88 A TEXTBOOK OF OCEANOGRAPHY 



as good averages from i : 5 to i : 6, in this respect differing 

 considerably from British estimates. 



Icebergs drift south from Smith's Sound into Baffin's Bay, 

 and to these the Arctic giants belong, those from the Umanak 

 and Jakobshavn district being as a rule much smaller. The 

 principal source of the icebergs of Baffin's Bay and the 

 Labrador Current is, then, North-West Greenland, only a few 

 coming from the east side, via the East Greenland Current. 

 These latter have to round Cape Farewell before they get into 

 the Labrador Current. 



Icebergs disappear gradually under the same influences 

 which cause the melting of the pack-ice, the under-water 

 influence being chiefly a high sea, the aerial influences sunlight, 

 rain, and fog. 



The Greenland icebergs are carried down, together with a 

 certain amount of pack-ice, by the Labrador Current over the 

 Newfoundland Banks to 45 N. and lower. The monthly 

 distribution of both icebergs and pack-ice throughout the year 

 on the Banks is shown on the Monthly Meteorological Charts 

 of the North Atlantic. The melting of this ice appreciably 

 lowers the temperature and salinity of the surface water in these 

 regions. Since each iceberg swims, as it were, in its own cold- 

 water bath, it is frequently possible to detect the presence of an 

 iceberg in thick weather by the sudden drop in the temperature 

 of the surface water. 



Icebergs which drift below 40 N. Lat. or to the eastward 

 of 40 W. Long, must be regarded as exceptional. There are 

 twenty-one authentic records from the commencement of the 

 twentieth century up to July, 1916, a period of fifteen and a 

 half years. The position of these is show r n on the appended 

 chart (Fig. 14). 



Icebergs are never met with off the Norwegian coast, or off 

 the coast of Siberia, or in the North Pacific. 



The Antarctic is the region par excellence for icebergs. 

 Here they are calved almost anywhere along the great ice 

 barrier which marks the limit of the land of the Antarctic 



