24 
M. Humboldt on Isothermal Lines, 
S5°.6, and that the thermometer sometimes sinks there even du- 
ring several days from 14° to 10°. 4. The region of potable wines 
extends in Europe between the isothermal lines of 6S°.6 and 50°, 
which correspond to the latitudes of 36° and 48°. The culti- 
vation of the vine extends, though with less advantage, even to 
countries whose animal temperature descends to 48°.2 and to 
47°. 48 ; that of winter to 33°.8, and that of summer to 66°.2 
and 68°. These meteorological conditions are fulfilled in Eu- 
rope as far as the parallel of 50°, and a little beyond it. In 
America, they do not exist farther north than 40°. They have 
begun, indeed, some years ago to make a very good red wine 
to the west of Washington, beyond the first chain of mountains, 
in the valleys which do not extend beyond 38° 54' of Lat. On the 
Continent of Western Europe, the winters, whose mean tempe- 
rature is 32°, do not commence till on the isothermal lines of 
48°.2 and 50°, in from 51° to 52° of latitude ; while in America, 
we find them already on the isothermal lines of from 51°.8 to 
53°.6, under from 40° to 41° of latitude. 
If, instead of considering the natural inflexions of the isother- 
mal lines, that is to say, those that propagate themselves pro- 
gressively at great intervals of longitude, we direct our atten- 
tion to their partial inflexions, or to particular systems cli- 
mates occupying a small extent of country, we shall still find 
the same variations in the division of the annual heat between 
the different seasons. These partial inflexions are most remark- 
able, 
1^^, In the Crimea, where the climate of Odessa is contrasted 
with that of the S.W. shores of the Chersonesus, sheltered by 
mountains, and fit for the cultivation of the olive and the orange 
tree. 
2dly, Along the Gulf of Genoa, from Toulon and the Hieres 
Isles to Nice and Bordighera, ( Annales du Museum, tom. xi. 
p. 219.), where the small maritime palm-tree, Chamcerops, 
grows wild, and where the date-tree is cultivated on a large 
scale, not to obtain its fruit, but the palms or etiolated leaves. 
Qdly, In England, on the coast of Devonshire, where the port 
of Salcombe has, on account of its temperate climate, been call- 
ed the Montpellier of the North, and where (in South Hams) the 
Myrtle, the Camellia Japonica, the Fuchsia coccmea, and the 
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