4. Of the Production of Fire by a Flint and Steel.
SOme learned Writers of Micrography, having observed the fiery sparks that are struck out by the violent motion of a Flint against Steel, suppose them to be little parcels either of the Flint or Steel, which by the violence of the stroke, are at the same time severed and made red hot; nay, sometimes to such a degree as they are melted together into glass. But whatsoever their opinion be, to my sense and reason it appears very dif∣ficult to determine exactly how the production of Fire is made, by reason there are so many different sorts of Productions in Nature, as it is impossible for any par∣ticular Creature to know or describe them: Never∣theless, it is most probable, that those two bodies do operate not by incorporeal but corporeal motions,