352 The Former Climate of the Polar Regions. [June, 
ON THE FORMER CLIMATE OF THE POLAR REGIONS! 
BY PROFESSOR A. E. NORDENSKIÖLD. 
A Ae a few years ago it was looked upon as an article of faith 
among geologists that the whole globe was once in a melted, 
incandescent state, and that the conditions of temperature now 
prevailing on the surface of the earth have been in process of 
time produced by the slow, gradual cooling of the once fused and 
lowing mass. It then appeared so natural that, in consequence 
of the earth’s internal heat, a tropical climate should extend from 
pole to pole, that no special weight was attached to the evidences 
of this fact which geology was at that time able to produce. 
The Dane Giesecke’s and the English Scoresby’s specimens of 
fossil plants from the east and west coasts of Greenland, evi- 
dencing a warm climate there, attracted so little attention that 
neither they, nor the fossil remains of Saurians found by the 
famous Arctic traveler, Sir Edward Belcher, in the American 
Polar Archipelago, could be found in the museums to which they 
had been confided. 
It was not till geologists had become fully convinced that the 
gradual transition from the time when a warm climate was sup- 
posed to have prevailed over the whole earth and the present 
time has at least once been interrupted by a period during which 
the greater part of the European and American continents were 
covered by mighty glaciers, that the geological theory of climates 
was taken up with real interest. People began gradually to per 
ceive that, even supposing the earth really to have once been in 
a state of glowing fusion, the cooling must already at the Cam- 
brian and Silurian epochs have proceeded so far that the quantity 
of heat which the earth lost by radiation was fully compensated 
by that which it received from the other heavenly bodies. It 
has also been supposed that the cause of the glacial period — 
when vast ice mountains scattered bowlders from Scandinavia 
over the plains of Northern Germany, and when the Swiss Alps 
formed the centre of an icy desert similar to-the present Green- 
land — is to be sought for in some trifling changes in the form 
of the earth’s orbit and the inclination of the equator, which 
have taken place and continue to take place periodically after the 
lapse of thousands or hundreds of thousands of years. The same 
causes which have once produced the glacial period have thus 
happened, not only during this last period nearer to our own 
1 A lecture delivered at the anniversary meeting of the Royal Swedish Academy 
of Science, March 31, 1875, and translated for The Geological Magazine. 
