- Museum number
THREE-QUARTER PLATE SUBSIDIARY SECONDS POCKET-CHRONOMETER MOVEMENT WITH SPRING DETENT ESCAPEMENT.
Spring detent escapement; altered.
Diameter: 42 millimetres
Thickness: 10.60 millimetres
- Curator's comments
- Comment from Anthony G. Randall and Richard Good, Catalogue of Watches in the British Museum. Vol. VI (1990)
Made by George E. Mylne, 1860
Signature: On the back plate 'George E. Mylne 2 Gt Percy S London 64/5408'. On the dial 'G. E. MYLNE LONDON 64/5408'.(1)
Dial and hands: Flat enamel dial with sunk subsidiary seconds, fixed to the front plate by three feet and pins. Blued steel hands.
Ebauche marks A & G, 14, 2 and 64 over 5408.
Front plate diam. 42.4 mm; back plate diam. 38.1 mm; frame h. 7.4 mm.
Frame: Typical half plate construction, three turned pillars, the back plate retained by recessed steel screws. The movement without a case hinge or catch or any provision for either, and retained in its case by a peg and two small screws passing into the edge of the front plate. All the brass parts gilded.
Fusee: Keywind fusee with the usual stop-work and maintaining power, the maintaining ratchet wheel steel. The setting-up work in a shallow recess on the front plate under the dial, the barrel arbor squared on that end only. The barrel flanged on the cover end.
Going train: The centre pinion solid and carrying the cannon pinion on its extended arbor. The brass wheel burnished and not gilded. The steel pinions and arbors polished, and with polished undercuts.
Jewelling: The pivots of the fourth and escapement arbors in pierced jewels, those of the escapement with endstones in screwed settings. A diamond endstone in a polished steel ring on the balance cock.
Escapement: A development of the Earnshaw spring detent escapement. The brass escape wheel with rim and arms sunk below the level of the teeth. The steel impulse roller polished all over and with a radial set jewel. The usual jewelled discharge roller. The detent a later replacement of very poor quality and finish, set with a half-round locking stone and a gold passing spring screwed on, and planted well inside a tangent to the locked escape wheel tooth. Detent banking provided against the end of a screw set in a polished steel bar integral with a semicircular ring concentric with the balance lower bearing, and secured in a recess by two marked screws.
Balance: Bimetallic two-armed balance with steel quarter screws, and platinum and gold compensation screws. Diam. 18.0 mm, h. 1.8 mm.
Balance spring: Blued steel helical spring of 6½ turns, with terminal curves, free-sprung to a diamond-shaped polished steel stud on the balance cock. The steel collet polished, and slotted to give it some spring on the balance staff.
Great wheel (fusee) 72 teeth
Centre pinion 12 leaves, wheel 80 teeth, 5 arms
Third pinion 10 leaves, wheel 75 teeth, 5 arms
Fourth pinion 10 leaves, wheel 80 teeth, 5 arms
Escape pinion 8 leaves, wheel 15 teeth, 3 arms
Beats per hour: 18,000
Cannon pinion 12 leaves, minute pinion 14 leaves
Hour wheel 42 teeth, minute wheel 48 teeth.
Provenance: Ilbert Collection, Purchased By Ilbert from Malcolm Gardner in 1933.
(1) Britten 1982 records ('Old Clocks and Watches and their Makers', 6th edn, London, 1932) that this maker was at one time Honorary Secretary of the British Horological Institute, and that he died in 1868 aged 53.
- Not on display
Latest: 3 (2017)
3 (Oct 1995) Balance arbor broken.
- Acquisition date
- 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.
- Britain, Europe and Prehistory
- Registration number
- Additional IDs
Previous owner/ex-collection number: CAI.1609 (Ilbert Collection)
Previous owner/ex-collection number: N9 (Ilbert Ledger)