40 HOBBS— THE FIXED GLACIAL ANTICYCLONE. 



tions over continental glaciers will be obtained through assembling 

 the observations recorded in the journals of sledging parties, notably 

 the wind direction, the orientation of sastrugi, temperature condi- 

 tions, snow surface and humidity. 



Dr. Simpson's discussion of the Antarctic blizzard suffers espe- 

 cially because in his evaluation of the available moisture content of 

 the air over the Antarctic region he has taken account, not of the 

 water content in all states of aggregation within the unit of space, 

 but of that portion only which is uncongealed and therefore regis- 

 tered by the usual hygrometric apparatus. Adiabatic changes readily 

 transform the ice needles of the cirri into moisture, which until 

 again congealed or crystallized is duly registered upon the hygro- 

 metric record, and if the congealed material is not to be entered in 

 the accounting the proper equating of available moisture before and 

 after an adiabatic meteorological change will be impossible. This 

 is obviously the reason why Dr. Simpson says of my theory of the 

 glacial anticyclone that it fails "to explain the origin of the pre- 

 cipitation and the mechanism of blizzards," and "Hobbs has left un- 

 solved . . . the greatest problem of the Antarctic anticyclone, 

 namely, the origin of the precipitation Vv^ithin the anticyclone." As 

 a matter of fact, in all my papers upon the subject this process of 

 precipitation and its origin in the blizzard itself has been elaborated, 

 not as an additional feature of the anticyclone, hut as a necessary in- 

 herent quality zvhich can in no zvise be omitted. 



The continental glacier in its evolution must be conceived to have 

 developed from enlargement of an ice-cap which is nourished like 

 the mountain glaciers by ascending moist air currents. Ice-cap 

 glaciers exist today on Iceland, in Norway, and as isolated masses on 

 the borders of continental glaciers. Though in form they resemble 

 continental glaciers, they are: (i) much smaller, (2) they are 

 nourished by a wholly different process, (3) they owe their exist- 

 ence to their location upon a pedestal-like base which is relatively flat 

 and extends above the snow line of the region. 



An interesting question arises, " At what stage of their develop- 

 ment will this type of glacier take on the auto-circulation of a con- 

 tinental glacier and by reaching up draw down the ice needles of the 



