History informs us that many of the countries of Europe which now
possess very mild winters, at one time experienced severe cold during
this season of the year. The Tiber, at Rome, was often frozen over, and
snow at one time lay for forty days in that city. The Euxine Sea was
frozen over every winter during the time of Ovid, and the rivers Rhine
and Rhone used to be frozen over so deep that the ice sustained loaded
wagons. The waters of the Tiber, Rhine, and Rhone, now flow freely
every winter; ice is unknown in Rome, and the waves of the Euxine dash
their wintry foam uncrystallised upon the rocks. Some have ascribed
these climate changes to agriculture--the cutting down of dense
forests, the exposing of the unturned soil to the summer’s sun, and the
draining of great marshes. We do not believe that such great changes
could be produced on the climate of any country by agriculture; and we
are certain that no such theory can account for the contrary change of
climate--from warm to cold winters--which history tells us has taken
place in other countries than those named. Greenland received its name
from the emerald herbage which once clothed its valleys and mountains;
and its east coast, which is now inaccessible on account of perpetual
ice heaped upon its shores, was in the eleventh century the seat of
flourishing Scandinavian colonies, all trace of which is now lost. Cold
Labrador was named Vinland by the Northmen, who visited it A.D. 1000,
and were charmed with its then mild climate. The cause of these changes
is an important inquiry.--_Scientific American._