Eggert & Son, New York c.1849 No.270

2 day marine chronometer in mahogany box

Eggert…..

Box/Mounting


Three-tier, brass-bound, mahogany box measuring 170mm high, 178mm wide, and 172mm deep. The lid of the box has special hinges allowing it to open to 170° only, the hinges stamped: “P.MOORE / REGISTERED / IPTS 271843” (?). The nicely figured mahogany lid, which has a brass inlaid tablet on top in the form of a ‘scalloped lozenge’, opens to a glazed panel retained with narrow half-round wooden beading. The front of the upper half has a push button brass catch with mother-of-pearl, ‘scalloped star’ inlaid escutcheon, and. A surface mounted oval ivory tablet, engraved: “EGGERT & SON / 270 / NEW YORK”. The lock on the lower half has a brass, ‘scalloped lozenge’ escutcheon. The box has a green baize covering to the top of the junction on the lower half, forming a dust seal when the upper half is closed.

The box fittings are standard, with brass drop handles on the sides, rectangular brass plates for the gimbal screws on the sides and lacquered brass gimbals with a screw-down bezel (2 ¼ turns) with a fine knurled edge, a silvered sight ring and a thick, flat beveled glass over the dial. The interior fittings are otherwise of standard layout except that the (probably original) non-ratchet winding key is mounted on a shelf at the rear left corner, and that all four pivots of the gimbals have friction damping springs attached to the outside of the bowl. Inside the bowl, the movement is contained in a secondary, straight-sided brass drum (scratched “260” inside), bayonet-fitted to the brass edge, and suspended within the bowl on curved, blued steel cross-over springs as a form of shock-protection. The dial is located over three tall headed steel screws at the edge, which allow for some vertical motion, against the springs, in the event of shock. The base of the bowl is recessed and has at the centre a swiveling circular shutter for the winding hole. The underside of the box has a green baize covering.

Dial and hands

The 88.0 mm Ø, engraved and wax-filled, silvered-brass dial is integral with the brass edge, seating directly into the bowl (on the vertical screws as mentioned above), the movement seating in a recess behind and secured with three brass dog-screws. The dial has roman hour numerals and Arabic five-minute figures. There is a large seconds dial at IV 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 and “56” at wound down. The dial is signed across the centre: “Eggert & Son / NEW YORK No.270”. The dial is scratched: “270” on the back. 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 middle, the potence plate fixed with four blued steel screws. The general level of finish of the movement is fair, with a reasonably high polish over a slightly roughly finished frame. The potence plate is engraved on its upper surface: “Eggert & Son New York No.270” in a slightly shaky hand. The underside of the pillar plate, of the potence plate, of the balance cock table, the barrel and of the blued steel set-up click, are stamped with three triangular dots and the underside of the blued steel set-up ratchet wheel also has three shallow triangular marks faintly perceptible. The inside of the pillar plate is stamped “TCW” and is scratched on the underside: “CK 872”.The signed blued steel mainspring, which only opens to just over three times the diameter of the barrel, has a square hooking on the mainspring. There is a four-wheel train and a great wheel, the fusee with Harrison’s maintaining power and a bell-mouth fusee pipe. 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.

Escapement, balance, spring and jewelling

Earnshaw-type spring detent escapement with grey-finished, foot detent screwed directly on the potence plate and with gilt-brass banking piece alongside. The banking piece screw, the banking screw itself, and the detent fixing screw are all of a characteristic design, with an extension to the end of the thread, terminating in a turned ball shape. The somewhat unevenly made and finished steel detent has a screwed-on, gold passing spring running alongside the detent blade, and with a light pink jewelled locking stone. The impulse roller is solid steel with a polished face and the discharge roller has a light pink stone inset.

The Earnshaw-type, two-arm bimetal balance has slightly tapered, steel arms. The rim segments, which are blued up to the junction with the arms, extend to within 10° of the opposite arm and have Earnshaw-type wedge weights positioned (as found) just beyond 90° from the arms. Brass meantime screws are attached at the end of the arms, and brass meantime nuts are fixed to brass studs on short pieces of rim segment extending on the other side of the arms.. The blued steel helical balance spring has terminals on both ends, the upper terminal with a steel stud fixed with two screws and washers to a gilt brass cock mounted on the potence plate. The jewelling, which is all clear stones mounted in brass settings (upper balance 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 with a few small knocks and dents but generally sound and clean. The drop handles and outer brasswork have been cleaned and re-lacquered 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 return spring for the bowl’s dust shutter was missing and has `been replaced. The rear, brass, pivot damping spring on the gimbals is broken, only the foot surviving on the right hand side of the bowl.

The dial silvering is generally sound, with a dark patch running across the lower part. The minute hand has been broken at its base and neatly repaired with hard solder.

The movement is in generally sound clean condition, though it was found to be thick with old, solidified oil. The movement has only been very lightly cleaned, and has been re-oiled, during inspection.

Commentary, Provenance, etc

The box was almost certainly all made in England. The shock-protection system is identical with that of Parkinson and Frodsham’s chronometers, and this chronometer may well have been supplied in component form, via P&F, for finishing by Eggerts in N.Y. Motion work probably finished up in NY. T&CW Thos and Charles Webster…..

Potence Plate Ø: 63.2

Pillar Plate Ø: 63.4

Plate distance: 11.8

Inside barrel Ø: 27.5

Arbor Ø: 8.7 steel, unsnailed.

Thickness: 0.29 – 0.26

Height: 11.0

(6 ½ full turns output from barrel)

Set up: 6 teeth (No set up, as found)

Signature: “G Quelet New York Oct 25th 1849” (scratched on outside of spring, 24cms from end)

TRAIN COUNT


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

Fusee/Great: 84 / 30.4 No.of Turns:8 (Chain 51cms, 162 links)

Ratchet: 40 / 14.4 Brass, 2 steel clicks

Maintaining Power: 120 / 28.7 Brass

Centre/2nd: 80 / 24.9 + 12 / 4.7 5 tapered crossings

Third: 75 / 20.1 + 10 / 3.4 “

Fourth: 80 / 18.8 + 10 / 2.5 “

Escape: 15 / appr.12.2 + 10 / 2.6 3 curved crossings

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

Hour: 54 / 15.9 Gilt brass

Minute Wheel: 56 / 17.0 “

Minute Pinion: 18 / 5.9 “

Cannon: 14 / 4.85 Steel

Up and down wheel: 80 / 24.6 Gilt brass (teeth rounded up by hand?)

Up and down pinion: 8 / 3.4 Brass, friction fit (“)

Set up ratchet: 16 / 8.8 Blued steel

Impulse pallet tip Ø: 6.2

Discharge pallet tip radius: 1.3

Detent length: 21.5

Balance Ø: 28.0 Balance Mass (incl. b/spring & stud): 6.0g

Balance spring Ø: 11.0 Material: Blued steel

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