DEPARCIEUX Antoine Nouveaux traités de trigonométrie rectiligne et sphérique. Démontrés par une méthode nouvelle & plus facile que celle que l’on a employé jusqu’à present… Avec un traité de Gnomonique.

DSB, IV, 38.

First edition.

Deparcieux (1703-1768), orphaned at the age of 12, received his early education at the Jesuit college in Alais. He then moved to Paris, where he worked as a sundial maker.

“He also investigated problems of hydraulics and conceived a plan for bringing the water of the Yvette river to Paris, which was carreid out after his death. In 1746 he was admitted to the Academy of Sciences. In his Nouveaux traités de trigonométrie rectiligne  et sphérique (Paris, 1741) Deparcieux gives a table of sines, tangents, and secants calculated to every minute and to seven places, and a table of logarithms of sines and tangents calculated to every ten minutes and to eight places” (DSB).

Much of his work contains calculations of sines, secants, logarithms and so on. The last part is entirely devoted to gnomonology.

Good copy, complete with its 17 technical plates.