ts in general has not been observed; and that it is as generally
thought, that the land is gaining upon the sea, as that the sea is
gaining upon the land.

To sum up the argument, we are certain, that all the coasts of the
present continents are wasted by the sea, and constantly wearing away
upon the whole; but this operation is so extremely slow, that we cannot
find a measure of the quantity in order to form an estimate: Therefore,
the present continents of the earth, which we consider as in a state of
perfection, would, in the natural operations of the globe, require a
time indefinite for their destruction.

But, in order to produce the present continents, the destruction of a
former vegetable world was necessary; consequently, the production of
our present continents must have required a time which is indefinite.
In like manner, if the former continents were of the same nature as the
present, it must have required another space of time, which also is
indefinite, before they had come to their perfection as a vegetable
world.

We have been representing the system of this earth as proceeding with
a certain regularity, which is not perhaps in nature, but which is
necessary for our clear conception of the system of nature. The
system of nature is certainly in rule, although we may not know every
circumstance of its regulation. We are under a necessity, therefore, of
making regular suppositions, in order to come at certain conclusions
which may be compared with the present state of things.

It is not necessary that the present land should be worn away and
wasted, exactly in proportion as new land shall appear; or, conversely,
that an equal proportion of new land should always be produced as the
old is made to disappear. It is only required, that at all times, there
should be a just proportion of land and water upon the surface of the
globe, for the purpose of a habitable world.

Neither is it required in the actual system of this earth, that every
part of the land should be dissolved in its structure, and worn away by
attrition, so as to be floated in the sea. Parts of the land may often
sink in a body below the level of the sea, and parts again may be
restored, without waiting for the general circulation of land and water,
which proceeds with all the certainty of nature, but which advances with
an imperceptible progression. Many of such apparent irregularities may
appear without the least infringement on the general