178. Natural History. [Chap. III. 



and the second in 1791; a work which abounds 

 with valuable instruction in botanical science; and 

 though the method which it contains is by no 

 means free from objections, the author is entitled 

 to much commendation for his labour, and must 

 ever be ranked among those who have made large 

 contributions to our knowledge of the vegetable 

 kingdom. 



The modern discoveries in chemistry have con- 

 tributed much to enlarge our acquaintance with 

 the composition, food, and growth of plants. Se- 

 veral of the vegetable physiologists mentioned in 

 the foregoing paragraphs have rendered important 

 aid to this branch of inquiry. To these may be 

 added Priestley, of Great Britain; Hassenfratz, 

 Fourcroy, Chaptal, Giobert, and Parmentier, of 

 France; and Ingenhousz atid von Humboldt, of 

 Germany; whose experiments and various works 

 have thrown new and very important light on some 

 of the laws of vegetation. 



Professor Tlmnberg, of Upsal, proposed j a few 

 years ago, to alter the method of Linnaeus, by sup- 

 pressing the classes Gijnandria^ Monoeciay Dioecia, 

 and Folygamia^ and assigning to other classes the ve- 

 getables arranged by Linnseus and hisfollowers under 

 these denominations. The professor has pursued 

 this method in his Flora Japonica, and in his Fro- 

 jdromus Florae Capensis. It is not generally consi- 

 dered as an impro^'cment on the method of Lin- 

 ncpus, but rather as rendering it, on the whole, 

 still more artificial and perplexed. In this altera- 

 tion, however, he has been followed by Gmelin, 

 Withering, Swartz, and several other eminent bo- 

 tanists. 



