細節
A fine early 19th Century overhead magnetic compass with double sided compass card -- 3¾in. (9cm.) diameter, signed on the top side GILBERT & SONS. London, and on the underside GILBERT & SONS near India House, London, in brass bowl glazed on top and bottom, mounted within brass bulkhead bracket, in fitted mahogany box with sliding lid and containing two sighting accessories which can be mounted on the side of the bowl -- 6½in. (16.5cm.) wide