Let us reason together:—­

The ice, say the glacialists, caused the Drift.  What caused the ice?  Great rains and snows, they say, falling on the face of the land.  Granted.  What is rain in the first instance?  Vapor, clouds.  Whence are the clouds derived?  From the waters of the earth, principally from the oceans.  How is the water in the clouds transferred to the clouds from the seas?  By evaporation.  What is necessary to evaporation? Heat.

Here, then, is the sequence: 

If there is no heat, there is no evaporation; no evaporation, no clouds; no clouds, no rain; no rain, no ice; no ice, no Drift.

But, as the Glacial age meant ice on a stupendous scale, then it must have been preceded by heat on a stupendous scale.

Professor Tyndall asserts that the ancient glaciers indicate the action of heat as much as cold.  He says: 

“Cold will not produce glaciers.  You may have the bitterest northeast winds here in London throughout the winter without a single flake of snow.  Cold must have the fitting object to operate upon, and this object—­the aqueous vapor of the air—­is the direct product of heat.  Let us put this glacier question in another form:  the latent heat of aqueous vapor, at the temperature of its production in the tropics, is about 1,000° Fahr., for the latent heat augments as the temperature of evaporation descends.

A pound of water thus vaporized at the equator has absorbed one thousand times the quantity of heat which

[1.  “The Great Ice Age,” p. 98.]

{p. 60}

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."[1]

Mr. Croll says: 

“Heat, to produce evaporation, is just as essential to the accumulation of snow and ice as cold to produce condensation."[2]

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."[3]

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,[4] 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.