1728—Ephraim Chambers publishes his *Cyclopaedia

or, An Universal Dictionary of Arts and Sciences. It goes through several editions in England and includes the following description: “The Sackbut is very fit for playing bass; and is contrived so as to be drawn out or shortened, according to the gravity or acuteness of the tones. The Italians call it Trombone, the Latins, Tuba Ductilis.* It takes asunder into four pieces, or branches; and hath frequently a wreath in the middle; which is the same tube, only twisted twice, or making two circles in the middle of the instrument; by which means, it is brought down one fourth lower than its natural tone. It has also two pieces or branches on the inside, which do not appear, except when drawn out by means of an iron bar, and which lengthen it to the degree requisite to hit the tone required” (Guion, Trombone 34).