a few miles of the ice front the stones still have a
fresh aspect. When we arrive within, say, half a mile of the moraine
now building, we come to the part of the glacial retreat of which we
have some written or traditional account. This is in general to the
effect that the wasting of the glaciers is going on in this century as
it went on in the past. Occasionally periods of heavy snow would
refresh the ice streams, so that for a little time they pushed their
fronts farther down the valley. The writer has seen during one of
these temporary advances the interesting spectacle of ice destroying
and overturning the soil of a small field which had been planted in
grain.

It should be noted that these temporary advances of the ice are not
due to the snowfall of the winter or winters immediately preceding the
forward movement. So slow is the journey of the ice from the _neve_
field to the end of a long glacier that it may require centuries for
the store accumulated in the uplands to affect the terminal portion of
the stream. We know that the bodies of the unhappy men who have been
lost in the crevices of the glacier are borne forward at a uniform and
tolerably computable rate until they emerge at the front, where the
ice melts away. In at least one case the remains have appeared after
many years in the _debris_ which is contributed to the moraine. On
account of this slow feeding of the glacial stream, we naturally may
expect to find, as we do, in fact, that a great snowfall of many
years ago, and likewise a period when the winter's contribution has
been slight, would influence the position of the terminal point of the
ice stream at different times, according to its length. If the length
of the flow be five miles, it may require twenty or thirty years for
the effect to be evident; while if the stream be ten miles long, the
influence may not be noted in less than threescore years. Thus it
comes about that at the present time in the same glacial district some
streams may be advancing while others are receding, though, on the
whole, the ice is generally in process of shrinkage. If the present
rate of retreat should be maintained, it seems certain that at the end
of three centuries the Swiss glaciers as a whole will not have
anything like their present area, and many of the smaller streams will
entirely disappear.

Following the method of the illustrious Louis Agassiz, who first
attentively traced the evidence which shows the geo