Tlie Cause of the Glacial Epoch. — Reed. 109 
A METEOROLOGICAL HYPOTHESIS OF THE 
CAUSE OF THE GLACIAL EPOCH.* 
By Howard S. Reed, Ann Arbor, Mich. 
Although we have acquired considerable knowledge con- 
cerning the history of the Glacial epoch, our ideas of the 
causes of that geological winter are, at best, few and vague. 
The theory under consideration attempts to account for 
continental glaciation upon a meteorological basis, inas- 
much as the author believes that former theories based upon 
astronomical, geological and geographical phenomena are 
insufficient. 
The histor)' of climate is divided into two marked eras — 
( I ), a past era, during which surface temperatures were con- 
trolled by internal heat. This heat, originally intense, 
gradually diminished until we now have (2) the present era, 
in which surface temperatures are controlled by solar heat. 
"The transition epoch — the date of passage from the 
control of earth heat to that of solar heat is the Ice age. 
The transition is still in progress for solar energ\^ has not 
)et fully established its control." 
"The objects in view are to explain (i) the peculiar uni- 
formity of climates prior to the practical exhaustion of in- 
ternal heat; (2) the occurrence of an age of general glacia- 
tion in all latitudes prior to the establishment of the control 
of solar heat; (3) the reasons of the differences between 
heat distribution during geological and present climates." 
He then states the problem in the form of a proposi- 
tion" — Given: a heated globe, constituted and circumstanced 
as the earth admittedly was and whose surface temperatures, 
by reason of internal heat, are above the boiling point of 
water, to prove that before its surface temperatures can pass 
under the control of solar heat (i) climatic changes must be 
independent of latitude, and (2) that continental areas must 
be glaciated. (The proposition here stated is applicable to 
any planet.)" 
The original intense heat of the earth caused the water, 
and probabl) other substances, .to be held as vapor in the 
atmosphere. "The earth ma)' thus be regarded as having 
*The Evolution of Climates. Marsden Manson. Amer. Geol. Vol. 
XXIV, pp. 93120,157-180, 205-209, 
