English translation of L’art de travailler les pierres précieuses à l’usage de l’horlogerie et de l’optique… Par N. Dumontier

I believe this is one of the earliest sources about using jewels in clock and watchmaking. I mainly used google translate and checked the translation where I felt the phrasing was off.

“The Art of Working Precious Stones For Use in Watchmaking and Optics, Taught in Ten Lessons; a completely new work, and the first to have appeared on this subject,

by N. Dumontier, Professor of Mechanics.

Price: 5 Francs [roughly equivalent to 40 dollars today]

Paris, Chez Dentu, Bookseller, at the Palais Royal

1843, 1844″