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Humboldt, Alexander von, 1769-1859

"COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1"


That which has been learned by an ingenious analytic calculation, expressly
perfected for this class of investigations,*
p 173
regarding the motion of heat in homogeneous metallic spheroids, must be
applied with much caution to the actual character of our planet, considering
our present imperfect knowledge of the substances of which the Earth is
composed, the difference in the capacity of heat and in the conducting power
of different superimposed masses, and the chemical changes experienced by
solid and liquid masses from any enormous compression.

[footnote] *Here we must notice the admirable analytical labors of Fourier,
Biot, Laplace, Poisson, Duhamel, and Lame. In his 'Theorie Mathematique de
la Chaleur', 1835, p. 3, 428-430, 436, and 521-524 (see, also, De la Rive's
abstract in the 'Bibliotheque Universelle de Geneve', Poisson has developed
an hypothesis totally different from Fourier's view ('Theorie Analytique de
la Chaleur'.) He denies the present fluid state of the Earth's center; he
believes that "in cooling by radiation to the medium surrounding the Earth,
the parts which were first solidified sunk, and that by a double descending
and ascending current, the great inequality was lessened which would have
taken place in a solid body cooling from the surface.


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