sides. He lowered a graduated tape into it, provided with an automatic register. In a few minutes he had completed his task, and then he went to rejoin his late companions in his cabin. "In about an hour," he said to them, "we shall be afloat. The water is rising at the rate of one-thirtieth of an inch per second." "No more than that?" asked Professor Jones with an accent of surprise. "That is quite enough," Cosmo replied. "One-thirtieth of an inch per second means two inches in a minute, and ten feet in an hour. In twenty-four hours from now the water will stand two hundred and forty feet above its present level, and then only the tallest structures in New York will lift their tops above it, if, indeed, they are not long before overturned by undermining or the force of the waves." "But it will be a long time before the hills and highlands are submerged," suggested Professor Jones. "Are you perfectly sure that the flood will cover them?" Cosmo Versál looked at his interlocutor, and slowly shook his head. "It is truly a disappointment to me," he said at length, "to find that, even now, remnants of doubt cling to your minds. I tell you that the nebula is condensing at its maximum rate. It is likely to continue to do so for at least four months. In four months, at the rate of two inches per minute, the level of the water will rise 28,800 feet. There is only one peak in the world which is surely known to attain a slightly greater height than that--Mount Everest, in the Himalayas. Even in a single month the rise will amount to 7,200 feet. That is 511 feet higher than the loftiest mountain in the Appalachians. In one month, then, there will be nothing visible of North America east of the Rockies. And in another month they will have gone under."