by calling them, instead of Earth, and Fire, and Vapour, Salt, Sulphur, and Mercury; to which they gave the canting title of Hypostatical Principles: but when they came to describe them, they shewed how little they understood what they meant by them, by disagreeing as much from one another, as from the truth they agreed in opposing: For they deliver their _Hypotheses_ as darkly as their Processes; and 'tis almost as impossible for any sober Man to find their meaning, as 'tis for them to find their Elixir. And indeed nothing has spread their Philosophy, but their great Brags and undertakings; notwithstanding all which, (sayes _Themistius_ smiling) I scarce know any thing they have performed worth wondering at, save that they have been able to draw _Philoponus_ to their Party, and to engage him to the Defence of an unintelligible _Hypothesis_, who knowes so well as he does, that Principles ought to be like Diamonds, as well very clear, as perfectly solid. _Themistius_ having after these last words declared by his silence, that he had finished his Discourse, _Carneades_ addressing himself, as his Adversary had done, to _Eleutherius_, returned this Answer to it, I hop'd for [Errata: for a] Demonstration, but I perceive _Themistius_ hopes to put me off with a Harangue, wherein he cannot have given me a greater Opinion of his Parts, then he has given me Distrust for his _Hypothesis_, since for it even a Man of such Learning can bring no better Arguments. The Rhetorical part of his Discourse, though it make not the least part of it, I shall say nothing to, designing to examine only the Argumentative part, and leaving it to _Philoponus_ to answer those passages wherein either _Paracelsus_ or _Chymists_ are concern'd: I shall observe to You, that in what he has said besides, he makes it his Business to do these two things. The one to propose and make out an Experiment to demonstrate the common Opinion about the four Elements; And the other, to insinuate divers things which he thinks may repair the weakness of his Argument, from Experience, and upon other Accounts bring some credit to the otherwise defenceless Doctrine he maintains. To begin then with his Experiment of the burning Wood, it seems to me to be obnoxious to not a few considerable Exceptions.