The EvobitioH of Climates. — Alanson. 93 
THE EVOLUTION OF CLIMATES.* 
Hy Maesden Manson. 
Chapter I. 
The Fundamental Problem. 
Since geology reached the initial stages of a science, at- 
tempts to accurately trace the history of the earth back into 
the infinite past have been hampered at the very outset by un- 
solved problems. 
The first of these problems is embraced in the question — 
What was the cause of the Ice age? Back of it lie others of 
a kindred nature, for there is as yet no satisfactory and ac- 
cepted cause assigned for the universally temperate climates 
of the early Quaternary and late Tertiary periods; nor for the 
universally tropical climates of the Mesozoic age; nor yet 
again for the torrid climates existing from pole to pole during 
the Palaeozoic ages. In each of these grand divisions of geo- 
logical time, glacial phenomena occurred which still further 
complicate these general problems. 
Confronting us there are also unsolved problems as to how 
the present climates were inaugurated at the close of the Ice 
age, and regarding the conditions towards which present 
climatic developments are tending. 
Closely linked with these problems are questions touching 
the stages reached in the climatic development of planets 
which are apparently further, and of planets which are ap- 
parently less advanced than the earth: for, whatever may have 
been the dates and modes of their origin, differences in mass, 
*The views expressed in this paper have in part appeared in the 
following desultory articles: 
The Cause of the Ice Age and an Explanation of Geological Cli- 
mates. Proc. Technical Soc. Pacific Coast, Sept., 1891. 
Geological and Solar Climates. Their Causes and Variations. A 
Thesis in Geology and Physics. University Cal., May, 1893. 
Circulation of the Atmosphere of Planets. Transactions, Technical 
Soc. Pacific Coast. Vol. IX, No. 5, Jan., 1892. Reprinted Astronom- 
ical Soc. Pacific Coast. 
The Cosmic Character of the Ice Age. Glacialists' Magazine, \v\. 
II, Nos. 5 and 6. 
The Cause of the Ice Age and of Geological Climates. Trans. Gcol. 
Soc. Australasia. Vol. I, Part VI. 
These papers, like the present one, are the result of work during 
spare moments from professional work in other lines. To co-workers, 
no other apology is necessary. 
