14 OE. Dutton—Ffect of a warmer Climate upon Glaciers. 
unit volume of air) is dependent upon the extent or amount of 
cooling, i. ¢., the difference between its initial and final temper- 
ature, and upon the temperature at which the cooling begins. 
This is expressed by the length and positions of the vertical 
lines in the front face of the solid. The curved line PP’ repre- 
sents the locus of these initial temperatures for every day in 
the year, and the line pp’ represents similarly the locus of the 
final temperatures. I have drawn them about equally apart 
for the whole year. Asa matter of fact they should be une- 
qual, most probably ; for the range of cooling is not ordinarily 
uniform in the storms of different parts of the year. But it 
will appear farther on that this is of no consequence so far as 
the final conclusion is concerned. The reader may imagine the 
intervals between PP’ and pp’ to be arranged in any way he 
n any case, The final conclusion will cover every admissible 
modification. Perhaps it will be said that at any given phase 
pendent variable. The temperature itself, and therefore the y 
and z ordinates, are harmonic functions of the time, the form of 
which is not exactly known. 
