INTRODUCTION. 25 



tions have heen smoothed or filled up. The consi- 

 deration of these phenomena constitutes a distinct 

 branch of natural science. 



The mountains, rocks, and strata, are composed 

 of ingredients which in themselves are worthy of 

 examination, and capable of affording intense inte- 

 rest. The extremely- diversified forms which these 

 substances assume, their various properties, their uses 

 in the economy of nature, and the purposes to which 

 they may be applied by man, render their investi- 

 gation not less useful than pleasant. 



A most extensive and delightful field of observa- 

 tion presents itself to us in the vegetable bodies with 

 which the surface of the land, and even the depths 

 of the ocean, are so profusely furnished. The va- 

 rious regions of the globe are not less characterized 

 by the form and grouping of the plants which have 

 been allotted to them, than by the comparative ac- 

 tivity of their vegetating power. The wastes of 

 Europe, covered by ling, heaths, rushes, and sedges, 

 exhibit little change of aspect under the variations 

 of temperature and the revolutions of the year ; 

 while the plains of Venezuela, which during the 

 drought are covered with a layer of sand, and pre- 

 sent only a few withered palms scattered along the 

 margins of muddy pools, are converted in the rainy 

 season into an ocean of luxuriant vegetation. In the 

 equinoctial regions of the globe, palms, arborescent 

 ferns, and a multitude of magnificent trees, inter- 

 twined with flowering lianas hanging in festoons, 

 form themselves into impenetrable forests, whereas 

 the frigid regions of the arctic circle hardly produce 

 plants a foot in height. The solemn and stately 

 pines of the north of Europe have a very different 



