Wind gun, maker unknown, before 1753. Once belonged to Stephen Demainbray.

This wind gun once belonged to Stephen Demainbray and was used by him in his lectures on natural philosophy. The gun is made of brass and has two barrels, one inside the other. A spring can be operated in the handle which forced air through a valve into a chamber behind the pellet. When the trigger was pulled another valve was opened which allowed the air to escape on to the pellet, which in turn was shot out. 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.