Invention of a new gun carriage. A signed and dated affidavit to patent the invention of a new gun carriage by Sir William Congreve (1772-1828), comptroller of the royal laboratory at Woolwich from 1814 until his death in 1828. A brilliant military technologist, Congreve had earlier won renown for the development of a rocket system based on a Mughal design which had been used with effect against the British during the Anglo-Mysore Wars.

His invention, of the 'simplest construction wither for land or sea service', was 'calculated to reduce very considerably the labour of working the gun to produce a smooth and even recoil and prevent the violent action that takes place in common carriages when the gun is fired' (Petition). To this effect wheels were to be placed on the trunnions of the guns themselves, rather than mounted on the gun-carriages as had previously been the case. The invention was later recorded as British Patent Number 3134.

The design was perfected over the next three years before being published in Congreve's An Elementary Treatise on the Mounting of Naval Ordinance in 1811. There is evidence that the Royal Navy took his idea seriously, and Congreve was confident that a team of 4 could replace the 13 men previously required to man a long 24-pounder cannon. A variety of the system designed for carronades, shorter ranged powerful weapons with a tendency to jump at recoil, was trialed in July 1808, and Sir Philip Broke, who commanded HMS Shannon to great effect during the War of 1812 considered employing the new technology.

Single leaf folded in three (23.5 x 19.5 cm open); signed 'William Congreve'; old catalogue description and MS note tipped to upper margin, blind stamped 'ii shillings vi pence'; minor soling to verso along fold lines, edges rubbed.