THE VARIATIONS OF GLACIERS. 285 
date ; to record the extent and thickness of the glacier as often 
as possible; to determine the velocity of flow of the ice; to 
determine the rate of melting of the ice. i 
General description—Name. Latitude, longitude and altitude 
of end. General direction of flow. 
General description of glacier (Is it long or broad? Is it in 
a narrow valley, or on a plateau? Is it simple or made up of 
several tributaries ? Is it smooth or much crevassed? Are there 
any ice-falls? Are there moraines on the ice? Altitude of 
névé line; size of névé fields and of tongue, a sketch map of an 
unsurveyed glacier is useful). 
Slope of glacier.—(1) Slope of surface in different parts of the 
glacier ; (2) estimate of slope of glacier’s bed, where possible. 
Old moraines.—Describe their forms, condition and distance 
from the glacier, if terminal, and their height above the ice, if 
lateral. 
Lakes.—Are they true rock-basins or dammed lakes? For 
rock-basins determine the form of the bed by soundings, if 
possible. 
Recent changes—(a) Question anyone who may be able to 
give information whether the glacier has recently been larger or 
smaller than at present, and when it began to advance or retreat. 
(0) Obtain photographs of the glaciers with date when 
taken. ‘‘The earlier recent movements of glaciers may be noted 
by the following signs: 
“When the ice is advancing, the glaciers generally have 
a more convex outline, the ice-falls are more broken into towers 
and spires, and piles of fresh rubbish are found shot over the 
grass of the lower moraines. Moraines which have been com- 
paratively recently deposited by advancing ice are disturbed, 
show cracks, and are obviously being pushed forward or aside 
by the glacier. 
‘‘When the ice is in retreat, the marks of its further recent 
extension are seen fringing the glacier both at the end and 
sides in their lower portions; the glacier fails to fill its former 
bed, and bare stony tracts, often interspersed with pools, or lake- 
