A London hall-marked silver bosun’s call bearing the date letter ‘e’ for 1740 and the maker's mark ‘RP', which appears to be that of Robert Perth. The buoy is embossed with a female classical head in profile (same on both sides). The ‘keel’ or plate bears a tooled chequer pattern on each side, with the marks stamped on the right face. An S-decoration in silver wire is attached to the mouthpiece end of the keel. There are three bands round the pipe and another at the mouth end. The keel is pierced for a welded silver suspension ring. The mark is identified as that of Robert Pertt or Perth by Arthur Grimwade (no. 3785). He entered his first mark as a largeworker in London on 21 July 1738 as Robert Pertt. Heal records him under than name on Newgate Street, 1738-44, and then as Robert Perth from 1738 to 1755.