14 MARION EXPEDITION TO DAVIS STRAIT AND BAFFIN BAY 



kSea ice has none of the hardness and extreme brittleness that char- 

 acterizes fresh ice under similar coldness. The fact that salts lodge 

 between the pure ice crystals prevents the latter from interlocking 

 tightly, materially reducing the tensile strength, and permitting a 

 maximum amount of bending without fracture. ^- 



IcE Tekmixology 



The folloAving definitions are apparently more or less standard in 

 ice terminology : 



S/ush or sludge. — The initial stages in the freezing of sea water 

 when it is of a gluey or soupy consistency and when the surface of the 

 water takes on the appearance of cooling grease, with a peculiar steel- 

 gray or lead tint. 



Pancake ice. — Small cakes of new ice approximately circular with 

 raised rims. The rims give them a striking resemblance to pancakes. 

 The diameter of the cakes is from 1 to 3 feet and their thickness is up 

 to 2 to 4 inches. 



Young ice. — A compact sheet formed by the repeated freezing to- 

 gether, breaking up, and refreezing of cakes of pancake ice. Its 

 initial thickness is 1 to 3 inches and this may increase to a maximum 

 during a Avinter in the Arctic regions of 6 to 9 feet. 



Fast Ice.- — Horizontal ice formed by the freezing of the sea out from' 

 the shore. The 12-fathom contour is approximately the outer limit 

 of the spread of fast ice along open coast lines in the polar basin. , 



Ice foot. — That part of the fast ice which forms and builds on the 

 .shore itself and therefore is unaffected by vertical motions such as the- 

 tides. 



Anchor ice. — All submerged ice attached to the bottom irrespective! 

 of its mode of formation. 



Pack ice. — Sea ice which has drifted from its original position. 



Polar cap ice. — Oldest and heaviest of ice pack, characterizing the 

 central portions of the north polar basin. 



Ice field. — An area of ice other than fast ice of such an extent that, 

 its limits can not be seen from the ship's masthead. 



Ice floe. — An area of ice other than fast ice from one-third of a 

 mile in diameter to the size of an ice field. 



Glagon. — Any piece of pack ice ranging in size from a cake 2 to 3i 

 feet in diameter to a floe. 



Hummock. — A piece of ice formed by marginal crushing and 

 heaping up of the sea ice. 



Hummocking. — The process of pressure on sea ice resulting in a 

 heaping up of the sea ice. 



FJoehei'g. — A massive hummock; the results of great jn-essur-- anii| 

 piling up of the heaviest forms of sea ice. 



Rotten ice. — Any pack ice Avhich has become much honeycombed 

 through the latter stages of melting .so that it lacks the strength of 

 other ice. 



Crack. — Any fracture oi- i-ift in sea ice but not sufficiently wide to 

 ])ermit navigation. Kinds: (c/) Tidal; (A) temperature; \r) shook 

 and pressure. 



'2 WpypredU (1870, p. 40) states that so.ui after tli.' formation of young ice in the 

 antuiiiii it iccdids every t'ootiiriiit as <>asily as newly fallen snow. 



