ARMILLARY SPHERE, an artificial sphere composed of a number of circles of the mundane sphere, put together in their natural order, to ease and assist the ima-
gination in conceiving the constitution of the heavens, Armillary and the motions of the celestial bodies. The armillary sphere revolves upon its axis within a silvered horizon, which is divided into degrees, and moveable every way upon a brass supporter. The other parts are the equinoctial, zodiac, meridian, the two tropics, and the two polar circles. See GEOGRAPHY.