Born in 1725, Benjamin Cole was the son of an instrument maker, also called Benjamin Cole. He was apprenticed to his father and was in partnership with him by 1751, until the latter's death in 1766. In 1748 his father had opened premises at 136 Fleet Street and Benjamin Jnr continued the business there until his retirement in 1782, when he sold it to J. and E. Troughton. He died in 1813.
The 'bayonet' tube is a straight glass tube which is crimped/bent below the register plates. This allows the lower part of the tube to be concealed behind a panel or plate upon which a thermometer is often mounted, as with the present example.