162 Bibliography. 
layers from six inches to four feet in thickness. When the icebergs are fully 
formed, they have a tabular and stratified appearance, and are perfectly wall-sided, 
varying from one hundred and eighty to two hundred and ten feet in height. 
These were frequently found by us in their original situation, attached to eo land, 
and having the horizontal stratification distinctly visible. 
‘In some places we sailed for more than fifty miles together, along a straight 
and perpendicular wall, from one hundred and fifty to two hundred feet in height, 
with the land behind it. The icebergs found along the coast afloat were from a 
quarter of a mile to five miles in length; their separation from the land may be 
effected by severe frost rending them asunder, after which the violent and fre- 
quent storms may be considered a sufficient cause to overcome the attraction which 
holds them to the parent mass. In their next stage they exhibit the process of 
decay, being found fifty or sixty miles from the land, and for the most part with 
their surfaces inclined at a considerable angle to the horizon. ‘This is caused by 
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 can be little changed by the melting process before they reach the lati- 
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 
distance from the land increases, they are found inall stages of decay ; some form- 
ing ohelisks ; others towers and Gothic arches; and all more or less perforated ; 
some exhibit lofty columns, with a natural bridge resting on them of a lightness 
and beauty inconceivable in any other material. 
‘** While in this state, they rarely exhibit any signs of stratification, and some 
appear to be formed of a soft and porous ice ; others are quite blue; others again 
show a green tint, and are of hard flinty ice. Large ice-islands are seen that re- 
tain their tabular tops nearly entire until they reach a low latitude, when their 
dissolution rapidly ensues ; whilst some have lost all resemblance to their original 
formation, and had evidently been overturned. The process of actually rending 
asunder 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 inferred 
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 
of the sea, they in many cases form large overhanging shelves, about two or three 
feet above the water, extending out ten or twelve feet ; the under part of this pro- 
jecting mass exhibits the appearance of a collection of icicles hanging from it. 
The temperature of the water when among the icebergs, was found below or 
about the freezing point. 
“TJ have before spoken of 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 range 
before they were let loose or deposited. 
“The ice-islands, on being detached from their original place of formation by 
some violent storm, are conveyed to the westward by the southeast winds which 
are prevalent here, and are found, the first season after their separation, about 
« Seventy miles north of the barrier. This was inferred from the observations of 
both the Vincennes and Porpoise, the greatest number having been found about 
