entional manner. When at last it was safely lodged, the height
proved to be 27 feet. I had hoped to find it much more than this, from
the grandeur of the effect of the whole mass, and I took the trouble
to measure the knotted string again with a tape, to make sure that
there was no mistake. The column formed upon the fir-tree was 3 or 4
feet lower.

I have since found many notices of this glaciere in the Memoirs of the
French Academy and elsewhere, extracts from which will be found in a
later chapter. These accounts are spread over a period of 200 years,
extending from 1590 to 1790, and almost all make mention of the columns
or groups of columns I have described; but, without exception, the
heights given or suggested in the various accounts are much less than
those which I obtained as the result of careful measurement. The latest
description of a visit to the glaciere states a fact which probably will
be held to explain, the present excess of height above that of earlier
times.[37] The citizen Girod-Chantrans, who wrote this description, had
procured the notes of a medical man living in the neighbourhood, from
which it seemed that Dr. Oudot made the experiment, in 1779, of fixing
stakes of wood in the heads of the columns, then from 4 to 5 feet high,
and found that these stakes were the cause of a very large increase in
the height of the columns, ice gathering round them in pillars a foot
thick. So that it is not improbable that the largest of the three masses
of the present day owes its height, and its peculiar form, to a series
of stakes fixed from time to time in the various heads formed under the
fissures in the roof, though nothing but the most solid ice can now be
seen. It would be very interesting to try this experiment in one of the
caves where, without any artificial help, such immense masses of ice are
formed; and by this means columns might, in the course of a year or two,
be raised to the very roof. Further details on this subject will be
given hereafter.

There was no perceptible draught of air in any part of the cave, and the
candles burned steadily through the whole time of my visit, which
occupied more than two hours. The centre was sufficiently lighted by the
day; but in the western corner, and behind the largest column,
artificial light was necessary. The ice itself did not generally show
signs of thawing, but the whole cave was in a state of wetness, which
made the process of measuring and investigat