ber, for his consolation
under such disappointments, that his failures are almost as important to
the cause of science and to those who follow him in the same road as his
successes. It is much to know what we _cannot_ do in any given
direction,--the first step, indeed, toward the accomplishment of what we
can do.

A like disappointment awaited me in my first attempt to ascertain by
direct measurement the rate of motion in the glacier. Early observers
had asserted that the glacier moved, but there had been no accurate
demonstration of the fact, and so uniform is its general appearance from
year to year that even the fact of its motion was denied by many. It is
true that the progress of boulders had been watched; a mass of rock
which had stood at a certain point on the glacier was found many feet
below that point the following year; but the opponents of the theory
insisted that it did not follow, because the mass of rock had moved,
that therefore the mass of ice had moved with it. They believed that the
boulder might have slid down for that distance. Neither did the
occasional encroachment of the glaciers upon the valleys prove anything;
it might he solely the effect of an unusual accumulation of snow in cold
seasons. Here, then, was another question to be tested; and one of my
first experiments was to plant stakes in the ice to ascertain whether
they would change their position with reference to the sides of the
valley or not. If the glacier moved, my stakes must of course move with
it; if it was stationary, my stakes would remain standing where I had
placed them, and any advance of other objects upon the surface of the
glacier would be proved to be due to their sliding, or to some motion of
their own, and not to that of the mass of ice on which they rested. I
found neither the one nor the other of my anticipated results; after a
short time, all the stakes lay flat on the ice, and I learned nothing
from my first series of experiments, except that the surface of the
glacier is wasted annually for a depth of at least five feet, in
consequence of which my rods had lost their support, and fallen down.
Similar disappointment was experienced by my friend Escher upon the
great glacier of Aletsch.

My failure, however, taught me to sink the next set of stakes ten or
fifteen feet below the surface of the ice, instead of five; and the
experiment was attended with happier results. A stake planted eighteen
feet deep in the ice, an