128 CRUISE OF STEAMEE COR WIN IN THE ARCTIC OCEAN. 



he saw the Polar Ocean at tbe western entrance to Melville Sound, speaks of ice found to be 42 

 feet in depth, and expresses astonishment at its enormous thickness. McClure saw ice off the 

 Mackenzie River aud on the west coast of Banks Laud drawing from 40 to 50 feet of water, and 

 sometimes even 70 to 80 feet. At one time he saw hummocks 90 feet high. Dr. Kane saw ice 60 

 feet high. Wrangel encountered hummocks 90 feet high off the north coast of Asia. Captain 

 Nares, R. N., estimates the thickness of the main pack to be upwards of 80 or 100 feet. A floeberg 

 stranded and turned on its edge near the winter quarters of the Alert was measured by Nares and 

 found to be 120 feet long, 105 feet broad, and 80 feet in depth. This floeberg, which is described as 

 by no means the largest in the vicinity, was shown by calculation to weigh about 25,000 tons. The 

 greatest thickness attained by direct freezing is about 18 feet,, at which thickness the increase by 

 freezing at the bottom does not exceed the waste at the top by evaporation, which goes on slowly 

 but surely at all times. The maximum thickness by direct freezing is generally reached the third 

 winter. It is seldom that more than 9 feet forms during one winter. The extraordinary thickness 

 attained by the pack is due to accumulations of these naturally formed layers, as they are forced 

 one over the other by pressure due to currents of air and water. On account of the difficulties of 

 ascertaining the thickness of the ice by measurement, the most reliable way appears to be by 

 noting the depth of water at which it touches the bottom. This we found at Herald Island, 

 Wrangel Island, and on the coast of Asia near Cape North, to be about 10 fathoms. In Bering 

 Sea we made fast to ice grounded in 6 fathoms, and passed a number of detached pieces grounded 

 in 8 fathoms. 



Field-ice, when not broken and piled up by the force to which it is subject, constantly grows 

 smoother on the surface. The hummocks are reduced by melting during the summer, and the 

 water thus formed partly fills the hollows. In winter the hollows are further filled by snow, so 

 that in time the surface becomes comparatively smooth. 



The lanes of water separating these floes or fields, and which at times penetrate, to a limited 

 extent, the pack itself, are called " leads" and " water-holes." Places where leads and water-holes 

 are numerous are called by the Russians " polynia." Lsind ice is that which adheres to the coast. 

 This, when broken and thrown up by the action of the sea, is called "ice-foot." The ice-pack is 

 seldom, if ever, seen from the mast-head more than 12 miles, and from the deck not more than 7 

 miles. 



Light reflected from the ice to the clouds above is called " ice-blink." The blink may often 

 be seen at a distance of 30 or 40 miles, and by it the nature of the ice, whether pack or drift, may 

 generally be determined. The blink, over drift ice, shows dark lines, while over the solid pack it 

 presents a uniform yellowish color to the horizou. This rule, however, is not invariable. The 

 vapors arising from a small lead or water-hole in the pack will sometimes change the entire 

 appearance of the blink and give the impression that a large body of open water exists. It is 

 not impossible that many of the reported discoveries of open polar seas may be accounted for in 

 this way. It should always be borne in mind that the pack can be seen but a short distance — 

 12 miles at best — and that, under certain conditions, no blink is shown, and that when looking 

 across ice for clear water beyond, or indications of it, a lead may produce as perfect a water-sky, 

 or one in which there is an entire absence of ice-blink, as an open sea. This was frequently 

 observed by Mr. Nelson during his sojourn at Saint Michael's, Norton Sound. In the winter-time, 

 from an unbroken ice-blink, a few hours' southerly wind would produce a perfect water-sky and 

 horizon, with no indication of ice beyond. Of course the only effect of this southerly wind on the 

 ice would be to open leads or water-holes of limited extent, which the first change of wind would 

 close again. 



The dark shadow over open leads of water is at times so perfect in outline as to be taken for 

 land. Au instance of this came under my observation during my cruise in the Arctic Ocean in 

 1880. Near Point Barrow the pack was in sight from the deck, probably 4 miles away, when 

 land was reported bearing northwest. The appearance was so perfect that, had it not been for 

 the fact that this part of the sea had many times been sailed over, I should have believed that I 

 was actually looking upon laud. Captain Nares attributes to this cause the erroneous report of 

 the existence of land to the north of Robeson Channel by the Polaris Expedition, and states that 



