etual equinox, and uniformity of seasons throughout the year;--that
the planet enjoyed this "paradisiacal" state until the era of the great
flood; but in that catastrophe, whether by the shock of a comet, or some
other convulsion, it lost its equal poise, and hence the obliquity of
its axis, and with that the varied seasons of the temperate zone, and
the long nights and days of the polar circles.

When the progress of astronomical science had exploded this theory, it
was assumed, that the earth at its creation was in a state of fluidity,
and red-hot, and that ever since that era, it had been cooling down,
contracting its dimensions, and acquiring a solid crust,--an hypothesis
hardly less arbitrary, yet more calculated for lasting popularity;
because, by referring the mind directly to the beginning of things, it
requires no support from observation, nor from any ulterior hypothesis.
But if, instead of forming vague conjectures as to what might have been
the state of the planet at the era of its creation, we fix our thoughts
on the connection at present existing between climate and the
distribution of land and sea; and then consider what influence former
fluctuations in the physical geography of the earth must have had on
superficial temperature, we may perhaps approximate to a true theory. If
doubts and obscurities still remain, they should be ascribed to our
limited acquaintance with the laws of Nature, not to revolutions in her
economy;--they should stimulate us to farther research, not tempt us to
indulge our fancies respecting the imaginary changes of internal
temperature in an embryo world.

_Diffusion of Heat over the Globe._--In considering the laws which
regulate the diffusion of heat over the globe, we must be careful, as
Humboldt well remarks, not to regard the climate of Europe as a type of
the temperature which all countries placed under the same latitude
enjoy. The physical sciences, observes this philosopher, always bear the
impress of the places where they began to be cultivated; and as, in
geology, an attempt was at first made to refer all the volcanic
phenomena to those of the volcanoes in Italy, so in meteorology, a small
part of the old world, the centre of the primitive civilization of
Europe, was for a long time considered a type to which the climate of
all corresponding latitudes might be referred. But this region,
constituting only one-seventh of the whole globe, proved eventually to
be the except