scientific culture formed. Among the notable workers and thinkers of the thirteenth and fourteenth centuries were Roger Bacon (1214-1292) in Cambridge and Paris, John Müller of Königsberg (1436-1476), and Leonardo da Vinci (1452-1519), the artist philosopher of Florence. In the early part of the sixteenth century the illustrious Copernicus appears (1473-1543). Copernicus, or Copernic, had a keen mind and a firm belief in what may be called the simplicity of nature. On examining the Ptolemaic system he was embarrassed by its epicycles and excentrics, producing, as they did, complexity where he believed there should be simplicity. He, therefore, turned with relief to the ancient ideas of Pythagoras, and of his system he says:
Under the hand of Copernic this system was elaborated and shaped 80 as to acquire a dignity equal to that of the older system, and, but
