x 
Physical Theory of Secular Changes of Climate. 83 
that he has pointed out with more precision than has, he be- 
lieves, hitherto been done, the different effects on climate of 
water in the liquid and solid states. ‘This is a somewhat 
those of England.’ 
_ “Another point,” he says, ‘of great importance in connex- 
ion with this subject is the fact, that this permanent storing-up 
of cold depends entirely on the annual amount of snowfall in 
proportion to that of the sun- and air-heat, and not on the 
actual cold of winter, or even on the average cold of the year.” 
{igh Land and Heavy Snowfall in relation to the Glacial 
Epoch.— According to Mr. llace, “high land and great 
Moisture” are essential to the initiation of a glacial epoch. 
indispensabl : a 
8 to the second of these conditions, great moisture is evi- | 
dently necessary only in order to produce a great snowfall ; oo 
