Y AN EBONY AND BRASS NAVIGATIONAL OCTANTSPENCER, BROWNING AND COMPANY, LONDON, CIRCA 1840The 11 inch frame incorporating central T-shaped hand-piece inset with bone signature plate inscribed .Spencer. Browning & Co. London. beneath turned bone finial unscrewing to reveal a pencil, the index arm mounted with mirror opposing Vernier aperture scale calibrated in minutes of arc for reading the inset curved scale stamped SBR divided for every twenty seconds of arc, the underside with pivot clamp and endless tangent screw adjustment, the sight vane with twin pin-holes and shutter opposing horizon glass and set of three hinged shades/filters, the tapered oak case with stepped lid applied with printed paper trade label inscribed C.G. KING, No. 7 Broad, third Srore from State Street, Boston, IMPORTER AND DEALER IN, Mathematical, Nautical, Surveying, AND GAUGING INSTRUMENTS... to the inside of the lid.The box 35.5cm (14ins) long, 32cm (12.5ins) wide, 11cm (4.25ins) high.The partnership between William Spencer, Richard Browning and Ebenezer Rust is recorded in Clifton, Gloria Directory of British Scientific Instrument Makers 1550-1851 as working from several addresses in Wapping, London 1784-1840. All of the founding partners had died by 1819 but the business continued trading in their name by their successors until becoming Spencer Browning and Company in 1840. They were agents for Alexander Adie and are noted for their navigational and surveying instruments.Charles Gedney King was a third-generation instrument maker who was born in 1808 and entered into partnership with his father at 7 Broad Street, Boston in 1832. He succeeded his father in 1839 and continued at that address until 1858 when the business relocated to Washington Street.注意: Y - This lot contains endangered species and may be subject to CITES regulations. Prospective bidders are advised to familiarize themselves with relevant customs regulations prior to bidding if they intend to import the lot into another country. A buyer’s inability to import or delay in obtaining a licence cannot justify delay in payment or cancellation of sale.