Beschreibung:

A mahogany cased two-day marine chronometer with Kullberg’s early form of compensated balance Negretti and Zambra, London, late 19th century The circular four pillar single chain fusee movement with Harrison's maintaining power, Earnshaw type spring detent escapement and split bimetallic balance incorporating Kullberg’s early form of middle-error temperature compensation with cylindrical weights and helical invar or palladium balance spring, the spotted backplate with spring set-up ratchet, faceted diamond endstone and blued steel movement pillar and backcock securing screws, the 4 inch circular silvered Roman numeral dial with subsidiary seconds dial, signature NEGRETTI & ZAMBRA, London, No. 3455 and WIND DOWN/UP dial to centre, with gold spade hands and secured by a screw-down bezel into a lacquered brass bowl with shuttered winding hole to underside and indistinctly stamped with a serial number 285? to interior, mounted via gimbals into a brass-bound mahogany three-tier box, the top with vacant brass shield-shaped name plate and capped corners over front with later vacant ivorine name plate, brass strap reinforced angles and the sides with recessed lacquered brass carrying handles to sides, the laft hand side also with electrical timing connections, 18cm (7ins) wide. The firm of Negretti & Zambra are recorded in Banfield, Edwin BAROMETER MAKERS AND RETAILERS 1660-1900 as being established in 1850 when a partnership between Enrico Negretti and Joseph Warren Zambra was formed. The firm became one of the most prolific makers of scientific instruments and continued trading well into the 20th century. The design of the middle-error temperature compensation to the balance of the present timepiece was developed Victor Kullberg (see Gould, Rupert T. THE MARINE CHRONOMETER, Its History and Development figure 68, opposite page 180). Victor Kullberg is recorded in Mercer, Tony Chronometer Makers of the World as born in Sweden 1824, he was apparently drawn to London by the Great Exhibition of 1851 and subsequently set up business at 105 Liverpool N1 (by 1870). Kullberg developed several balances with middle error temperature compensation and became one of the finest makers of marine chronometers of the period; he died in 1890 leaving the business to be continued by George and Peter Wannerstrom. The current lot is also fitted with electrical connection posts to the box; in addition to this the movement 4th wheel also incorporates an auxiliary ratchet wheel which would have previously engaged with a detent to open and close electrical contacts (now removed). This would suggest that at some point in its life the current lot was used for electrical timing, perhaps in a laboratory. Condition report disclaimer