A fine early 19th century ebony octant, the "A" cross-arm with makers ivory plaque signed SPENCER, BROWNING & RUST, London the main index scale reading 0o -95o and inscribed S.B.R., brass circle arm, adjustable horizon mirror, peep-hole sight, five shades in fan shaped oar carrying case with good engraved trade labelof Samuel Emery, Mathematical Instrument Maker, Water Street, Salem - 13½in.(34cm) radius