vii 



natural history of the ocean, and of the 

 productions of islands and coasts, their ex- 

 peditions seem less fitted to advance the 

 progress of geology, and other parts of ge- 

 neral physics, than travels into the interior 

 of a continent. The advancement of the 

 natural sciences has been subordinate to 

 that of geography and nautical astronomy. 

 During a navigation of several years, the 

 land but seldom presents itself to the ob- 

 servation of the mariner ; and when, after 

 lengthened expectation, it is descried, he 

 often finds it stripped of it's most beautiful 

 productions. Sometimes beyond a barren 

 coast he perceives a ridge of mountains 

 covered with verdure, but it's distance for- 

 bids his examination, and the view serves 

 only to increase his regrets. 



Journeys by land are attended with con- 

 siderable difficulty in the carriage of in- 

 struments and collections ; but these diffi- 

 culties are compensated by real advantages, 

 which it would be useless to enumerate. 

 It is not by sailing along the coast, that we 

 can discover the direction of the chains of 

 mountains, and their geological constitu- 

 tion, the climate of each zone, and it's in- 



