174 Natural History. [Chap. III. 



and tedious and hazardous journeys, for the pur- 

 pose of exploring such regions of the earth as were 

 before unknown; and thus daily brought home 

 new stores of knowledge from every quarter of the 

 globe. 



Since the publication of the Sexual System^ se-^ 

 veral new methods of classification have been pro 

 posed, and still more numerous plans suggested, 

 for modifying and improving that of Linnaeus. 

 Among the former of these the following are most 

 conspicuous. Beside his sexual system, the great 

 Swedish naturalist founded a method of arrange- 

 ment on the form and other circumstances of the 

 calyx. To this method, which he published in the 

 year 17375 he gave the name of Methodus Caly-* 

 chia. In this system the vegetable kingdom is 

 divided into eighteen classes. In the same year 

 Christian Gottlieb Ludwig, a native of Silesia, and 

 a professor at Leipsic, published a new method, 

 in which he divided vegetables into twenty classes, 

 taking their distinctive characters from thejioiver*. 

 Next followed the natural method of van Royen, 

 professor at Leyden, exhibited in his Prodromus 

 Florae Leydenensis, published in 1740, and which 

 sustained a high character among botanists for in- 

 genuity and elegance. To this succeeded that of 

 baron Haller, one of the greatest men of the age 

 in which he lived. He proposed, in 174:2, a new 

 natural system, founded on an assemblage of the 

 various characters chosen by others. The botani- 



* Ludwig was the author of several valuable works, of which 

 his JiLstitutiones Jlistorico-Physica: Regni Vcgetabilis, Sec, printed 

 at Leipsic in lydjj is the principal one. 



