Grand orreries were educational tools and status symbols, affordable only to the most wealthy. This one stands on a polygonal black wooden base with four trestle legs and brass feet, surmounted by a shallow glass dome. Panels around the side of the base are gilt framed and painted with the twelve signs of the zodiac and, between Leo and Gemini, there is a clock signed by the maker (James Simmonds, London), which strikes on the hour. The upper surface of the orrery consists of four moveable wooden circles of different dimensions that are coloured blue. This surface conceals all the supports and gearing, made by Malby & Co., in the cavity beneath. Although mechanically driven, the orrery can be speeded up by inserting a handle in a socket and rotating it. Around the outside of the orrery there is a brass ecliptic scale which show the degrees of the zodiac, the corresponding dates for the Sun's position in the zodiac and the celestial longitude. It represents the relative motions of the six planets (to Saturn) and their known moons around the Sun. Earth (a replacement model) has its single moon, Jupiter has four and Saturn has a ring and seven moons, although these satellites are not mechanically driven. It was possible for the user to set the instrument to a particular date and time so that it would the planets to the correct position for this moment.