Camera obscura made before 1753. The camera obscura was a popular sketching instrument during the eighteenth century. A lens in the draw tube and a mirror at 45 degrees to the horizontal focussed the image onto a ground glass screen on the top of the box. A piece of paper was put onto the screen and the image was copied directly. This camera obscura is thought to have once belonged to Stephen Demainbray who used it in his lectures on natural philosophy. 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. A second camera obscura was itemised in the Queen's Catalogue and recorded as having been placed there by Her Majesty.