Graphometer - Brass - 1800-1850

Grafometer Sacré – Brussels

Manufacturer: E.ᵈ Sacré, Brussels
Dating: circa mid-19th century
Dimensions: maximum width 27 cm
Materials: brass and bronze
Condition: excellent; original lacquer preserved.

Description
A generously sized grafometer, entirely made of brass and bronze, equipped with four graduation pinnules: two fixed, solid with the graduated semicircle, and two movable ones placed at the ends of the alidade mounted at the instrument’s center.
On the outer edge of the semicircle is engraved the main graduation, with a sexagesimal scale from 0° to 180° and a complementary indication of angular values. The numbering is shown every 10°, while the smallest division of the scale is 0.5 degrees.
At the two ends of the alidade there are corresponding nonii, each divided into 30 parts and numbered 10–20–30, intended for precise reading of angular measurements.

In the center of the instrument is inserted a circular compass about 5.5 cm in diameter. The compass lid bears a complete graduation from 0° to 360°, with numbers every 20°. The magnetic needle is provided with a stop mechanism operated by a small lever: when the instrument is not in use, the mechanism lifts the needle from the suspension pivot and locks it against the glass, preserving the tip and pivot from wear and stress during transport.
At the bottom, beneath the crosspiece and corresponding to the instrument’s main axis, is fixed the plug intended for mounting on a tripod or topographic staff.
The instrument is in excellent condition, with surfaces and original lacquer broadly preserved.

Édouard Sacré
Édouard Marie Sacré was a mechanic and instrument maker active in Brussels from the first half of the 19th century, belonging to a family of watchmakers and mechanics specialized in precision instruments. He is documented in 1841 as mécanicien and in the same period as a builder of physics instruments; in 1845 he presented to the Académie royale de Belgique a precision balance, examined favorably by Laurent-Guillaume de Koninck and chemist Jean-Servais Stas.
His activity was closely linked to the Musée de l’Industrie of Brussels, where he later appears as mécanicien. The museum’s collections included several instruments built by Sacré, including a camera lucida according to the system of Giovanni Battista Amici. His production included physics and measuring instruments, precision balances, and metrological apparatus. Sacré also collaborated with Adolphe Quetelet and Jean-Servais Stas, two central figures of 19th-century Belgian science.

Particularly significant was his relationship with the Observatoire royal de Bruxelles. In 1849 the inventory compiled by Quetelet records a precision balance built by Sacré and a large oak support for an astronomical lunette by Cauchoix; in the same years the documentation relating to the Commission des poids et mesures records instruments and sets of weights devised by Sacré. The rapport with the Observatory milieu also fits a family tradition: as early as 1829–30 Quetelet had used in his magnetic observations a portable device built by a previous member of the Sacré family.
Édouard indeed belonged to a Brussels family of watchmakers and instrument makers, in which Jean-François, Charles-Antoine, Charles-Auguste, and Gustave Sacré are documented among others. This tradition probably explains the high technical level of his production and his relations with Belgium’s leading scientific institutions. In 1866 Édouard Marie Sacré, at about fifty years old, is still registered in Brussels with the profession of mécanicien.

For the grafometer signed “Edᵈ Sacré – Bruxelles,” the attribution to Édouard Sacré currently appears plausible, but not yet definitively proven, since the abbreviation Ed. can also refer to Edmond Sacré, another family member documented since 1852 as mécanicien et constructeur d’instruments. On constructive characteristics and professional context, a dating around the mid-19th century remains consistent with Édouard’s activity.