In 1735 La Condamine joined an expedition sent to Peru to determine the length near the Equator of a degree of the meridian. In 1743 he left the party, traveled from Quito (now in Ecuador), and began a four-month raft journey down to the mouth of the Amazon. During the trip he made ethnographic observations of the regions through which he passed. In addition to a scientific account of his journey, he published Journal du voyage fait par ordre du roi a l'équateur (1751; “Journal of a Voyage to the Equator Made by Order of the King”).