68 
AMERICAN AGRICULTURIST. 
[February, 
®©YS & OILIJMIM 
Xlie Doctor's Correspondence. 
Last month, in speaking of the perpetual snow 
I said that one of the methods by which the snow 
was kept from accumulating upon the high moun¬ 
tains was that a large share of it disappeared in the 
glaciers. In some alpine localities, the glacier is called 
A Mer de Glace, or Sea of lee. 
Were it called “river of ice,” the name would better 
describe what it really is. But before showing how 
the snow finally appears as ice, I will briefly describe 
my visit to the Grindelwald 
Glacier. Starting out in the 
morning from Interlaken, 
(described last month), the 
driver and all the rest pre¬ 
dicted a fine day, but before 
we had made the 12 miles 
to Grindelwald, it rained in 
such a lively manner that I 
wished for my rubber over¬ 
coat. The journey let us 
see much of Swiss life, as 
It took us through small 
farm villages, but the heavy 
clouds shut out the distant 
view. When we reached the 
Hotel du Glacier, how it did 
rain ! But I had longed to 
see a glacier ever 6ince I 
heard Agassiz tell in his 
wonderful manner of his 
many winters spent upon, 
and in measuring, the gla¬ 
ciers. Here was a glacier 
at only an hour’s distance, 
and should I let the fear of 
a wet skin prevent my go¬ 
ing to that which I had so 
long wished to see ? Horses 
were brought, and with my 
companion, the other Doc¬ 
tor, we started with a boy 
of 12 or 15 years as a guide. 
As the boy could speak 
neither English nor French, 
and we could not speak 
German, you may suppose 
that we were not a very 
sociable party. But the 
horses had probably gone 
to the glacier almost daily 
for years, and only needed to 
be let alone, to take us safe¬ 
ly up the very steep path. 
Before we reached the glacier itself, we stopped at 
The Source of the Black Liutschine. 
Here the water from the lower part of the glacier 
comes down through a rocky gorge, as shown in 
figure 1, from a photograph. Nothing gave me 
such an idea of the immensity of the glacier, as to 
see a good-sized river, one which we had crossed, 
on bridges, several times on our way here, roaring 
and tearing down merely from the melting of the 
lower part of the glacier. But from this point it 
was a good climb up to the glacier it¬ 
self. As we went up there was less and 
less of vegetation, and at last we came 
to a great bank of ice—the lower end 
of the glacier. There was a wooden 
shanty, at which was a man ready to 
earn a fee by showing us the wonders 
of the place. You can get no better 
idea of a glacier than by imagining that 
a river, flowing down a narrow valley, 
has become frozen solid. As we went 
up we saw the railway used for sending 
the ice down into the valley from this 
great natural ice-house. In taking out 
the ice, a large artificial grotto has been 
formed in the glacier, as shown in figure 
2, and one can walk into the interior 
of this “sea of ice” for a hundred 
feet or more. How beautiful it was! 
Tlic Ice of a Wonderful Blue, 
as the daylight stole through it, was 
made into a fairy scene by the guide, 
who went into a recess at the end of the 
grotto and lighted a powerful lamp. 
,1 do not expect to ever see a more 
strange, and at the same time en¬ 
chanting scene than this. “Was it 
cold ? ” you will ask. I really did not think of 
that, but as there was ice above, below, and all 
around for yards and yards in thickness, I do not 
think it could have been very hot. Having seen 
how the glacier brought down its heaps of stones 
and rubbish, of which more presently, we made the 
descent, which, like the ascent, was through a driv¬ 
ing rain. One does not notice the difficulties in 
going up, but in going down I found it better to 
look up, and trust to the four sure feet under me.. 
Having shown you that the glacier is a vast mass— 
a river—of the purest solid ice, you will wonder 
How Snow can form a Glacier. 
You know that snow and ice are both frozen water; 
though snow is bright white and opaque, and ice is 
as transparent as glass, they are both the same 
thing. The difference in appearance is owing to 
the fact that the snow is finely divided, and each of 
its many little particles reflects the light. If you 
have a piece of rock-salt, which is as transparent 
as glass, and break it into small pieces—powder it 
—you will have fine silt, which is dead white like 
snow. You know that when you skate on per- 
Fig. 3.— AN ILLUSTRATION OF REGELATION. 
fectly clear ice, the track of your skate will be quite 
white, the ice being broken into fine dust On the 
other hand (and this is an experiment that you 
cannot readily try yourself, so you must take my 
word for it, as I have made it), if you put a mass 
of 6now under sufficient pressure, so as to squeeze 
the air out and bring the particles close together, 
you will get pefectly transparent ice. It takes a 
more powerful press than you are likely to have to 
do this, but it is easily done with a press of suffi¬ 
cient power, and snow may be squeezed into beauti¬ 
ful ice. Here another curious fact comes in. Ice 
under great pressure melts, and when this pressure 
is removed, the water again freezes. This is called 
regelation, and the word describes exactly what 
takes place—freezing again. There are several ways 
of illustrating this, but we will recall one that I used 
several years ago, which is as striking as any. Let a 
block of ice be supported, as in figure 3, and a wire 
placed over it (copper wire is the best) arranged as 
shown in the engraving, with a basket of stones, 
or other weight below. After some hours the wire 
will be found to be completely imbedded in the ice,, 
and yet no mark, showing where the wire went in, 
can be seen. The ice directly under the wire is 
melted by the pressure, and the wire sinks; as soon 
as this pressure is no longer felt, the water above 
the wire becomes solid ice again. I think you can 
now understand how snow can become a mass of 
Solid Ice in the Glaciers. 
The weight of the snow above presses the lower 
snow particles together, and this thawing under 
pressure and regdaiion is sufficient to account for 
the change into beautifully clear ice. Snow is yearly 
falling above, and, as I mentioned a while ago, the 
glacier is continually, at least in summer, melting 
away at the lower end of the glacier, and you would 
naturally expect to find the end of the glacier farther 
and farther back. Here comes up another curious 
fact about this “ sea of ice.” The glacier is gradu¬ 
ally flowing down the mountain. As it is described 
as ice, and appears as one sees it to be perfectly 
solid ice (except the great cracks —crevasses as they 
are called) running across it, you will wonder how 
such a mass of ice can move. It was early noticed 
that points on the glacier were not in the same 
place that they were the year before, and Agassiz, 
Tyndal and others, have made very careful measure¬ 
ments and learned the fate at which the different 
glaciers move. The measurement of one glacier 
showed that it moved, in different parts, from 12 to 
33 inches each day; some move much more slowly 
than this, but all move from above downwards. 
The glacier here described moves in summer from 
Fig. 1.— GLACIER SOURCE OF THE BLACK LUTSCHINE. 
Fig. 2.— AN ARTIFICIAL GROTTO IN A GLACIER. 
