- Museum number
Lever escapement; winds by releasing sliding case to read time.
Metal dial with luminous figures.
Silver 'hermetic'-type case, decorated with 1930's-style red and black plastic material 'inlaid' on silver.
- Production date
- 1925-1935 (?)
Length: 48.50 millimetres (case)
Thickness: 12.90 millimetres
Width: 31.20 millimetres
- Curator's comments
Text from 'Watches', by David Thompson, London, 2008, p. 146-147.
HERMETIC PURSE WATCH
LA CHAUX DE FONDS, c. 1930
The hermetic or sealed watch was pioneered by the Swiss watch-case manufacturers Huguenin, Davoine and Huguenin of Le Locle, who traded as Huguenin Frères et Cie, Fabrique Niel. Their English patent no. 278,669 of 11 October 1926 details the construction and performance of a watch case made in two halves, which closed to seal the watch inside. Initially these watches were designed to be wound in the normal way using a button on the movement. Soon, however, the firm of Movado in La Chaux de Fonds took over the concept and in 1927 patented their modification of the system to incorporate an automatic winding system that used racks fitted inside the case to rotate a winding pinion when the case was opened and closed. The mainspring was provided with a slipping system to prevent it from being 'over-wound'. The design was given the English patent no. 296,721 on 6 September 1927.
The hermetic was developed to create a completely sealed watch, which could be carried anywhere in a pocket, purse or handbag. The movement and dial were contained within the two halves of the case, which were pulled apart to reveal the watch. One disadvantage of the early version was that it required both hands to open and close it.
Soon after the invention of the hermetic, other Swiss companies began to make their own versions, one of which was the firm Ebel SA of La Chaux de Fonds. Ebel SA was founded in 1911 by Eugène Blum and it is said that the name comes from Blum's initials and the maiden name of his grandmother: E. Blum et Levy. Ebel developed its own watch, the Ebello, which had a winding system patented in Switzerland in 1930, no. 144,352. In this design, the case is spring-loaded so that the two halves spring open when two small buttons on the case are pressed. To operate the winding mechanism there is a long stud screw in the case, which engages in a slot in a curved sector on the back of the movement so that, when the case is opened and closed, it moves a sector which pivots on a pinion. The resultant rotation of the pinion is used to wind the mainspring, which has a slipping device. The hands are set using the button at the base of the movement.
The watch case is beautifully made in the Art Deco style of the 1930s. The silver box is stove-enamelled in red and black to produce an eye-catching watch. At one corner there is a small ring for attaching it to a safety chain or a pendant chain, and there is a fold-out strut at the back which allows the watch to be used as a small desk- or bedside-clock. The movement is a standard 17-jewel bar movement with a club-tooth lever escapement and split bimetallic compensation balance. The silver case and the plate at the back of the movement are all marked with the silver purity mark for La Chaux de Fonds, a bear in a shield with the letter 'c'. In an article published in the Bulletin of the NAWCC in June 1994, Bernard Bowman notes that in 1928 5,000 Ebello watches were made, which sold in the shops for 1,200 Swiss francs.
Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript)
Made by EBEL S.A.
Switzerland, c. 1930
Silver cased self winding pendant watch with a club tooth lever escapement.
Signature: "Ebello (Fab Suisse)" on the dial.
Case: A rectangular cushion silver case which on being opened winds the watch. A small strut can be swivelled out so that the watch may be stood on a table when opened. The case is embellished with black and red enamel paint in a 1930 Art Deco style. The inner case is silver with a shaped central web and is numbered 10408. A false silver back is numbered the same. The front is polished silver and is scratched 10408. A T shaped slot in the false back allows a screw in the case to operate an arm. The arbor on which this is pivoted carries a winding wheel which is turned by a ratchet on the arm.
The false back is quality marked 0.935, the mark a bear with a C, for Chaux de Fonds.
Dial and Hands: A square silver dial 19.4 mm x 19.2 mm with skeleton Arabic numerals filled with luminous paint. Skeleton luminous filled hands.
Ebauche Marks: 10432
Frame: A bridge for the keyless work and the barrel, another for the train, cocks for the escape wheel, pallets and balance.
Barrel and Mainspring: A recessed cover to the going barrel scratched 20. Barrel I. diameter 7.5 mm., height 1.35 mm.
Mainspring: height 1.3 mm, thickness 0.09 mm.
Arbor: diam. 2.8 mm., snailed.
A slipping mainspring. Four notches are milled into the barrel wall and a reinforced end to the mainspring slips from notch to notch when the spring is fully wound.
Wheels: Brass wheels gilded on one side and not to the centre. The centre, third and fourth with five crossings but the steel escape wheel with four.
Jewelled: from the centre onwards in the back and from the third in the front. The jewels pressed into chatons. Ruby endstones to the balance jewels.
Escapement: Club tooth lever, straight line layout, short lever, double roller, impulse pin D shaped. The pallet stones exposed and flat on the acting faces. A steel escape wheel.
An equidistant locking escapement.
No. of teeth embraced 3 ½.
Balance and Spring: A split bimetallic balance with brass screws, diameter 7.5 mm., height 0.5 mm. Blued-steel flat spiral spring with 12 turns.
Means of Regulation: Index on the balance cock registering against a divided scale with engraved 'R A'.
Train Counts and Beat Rate:
Great wheel (barrel) 65
Centre wheel 64 pinion 10
Third wheel 60 pinion 8
Fourth wheel 60 pinion 8
Escape wheel 15 pinion 6
Beat rate: 18,000
Motion work: cannon pinion 10
Minute wheel 30, minute pinion 8
hour wheel 32
Winding System: Positive set keyless work but the winding pinion removed so that the watch can only be handset from the button and has to be wound using the case.
Dimensions: When closed the rectangular cushion case is 48 mm. long, 31 mm. wide and 15 mm. thick.
Movement diameter 19.5 mm, height 5.6 mm.
Provenance: Given by Mrs S. M. Oldham, 1970.
Note: This watch is of the type known as the Hermetic.
- On display (G39/dc14/no77)
- Exhibition history
1991, London, The British Museum, Collecting the Twentieth Century
- Latest: 2 (2016)
- Acquisition date
- Britain, Europe and Prehistory
- Registration number