Description

[Paris, Delalain, ca 1774].
Large 8°, 14 pages and one folding plate ; original contemporary wrappers. Item #3826

Extremely rare offprint from the second edition of Bedos de Celles’ Gnomonique pratique (1774).
This practical manual is illustrated with a fine and large engraved copperplate by Pierre Claude de La Gardette. It has an individual title page and page numbering, and the composition of the text has been completely rearranged compared with Bedos de Celles’ original printing.
This is the unique and personal copy of Cardinal Paul d’Albert de Luynes (1703-1788), the inventor of the eponymous universal equinoctial ring, with an autograph inscription on the front cover : “Description de l’Anneau Astronomique que jay fait exécuter, avec le dessein le plus exact de l’Anneau, et de toutes les pieces dont il est composé, et qui est parfaitement gravé [Description of the astronomical ring that I have had crafted, with the most exact drawing of the Ring, and of all the parts composing it, and which is perfectly engraved.]”
The Cardinal de Luynes was the archbishop of Sens and first chaplain to the Dauphine (mother of Louis XVI). Passionate about sciences and notably astronomy, he is best known for an astronomical ring that he “perfected and had built before his eyes for his particular use, by the sieur [Jacques-Nicolas] Baradelle the younger, an engineer of mathematical instruments, in Paris”. The Cardinal’s ring is considered today as the most successful of this type of instruments.
De Luynes and Bedos de Celles probably knew each other : in the 1770s, Dom Bedos was the guest of Duhamel du Monceau, a member of the Academy of Sciences (like Luynes), at his castle of Denainvilliers in the town of Dadonville, located in the diocese of the Cardinal. While he stayed with Duhamel, he drew several sundials and probably devoted himself to the second edition of his Gnomonique, the first containing the description of the Cardinal’s ring.
J. Kugel, Spheres : The art of celestial mechanics, Paris, Kugel, 2002, p. 244.