+ Mr Theodore Kjerulf on the Phenomena 
infer that we have obtained the key to all the phenomena ~ 
of friction which we have to explain. The comparatively 
small scale of the glacier phenomena with which we are 
acquainted, leaves, indeed, many difficulties in our way ; 
but here, fortunately, we meet with Mr Rink’s valuable ob- 
servations, prosecuted during the many years of his stay on 
the west coast of Greenland, of glacier action in that 
country. From his descriptions, it is obvious that here, as 
in our own land, we have an enormous stretch of country ; 
that this country is completely covered with ice, which, on 
the west coast, is ever slowly pressing outwards to the sea, 
where it ‘“‘calves;” that immense loads of these ice ‘‘calves” 
are every year floated away by currents in the same con- 
stant direction ; and finally, that this ice-cake attains a 
thickness of no less than 1000 feet. 
Here, then, all the conditions of our problem are provided 
for. Let us figure to ourselves a universal ice covering, a 
complete glaciation instead of mere individual glaciers, and 
the phenomenon of friction takes its place harmoniously 
with all the other phenomena of the glacial epoch. In the 
existing state of Greenland is the very analogy we needed 
to justify our supposition—a gigantic cake of ice slowly 
moving outwards, and with the might of its tremendous 
pressure, stripping, polishing, and striating the rocks over 
which it glides, just like a common glacier, only in so much 
greater a proportion as the ice-cake of Greenland surpasses 
any glacier of Switzerland. 
I shall endeavour to show that, in explaining the pheno- 
mena of friction, we know of no better agent than the ice- 
cake. 
In respect of the direction of the scratches inferences have 
been drawn, (1.) From the boulders or erratic blocks. (2.) 
From the so-called ‘lee and weather sides.” All the ar- 
rows on the striation maps have been laid down on the 
supposition that the blocks were moved by the same stream 
which was striating the rocks, and that all this tallies with 
the lee and weather sides which present themselves to our 
notice. Now, here it is important to observe, 
1. That the boulders in the lower districts do not indi- 
cate the direction either whence or whither of the friction. 
