SCIENTIFIC EESULTS 



97 



American shores. If 7,500 bergs be representative then normally 

 only 1 berg in 20 finally succeeds in drifting out of Davis Strait and 

 south of Newfoundland. The Mar'io)! expedition's estimate of 2,200 

 bergs south of Disko Bay in the summer of 11)2<S in conjunction with 

 the numl)cr of bergs south of Xewfoundland during the preceding 

 spring indicates tliat the crop is not entirely destroyed during one 

 summei'. but that one. two, and ))ossible three year age groups per- 

 sist in Baffin Bay and Davis Strait. 



Manner in Which Icebergs Calve 



The so-called calving process by wdiich end portions of a glacier 

 break away from their main nuiss creating icebergs is a ])h(uiomenon 



Great Karajak Glacier Prior to a Major Calving 



Figure 



GLEE .JC. — The fn>iit wall of Gie:it Kaiaink Glacier in T'manak Fjord, west Green- 

 land (lat. 70° L'.")' X.. long. 50" '60' W. ) before a major calving. August 13. 1892. 

 (Jrcat Kai'ajak is one of the most productive iceberg glaciers in the north. (Photo- 

 graph by E. von Dr.vga!ski.) 



which has been under discussion for many years. The original con- 

 ception held tliat the glacier end protruding out across the threshold 

 of its molded bed lost support and through the continual accumula- 

 tion of weight finally exceeded its structural strength and broke off. 

 Such a process assumes, of course, that the bed on which the glacier 

 slides has a steeper slope than the ice stream, which is not invariably 

 the cai.e. 



A later theory introduced by Rink (ISSI), p. 276), maintains that 

 icebergs are formed when the downward, slanted axis of the glacier 

 prolonged into the greater dei)ths of the fjord is more and more 

 buoyed up until finally the end fractures, the iceberg rising to the 

 surface. Rink qualified the foregoing by admitting that small 

 pieces of ice are also calved by splitting away and falling dow^n 



