IN AMERICA. 345 



tions on the lunar distances and the eclipses of Jupiter's CHAJTEP. 



satellites, together with the barometrical elevations, ' 



which have been calculated and verified by M. Prony 

 according to the formulae of La Place. 



In 1817 Humboldt laid before the Academie des Geograpliiciii 

 Sciences his map of the Orinoco, exhibiting the junction ° senfations. 

 of that river with the Amazon by means of the Casiqui- 

 are and Rio Negro. 



The brief account of New Spain which is presented in 

 the preceding pages has been extracted from the Essai 

 Politique sur la Nouvelle Espagne, originally published 

 in 2 vols. 4to, and translated into English. With respect 

 to Humboldt's translators it may be remarked, that their 

 want of scientific knowledge, and more especially of 

 natural history, renders the English very much inferior 

 to the French editions. 



Most of the above-mentioned publications have ap- Extensive 

 peared in the names of both travellers. The various ^^ 

 works relating to the journey will make, when complete, 

 twenty-eight volumes, of which seventeen are in folio 

 and eleven in quarto. The detailed narrative of the ex- 

 pedition occupies four of these volumes ; but an octavo 

 edition has also been published under the title of Voyage 

 aux Regions Equinojciales du Nouveau Continent, pendant 

 lesanneea 1799, 1800, 1801, 1802, 1803, et 1804. The 

 translation of this work by Mrs Williams is familiar to 

 the English reader. 



The labour necessary for reducing the observations Great liter- 

 made by our travellers to a condition fit for the public ^'^ 

 eye must have been very great ; yet, possessed of a mind 

 not less characterized by activity than the vastness of its 

 acquirements, Humboldt in the mean while engaged in 

 various investigations, which he has partly published in 

 the foreign journals. In concert with M. Gay Lussac, 

 with whom he lived for several years in the most intimate 

 friendship, he has made numerous magnetic experiments, 

 and verified Biot's theory respecting the poi^itien of the 

 magnetic equator. They have found that the great 



