Longcase astronomical regulator

Technical characteristics

Date

ca. 1768–70

Type

Longcase astronomical regulator

Maker

Ferdinand Berthoud

Material

Oak, ebony, brass, gilt-bronze, enamel

Case maker

Balthazar Lieutaud

Dimensions

90 1/2 × 21 × 12 3/4 in.

Mechanism type

Graham-type dead-beat escapement

Place recorded

France

Maker / attribution

Ferdinand Berthoud

Design

Visible features

• Case features linear styling with decorative Chinese fretwork motifs on the base. • White enamel dial includes Roman hour numerals and Arabic minute markers. • Hinged bezel frame is modeled as a snake biting its tail. • Kidney-shaped cam component modulates the solar time display.

Case Construction

The case for the regulator is the product of collaboration between clockmaker Ferdinand Berthoud and master ébéniste Balthazar Lieutaud. It is constructed from an oak carcass finished with ebony veneer and brass inlay. Decorative gilt-bronze mounts are applied throughout, featuring a classicizing vase ornament atop the hood. The trunk includes a glazed panel that exposes the length of the pendulum. While the design shares features with other regulators in a series—such as the use of Neoclassical elements—this example includes unique details like the Chinese fretwork patterns on the base. The bezel framing the dial is designed in the form of a serpent biting its tail, accompanied by vegetal spandrel ornaments.

Provenance and Condition

The clock is identified in the records of the Metropolitan Museum of Art as part of the Jack and Belle Linsky Collection. It was previously documented in the 1955 Art Treasures Exhibition in New York. A 1959 sale record indicates that the object was previously owned by Thelma Chrysler Foy and Madame Jacques Balsan. Regarding its physical condition, the base of the wooden structure required replacement upon the museum's acquisition due to severe damage. The ball finial currently positioned on top of the vase is believed to be a later replacement. The movement was cleaned and repaired to a running state, though it is currently not kept in operation to preserve its condition.

Movement and Functionality

The movement is constructed with two square brass plates held by five cylindrical pillars. It comprises a weight-driven going train featuring maintaining power and a spring-driven striking train. Regulation is provided by a Graham-type dead-beat escapement acting upon a heavy bimetallic gridiron pendulum. The pendulum, designed to compensate for temperature-induced variations, incorporates brass and steel rods. The regulator is engineered to indicate both mean time and true solar time. An epicyclic equation mechanism, described in the maker's 'Essai sur l’horlogerie', utilizes a kidney-shaped cam mounted behind the calendar dial. A spring-loaded arm follows the cam's profile to regulate the motion of the solar time hand. The clock operates for approximately thirty-four and a half days on a single winding.

Identification

Accession Number

1982.60.50

Source note

Facts transcribed from the linked source listing or collection record. Attribution and specifications are source-reported and have not been independently authenticated.

Catalogue references

No catalogue numbers recorded. Numbers are only published once transcribed from a verified edition of a standard catalogue — they are never inferred.