High Quality Content by WIKIPEDIA articles! Spencer, Browning & Rust was a London firm that manufactured instruments for navigational use during the 18th and 19th centuries. The predecessor company of Spencer and Browning was established by William Spencer and Samuel Browning in 1778, before they entered into partnership with Ebenezer Rust in 1784. After the death of Ebenezer Rust`s son, the successor business was known as Spencer, Browning & Co. The firm of Spencer, Browning & Rust made a variety of navigational instruments, including octants and sextants.