SCIENTIFIC RESULTS 



95 



Due to the scantiness of data the foregoing estimate of 7,500 size- 

 able icebergs calved annually from west Greenland may be criticized 

 as speculative. It is justified, however, even if it does no more than 

 roiivey a general idea of the i:)oints of discharge and of the relative 

 proportions in which their glaciers combine to make up the grand 

 j total. The figures of 1,350 bergs for Jacobshavn, 750 for Torsuka- 

 itak, etc., are largely based on Helland's (1876, p. 108) measurement 

 1 5.8" kilometers and 2.3" kilometers as the total annual calvings of 

 Jacobshavn and Torsukatak fjords, respectively. It has further been 

 assumed that the average of sizeable bergs has a volume of 50,000,000 

 cubic feet (0.00145^ kilometers) and that such bergs constitute one- 

 third of the total calved ice, the other two-thirds consisting of smaller 

 pieces and detritus. In other words, if Jacobshavn calves 5.8^ kilo- 

 meters a year, then 1.93' kilometers are in the form of sizable bergs^ 

 which, in 50,000,000 cubic-foot sizes, totals 1,350.^'^ 



The number of bergs frojn the respective fjords and glaciers is also 

 subject to a slow change within certain limits over a series of years. 

 For example, the retreat of Jacobshavn Glacier, first observed in 

 1850, is being reflected in the rate of its berg productivity.^*' 



According to the foregoing table nearly 70 per cent of the North 

 Atlantic bergs come from Northeast Bay and Disko Bay; about 20 

 per cent from the Melville Bay district; and only 2 per cent from the 



55 Di-ygaiski (1895, p. 402). after careful measurements, found Great Karajak Glacier 

 calved 13. S'' kilometers annually and he criticizes Helland's estimate of 5.8^ kilometers as 

 far too low for Jacobshavn. If Drygalski is correct, then the output of Jacobshavn ac- 

 cording to the relative weights given, page 95, would be 25.5^ kilometers. But this seems 

 too great, and does not agree with de Quervain"s estimate of HP to 100=* kilometers for the 

 entire wastage in solid form from the western side of the ice sheet. Surely Jacobshavn 

 can not account for approximately one-fourth the total yearly output of west Greenland. 



^^ Lauge Koch told me that he had not visited Disko Bay for 15 years, although he had 

 passed it several times, but tliat he never saw so few bergs as in 1928. Umiamako Glacier 

 in Umanak Fjord, on the other hand, appeared to have increased in activity, for the fjord 

 was simply littered with bergs in 192S, very similar to conditions prevailing in Disko Bay 

 Bevei'al years ago. 



