ties 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, & their dryness, put it past doubt that they belong to the Element
