companied by a map.

[199] See Proceedings of Geol. Soc. vol. ii. p. 334.

[200] It may be observed, that the facts and inferences
exhibited in this map bear not merely on the theory of climate
above proposed, but serve also to illustrate the views
explained in the third book respecting the migration of animals
and plants and the gradual extinction of species.

[201] See Sir R. Murchison's Paper on the Alps, Quart. Journ.
Geol. Soc. vol. v. and my Anniversary Address for 1850, ibid.
vol. vi.

[202] Allgemeine Literatur Zeitung, No. cxxxix. July, 1833.

[203] In this estimate, the space within the antarctic circle
is not taken into account: if included, it would probably add
to the excess of dry land; for the late discoveries of Capt.
Sir James Ross, who penetrated to lat. 78 degrees 10 minutes S.,
confirm the conjecture of Captain Cook that the accumulation of
antarctic ice implies the presence of a certain quantity of
terra firma. The number of square miles on the surface of the
globe are 148,522,000, the part occupied by the sea being
110,849,000, and that by land, 37,673,000; so that the land is
very nearly to the sea as 1 part in 4. I am informed by Mr.
Gardner that, according to a rough approximation, the land
between the 30 degrees N. lat. and the pole occupies a space
_about equal to that of the sea_, and the land between the 30
degrees S. lat. and the antarctic circle about one-sixteenth of
that zone.

[204] See papers by Mr. Smith of Jordanhill, F. G. S., and the
author, Proceedings Geol. Soc. No. 63, 1839, also that of Prof.
E. Forbes, before cited, p. 86, note.

[205] The theorem is thus stated:--"The eccentricity of the
orbit varying, the total quantity of heat received by the earth
from the sun in one revolution is inversely proportional to the
minor axis of the orbit. The major axis is invariable, and
therefore, of course, the absolute length of the year: hence it
follows that the mean annual average of heat will also be in
the same inverse ratio of the minor axis."--Geol. Trans. second
series, vol. iii. p. 295.

[206] Ann. du Bur. des Long. 1834.

[207] Poisson, Thaorie Mathamat. de la Chaleur, Comptes Rendus
de l'Acad. des Sci., Jan. 30, 18