ome more central part.

_2dly_, We find a fluid body of water. This, by gravitation, is reduced
to a spherical form, and by the centrifugal force of the earth's
rotation, is become oblate. The purpose of this fluid body is essential
in the constitution of the world; for, besides affording the means of
life and motion to a multifarious race of animals, it is the source of
growth and circulation to the organized bodies of this earth, in being
the receptacle of the rivers, and the fountain of our vapours.

_3dly_, We have an irregular body of land raised above the level of the
ocean. This, no doubt, is the smallest portion of the globe; but it is
the part to us by far most interesting. It is upon the surface of this
part that plants are made to grow; consequently, it is by virtue of
this land that animal life, as well as vegetation, is sustained in this
world.

_Lastly_, We have a surrounding body of atmosphere, which completes the
globe. This vital fluid is no less necessary, in the constitution of the
world, than are the other parts; for there is hardly an operation upon
the surface of the earth, that is not conducted or promoted by its
means. It is a necessary condition for the sustenance of fire; it is the
breath of life to animals; it is at least an instrument in vegetation;
and, while it contributes to give fertility and health to things that
grow, it is employed in preventing noxious effects from such as go into
corruption. In short, it is the proper means of circulation for the
matter of this world, by raising up the water of the ocean, and pouring
it forth upon the surface of the earth.

Such is the mechanism of the globe: Let us now mention some of those
powers by which motion is produced, and activity procured to the mere
machine.

First, There is the progressive force, or moving power, by which this
planetary body, if solely actuated, would depart continually from the
path which it now pursues, and thus be for ever removed from its end,
whether as a planetary body, or as a globe sustaining plants and
animals, which may be termed a living world.

But this moving body is also actuated by gravitation, which inclines
it directly to the central body of the sun. Thus it is made to revolve
about that luminary, and to preserve its path.

It is also upon the same principles, that each particular part upon the
surface of this globe, is alternately exposed to the influence of light
and darkness, in the diurnal rot