18 ALEXANDER VON HUMBOLDT. 



maps, Paris, 1812, in folio, and five volumes of letter-press, 

 Paris, 1811, 8vo.). 



The fourth part is c Recueil d'Observations astronomiques, 

 d'Operations trigonometriques et de Mesures barometriques, 

 faites pendant le cours d'un voyage aux Regions equinoxiales 

 du Nouveau Continent depuis 1799 jusqu'a 1804, redigees et 

 calculees d'apres les tables plus exactes par Jabbo Oltmanns. 

 Ouvrage auquel on a joint des Eecherches historiques sur la 

 position de plusieurs points importants pour les navigateurs et 

 pour les geographes' (two volumes, Paris, 1808 and 1810, in 

 quarto). A German edition l was also printed in Paris in two 

 octavo volumes in 1810, for which Humboldt wrote an intro- 

 duction of eighteen pages, and dedicated the work 'to those 

 estimable men, Franz, Baron von Zach, Comptroller to the 

 Duke of Saxe-Grotha, and Herr Friedrich Gauss, Eoyal Pro- 

 fessor at Grottingen.' All the calculations and results therein 

 given are the work of Oltmanns, by whom they were reduced 

 from Humboldt's observations. 



The fifth part, of which Humboldt is again the sole author, 

 contains : ' Physique generale et Greologie ; essai sur la geo- 

 graphie des plantes, accompagne d'un tableau physique des 

 regions equinoxiales, fonde sur des mesures executees depuis le 

 dixieme degre de latitude boreale jusqu'au dixieme degre de 

 latitude australe, pendant les annees 1799-1803' (one volume, 

 Paris, quarto). 



The sixth part is: 1. 'Plantes equinoxiales, recueillies au 

 Mexique, dans 1'Ile de Cuba, dans les provinces de Caracas, de 

 Cumana et de Barcelone, aux Andes de la Nouvelle-Grenade, 

 de Quito et du Perou et sur les bords du Rio Negro, de 

 1'Orenoque et de la riviere des Amazones ' (two volumes, with 

 146 engravings, Paris, 1809-1818, large folio). 2. 'Mono- 



1 In the year 1850, Humboldt wrote in his own copy : c This abridged 

 edition is very scarce, since in consequence of some speculative transactions 

 undertaken during the reign of Napoleon, whereby English goods were to 

 be brought into France in exchange for an equal value of French books, the 

 whole stock of this German edition of my astronomical observations was 

 thrown into the sea by order of the trade, in order to escape the duty on 

 books. A few copies only were saved. 



' A. VON HUMBOLDT. 



6 Potsdam : 4 December, 1850. 



' A memento of the barbarism of booksellers ! ' 



