G. F. Becker—Temperature and Glaciation. 169 
prevail at great elevations during the winter months. A _por- 
tion of the snow thus removed from the higher parts of the 
snow belt will lodge at lower levels in névé basins, and the 
snow falling upon these basins from the clouds at temperatures 
considerably below the mean will also in part be swept away, 
and not contribute to the mass of névé. The actual precipita- 
tion on a névé field is, therefore, not an accurate gauge of the 
frozen water which it receives. 
While both snow and rain, or melted ice, are essential constit- 
uents of the névé, it is evident that the formation of the glacial 
ice will not be most rapid at the extreme lower edge of the 
snow belt, for if the heat received is more than sufficient to 
raise the frozen water to the temperature at which regelation is 
most easy, the excess of heat will produce further liquefaction, 
and diminish the accumulation. This, therefore, will be most 
rapid, and the resulting glaciers largest neither at the upper nor 
the lower limit of the snow belt, and, other conditions remain- 
Ing equal, it appears certain that the maximum accumulation 
will take place along a certain isothermal line, the temperature 
of which will not in general be very far removed from zero, 
though its precise temperature will depend upon local cireum- 
Stances, such as the average humidity; the shelter from the 
direct rays of the sun, the distribution of moisture through the 
year, etc. - 
As has already been seen, the formation of glaciers is de- 
pendent upon topographical, as well as meteorological condi- 
tions. In order therefore to institute a comparison between 
Sunshine and the strength of the winds to be the same at the 
two periods, then during the warmer epoch the maximum ten- 
F d ; 
