Note a — BOOK I.

It is not worth while to enumerate the Opinions of the Aristotelians, Cartesians, and others, about the Nature of Light, Aristotle making it a Quality; Cartes a Pulsion, or Motion of the Globules of the second Element, Vid. Cartes Princip. p. 3. §. 55, &c. But with the Moderns, I take Light to consist of material Particles, propagated from the Sun, and other luminous Bodies, not instantaneously, but in time, according to the Notes following in this Chapter. But not to insist upon other Arguments for the Proof of it, our noble Founder hath proved the Materiality of Light and Heat, from actual Experiments on Silver, Copper, Tin, Lead, Spelter, Iron, Tutenage, and other Bodies, exposed (both naked and closely shut up) to the Fire: All which were constantly found to receive an Increment of Weight. I wish he could have met with a favourable Season to have tried his Experiments with the Sun-beams as he intended. Vid. Boyl Exp. to make Fire and Flame ponderable.