Compound microscope mounted on a large wood case with brass edgings. Three drawers with some accessories and a total of six objectives. Focus by Hevelius-type mechanism on the side of the square supporting pillar.  Body tube is of the Cuff-type. Stage is large with attached fish-plate, condenser lens and tweezers. Bonanni spring plate accessory. Engraved on base plate on its circumference: "Passémant Ingenieur du Roi au Louvre".

Claude Simeon Passémant (1702-1769) knew he wanted to be an instrument maker at an early age, but it took a while before he could work at his chosen profession.  First he tried to qualify as a lawyer, but failed, so he became a haberdasher.  He married, then turned the business over to his wife and devoted his time to the study of optics and scientific instrumentation..  He published several papers on optics and precision mechanics, constructed  a variety of instruments, including an astronomical clock which he presented to Louis XIV in 1749.  He then was given the title of official instrument-maker to the King, a pension, and space to live in the Louvre in Paris.  Although he became very prominent among scientists of the time and claimed fanciful magnifying powers for his microscopes, his fame was due more to the quality of his workmanship rather than any special technical improvements in his instruments.