162 Bibliography. 
ers from six inches to four feet in thickness. When the icebergs are full 
pant they mre a tabular and stratified appearance, and are perfectly wall-sided, 
varying from one hundred and vey to two hundred and ten feet in height. 
These were acceiiity. found by us in their original situation, attached to the land, 
and having the horizontal ets Poa distinctly visi 
“‘ In some places we sailed for more than fifty miles ninth along a straight 
with the land behind it. The icebergs found along the coast afloat were from a 
quarter of a mile to five miles in Jength; their separation from the land may be 
effected by severe frost rending them asunder, ane which ne: ela — fre- 
which 
a change in the position of the centre of gravity, arising from the abrading action 
of the waves. 
“ By our observations on the temperature of the sea, it is evident that these 
ice-islands ean be little changed by-the melting process before they reach the Iati- 
tude of 60. The temperature of the sea (as observed by the vessels going to and 
returning from the south) showed but little change above this latitude, and no 
doubt it was at its maximum, as it was then the height of the summer season 
“ During their drift to the northward, on reaching lower latitudes, and as their 
some exhibit lofty columns, with a natural Kasi resting on them of a lightness 
aor beauty inconceivable in any other materia 
“ While in this state, they rarely exhibit pay signs of stratification, and some 
appear to be formed of a soft and porous ice ; others are quite blue; others 
show a green tint, and are of hard flinty ice. Large ice-islands are seen that re 
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ilst some have lost all resemblance to their original 
formation, and had evidently been overturned. The process of actually rending 
er was not witnessed by any of the vessels, although in the Flying-Fish, 
when during fogs they were in close proximity to large ice-islands, they in 
from the loud crashing, and the sudden splashing of the sea on her, that such oc- 
currences had taken place. As the bergs gradually become worn by the abrasion 
The temperatore:o f the water when among the icebergs, was found below oF 
about tie fexsing pint 
nist RS 
f the boulders imbedded in the icebergs. All those that 
I had an opportunity of observing, apparently formed a part of the nucleus, and 
were surrounded by extremely compact ice, so that they appear to be connected 
with that portion of the ice that would be the last to dissolve, and these boulders 
would therefore in all probability, be carried to the farthest extent of their rang 
—_— pes were let loose or deposited. 
both the Vincennes and Porpoise, the greatest number having been found about 
