OF ARTS AND SCIENCES. 243 



rapliy is no longer taught in the old routine. Having completed his 

 American labors, Humboldt published three works, partly connected 

 with his investigations in America, and partly with his further 

 studies in Europe since his return ; and, among others, a book which 

 first appeared as a paper in the Dictionnaire des Sciences Natu- 

 reJles, but of which separate copies were printed under the title of 

 Essai stir la Constitution des Roches dans le deux Hemispheres. This 

 work has been noticed to the extent which it deserved by only one 

 geologist, Elie de Beaumont. No other seems to have seen what 

 there is in that paper, for there Humboldt shows for the first time, 

 that, while organic nature is the same all the world over, — granite 

 is granite, and basalt is basalt, and limestone and sandstone limestone 

 and sandstone, wherever found, — there is everywhere a difference 

 in the organized world, so that the distribution of animals and plants 

 represents the most diversified aspects in different countries. This 

 at once explains to us why physical sciences may make such rapid 

 progress in new countries, while Botany and Zoology have to go 

 through a long process of preparation before they can become popular 

 in regions but recently brought under the beneficial influence of civili- 

 zation. For while we need no books of our own upon. Astronomy, 

 Chemistry, Physics, and Mineralogy, we have to grope in the dark 

 while studying our plants and animals, until the most common ones 

 become as familiar to us as the common animals of the fields in the 

 old countries. The distinction which exists in the material basis of 

 scientific culture in different parts of the world is first made evident by 

 this work. By two happily chosen words, Humboldt has presented 

 at once the result of our knowledge in Geology at the time, in a most 

 remarkable manner. He speaks thex-e of ' independent formations.' 

 Who, before Humboldt, thought there were successive periods in the 

 history of our globe, which were independent one of the other ? 

 There was in the mind of geologists only a former and a present 

 world. Those words expressing the thought, and expressing it in 

 reference to the thing itself, for the first time occur in that memoir ; 

 thus putting an end to those views prevailing in Geology, according 

 to which the age of all the rocks upon the earth can be determined by 

 the mineralogical character of the rocks appearing at the surface. 

 The different geological levels at which rocks belonging to the same 

 period have been deposited, but which have been disturbed by subse- 

 quent revolutions, he happily designated as ' geological horizons.' 



