collateral, or correspondent, in the
progress of those natural events. This is the time required, in the
natural operations of this globe, for the destruction of a former
earth; an earth equally perfect with the present and an earth equally
productive of growing plants and living animals. Now, it must appear,
that, if we had a measure for the one of those corresponding operations,
we would have an equal knowledge of the other.

The formation of a future earth being in the bottom of the ocean, at
depths unfathomable to man, and in regions far beyond the reach of his
observation, here is a part of the process which cannot be taken as a
principle in forming an estimate of the whole. But, in the destruction
of the present earth, we have a process that is performed within the
limits of our observation; therefore, in knowing the measure of this
operation, we shall find the means of calculating what had passed on a
former occasion, as well as what will happen in the composition of a
future earth. Let us, therefore, now attempt to make this estimate of
time and labour.

The highest mountain may be levelled with the plain from whence it
springs, without the loss of real territory in the land; but when the
ocean makes encroachment on the basis of our earth, the mountain,
unsupported, tumbles with its weight; and with the accession of hard
bodies, moveable with the agitation of the waves, gives to the sea the
power of undermining farther and farther into the solid basis of our
land. This is the operation which is to be measured; this is the mean
proportional by which we are to estimate the age of worlds that have
terminated, and the duration of those that are but beginning.

But how shall we measure the decrease of our land? Every revolution of
the globe wears away some part of some rock upon some coast; but the
quantity of that decrease, in that measured time, is not a measurable
thing. Instead of a revolution of the globe, let us take an age. The age
of man does no more in this estimate than a single year. He sees,
that the natural course of things is to wear away the coast, with the
attrition of the sand and stones upon the shore; but he cannot find a
measure for this quantity which shall correspond to time, in order to
form an estimate of the rate of this decrease.

But man is not confined to what he sees; he has the experience of former
men. Let us then go to the Romans and the Greeks in search of a measure
of our coasts