The firm of Spencer, Browning & Rust made a variety of navigational instruments, including octants and sextants.

[1] In addition, a 1796 portrait of a German sea captain, painted in Spain, depicts him with an octant that has the Spencer, Browning & Rust name.

Spencer, Browning & Rust would deliver divided instruments to those other manufacturers, who would then assemble the components and offer them for sale.

[1] Spencer, Browning & Rust manufactured a variety of navigational instruments, including octants, sextants, telescopes, and compasses.

[10][11][12] The contract of indenture to Richard Rust, "citizen and grocer of London," was for a term of seven years, and was dated 4 November 1766.

[10] William Spencer, died in 1816 and his will was proved on 20 August 1816, Samuel Browning (c.1752–c.1819) was apprenticed to Richard Rust in 1768.

The seven-year contract of indenture referred to the elder Ebenezer as a "mathematical instrument maker" and as a "Citizen and Grocer of London."

The firm was succeeded by Spencer, Browning & Co. in 1840,[3] following the 1838 death of Ebenezer Rust, Junior, son of the original partner.

[18] The Smithsonian Institution houses four navigational instruments manufactured by Spencer, Browning & Rust in its National Museum of American History.

The box containing the sextant has several inscriptions: "Captain Halls Quadrant – To be given to his family" and "To the Honorable George M. Robeson, U.S. N., Secretary to the Navy" and "from William Reid.

It is inscribed: "Spencer Browning & Rust London" and "SBR" and was owned at one time by Mount St. Mary's University in Emmitsburg, Maryland, United States of America.

[21] The fourth object in the museum's collection is a mahogany and brass telescope which dates from the early nineteenth century.

[23] The Powerhouse Museum in Sydney, Australia has an ebony octant manufactured by Spencer, Browning & Rust.

It features an ivory scale and a double silvered horizon mirror and is on display in the Boulton and Watt Exhibition.

[25] On 24 March 2007, an octant manufactured by Spencer, Browner, & Rust was sold for $2,500 at the Science & Technology Auction held in Boston, Massachusetts, United States of America.