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 rotation of the earth, as well as in its
annual revolution. In this manner are produced the vicissitudes of night
and day, so variable in the different latitudes from the equator to the
pole, and so beautifully calculated to equalise the benefits of light,
so variously distributed in the different regions of the globe.

Gravitation, and the _vis infita_ of matter, thus form the first two
powers distinguishable in the operations of our system, and wisely
adapted to the purpose for which they are employed.

We next observe the influence of light and heat, of cold and
condensation. It is by means of these two powers that the various
operations of this living world are more immediately transacted;
although the other powers are no less required, in order to produce or
modify these great agents in the economy of life, and system of our
changing things.

We do not now inquire into the nature of those powers, or investigate
the laws of light and heat, of cold and condemnation, by which the
various purposes of this world are accomplished; we are only to mention
those effects which are made sensible to the common understanding of
mankind, and which necessarily imply a power that is employed. Thus,