Ebony frame with inset scale stamped 'SBR' at centre and divided to 105º, makers' plate signed as per title, pencil, lacquered-brass index arm, pinnhole sights, mirrors and shades, contained within stepped keystone box with embossed lock plate and key -- 14in. (35.5cm.) high. The SBR sign on the scale indicates the scale was mechanically devided: It was Found on all Spencer Browning & Rust and Spencer Browning &Co octants and wooden framed sextants.