Page:Physical Geography of the Sea and its Meteorology.djvu/280

254 They hooked on to it, and were towed to the north by it. Captain Duncan, master of the English whale-ship Dundee, says, at page 76 of his interesting little narrative: December 18th (1826). It was awful to behold the immense icebergs working their way to the north-east from us, and not one drop of water to be seen; they were working themselves right through the middle of the ice." And again, at page 92, etc.: February 23rd. Latitude 68° 37' north, longitude about 63° west. The dreadful apprehensions that assailed us yesterday by the near approach of the iceberg were this day most awfully verified. About three p.m. the iceberg came in contact with our floe, and in less than one minute it broke the ice; we were frozen in quite close to the shore; the floe was shivered to pieces for several miles, causing an explosion like an earthquake, or one hundred pieces of heavy ordnance fired at the same moment. The iceberg, with awful but majestic grandeur (in height and dimensions resembling a vast mountain), came almost up to our stern, and every one expected it would have run over the ship The iceberg, as before observed, came up very near to the stern of the ship; the intermediate space between the berg and the vessel was filled with heavy masses of ice, which, though they had been previously broken by the immense weight of the berg, were again formed into a compact body by its pressure. The berg was drifting at the rate of about four knots, and by its force on the mass of ice was pushing the ship before it, as it appeared, to inevitable destruction. Feb. 24th. The iceberg still in sight, but drifting away fast to the north-east. Feb. 25th. The iceberg that so lately threatened our destruction had driven completely out of sight to the north-east from us."

483. Temperature of the under current.—Now, then, whence, unless from the difference of specific gravity due to sea water of different degrees of saltness and temperature, can we derive a motive power in the depths of the sea, with force sufficient to give such tremendous masses of ice such a velocity? What is the temperature of this under current? Rodgers's observations (§ 480) would seem to indicate that at the depth of 150 feet it is not below 40°. Assuming the water of the surface current which runs out with the ice to be all at 28°, as De Haven found it (§ 479), we observe that it is now unreasonable to suppose that