Jean le Rond d’Alembert writes that in 1746 or 1747 he gave to the Académie royale des sciences two or three mémoires on the orbit of the moon. He notes that he has not printed these as he has since produced something better on the same subject but that he would like either the original memoirs or copies of them returned to him along with the precise dates of when they were discussed. He apologises for the trouble this may cause the General Secretary, but asks that the mémoires are sent as soon as possible via the post, adding that the General Secretary needs not worry about the postage price that Jean le Rond d’Alembert will pay. He adds that he thinks it would be good for at least one copy of the mémoires to remain in the Académie’s archives.