[NAVAL CHRONOMETER]. James McCabe Warship Chronometer. London: James McCabe Royal Exchange, [1830]. This rare and historically significant two-day chronometer is signed James McCabe, Royal Exchange, London on the top plate, and numbered #172. Obtained at Asprey & Co, London, during the exhibition of Marine Chronometers in May, 1979. The catalog entry for this instrument at the exhibition states that it was assigned to H. M. S. Meda at Greenwich on July 14, 1828 (although the plate dial is engraved 1830) and then established that the chronometer served on a series of warships until 1906, when it was given to Dent & Co., London, in exchange for a new deck watch. This is a rare, early style convex 48-hour chronometer, with an Earnshaw type spring detent escarpment and blued steel spring with diamond endstone. The balance uses segmented weights. The mechanism is gimbaled in a double lid mahogany box with brass inlays and recessed handles. Box approximately 6 ¼ “ square, 6 ¾” high; the dial approximately 3 ¾” in diameter.

The chronometer was one of the most important and essential pieces aboard ship at the period and together with the compass, the sole source of Navigation. Chart distances and navigational headings were maintained only through accurate measurement of time through devices such as these. The instrument is linked to several sources of provenance including two of the Asprey catalogs mentioned previously, purchase records from 1979, correspondence with the Naval Museum and copies of period service records. Very rare. This chronometer served on the H. M. S. Eclipse (1873); the chronometer was then sent to various locations, including McCabe (1878), Devonport (1879), Pyott (1887), Sydney (1888), Portsmouth (1892), Cape of Good Hope (1896), Portsmouth (1900).