The dial has roman hour numerals and the seconds dial has Arabic ten-second figures with straight batons at alternate five second intervals. The dial is signed across the centre: ‘John Poole / MAKER TO THE ADMIRALTY, / London No.1853’. The up and down dial, below XII, is marked in Arabic numerals in six hour intervals: ‘0…54’ and is marked ‘~UP~’ by 0, ‘WIND’ by 24, and ‘DOWN’ by 54. The chronometer has polished gold spade and poker hands with a fine pointer blued steel second hand with a counter poised tail and a blued steel up and down pointer.

The chronometer has a fine, standard type, two-day full plate fusee movement with four turned pillars, all fixed with polished and blued steel screws. The general level of finish of the brass-work is very high with all brass movement parts highly polished. The fusee, which has Harrison’s maintaining power, has a brass pipe around the winding square. It has a four-wheel train plus a great wheel, the third wheel run within the pillar plate with a third/fourth wheel bar.

It has a typical Earnshaw spring detent escapement with a fine, highly polished foot detent, a screwed on, gold passing spring and light pink locking stone, with a gilt-brass detent banking piece. The impulse roller has a radially set, red impulse jewel and the discharge roller has a similar stone inset. The two-arm bimetallic balance has Poole’s auxiliary for MTE correction. Brass, mean-time nuts are mounted on fixed threads at the end of the arms and the bimetal rims extend to within a couple of degrees short of extensions of the rim on the other side of the arms. Round brass compensation weights, with narrow bevelled top edges, are attached to the middle of the rims. The finely polished, blued steel helical balance spring has terminals on both ends; the upper terminal is attached to a brass pointer stud. The jewelling extends to the balance (diamond upper endstone in a blued steel setting) and escape wheel, with endstones, the lower fourth hole and the escapement parts as mentioned.

The chronometer is contained in a three tier, brass-bound, rosewood box, 190mms high, 190mms wide and 185mms deep, with inlaid, brass, waisted-lozenge escutcheon on front. The lid of the box is on butt hinges and has a brass, waisted-lozenge inlay in the lid, without engraving. The upper half is on a full-width hinge and has a narrow scratched moulding just below the junction with the lid and just above the junction with the lower half. On the front is a rectangular ivory plaque marked in pen: ‘POOLE / 1853’. The box has raised beading running along the centre of the junction on the lower half, mating with a groove in the junction of the upper half and forming a dust seal when closed. The box fittings are standard, with brass drop handles on the sides and lacquered brass gimbals. The interior fittings are of standard layout, with a strut to the upper half, stopping it open at ninety degrees. The original, rising-ratchet winding key has a typical, waisted handle. The bezel is of the open, silvered site-ring form, without knurling on the edge, and has a flat bevelled glass over the dial. The brass bowl has turned rings and sweeps out slightly at the top in the standard pattern. A recess in the base of the bowl has an off-set, revolving shutter for the winding square. The mahogany bottom of the box has a coarse, dark green baize covering. Inside the back of the upper half is a circular label stating that the chronometer was issued from H.M. Chronometer Depot at Bradford on Avon on 12 December 1946.

The chronometer is in fine, original condition. The box has a few slight knocks and dents to the finish, and the brass furniture and gimballing are slightly spotted and worn in places, but are stable and appear to retain the original lacquer. The dial silvering is good and the movement is in excellent condition.

The chronometer was almost certainly acquired during World War II and appears to have been in R.N. service until 1972 when it was placed on permanent loan to the NMM.