T.S. & J.D.Negus, New York c.1850 No.1740

2 day marine chronometer in rosewood box

Negus…..

Box/Mounting

Three-tier, brass-strung and edged rosewood box measuring 188mm high, 180mm wide, and 176mm deep. The lid of the box has a full-width butt-piano hinge allowing it to open to 175° only. The nicely figured lid, which has a brass inlaid tablet on top in the form of a ‘scalloped lozenge’, opens to a glazed panel retained with narrow 7mm tall ebony beading, the lid lined on its underside with folded blue velvet. The front of the upper half has a push button brass catch with brass, ‘scalloped star’ inlaid escutcheon, and a rectangular mother-of-pearl tablet, inscribed in pencil: “NEGUS 1740”. The tablet has been reversed, and the other, bevelled (‘front’) side is engraved and reads: “JOHN POOLE. / MAKER TO THE ADMIRALTY. / 1 Upper East Smithfield & Commercial Rd / London / 1946”. The lower half has a full-width butt-piano hinge, as well as a brass strut, allowing the upper half to open to 90° only, and the lock, which is `stamped: “PATENT” on the top edge, has a brass, shield-shaped escutcheon on the front of the box. Inside the upper half, at the back, is fixed an aluminium label engraved: “CORK AS SHOWN BEFORE SHIPPING”, “CORK, ACTUAL SIZE” and: “SEE SHIPS / CHRONOMETER / RECORD BOOK / (FORM N.B.S. 702) / “TRANSPORTATION” / PARAGRAPH 2 (A)” along with a diagram of a wedged balance. The box has a raised beading on the top of the junction on the lower half, forming a dust seal with a groove in the upper edge when the upper half is closed.

The box fittings are standard, with inset, round-section, brass drop handles on the sides, the gimbal pivots screwed directly into the wood of the box on the sides. The movement and bowl are mounted in lacquered brass gimbals and have a screw-down bezel (2 ¾ turns) with a fine knurled edge, a silvered sight ring and a flat beveled glass over the dial. The interior fittings are of standard layout, and the rising ratchet winding key is probably later. The base of the bowl is recessed and has at the centre a swiveling circular shutter for the winding hole, which is engraved :”HS↑1” and has “NEGUS 1740” penciled on the underside. The underside of the box has a green baize covering.

Dial and hands

The 99.0 mm Ø, engraved and wax-filled, silvered-brass dial seats in a recess in the brass edge, secured with three brass dome-headed (dot-marked) screws, the brass edge then seating in the usual recess in the bowl. The dial has roman hour numerals and Arabic five-minute figures. There is a large seconds dial at VI o’clock having Arabic ten-second figures with straight batons at alternate five-second intervals, and an up-and-down dial below XII, marked in 8 hour intervals, beginning with “0” at fully wound (also marked: “UP”) and “56” at wound down (also marked: “DOWN”). The dial is signed across the centre: “T.S.& J.D.NEGUS. / New York No 1740”. On the back, the dial is stamped: “1000” and has a row of 4 and a row of 6 drilled dots. It is also is scratched: “Cleaned by / R.F.NUCKOLLS / 1902 – 1905 – 1909 - 1934” . The area right across the centre of the dial behind the makers name, has been punched out deeply from behind, as has the area under “1740”, but nowhere else, and the whole of the back of the dial appears to have been refinished with curling. Just perceptible on the back, but nearly obliterated by this refinishing, are the scratched words: “Cleaned by F …….65”, “……..Sep 69..F..77”, and :” Feb77” where the punching is. Gold spade and poker-hands with a gold up and down pointer and a fine, blued steel pointer seconds hand with a counter-poised tail.

Movement

Full-plate fusee movement with four pillars with flanges and fins at either end and one fin in the lower middle, the potence plate fixed with four blued steel screws (dot-marked for position). The movement fits into a recess in the brass edge and is secured with three (dot-marked) brass screws. The general level of finish of the movement is very good, with a high polish with the potence, barrel and the great wheel having a ‘curled stripe’ (series of elongated ovals) finish, while the main frame parts have neat ‘oval spotting’, by hand. The underside of the pillar plate, of the potence plate, of the balance cock table, of the barrel bridge, of the train bar, of the blued steel set-up click, and of the blued steel set-up ratchet wheel are all stamped with four triangular dots. The set-up click is also stamped with a separate, larger triangular dot. The maintaining power detent has one dot marked on its inside. The inside of the great wheel is marked with four dots and the blued steel maintaining power spring is marked on its underside with four straightlines and two small dots. The inside of the pillar plate is stamped “TCW” and the inside of the pillar plate and the underside of the balance cock foot are stamped: “1000”. The underside of the train bar is scratched “1000”, the last 0 interrupted by one of the steady pins. The maintaining power wheel is scratched on the underside: “JGF 1865”.The highly polished and smooth, signed, blued steel mainspring, which only opens to just over three times the diameter of the barrel, has a square hooking on the mainspring. The highly finished, five-wheel train (including great wheel), has a fusee with Harrison’s maintaining power and a straight-sided fusee pipe (dot-marked for position on square). The train wheels are brass with the third, fourth and escape wheels run on a bar on the pillar plate. All train holes have been plugged and re-pitched from new. There is a small hole in the pillar plate, directly under the balance centre.

