- Museum number
- 1958,1201.1753
- Description
-
SUBSIDIARY SECONDS POCKET-CHRONOMETER MOVEMENT WITH SPRING DETENT ESCAPEMENT.
Chronometer watch.
Spring detent escapement; long detent.
Enamel dial.
- Production date
- 1859-1862
- Dimensions
-
Diameter: 36.10 millimetres (back-plate)
-
Diameter: 40.80 millimetres (dial)
-
Thickness: 10.20 millimetres
- $Inscriptions
-
- Curator's comments
- Comment from Anthony G. Randall and Richard Good, Catalogue of Watches in the British Museum. Vol. VI (1990)
Made by Alexander Watkins, Late 19th century
Chronometer movement
Signature: On the back plate 'Alex-Watkins, 67 Strand LONDON No. 4682'. On the dial 'WATKINS 67 STRAND LONDON'.
Dial and hands: Flat enamel dial on the back faintly in red XII and a line showing its position. The centre part of the subsidiary seconds dial sunk, the dial secured directly to the front plate by three feet, one broken, and pins.
Gold minute and hour hands, hour hand tip broken off, blued steel seconds hand.
Movement:
Ebauche marks 12, 2.
Front plate diam. 40.8 mm; back plate diam. 36.3 mm; frame h. 7.0 mm.
Frame: Three-quarter plate construction with three turned pillars, the back plate secured by recessed blued steel screws. The movement was fixed in its case by a hinge screwed to the front plate under the dial, and a case catch and spring opposite. All the brass parts gilded.
Fusee: Keywind fusee with the usual stop-work and maintaining power with steel maintaining ratchet wheel. The setting-up-work fitted in a shallow recess on the dial side of the front plate, the barrel arbor with an extended square on that end only.
Going train: Typical layout and construction, the brass wheels gilded, the steel pinions and arbors well finished and polished.
Jewelling: The pivots of the third, fourth and escapement arbors in pierced jewels, those of the escapement with endstones. A diamond endstone set in a blued steel ring on the balance cock.
Escapement: A development of Earnshaw's spring detent escapement, the brass escape wheel with arms sunk below the level of the rim and teeth. The polished steel impulse roller with radial impulse surface, the usual jewelled polished steel discharge roller without an adjusting flat. The unusually long detent overhanging the fourth wheel fitted with a triangular locking stone and a gold passing spring held by a screw. Banking for the detent provided by a gold block screwed and steady pinned to the front plate, and with a small protuberance touching the lower end of the locking stone pipe.
Balance: Bimetallic two-armed balance with gold quarter and compensation screws. Diam. of rim 13.3 mm, h. 1.33 mm.
Balance spring: Blued steel helical spring of comparatively large diameter, and having 5½ turns, with terminal curves. A polished steel stud on the balance cock, and a brass block-shaped collet.
Going-train counts:
Great wheel (fusee) 70 teeth
Centre pinion 10 leaves, wheel 64 teeth, 5 arms
Third pinion 8 leaves, wheel 60 teeth, 5 arms
Fourth pinion 8 leaves, wheel 60 teeth, 5 arms
Escape pinion 6 leaves, wheel 15 teeth, 3 arms
Beats per hour: 18,000
Motion work:
Cannon pinion 12 leaves, minute pinion 14 leaves
Hour wheel 42 teeth, minute wheel 48 teeth.
Provenance: Ilbert Collection; purchased by Ilbert from Benson in 1935.
- Location
- Not on display
- Condition
-
Latest: 4 (2017) verdigris on centre wheel
-
4 (Oct 1995) Tip broken from hour-hand.
- Acquisition date
- 1958
- Acquisition notes
- Following the successful acquisition of the celebrated Ilbert collection of clocks (1958,1006 collection), prints and other related materials made possible by the generous donation of funds by Gilbert Edgar CBE Ilbert's watches were then acquired using funds provided by Gilbert Edgar, public donations and government funds.
- Department
- Britain, Europe and Prehistory
- Registration number
- 1958,1201.1753
- Additional IDs
-
Previous owner/ex-collection number: CAI.1753 (Ilbert Collection)
-
Previous owner/ex-collection number: N285 (Ilbert Ledger)
