Compound lever demonstration model for explaining the function of different combinations of levers, unknown maker, before 1753. Once belonged to Stephen Demainbray.

Compound lever demonstration model that once belonged to Stephen Demainbray and was used by him in his lectures on natural philosophy. A lever, one of the 'simple machines' known since antiquity, enables a heavier load to be lifted using a lighter one. This device uses a series of three levers so that the weight to be lifted can be sixty times greater than the 'power' required to lift it. The model was itemised in the Queen's Catalogue and therefore believed to have belonged to Demainbray. Demainbray worked as superintendent at the King's observatory at Kew from 1768 and his collection of instruments and apparatus was absorbed into the King's own collection.