274 J. Croll—Examination of Wallace's Modification of the 
there is now a moderate amount of eccentricity and the winter 
of the southern hemisphere is in aphelion ? The mere geograph- 
ical position of the southern extremity of America does not seem 
especially favorable to the production of such a state of glaciation, 
he land narrows from the tropics southward, and terminates 
altogether in about the latitude of Edinburgh; the mountains are 
of moderate height ; while during summer the sun is three millions 
of miles nearer, and the heat received from it is equivalent toa | 
rise of 20° F: as compared with the same season in the northern 
hemisphere.”—P. 142. 
. In a similar glacial condition are the islands of South Geor- 
3 ga South Shetland, Graham Land, Enderby Land, Sandwich 
and. There can be little doubt that the present extension of 
ice in the antarctic regions is to a considerable extent due 
also to the influence of eccentricity. 
et us now glance for a moment at the influence which this 
" - 
ern. Another result which a 
follows, as has also been shown, is that the great a atorial e 
currents are made to lie at some distance to the nort uy 
present small amount of eccentricity, how much greater mush: | 
have been the effect during the glacial epoch, when the ecceD” — 
tricity was more than three times its present value and the — 
southern winter also, as now, in aphelion! All those effects 
which we have just been considering would then have eee 
magnified far more than threefold. As 
Climatic conditions of the two Hemispheres the reverse 10,000 e 
or 12,000 years ago: Argument —Ten or twelve thousand’ 
* 
| , Jears ago, when our northern winter solstice was last in ap 
