Introduction to the Supplement.

It is now almost forty Years since I translated Mr Bion’s French Book of Mathematical Instruments into English. I did it with Reluctance, at the Desire of Friends, and a little for the Sake of Interest, the Subject becoming somewhat unpleasant to me, at that Time, by Use and long Acquaintance; for having at first mostly applied myself, even from twelve Years of Age, in the Knowledge of Mathematical Instruments, I began to be tired and satiated, as I may say, with them, when I undertook this Work, although they are generally so pleasing and useful, and betook myself to the more refined and difficult Branches of the Mathematicks. I was reading, and trying to understand Sir Isaac Newton’s Mathematical Principles of Natural Philosophy, at the Time I was prevailed upon to translate Mr Bion’s Book, which I liked to do much better. The desire of travelling further, and acquiring new Knowledge in this amiable Science is very natural to one who loves it. But having set about the Business, I soon perceived that many French Instruments of Mr Bion’s were excelled by some of ours, of the same kind in Contrivance; and as to Workmanship, I never did see one French Instrument so well framed and divided, as some of ours have been; for Example, Mr Sutton’s Quadrants, made above one hundred Years ago, are the fined divided Instruments in the World; and the Regularity and Exactness of the vast Number of Circles drawn upon them is highly delightful to behold. The mural Quadrant at the Royal Observatory at Greenwich, far exceeds that of the Royal Observatory at Paris. Also the Theodolites of Mr Sisson and Heath. The Clocks and Watches of Mr Graham, Tompion, and Quare. The Orreries of Mr Graham and Mr Wright. And many more curiously contrived, and well executed Mathematical Instruments which I could mention, far exceed those of the French, or indeed any other Nation in the World. The making good Mathematical Instruments is almost peculiar to the English, as well as their Skill in all Branches of the Mathematicks and Natural Philosophy has been generally superior to that of other Nations.

I therefore thought of adding some English Instruments to those of Mr Bion, and accordingly made choice of such which I thought were then preferable to his of the same Kind, and most pleasing to me.

This first Impression being published, imperfect as it was, rather for want of Inclination in me, than Abilities to make it better, was soon sold off; and the Bookseller and others, at Times for many Years last past, were putting me in mind of preparing a second Impression with Additions. But being at those Times always immerged in other more delightful Branches of the Mathematicks, especially pure Geometry and Mechanicks, I declined doing it. But having at last been prevailed upon, through several Motives, this second Impression is here published, with a Supplement or Appendix, containing the Descriptions, and some of the Uses of such Instruments as were before omitted, or have been made better, as I thought since, for the Purposes designed by them, and wherein there are some other Instruments, though just touched upon and described, yet there is given so much of their Nature and Use, as may satisfy the Curiosity of some; and for those who desire more ample and compleat Descriptions of them, I have so far satisfied their Wishes, as to point out some of the several Writings where they are treated of more at large.

In a Word, this Treatise here published is a sufficient Explanation of the main Body of all the Instruments of the most Value, and in the greatest Esteem, that are generally made, and sold in the Shops of the Mathematical Instrument-Makers, and which have been contrived to answer the various useful Purposes of practical Mathematicks. And if a better Book on this Subject has not yet been compiled, it is because the able Geometricians, who are the most capable of making one, have the least Inclination for it, because of the small Honour and Reputation they would acquire by it; and thus it has happened that there never has yet been a very good Book upon this Subject.