286 WILE, OI MIAIL (2 (IROL OE 3 
lets, lie between the end of the glacier and the mounds of recent 
terminal moraines.”’? 
Future changes.—¥or this purpose all records of the extent 
and thickness of the ice at date of observation are useful. 
The position of the end may be recorded as follows : 
(a) Measure distance of one or more points of the glacier’s 
end from cairns or prominent rocks, which should be marked by 
paint or chisel. Or, take magnetic bearings of a tangent to the 
end of the glacier from a station on the valley’s side; this tangent 
should be about at right angles to the direction of the valley. 
(6) Photographically.—(1) All photographs of the end of the 
glacier are useful; particularly if the magnetic bearings of the 
camera, and the approximate distance from the glacier are given. 
(2) Select two stations, one on each side of the valley, com- 
manding a view of the glacier’s end. Photograph the end from 
these two stations; two photographs from each station may be 
required to show all the end. Mark the stations, describe them 
carefully and leave an account at the ranch or hotel from which 
the glacier is usually visited so that they can easily be found by 
later observers, who should take photographs from these points 
in preference to all others. This will be the beginning of a sys- 
tematic record of the glacier. From these photographs it will 
be possible to make a map of the glacier’s end if we know: the 
distance between the stations; the angle at each station between 
the other and some point in each photograph and the focal 
length of the lens, or the angles at each station between the 
other and two points in each photograph, not less than half the 
length of the plate apart; the bearings of these two points will 
enable us to determine both the direction in which the camera 
was pointed and the focal length of the lens. 
An observer, provided with a small theodolite (or even a 
prismatic compass) should measure from each of the stations 
the angle between the other and all prominent peaks or other 
points likely to appear in the photographs, and should deter- 
mine the distance between the stations. This need only be 
*Memorandum on Glacier Observations, issued by the Alpine Club, June, 1893. 
