228 A SHORT HISTORY OF SCIENCE 



twenty-six books De Animalibus, of Albertus Magnus (d. 1282) 

 were not printed until 1478, but were apparently well known in 

 manuscript copies. No great worker appears in this almost neg- 

 lected field until we come to Conrad Gesner (or Gessner) (1516- 

 1565), the first famous naturalist of modern times, on account 

 of his vast erudition surnamed "the German Pliny." Professor of 

 Greek at Lausanne and later of Natural History at Basel, he was 

 almost as prolific an author as was della Porta fifty years later, 

 for he wrote extensively upon plants, animals, milk, medicine, 

 and theology, as well as various classical subjects. Yet he ranks 

 high in the history of biology, both for the extent and the quality 

 of his work in zoology and botany. It is significant that Gesner 

 was a Swiss, and as such probably safe from persecution at a 

 time when William Turner, an English ornithologist, worked and 

 published in Cologne. 



At the end of the fifteenth and beginning of the sixteenth 

 centuries Leonardo da Vinci (1452-1519) turned his attention in 

 part from art to science, engineering, and inventions, making 

 interesting studies in architecture, hydraulics, geology, etc. He 

 is regarded as the first engineer of modern times, and has 

 been called "the world's most universal genius." Palissy, "the 

 Potter," later examined minutely various fossils and took the then 

 advanced ground (as Xenophanes and Pythagoras had done, 

 however, some two thousand years earlier) that these are in 

 reality what they appear to be, i.e. petrified remains of plant and 

 animal life, and not "freaks of nature." Palissy's bold stand on 

 this subject marks one of the first steps in modern times toward 

 rational geology. 



It was not until the end of the sixteenth century, when Wil- 

 liam Gilbert, an eminent practising physician of Colchester, 

 England (1540-1603), published his now famous work on the 

 magnet (De Magnete) that further progress was made through 

 the first rational treatment of electrical and magnetic phenomena. 

 To him is due the name electricity (vis electrica). He regarded 

 the earth as a great magnet and, accepting the Copernican 

 theory, attributed the earth's rotation to its magnetic character. 



