OF BARON IJUMBOLDT. 123 



Thus Bonpland alone published two works, 

 viz., " Plantes equinoxiales au Mexique, dans 

 1'Isle de Cuba, dans les Provinces de Caracas, 

 Cumana," &c., a methodical description of plants 

 in the French and Latin languages, with notices 

 regarding their medical qualities and industrial 

 applications. The other work is called " Mono- 

 graphie des Rhexia et des Melasthomas," fami- 

 lies of plants almost exclusively confined to 

 South America, and, for the most part, trees 

 and shrubs. 



In the departments of geology and astro- 

 nomy, Humboldt contributed a series of works. 

 With the assistance of Oltmann, two volumes 

 appeared : * ' Observations Astronomiques," which 

 contained the results of Humboldt' s observations 

 between 12 S. and 41 N". lat., with regard to 

 the passage of the suns and the stars through 

 the meridian ; with reference to eclipses, the 

 refraction of the rays of light in the torrid 

 zone, and likewise barometrical mensuration 

 of the Andes of Mexico, Venezuela, Quito, and 

 New Granada. 



Humboldt furnished an interesting history of 

 the geological formations of the earth in the 

 Old and the New World, in his " Essai sur le 

 Gisement des Eoches dans les deux hemi- 

 spheres." The price of a single copy of the 



