TRAMMEL

(Old French, tramel.) An instrument for drawing ovals, much in use among joiners and other artificers. It consists of a cro , C D E F, in which are cut two grooves at right angles to each other; and a beam, A B, carrying two pins, G, H (which are clamped to A B, and slide in their grooves), as well as a pencil, P: these parts are called the cro and the beam. By turning A B round, the pins G, H slide along the grooves, and the pencil P describes an elliptic curve. A demonstration of the properties of this instrument may be seen at p. 700. vol. xiv. of Hutton's Abridgment of I he Philosophical Transactions. [s. 1263]