He was chief of the Bureau of Ordnance in 1893-1897.
Among the curiosities of the capital is the celebrated monster gun (Malik-i-Maidan), stated to be the largest piece of cast bronze ordnance in the world.
In acknowledgment of this, several pieces of ordnance, small arms and ammunition, with much of the surplus stores, were handed over to him, and the English troops left the country in May 1868.
Rivers now met with marked favour at court, being entrusted with a delicate mission to the elector of Hanover in 1710, which was followed by his appointment in 1711 as master-general of the ordnance, a post hitherto held by Marlborough himself.
A soft bronze or gun-metal is formed with 16 parts of copper to 1 of tin, and a harder gun-metal,, such as was used for bronze ordnance, when the proportion of tin is about doubled.