DARWIN AND HUMBOLDT. 



[343] 39 



The contrast between the Siberian 

 winter and the great fertility of the 

 neighborhood of Astracan, where he 

 found the finest vineyards he had ever 

 seen, led him to consider anew the 

 causes of the irregularities of tem- 

 perature under corresponding lati- 

 tudes, and thus to enlarge his knowl- 

 edge of the isothermal lines, which he 

 had first sketched in his younger 

 years, and the rationale of which he 

 now clearly set forth. In one com- 

 prehensive view he showed the con 

 nection between the rotation of the 

 earth, the radiation of its surface, the 

 currents of the ocean, and especially 

 among the latter the Gulf Stream, in 

 their combined influence upon condi- 

 tions of temperature, producing under 

 identical latitudes such contrasts of 

 climate as exist between Boston, 

 Madrid, Naples, Constantinople, Tif 

 lis on the Caucasus, Hakodadi in 

 Japan, and that part of our own 

 coast in California, where stands the 

 city which bears his own venerated 

 name. 



The second work relating to the 

 Asiatic journey appeared under the 

 title of " Central Asia," being an ac- 

 count of his researches into the 

 mountain systems and the climate of 

 that continent. The broadest gen- 

 eralizations relating to the physics of 

 the globe, showing Humboldt's won- 

 derful familiarity with all its external 

 features, are here introduced in a 

 short paper upon the average eleva- 

 tion of the continents above the level 

 of the sea, as compared with the 

 average depths of the ocean. La- 

 place, the great geometer, had al- 

 ready considered the subject; but 

 Humboldt brought to the discussion 

 an amount of facts which showed 

 conclusively that the purely mathe- 

 matical consideration of the inquiry, 

 as handled by Laplace, had been 

 premature. Taking separately into 

 consideration the space occupied upon 

 the earth's surface by mountain 

 ridges with that occupied by high 

 table-lands, and the far more ex- 

 tensive tracts of low plains, Hum- 

 bold i showed that the average eleva- 



tion of the earth, estimated by La- 

 place at more than one thousand 

 metres, could in fact be scarcely one 

 third that amount, — a great deal less, 

 indeed, than the average depth of the 

 sea. 



In 1830, after his return to Berlin, 

 he was chosen as the fitting mes- 

 senger from one great nation to an- 

 other. The Restoration which fol 

 lowed the downfall of Napoleon had 

 been overturned by the July revolu- 

 tion, and Humboldt who had lived 

 through the glory of the Republic 

 and the most brilliant days of the 

 Empire was appointed by the King 

 of Prussia to carry an official greeting 

 to Louis Philippe and the new dy- 

 nasty. He had indeed the most 

 friendly relations with the Orleans 

 family, and was, from private as well' 

 as public considerations, a suitable 

 ambassador on this occasion. 



Paris had greatly changed since 

 his return from his first great journey. 

 Many of those who had made the 

 glory of the Academy of Sciences, 

 in the beginning of the century, had 

 passed away, and a new generation 

 had come up. Elie de Beaumont, 

 Dufrenoy, the younger Brongniart, 

 Adrien de Jussieu, Isidore Geoff - 

 roy, Milne Edwards, Audouin, 

 Flourens, Guillemain, Pouillet, 

 Ddperrey, Babinet, Decaisne, and 

 others, had risen to distinction, while 

 the older Ampere, the older Brongni- 

 art, Valenciennes, De Blainnille, 

 Arago and Geoffroy St.-Hilaire, 

 had come forward as leaders in 

 science. Cuvier, just the age of 

 Humboldt himself, was still active 

 and ardent in research. His salon, 

 frequented by statesmen, scholars, 

 and artists, was, at the same time, the 

 gathering-place of all the most orig- 

 inal thinkers in Paris ; and the 

 pleasure of those delightful meetings 

 was unclouded, for none dreamed how 

 soon they were to end forever, — how 

 soon that bright and vivid mind was 

 to pass away from among us. 



In those days a fierce discussion 

 i was carried on before the Academy 

 as well as in public lectures. Goethe 



