SCS M. Humboldt on Isothermal Lines^ and the 
the Atlantic region of the United States, exhibits excessive cli- 
mates, and seasons strongly contrasted, while the coasts of New 
California, and the embouchure of the Colombia, have winters 
and summers almost equally temperate. The meteorological 
constitution of these countries in the N. W. resembles that of 
Europe as far as 50° or 5T of latitude ; and without wishing to 
ascribe the great revolutions of our species solely to the influ- 
ence of climate, we may affirm that the difference between the 
eastern and western shores of continents, has favoured the an- 
cient civilisation of the Americans of the west, — facilitated their 
migrations towards the south, and multiplied those relations with 
eastern Asia, which appear in their monuments, their religion, 
traditions, and the division of the year. In comparing the two 
systems of climates, the concave and convex summits of the 
same isothermal lines, we find at Nezv York the summer of 
Rome and the winter of Copenhagen ; — at Quebec the summer 
of Paris and the winter of* Petersburg. In China, at Pekin 
for example, where the mean temperature of the year is that of 
the coasts of Britanny, the scorching heats of summer are great- 
er than at Cairo, and the winters as rigorous as at Upsal. 
The mean temperature of the year being equal to the fourth 
part of the winter, spring, summer and autumnal temperatures, 
we shall have upon the same isothermal line of 53° 6' (12° cent.) 
At the concave summit in America, ) £• 32° -f- 52°. 3 -I- 7.5°-6 - t- 54°. 5 
74° 40' west long. i ' ~ 4 
At the convex summit in Europe, ) ^ _ 4 0°. 1 4- 51° B ^ 68°.4 4- 54°. I 
2° 20' west long. | .o _ ^ 
At the concave summit in Asia, ) ^oo /j ’^4°.7 + 80°.8 4- .54.3 
11 0° 20' east long. j * 4 
This analogy between the eastern coasts of Asia and Ameri- 
ca, sufficiently proves that the inequalities of tlie seasons, of 
which w'e have endeavoured to fix the numerical relations, de- 
pend on the prolongation and enlargement of continents towards 
the pole ; of the size of seas in relation to their coasts, and on the 
frequency of the N. W. winds, which are the Vents de Remous 
of the temperate zone, and not on the proximity of some plateau 
or elevation of the adjacent lands. The great plateaus of Asia, 
do not stretch beyond 52“ of latitude ; and in the interior of the 
New Continent, all the immense basin bounded by the Allegha- 
ny Bange, and the rocky mountains, and covered with secon- 
dary formations, is not more than from 656 to 920 feet above 
