Ragnarok : the age of fire and gravel

60 THE DRIFT.

would raise a pound of the liquid one degree in temperature... . It is perfectly manifest that by weakening the sun’s action, either through a defect of emission or by the steeping of the entire solar system in space of a low temperature, we should be cutting off the glaciers at their source.” *

Mr. Croll says :

“ Heat, to produce evaporation, is just as essential to the accumulation of snow and ice as cold to produce condensation.” +

Sir John Lubbock says :

“ Paradoxical as it may appear, the primary cause of the Glacial epoch may be, after all, an elevation of the temperature in the tropics, causing a greater amount of evaporation in the equatorial regions, and consequently a greater supply of the raw material of snow in the temperate regions during the winter months.” {

So necessary did it appear that heat must have come from some source to vaporize all this vast quantity of water, that one gentleman, Professor Frankland,* suggested that the ocean must have been rendered hot by the internal fires of the earth, and thus the water was sent up in clouds to fall in ice and snow ; but Sir John Lubbock disposes of this theory by showing that the fauna of the seas during the Glacial period possessed an Arctic character. We can not conceive of Greenland shells and fish and animals thriving in an ocean nearly at the boiling-point.

A writer in “The Popular Science Monthly” || says :

“These evidences of vast accumulations of ice and snow on the borders of the Atlantic have led some theo-

* “ Heat considered as a Mode of Motion,” p. 192. + “Climate and Time,” p. 74.

+ “Prehistoric Times,” p. 401.

# “ Philosophical Magazine,” 1864, p, 328.

|| July, 1876, p. 288.