Escapement, balance, spring and jewelling

Earnshaw-type spring detent escapement with fine-grained foot detent screwed directly on the potence plate and with gilt-brass banking piece alongside. The finely made and finished steel detent has a screwed-on, gold passing spring running alongside the detent blade, a highly polished horn and pipe, and with a clear jewelled locking stone. The impulse roller has a radially-mounted pink impulse stone, and the discharge roller has a pink stone inset.

The two-arm bimetal balance has tapered, steel arms. The rim segments, which are un-blued, extend to within 5° of the opposite arm and have round brass weights positioned (as found) just before 90° from the arms. Brass meantime nuts are attached at the end of the arms. The blued steel helical balance spring has terminals on both ends, the upper terminal with a brass pointer stud. The jewelling, which is all in very light pink or clear stones, mounted in brass settings (upper balance faceted diamond endstone is in a blued steel setting), extends to the balance and escape wheel with endstones, the lower fourth and the escapement parts as mentioned.

Alterations/condition

The wooden box is in sound and clean condition but has a crack running across the middle of the top, and has a small piece of rosewood missing from the front-left of the lower half. The drop handles and outer brasswork have been cleaned at some stage and are sound. The inner brasswork is well preserved though a little dull, and the lacquer is slightly patchy with tarnish coming through in places.

The dial silvering is fine and clean.

The movement is in generally sound clean condition, though it was found to be thick with old, solidified oil. Burrs under the balance cock foot suggest that the balance staff may have been repivoted or replaced at some stage. The movement has only been very lightly cleaned, and has been re-oiled, during inspection.

Commentary, Provenance, etc

Separate chronometers, likely scenarion (graffiti). Aluminium label, NBS, US service, RN service. TCW = Webster

Potence Plate Ø: 78.9

Pillar Plate Ø: 78.9

Plate distance: 17.9

Inside barrel Ø: 34.5

Arbor Ø: 11.6 steel, unsnailed.

Thickness: 0.43 – 0.36

Height: 15.2

(6 ½ full turns output from barrel)

Set up: 8 set up (as found)

Signature: “New York May 9th 1855” (scratched on outside of spring, 25cms from end)

TRAIN COUNT


Wheel / Pinion (+ext dia) Comment: Crossings? Marks?Jewelled?

Fusee/Great: 90 / 38.1 No.of Turns:8 ½ (Chain 67cms, 163 links)

Ratchet: 42 / 17.6 Brass, 2 steel clicks

Maintaining Power: 120 / 36.0 Brass

Centre/2nd: 90 / 24.9 + 14 / 6.4 5 tapered crossings. Wheel and pinion
superbly finished

Third: 80 / 22.0 + 12 / 4.4 “ “

Fourth: 80 / 19.1 + 10 / 3.0 “ “

Escape: 15 / appr.14.2 + 10 / 2.6 3 curved crossings “

Balance Frequency: 14,400 vbs/ hr (half seconds)

Hour: 54 / 18.2 brass

Minute Wheel: 56 / 19.3 “

Minute Pinion: 18 / 6.7 “ secured with b.steel screw

Cannon: 14 / 5.4 polished steel

Up and down wheel: 110 / 34.4 brass, 5 crossings finely finished

Up and down pinion: 10 / 3.6 brass, friction fit dot-marked for which way on

Set up ratchet: 16 / 11.3 blued steel

Impulse pallet tip Ø: 6.9

Discharge pallet tip radius: 1.3

Detent length: 26.7

Balance Ø: 30.5 Balance Mass (incl. b/spring & stud): 10.3g

Balance spring Ø: 11.8 Material: Blued steel

Turns incl. terminals: 11 (c/w down)