TROGRESS OF SCIENTIFIC CLASSIFICATION. 183 



mg fixity and diffusion to the truths disclosed ; and that on 

 the other hand, they have caught from it that increasing 

 quantitativeness, and that progress from considerations 

 touching single phenomena to considerations touching the 

 relations among many phenomena, which we have been de 

 scribing. 



Of this last influence a few illustrations must be given. 

 In chemistry it is seen in the facts, that the dividing of mat- 

 ter into the four elements was ostensibly based upon the 

 single property of weight ; that the first truly chemical di- 

 vision into acid and alkaline bodies, grouped together bod- 

 ies which had not simply one property in common, but in 

 which one property was constantly related to many others ; 

 and that the classification now current, places together in 

 groups supporters of combustion^ metallic and ^ion-metallic 

 bases, acids, salts, &c., bodies which are often quite unlike 

 in sensible qualities, but which are like in the majority of 

 their relations to other bodies. In mineralogy again, 

 the first classifications were based upon differences in as- 

 pect, texture, and other physical attributes. Berzelius 

 made two attempts at a classification based solely on chem- 

 ical constitution. That now current, recognises as far as 

 possible the relations between physical and chemical char- 

 acters. In botany the earliest classes formed were trees, 

 shrubs, and herbs : magnitude being the basis of distinction. 

 Dioscorides divided vegetables into aromatic, alimeyitary, 

 medicinal, and vinous : sl division of chemical character. 

 Ca3salpinus classified them by the seeds, and seed-vessels, 

 which he preferred because of tne relations found to sub- 

 sist between the character of the fructification and the 

 general character of the other parts. 



While the "natural system" since developed, carrying out 

 the doctrine of Linnseus, that " natural orders must be formed 

 by attention not to one or two, but to all the parts of plants," 

 bases its divisions on like peculiarities which are found 



