330 



ANTARCTIC CRUISE. 



rapid than is generally supposed. The manner of their formation 

 claimed much of my attention while among them, and I think it may 

 be explained satisfactorily and without difficulty. In the first place, 

 I conceive that ice requires a nucleus, whereon the fogs, snow, and 

 rain, may congeal and accumulate ; this the land affords. Accident 

 then separates part of this mass of ice from the land, when it drifts off, 

 and is broken into many pieces, and part of this may again join that 

 which is in process of formation. The sketch in Chapter IX. has 

 already given the reader some idea of its appearance in this state. 



From the accumulation of snow, such a mass speedily assumes a 

 flat or table-topped shape, and continues to increase. As these layers 

 accumulate, the field-ice begins to sink, each storm (there of frequent 

 occurrence) tending to give it more weight. The part which is now 

 attached to the land remains aground, whilst that which is more 

 remote being in deep water is free to sink. The accumulated weight 

 on its outer edge produces fissures or fractures at the point where it 

 takes the ground, which the frosts increase; thus separated, the surface 

 again becomes horizontal, and continues to receive new layers from 

 snow, rain, and even fogs, being still retained to the parent mass by 

 the force of attraction. The fogs have no small influence in con- 

 tributing to the accumulation : some idea may be formed of the 

 increase from this cause, from the fact that during a few hours the ice 

 accumulated to the thickness of a quarter of an inch on our rigging 

 and spars, though neither rain nor snow fell. It may, therefore, I 

 think, be safely asserted that these icebergs are at all times on the 

 increase ; for there are few days, according to our experience in this 

 climate, in which some mode of precipitation does not prevail in these 

 high latitudes, where, according to our observations, ice seldom melts. 

 The temperature of even the summer months being rarely above the 

 freezing point, masses of a thousand feet in thickness might require 



TABULAR ICEBERG. 



but few years to form. Icebergs were seen in all stages of formation, 

 from five to two hundred feet above the surface, and each exposed its 



