Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 142,972 pages of information and 229,026 images on early companies, their products and the people who designed and built them.
An instrument maker, brother of Samuel Browning
John Browning was apprenticed to Richard Rust in 1768
He was a mathematical instrument maker in London from 1781-1811 (sic).
Apparently not involved in the prolific scientific instrument making firm of Spencer, Browning and Rust which worked contemporaneously with him from 1784.