284 Notices respecting New Books, 



Silex 72 



Alumina 10 - 1 



Lime 1*2 



Magnesia 2*2 



Iron 2 



Chrome a trace 



Potash 11-1 



99-6 

 In some preliminary experiments I detected fluoric acid ; but 

 on more minute examination of the specimen, small portions 

 of distinct fluate of lime were found connected with the feld- 

 spar ; the source of the acid consequently became evident. 1 

 also noticed some metallic particles in the compound, which 

 are probably oxide of titanium. 



L. Notices respecting New Books. 



The English Flora, Vols. I. and II. By Sir J. E. Smith, M.D. 

 F.R.S. President of the Linn. Soc. SfC. &;c. $c. 1824. 

 [Continued from p. 233.] 

 T\7"E now proceed to notice the second volume of this ex- 

 " ™ cellent work ; and we cannot forbear to express our ap- 

 probation that the author should so readily, and with such a 

 liberal spirit, have adopted the innovations of the younger 

 naturalists ; and it is the best evidence of the soundness of his 

 scientific pi-inciples, that he has made all his early predilec- 

 tions, which, as possessor of the Linnsean Hei'barium, cannot 

 have been few, accommodate themselves to the advancement 

 of science. The new modelling the genera of which Linnaeus 

 was the author, had become absolutely necessary from the 

 vast accession of species. It was a convenience in many cases 

 to break them down into smaller divisions, and in others it 

 was quite irreconcileable with our present knowledge to suffer 

 so many artificial assemblages of plants to remain combined. 

 This was more particularly the case in all his natural orders, 

 which, from the circumstance of their being natural, were 

 with the greater difficulty subdivided into distinct and ob- 

 vious genera. The more closely the groups of nature are re- 

 lated, the more difficult it is in all cases to break them down 

 into subordinate divisions. Thus in the Umbelliferous group, 

 which is completely natural, it is not easy to distribute the 

 genera, and most of them in consequence are artificial. 

 " Umbellatarum genera characteribus distinguere est res diffi- 

 cillima," says Linnaeus ; and Jussieu makes a more pertinent 



remark 



