He retired from military service at the age of twenty-four with the simple rank of colonel and instead undertook the study of natural sciences.
He gave instructions to his valet and, when he had practised enough, he shut himself in a glass cabinet, sat on a mattress and surrounded himself with burning charcoal.
The author recounts his fruitless attempts to make plaster casts of the superb hieroglyphs and gives other curious details.
He also published Mémoire et Expériences sur l'air fixe qui se dégage de la bière en fermentation, included in vol.
On 11 February 1773 The Duke of Chaulnes had an altercation with Caron de Beaumarchais who accused him of stealing his mistress, the actress Mademoiselle Ménard.