ii8 PERIOD IV. 



yield precious knowledge, not only to botanists but 

 all students of biology. 



Humboldt as a Traveller and a Biologist. 



The career of Alexander von Humboldt (b. 1769, 

 d. 1859), nearly coinciding- with the period on which 

 we are now engaged, was devoted to a gigantic task — 

 nothing less than the scientific exploration of the globe. 

 His great natural powers were first cultivated by wide 

 and thorough training, not only in astronomy, botany, 

 geology, mineralogy, and mining, which had an obvious 

 bearing on his future enterprise, but also in anatomy, 

 physiology, commerce, finance, diplomacy, and lan- 

 guages. Thus equipped, he sailed in 1799 with the 

 botanist Bonpland to South America, and spent the 

 next five years in exploring the Orinoco and Amazon, 

 the Andes, Cuba, and Mexico. The expedition marks 

 an epoch in scientific geography. It is enough to 

 mention the collection of data for the more accurate 

 mapping of little-known countries, the exploration of 

 the river-systems of equatorial America and the dis- 

 covery of a water-connection between the Orinoco and 

 the Amazon, the ascent of lofty mountains, the study of 

 volcanoes, the description of remarkable animals such 

 as the howler-monkey and the gymnotus (electric eel), 

 and of remarkable plants, such as the buU's-horn 

 acacia, whose enlarged and hollow spines are occu- 

 pied by ants.^ After his return to Europe Humboldt 

 published many important treatises on terrestrial 

 magnetism, geology, meteorology, and plant-distri- 

 bution. His new graphical method of isothermal 

 lines did much for the study of climate in all its bear- 

 ings. His Personal Narrative not only disseminated 



* See the account of Cartagena in the Personal Narrative, 



