356 THE POPULAR SCIENCE MONTHLY 



scriptions of nature. Of August de Chateaubriand, who died July 4, 

 1848, he speaks as his " old friend, famous for his descriptive powers." 

 Nor does he fail to speak of Arago in the most affectionate terms, quo- 

 tations from whose letters fill many pages of notes, and for whose at- 

 tainments he had profound respect. 



Humboldt begins his work with a description of celestial phenomena 

 and then comes down to the earth. He refers with respect to the labors 

 of Hipparchus, Eratosthenes and Euclid, as of mathematicians of the 

 first rank. He credits Aristarchus of Samos with having anticipated 

 Copernicus in his theory of the universe. He recognizes the value of 

 Strabo's geography, written after its author had entered his eighty- 

 third year, and makes use of the works of the Plinys, the elder and 

 the younger. To Hipparchus of Sicily, and Galen of Pergamos, phy- 

 sician and anatomist, he refers as men of the highest attainments. He 

 praises the Arabs not only for their observations of the heavens and 

 their careful mathematical calculations, but for their skill in chemistry 

 and their experiments in order to discover its value in medicine. He 

 says they were acquainted with many of the qualities and uses of sul- 

 phuric and nitric acid, and were aware of the fact that bodies can be 

 decomposed and reunited. He is at pains to show how nearly related 

 to each other most discoveries are, and that they are made in almost 

 every instance by men who miss only by a little the discovery of some 

 great truth which a little while after, other more fortunate men 

 see. Preparations, Humboldt tells us, for the voyages of great sailors 

 just before Columbus were made in the twelfth century. Three men in 

 the thirteenth century, Roger Bacon, Albertus Magnus and Vincentius 

 of Beauvais, would have been eminent in any century. As independent 

 thinkers. Duns Scotus, William of Occam and Nicolas of Cusa led the 

 thought of the world from the time of Eamus, Campanella and Bruno 

 to Descartes. It was in 1250 that Vincentius wrote his " Secula 

 Naturae " for the use of St. Louis and his queen Margaret. This and 

 other works of his were forerunners of of the " Margarita Philosophia " 

 of Father Eeisch, published in 1486, a book which Humboldt praises 

 and of which he made some use and which he declares was instrumental 

 in diffusing knowledge in the last half of the fifteenth century. Of the 

 writings of Father Joseph Acosta, the Jesuit who published his " Nat- 

 ural History of the Indies " in 1590, it is enough to say that they pre- 

 pared the way for works of Vossius, which Newton used, and in which 

 Humboldt finds the groundwork of physical geography. Many events 

 which were of importance in his day Humboldt traces back to the fif- 

 teenth and the beginning of the sixteenth centuries. These are the 

 doubling of the Cape of Good Hope by Vasco di Gama, the discovery 

 of America by Columbus, the voyages of Amerigo Vespucci and his son, 

 and Magellan's circumnavigation of the globe. That same period wit- 

 nessed a rare manifestation of intellectual power as well as the growth 



