Complete Revolutionary-Era French 20-pc Mathematical Instrument Set
Bourjaunaux, Opticien, Quai de l’Horloge, Paris
Circa 1798–1805
A rare and complete late 18th century French mathematical and engineering instrument set, retailed by Bourjaunaux, Opticien, “à la Boussole,” located Quai de l’Horloge du Palais, No. 65, between the Pont Neuf and rue de Harlay, Paris. The original printed trade label remains intact inside the lid, firmly situating the firm within the historic scientific instrument quarter of the Île de la Cité.
The engraved scales include the early “Mètre,” placing the ensemble securely after the adoption of the metric system in 1795 and within the transitional decade of Revolutionary and early Consulate France. The engraving style, hinge construction, and proportional scale layout are entirely consistent with high-quality Parisian production of the period. The RARE pieces include Folding plumb square; tripod; brass protractor, also known as a demi-rapporteur; sector, and various plus-plus unique 18th century engraved finest quality tools.
We are not selling a drafting kit; we are offering a complete Revolutionary-era Paris engineer’s instrument set with intact label, metric transition scale, and tripod support. This is a true professional engineer’s kit, not a student drawing case. Nothing missing in the fitted and expansive set. The set includes a finely engraved brass sector with proportional scales marked Parties Égales, Polygones, and related geometric divisions; a full beam compass with extension; proportional dividers; bow compasses with pen fittings; large semicircular brass protractor (demi-rapporteur); folding and fixed rules; try-square; and the rare tripod support used to stabilize large-radius compass work. The presence of the tripod is especially telling, as it appears only in advanced architectural and military engineering sets intended for serious field or drafting-room work. The instruments retain original surfaces and deep untouched patina throughout, with consistent engraving style and construction. All components are present and original to the set.
During this period, opticians along the Quai de l’Horloge commonly acted as retailers and commissioners, sourcing instruments from specialist brass workshops and assembling them under their shop name. Bourjaunaux is identified as “Opticien,” reflecting this commercial role. Comparable Revolutionary-era mathematical instruments are preserved in institutional collections including the Musée des Arts et Métiers, est c.1794, Paris, and the Smithsonian National Museum of American History.
What distinguishes this example is its completeness, the survival of the Bourjaunaux trade label, the metric transition engraving, and the inclusion of the tripod beam support — a feature absent from most surviving sets. The instruments retain original surfaces and a deep, undisturbed patina throughout. No components are missing. The set represents the material culture of Enlightenment geometry at the precise moment France formalized metric reform and institutionalized technical education under the École Polytechnique (est. 1794).
A rare and historically compelling Paris scientific instrument set from the golden age of French engineering, embodying both intellectual history and masterful brass craftsmanship.
Condition: Exceptional for age and type, with the exception of the original box which flaws we've photographed. It has been locked, key lost, then pried open, as you can see. In this type set, 'cleaning' instruments is not advised, and the patina remains. The set is complete, with no missing components, and retains original surfaces and a deep, undisturbed patina throughout. The survival of the Bourjaunaux trade label, the metric transition engraving, and the inclusion of the tripod support distinguish this example from the majority of surviving French drafting cases of the period.
