392 
REVIEW. 
by water; an,d some of the larger hummocks, whose 
colossal blocks had attracted my attention during the 
winter, were now wet and marshy to approach. Upon 
excavating blocks of ice with the saw and pickaxe, it 
was found, in many cases, to have lost its well-con-f 
densed character. It was divided by vertical lines 
into prisms, which stood prominently out, and ran 
continuously from the watery to the atmospheric sur- 
face, with an arrangement almost basaltic.^ 
Struck by this circumstance, I was led to test the 
ice of different localities by both the Marcet's bottle 
and the nitrate of silver, and discovered that the floes, 
which had formed in midwinter at temperatures be- 
low -30, were still fresh and pure, while the floes of 
slower growth, or of the early and late portions of the 
season, were distinctly saline. Indeed, ice which only 
two months before I had eaten with pleasure, was now 
so salt that the very snow which covered it was no 
longer drinkable. 
This is a subject well worthy of future examina- 
tion. The dissolution of the great ice-fields of the 
Polar regions bears upon physical questions of the 
highest importance; and it really seems to me that 
changes, independent of expansion and contraction, 
must take place in the molecular condition of the ice 
at temperatures greatly below the freezing point. 
Another element in the disintegration of the floes, 
of which this was but a preliminary process, struck 
me forcibly a little later in the season. The invasion 
of the capillary structure of the ice by salt water from 
below would act, both chemically and mechanically 
in destroying its structure; but I am led to believe 
* I am happy to find since my return, that this basaltic arrangement of the 
ice has been noticed also by Sir John Richardson. 
