Ebony 19th Century Octant – Spencer Browning & RustA 19th century octant, ebony frame with ivory plate and scale, signed by Alexander Yarmouth. The scale has been engraved with the initials SBR for Spencer, Browning and Rust. An example of Alexander with SBR scale is also in the Greenwich National Collection. The retailers name H Duren, New York was added later and the inner lid has the retailers label FW Lincoln, JR & Co Boston.