A well-preserved and easily readable manuscript containing astronomical and observations made between 1738 and 1761, chiefly at Château de Sainte-Assise near Seine-Port (south-east of Paris), here spelled Sain-Port, and Château Saint Assise, or Saint Assize. In his Voyage Pittoresque des Environs de Paris (1757), the French landscaper, botanist and malacologist Antoine-Nicolas Dezalliers d'Argenville (1723-1796), described the Château de Sainte-Assise as follows: "Six leagues from Paris, on the banks of the Seine, is a castle of the best located. You arrive there via a crow's foot pierced in the woods and which leads to a vast esplanade followed by the forecourt and the courtyard. A beautiful terrace spanning the entire extent of the garden is in front of the castle which is a main building flanked by two pavilions. Next to it is another pavilion where is the new dining room whose decoration is very sought after. The terrace of which I have just spoken leads to the left into two groves, and to the right, into a quincunx above which is the orangery. The top of the garden is a high forest with paths. At the bottom of the terrace, opposite the castle, is a flowerbed which extends to the edge of the river." King Louis XV and the famous French Rococo painter Jean Antoine Watteau (1684-1721) were regular visitors. Although not signed, the note was most certainly written by the biologist, physicist and astronomer Jean-Jacques d'Ortous de Mairan (1678-1771), as De Mairan stated that he made scientific - in particular astronomical - observations at the chateau ( Traite Physique et Historique De l'Aurore Boreale, seconde edition, p. 430). "Over the course of his life, De Mairan was elected to numerous scientific societies and made key discoveries in a variety of fields including ancient texts and astronomy. His observations and experiments also inspired the beginning of what is now known as the study of biological circadian rhythms. In 1698 he went to Paris to study mathematics and physics. In 1702, he returned home to Béziers and began his lifelong study of several fields, most notably astronomy and plant rhythms. 1723, De Mairan, who had become a member of the Académie Royale des Sciences, co-founded the Académie de Béziers. Eventually, De Mairan received official lodging in the Louvre where he remained pensionnaire until 1743 and served as secretary from 1741 to 1743.[1] In 1746, he was reinstated as pensionnaire géomètre, or full-time boarding surveyor. In 1731, he published Traite Physique et Historique De l'Aurore Boreale (a short summary appeared in the Philosophical Transactions in which he put up a novel hypothesis that the Northern Lights are caused by the Sun, as the interaction of the atmosphere with the zodiacal light. At the time, the aurorae were thought to be 'flames' caused by sulfurous effluvia emanating from the Earth. In 1729, De Mairan constructed an experiment showing the existence of a circadian rhythm in plants, presumably originating from an endogenous clock. read more