[footnote] *Humboldt, 'Essai sur la Geographie des Plantes', 1807, p. 90;
and in 'Rel. Hist.', t. iii., p. 313; and on the diminuation of atmospheric
pressure in the tropical portions of the Atlantic, in Poggend., 'Annalen der
Physik', bd. xxxvii., s. 245-258, and s. 463-486.
If with K??mtz we connect together by 'isobarometric' lines those places
which present the same mean difference between the monthly extremes of the
barometer, we shall have curves whose geographical position and inflections
yield important conclusions regarding the influence exercised by the form of
the land and the distribution of seas on the oscillations of the atmosphere.
Hindostan with its high mountain chains and triangular peninsulas, and the
eastern coasts of the New Continent, where the warm Gulf Stream turns to the
east at the Newfoundland Banks, exhibit greater isobarometric oscillations
than do the group of the Antilles and Western Europe. The prevailing winds
exercise a principal influence on the diminution of the pressure of the
atmosphere, and this, as we have already mentioned, is accompanied,
according to Daussey, by an elevation of the mean level of the sea.??
[footnote] *Dausay, in the 'Comptes Rendus', t. iii., p. 136.
As the most important fluctuations of the pressure of the atmosphere,
whether occurring with horary or annual regularity, or accidentally, and
then often attended by violence and danger,* are like all the other
phenomena of the weather, mainly owing to the heating force of the sun's
rays, it has long been suggested (partly according to the idea of Lambert)
that the direction of the wind should be compared with the height of the
barometer, alternations of temperature, and the increase and decrease of
humidity.
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