Claude-Siméon Passement (1702-1769) was an inventor who served as an ingénieur du Roi. Trained as a button salesman he began his practice at a shop under the sign of the golden apple but as he was more interested in scientific experiments he quickly relocated the business to his wife. In 1748 he was given lodgings at the Louvre so that he could serve the Crown and in 1754 celebrated astronomical clock designed by him with the ormolu case executed by Jacques and Philippe Caffieri was given to Louis XV and installed in the cabinet du Roi at Versailles which thereafter was renamed the cabinet de la pendule. Passement also devised barometers, microscopes and telescopes. In October 1767 he delivered two barometers to Louis XV at Château de Bellevue and was responsible for a barometer-thermometer for Madame du Barry delivered to her by Simon-Philippe Poirier in 1769. Since after his death in 1769 Passement's practice passed on to his brother-in-law, it is most likely that the present barometer which is marked with a temperature date of 1776 was completed posthumously by the workshop.