Memorandum on glacier observations. 
8i 
snout at the end of the glacier with the greatest accuracy. Two methods 
can be employed for this purpose, either of which may be selected accord¬ 
ing to circumstances. 
Paint some signs on large boulders, not too far from the end of the 
glacier, and measure their distance from it by a tape (Richter’s system), 
or build a low wall of stones of a few yards in length, and, say 15 to 20 
inches in height, some distance from the ice-end, and measure this distance 
(Gosset’s system). It is to be recommended that the stones of these walls 
should also be painted. If the traveller himself returns after some interval 
—even after only two or three weeks—he will be able to judge of the 
movement of the glacier, and he will have laid down a basis for further 
observations by future travellers. 
One of the results most to be desired is an exact knowledge of the 
dates: 
I. Of the maximum extension of the ice. 
II. Of the commencement of retreat. 
III. Of the minimum. 
IV. Of the commencement of fresh increase. 
In dealing with a mountain group, therefore, the traveller should note 
(where he can get the information as to the past) the date of the commence¬ 
ment of the actual movement of each glacier , and in all cases whether the 
ice is in advance, or retreat, or stationary. Of course the rate of forward 
movement, or velocity of the ice, and the oscillations in the extension of 
the ice must be kept carefully distinct. 
Should time and circumstances permit, a series of observations of the 
velocity of the ice is of value. These may be made after Tyndall’s method, 
by planting a line of sticks across the glacier, or by painting marks 
on boulders, the position of which relatively to ascertained points on the 
mountain-side has been accurately fixed. The size of the glacier, that is, 
the area of its basin and its length, as well as the slope of its bed above, 
as well as at the point measured, should be noted. The rate of movement 
of the ice appears to be connected both with the volume of the glacier 
and the inclination of its bed. 
The advance or retreat of a glacier are not the only factors to take into 
account in estimating the increase or diminution of the volume of ice. 
The highest level of the transverse convexity of the glacier at various 
VOL. IT. g 
