e brightness, mankind will find, from pole to pole,
under each latitude, the climates which have permitted them to live and
to establish their residence. These, Gentlemen, are great, magnificent
results. While recording them in the annals of science, historians will
not neglect to draw attention to this singular peculiarity: that the
geometer to whom we owe the first certain demonstration of the existence
of a heat independent of a solar influence in the interior of the earth,
has annihilated the immense part which this primitive heat was made to
play in the explanation of the phenomena of terrestrial temperature.

Besides divesting the theory of climates of an error which occupied a
prominent place in science, supported as it was by the imposing
authority of Mairan, of Bailly, and of Buffon, Fourier is entitled to
the merit of a still more striking achievement: he has introduced into
this theory a consideration which hitherto had been totally neglected;
he has pointed out the influence exercised by the _temperature of the
celestial regions_, amid which the hearth describes its immense orb
around the sun.

When we perceive, even under the equator, certain mountains covered with
eternal snow, upon observing the rapid diminution of temperature which
the strata of the atmosphere undergo during ascents in balloons,
meteorologists have supposed, that in the regions wherein the extreme
rarity of the air will always exclude the presence of mankind, and that
especially beyond the limits of the atmosphere, there ought to prevail a
prodigious intensity of cold. It was not merely by hundreds, it was by
thousands of degrees, that they had arbitrarily measured it. But, as
usual, the imagination (_cette folie de la maison_) had exceeded all
reasonable limits. The hundreds, the tens of thousands of degrees, have
dwindled down, after the rigorous researches of Fourier, to fifty or
sixty degrees only. Fifty or sixty degrees _beneath zero_, such is the
temperature which the radiation of heat from the stars has established
in the regions furrowed indefinitely by the planets of our system.

You recollect, Gentlemen, with what delight Fourier used to converse on
this subject. You know well that he thought himself sure of having
assigned the temperature of space within eight or ten degrees. By what
fatality has it happened that the memoir, wherein no doubt our colleague
had recorded all the elements of that important determination, is not t