Brass equinoctial sundial of octagonal shape.
Five city latitudes on the base plate and the signature "Langlois A Paris aux Galleries du Louvre". The bottom of the compass is silver plated and engraved with a compass rose with sixteen directions and the four cardinal points. Original blued steel needle with brass pivot.
The hour circle is graduated on the top in Roman numerals from 3 to 12 and from 1 to 8, and on the inside in Arabic numerals from 4 to 12 and from 1 to 8. The underside of the hour circle is engraved with six cities and their latitudes, with the rotating gnomon at its centre.
The mobile arc of the latitudes is graduated from 0 to 70. The underside of the base plate is engraved with numerous cities with their latitude, some of which are very rare: "Isle of Iron" (El Hierro), "Portobello" (Panama), "New Orleans", "Cape B. Esper" and "Archangel" (Russia).
In its black chagrin case with red velvet interior.
Note: this sundial is a traveller's sundial with notably the Iron Island, Archangel (Russian port on the White Sea) and Portobello (port city located in Panama which was the most important colonial port from where Spain sent most of its wealth to Europe in the 16th and 17th century).
Literature:
a) Claude Langlois (1703 - 1756) engineer of the King for mathematics, after having had his workshops on the quai de l'horloge until 1735, he then moved to the Galeries (du Louvre). It is said of him: "The best builder of the time was without question Claude Langlois, usual supplier of the astronomers of the Observatory. It is Langlois who built all the octants and quarter circles of the expeditions of La Condamine, Maupertuis, the abbot of La Caille, etc. In 1743 he traced the meridian of Saint-Sulpice and was the first engineer in mathematical instruments of the Academy." Revue des sciences et de leurs applications - 1950 - volume 3 - page 369.
b) Langlois Claude active in 1720/1756. All dates on Langlois' instruments are before 1751.
Dimensions: length of 9 cm x width of 9 cm.
Paris c. 1740 (according to the address).
Reference : D ex VD 8
Price on request.
Also discover many more sundials and equinoxial rings in the dedicated section of our French website : « Cadrans solaires en argent et laiton ».
