THE NARRATIVE OF CHARLES WILKES. 405 
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, 
TABULAR ICEBERG. 
rain, and even fogs, being still retained to the parent mass by the 
force of attraction. The fogs have no small influence in contributing 
to the accumulation; some idea may be formed of the increase from 
this cause, from the fact that during a few hours the ice accumu- 
lated 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 1000 feet in thickness might require but few years to form. Icebergs 
were seen in all stages of formation, from 5 to 200 feet above the surface, 
and each exposed its stratification in horizontal layers from 6 inches to 
4 feet in thickness. When the icebergs are fully formed they have a 
tabular and stratified appearance, and are perfectly wall-sided, varying 
from 180 to 210 feet in height. These were frequently found by us in 
their original situation, attached to the land, and having the horizontal 
stratification distinctly visible. 
