SCIENTIFIC RESULTS 191 



an'ii also exceeds in etf'ect that of the <rhu-ial ice croji and the annual 

 volume of snowfall even, that falls on the waters in questi<ui. if 

 expressed as ice, closely approaches the annual <j:lacial discharge 

 of Avest Greenland. 



In the case cited for comparison we selected one of the most })rolific 

 glacial discharging regions in the north. If the annual production 

 of all sea ice from all sections in the north had been compared wdth 

 the total glacial discharge from all xVrctic lands, the relative insig- 

 nificance of the hitter's mass would become still more emphasized. 



The annual iceberg discharge appears much greater in volume than 

 it relatively is. for one reason, on account of the conventional method 

 of recording the positions of icebergs on a map as snuill circles or 

 triangles. These symbols necessarily can not be drawn to scale; if 

 so. they would be invisible, so actually they appear on the chart 

 greatly exaggerated. If all the glacial discharge from west Green- 

 land for one year could be amassed in a single berg and then drawn 

 to the scale of Figure 121. page 200, it would be represented by the 

 minute black rectangle off Cape Farewell, Greenland, marked " M.'' 

 If the annual amount of glacial ice be spread out to a thickness of 6 

 feet (the same dimension as that assumed for the sea ice), and then 

 drawn to scale on Figure 121 it will equal the area of the shaded 

 rectangle south of Greenland marked " N." *^ 



We have estimated that about one-twentieth of the sizable icebergs 

 calved from west Greenland each year (100) find their way south of 

 Xew^foundland. If it were possible for the annual production of 

 sea ice to form itself into separate sizable bergs, and the same rela- 

 tive distribution prevailed, the North Atlantic would be invaded 

 every spring by approximately 230.000 icebergs. 



EFFECT OF NORTHERN ICE ON TEMPERATURE AND CIRCULATION 

 OF THE WATERS OF THE NORTH ATLANTIC 



Among the most important, far-reaching events in northern seas, 

 according to many oceanographers and meteorologists, are the ther- 

 mal effects wdiich accompany ice formation and its dissipation. That 

 energy necessary to lower by 1° F. the temperature of a surrounding 

 volume of water about eighty times the size of the ice is a common- 

 place.*^ The relatively great number of units of heat energy needed 

 for the foregoing process represents the energy required to overcome 

 the cohesion of the solid ice molecules as the compact crystals are 

 changed into liquid form.*'' More than 1,000 cubic miles of ice, it is 



^^ Ricketts (1930, p. 100 1 has similarly ompliaslzed the exaggerated notion regarding 

 icebergs by stating that if the whole season's licrgs south of Newfoundland for the year 

 1920 (1350) be spread out over the Newtmuidhind shelf region they would niaki^ a uni- 

 form layer of ice only about one-eighth inth thick. If glacial ice did not take form as 

 massive iceberg bodies, such ice would be a rarity south of Labrador. 



" Heat of fusion in case of sea-water ice is approximately 67 calories. 



^ The heat of fusion is defined as the energy consumed or liberated upon transition of 

 matter from a solid to a liquid state, or vice versa, at a constant temperature The com- 

 position of sea ice. it will be recalled, is a conglomeration (not uniform) of pure ice ciTs- 

 tals. salt crystals and brine, and theoretically, therefore, under natural conditions, sea ice 

 never can exhibit a definitely fixed melting or freezing point. The heat of fusion of sea 

 ice in its commonly accepted solid state is found to vary inversely as the salinity. Pet- 

 *ersson ( ] ,SS3, p. 268 1 gives the following data: 



