The trigonall sector, the description and use thereof : being an instrument most aptly serving for the resolution of all right lined triangles, with great facility and delight. By which all planimetrical, and altimetrical conclusions may be wrought at pleasure. The lines of sines, tangents, secants, and chords, pricked down on any instrument: many arithmeticall proportions calculated, and found out in a moment. Dialls, delineated upon most sorts of plaines: with many other delightfull conclusions. Lately invented and now exposed to the publique view. By John Chatfeilde.