ICSE WINES. 
Om klimatets andringar 1 geologisk och slustorisk tid samt deras 
orsaker. |On Changes of Climate in Geologic and Historic 
Time and their Causes. | By Nits ExHoim, Ymer, Arg. 
1899, H. 4, pp. 353-403. Published by Svenska Sallskapet 
for anthropologi och geografi, Stockholm. 
The first section of the paper discusses, in a general way, the causes 
of telluric temperature changes. ‘The author states at the outset that 
the temperature of the earth depends upon the ratio of the amounts 
of insolation and radiation. He thinks that the solar radiation has 
very likely not been subject to any considerable changes during the 
time the earth has been an abode of life. But the transparency of the 
atmosphere to different kinds of heat rays, and hence also to radiation, 
has, no doubt, varied greatly and caused the great changes in climate 
known to geology. Only in the second place would he put the eccen- 
tricity of the earth’s orbit and the inclination of its axis as a cause of 
climatic changes. He does not think that the eccentricity of the 
earth’s orbit has caused any climatic variations which have left traces 
known to geologists. But the variations in the inclination of the 
earth’s axis have caused changes of considerable magnitude in the 
polar regions, and in the adjacent zone, at least as far down as the 
latitude of 55° in the northern hemisphere. 
The old notion that the internal heat of the earth has appreciably 
affected climatic conditions in geological time must be set aside. The 
earth was, no doubt, at one time in the same condition in which we 
now find the planet Jupiter. There was a dense atmosphere filled with 
steam. After the temperature of this atmosphere of the cooling globe 
sank below the boiling point of water its vapor rapidly (in a few hun- 
dred years) condensed to a boiling sea. While the convection of this 
sea was in effective action, the temperature of the sea bottom, the 
upper crust of the earth, was rapidly lowered, which caused the outer 
crust to crack open as it contracted relatively more rapidly than the 
interior. This process went on until the radiation of the crust, outward 
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