IV PREFACE. 



ence that climate exercises upon their developement ; 

 and, lastly, from botany as now understood, in its 

 most extensive signification, is inseparable the know- 

 ledge of the various ways in which the laws of vege- 

 table life are applicable to the augmentation of the 

 luxuries and comforts, or to the diminution of the 

 wants and miseries, of mankind. It is by no means, 

 as some suppose, a science for the idle philosopher in 

 his closet ; neither is it merely an amusing accom- 

 plishment, as others appear to think ; on the con- 

 trary, its field is in the midst of meadows, and 

 gardens, and forests, on the sides of mountains, and 

 in the depths of mines, — wherever vegetation still 

 flourishes, or wherever it attests by its remains the 

 existence of a former world. It is the science that 

 converts the useless or noxious weed into the nutri- 

 tious vegetable ; which changes a bare volcanic rock, 

 like Ascension, into a green and fertile island ; and 

 which enables the man of science, by the power it 

 gives him of judging how far the productions of one 

 climate are susceptible of cultivation in another, to 

 guide the colonist in his enterprises, and to save him 

 from those errors and losses into which all such per- 

 sons unacquainted with Botany are liable to fall. This 

 science, finally, it is which teaches the physician how 

 to discover in every region the medicines that are 

 best adapted for the maladies that prevail in it ; and 

 which, by furnishing him with a certain clue to the 

 knowledge of the tribes in which particular proper- 

 ties are, or are not, to be found, renders him as much 

 at ease, alone and seemingly without resources, in a 

 land of unknown heibs, as if he were in the midst of 

 a magazine of drugs in some civilised country. 



Tlie principles of such a science must necessa- 

 rily be comphcated, and in certain branches, which 



