ALEXANDER VON HUMBOLDT 357 



of a desire for religious freedom. It was in this period that the 

 Laocoon, the Torso of Hercules, the Apollo Belvidere, the Medicean 

 Venus were rediscovered. Michael Angelo was living in Rome, 

 Leonardo da Vinci in Venice. It was the period of Titian and 

 Eaphael, of Holbein and Albert Diirer. Fourteen years after the dis- 

 covery of the new world, or in the year that its discoverer died (1507), 

 Copernicus made known his system of the world. Almost immedi- 

 ately followed an era of invention and the skilful use of instruments of 

 research. ISTew wonders in the heavens were constantly appearing. The 

 results of mathematical calculations made astronomy an exact science. 

 The law of gravitation, Kepler's laws of motion, knowledge of the pres- 

 sure of the atmosphere, of the propagation of light, its laws of refrac- 

 tion and polarization, the radiation of heat, electro-magnetism, re- 

 entering currents, vibration chords, capillary attraction, in their 

 discovery and in the increase of knowledge concerning their nature and 

 importance, are all closely connected. Galileo, Lord Bacon, Tycho 

 Brahe, Descartes, Huyghens, Fermat, are more nearly related to each 

 other in the work they each accomplish than is generally understood. 

 A list of some of the subjects treated in Volume I. of " Cosmos " 

 will give a hint of the wealth of learning it contains and of the ability 

 of the author to bring together a vast amount of knowledge on a great 

 variety of topics without confusing his readers or for a moment per- 

 mitting them to lose sight of his purpose to show how all knowledge is 

 related and that the heavens and the earth belong to the same general 

 plan, and are under the government of a single intelligent will. Be- 

 ginning with a review of what is known of celestial phenomena, he 

 comes down to those which are terrestrial in their character. Under 

 celestial phenomena sidereal systems are treated as well as the solar 

 system. Comets are carefully considered, aerolites, also, the zodiacal 

 light and the milky way with its starless openings. Under terrestrial 

 phenomena are grouped such subjects as the distribution of mountain 

 chains, great plains, arid and fertile, oceans, inland seas, lakes, rivers, 

 the figure of the earth, its internal heat, terrestrial magnetism, the 

 aurora borealis, geognostic phenomena, earthquakes, gaseous emana- 

 tions, hot springs, salses, volcanoes, isolated, in groups, and along cer- 

 tain lines, paleontology, geognostic periods in the earth's history with 

 reference to certain marked changes in the physical features of the 

 globe, atmospheric pressure, meteorology, the snow line of mountains, 

 hygrometry, atmospheric electricity, organic life, the geographical dis- 

 tribution of plants and animals, of races of men and of language. One 

 can see from this enumeration of titles how broad is the outlook over 

 the world of knowledge in this little volume of less than 400 duodecimo 

 pages. On every subject treated Humboldt either gives his own opin- 

 ions or those of men whom he deems competent to speak. On astron- 

 omy we have not only what the ancients have thought, and the astrol- 



