Lot Content

Global notice COVID-19 Important notice
Longines. A fine and rare steel openface precision keyless lever chronometer with Guillaume balance, made especially for observatory contest, in wooden testing box and with Bulletin de Marche from L’Observatoire de Neuchâtel
This lot is offered without reserve. On lots marke… Read more LONGINESObservatory Chronometer
Longines. A fine and rare steel openface precision keyless lever chronometer with Guillaume balance, made especially for observatory contest, in wooden testing box and with Bulletin de Marche from L’Observatoire de Neuchâtel

SIGNED LONGINES, CHRONOMÈTRE, MOVEMENT NO. 10’557’080, MANUFACTURED IN 1958

Details
Longines. A fine and rare steel openface precision keyless lever chronometer with Guillaume balance, made especially for observatory contest, in wooden testing box and with Bulletin de Marche from L’Observatoire de Neuchâtel
Signed Longines, Chronomètre, movement no. 10’557’080, manufactured in 1958
Movement: cal. 260, manual, 17 jewels, Guillaume balance, signed
Dial: subsidiary seconds with observatory testing markers, signed
Case: glazed display back, 68 mm. diam.
With: wooden testing box, Bulletin de Marche from the Observatory of Neuchâtel dated 9th February 1970, Extract from the Archives confirming manufacture of the present watch with movement made without chronograph function in August 1958 especially for observatory contests
Special Notice

This lot is offered without reserve.
On lots marked with an + in the catalogue, VAT will be charged at 8% on both the premium as well as the hammer price.
On lots marked with an + in the catalogue, VAT will be charged at 7.7% on both the premium as well as the hammer price.

Condition Report

If you wish to view the condition report of this lot, please sign in to your account.

Sign in
View condition report

Lot Essay

This large watch was made by Longines specifically as a high-precision timepiece to be submitted for observatory testing. As confirmed by the Extract from the Archives, the ébauche is a Longines chronograph caliber 260 but without the chronograph mechanism fitted so that only the going train is present. It is likely that it was made this way because a large-size movement may contribute in itself to a more stable running rate. It is fitted with a Guillaume balance, regarded as the optimum balance to eliminate errors arising from fluctuations in temperature.

Charles Edouard Guillaume invented two nickel-steel alloys he named “invar” and “elinvar”. Invar has a near-zero coefficient of thermal expansion, making it useful in constructing parts whose dimensions need to remain constant in spite of varying temperature. Elinvar has a near-zero thermal coefficient of the modulus of elasticity, making it useful for springs that need to be unaffected by varying temperature. Elinvar is also non-magnetic, which is a secondary useful property for the making of watch springs. Most competition chronometers made by Longines used the smaller oblong caliber 360 making the present watch unusual among them.

Submitted for testing at the Observatory of Neuchâtel between December 1969 and February 1970 where it was awarded a Bulletin de Marche recording an average running variation of +- 0.07 seconds, coefficient thermique +0.018, Erreur secondaire de la compensation -0.31, reprise de marche -0.81 and positions +-0.07.

More from Rare Watches

View All
View All