this kind, I must proceed to tell You, that though the Assertors of
the four Elements value Reason so highly, and are furnish'd with
Arguments enough drawn from thence, to be satisfi'd that there must be
four Elements, though no Man had ever yet made any sensible tryal to
discover their Number, yet they are not destitute of Experience to
satisfie others that are wont to be more sway'd by their senses then
their Reason. And I shall proceed to consider the testimony of
Experience, when I shall have first advertis'd You, that if Men were
as perfectly rational as 'tis to be wish'd they were, this sensible
way of Probation would be as needless as 'tis wont to be imperfect.
For it is much more high and Philosophical to discover things _a
priore_, then _a posteriore_. And therefore the Peripateticks have not
been very sollicitous to gather Experiments to prove their Doctrines,
contenting themselves with a few only, to satisfie those that are not
capable of a Nobler Conviction. And indeed they employ Experiments
rather to illustrate then to demonstrate their Doctrines, as
Astronomers use Sphaeres of pastboard, to descend to the capacities of
such as must be taught by their senses, for want of being arriv'd to a
clear apprehension of purely Mathematical Notions and Truths. I speak
thus _Eleutherius_ (adds _Themistius_) only to do right to Reason, and
not out of Diffidence of the Experimental proof I am to alledge. For
though I shall name but one, yet it is such a one as will make all
other appear as needless as it self will be found Satisfactory. For if
You but consider a piece of green-Wood burning in a Chimney, You will
readily discern in the disbanded parts of it the four Elements, of
which we teach It and other mixt bodies to be compos'd. The fire
discovers it self in the flame by its own light; the smoke by
ascending to the top of the chimney, and there readily vanishing into
air, like a River losing it self in the Sea, sufficiently manifests to
what Element it belongs and gladly returnes. The water in its own form
boyling and hissing at the ends of the burning Wood betrayes it self
to more then one of our senses; and the ashes by their weight, their
firiness, and their dryness, put it past doubt that they belong to the
Element of Earth. If I spoke (continues _Themistius_) to less knowing
Persons, I would perhaps make some Excuse for building upon such an
obvious and easie _Analysis_, but 'twould be, I fear, injurious, not
to think such an Apology needless to You, who are too judicious either
to think it necessary that Experiments to prove obvious truths should
be farr fetch'd, or to wonder that among so many mixt Bodies that are
compounded of the four Elements, some of them should upon a slight
20