There is another sort of books, which I had almost forgot, with which a gentleman's study ought to be well furnished, viz. dictionaries of all kinds. For the Latin tongue, Littleton, Cooper, Calepin, and Robert Stephens's "Thesaurus Linguæ Latinæ," and "Vossii Etymologicum Linguæ Latina." Skinner's, "Lexicon Etymologicum," is an excellent one of that kind, for the English tongue. Cowel's "Interpreter" is useful for the law terms. Spelman's "Glossary" is a very useful and learned book. And Selden's "Titles of Honor," a gentleman should not be without. Baudrand hath a very good "Geographical Dictionary." And there are several historical ones, which are of use; as Lloyd's, Hoffman's, Moreri's. And Bayle's incomparable dictionary, is something of the same kind. He that hath occasion to look into books written in Latin since the decay of the Roman empire, and the purity of the Latin tongue, cannot be well without Du Canges's "Glossarium mediæ infimæ Latinitatis." Among the books above set down, I mentioned Vossius's “Etymologicum Linguæ Latinæ ;" all his works are lately printed in Holland in six tomes. They are fit books for a gentleman's library, containing very learned discourses concerning all the sciences. ELEMENTS OF NATURAL PHILOSOPHY. CHAP. I. Of matter and motion. MATTER is an extended solid substance; which being comprehended under distinct surfaces, makes so many particular distinct bodies. Motion is so well known by the sight and touch, that to use words to give a clear idea of it, would be in vain. Matter, or body, is indifferent to motion, or rest. There is as much force required to put a body, which is in motion, at rest; as there is to set a body, which is at rest, into motion. No parcel of matter can give itself either motion or rest, and therefore a body at rest will remain so eternally, except some external cause puts it in motion; and a body in motion will move eternally, unless some external cause stops it. A body in motion will always move on in a straight line, unless it be turned out of it by some external cause; because a body can no more alter the determination of its motion, than it can begin it, alter or stop its motion itself. The swiftness of motion is measured by distance of place, and length of time wherein it is performed. For instance, if A and B, bodies of equal or different bigness, move each of them an inch in the same time; their motions are equally swift; but if A moves two inches, in the time whilst B is moving one inch; the motion of A is twice as swift as that of B. The quantity of motion is measured by the swiftness of the motion, and the quantity of the matter moved, taken together. For instance, if A, a body equal to B, moves as swift as B; then it hath an equal quantity of motion. If A hath twice as much matter as |