Page:Popular Science Monthly Volume 81.djvu/259

Rh On this expedition he took with him as his immediate family, Franz Plante, his court preacher (who afterwards became professor of theology at Breda), and William Piso, his body physician, while later there joined him George Marcgrave, astronomer and geographer, and Henry Cralitz, a young German student, who unfortunately died shortly after arriving in Brazil.

Piso was physician to Count Maurice and chief surgeon of the troops. It seems probable that he was also head of the scientific work of the expedition (Driesen, De Crane) since he was a much older and more experienced man than Marcgrave. However, so far as the natural history work was concerned, Piso limited himself closely to that aspect of it which was purely medical, as will be shown later. Marcgrave on the other hand had a much wider field. He certainly practised medicine to some extent, but his larger activities were given to astronomy, geography and natural history, in all three of which branches he did an enormous amount of work, as the sequel will show.

Marcgrave, who seems possibly to have been known to Count Maurice in Holland, before he had been in Brazil many months thoroughly established himself in the favor of his patron. Manget assures us that this was due first of all to the fact that Marcgrave had some knowledge of military architecture. This knowledge was probably made of service to the Count in the building of his new capital, Mauritia, in the environs of Pernambuco.

Be that as it may, Marcgrave certainly rose rapidly in the esteem of his chief, for we find that the latter built for him in 1639 in the city of Mauritia an astronomical observatory of stone from which Marcgrave studied the motions of the stars, their risings and settings, their sizes, distances and other phenomena.

To care for these extensive collections, his generous friend and