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XXXVI. Answer to >ir. Brown on Professor Jameson's 

 System of Mineralogy. By A Correspondent* 



To Mr. Tilloch. 

 J Cornwall, Feb. 28, 1820. 



Sir, — 1 OBSERVED in the Number of your Magazine for Ja- 

 nuary, some remarks on the new edition of Professor Jameson's 

 System of Mineralogy, by Mr. P.J. BroU^n, which appear to me 

 to be written in a very uncandid spirit of criticism. 



Mr. Brown begins with confounding a natural history method 

 with what he calls a natural method, which latter, though very 

 indistinctly stated, seems to be neither more nor less than an 

 arrangement according to chemical composition. He thus takes 

 occasion to animadvert severely on deviations from an arrange- 

 ment with which Mr. Jameson at once disclaims all connexion. 

 Though thus severe upon inconsistences which proceed entirely 

 from his own mistake, Mr. Brown seems quite incapable of ob- 

 serving the beauties, or appreciating the excellencies, of the na-* 

 tural history method. He cannot perceive the high advantage 

 of being able at once to place a mineral either in the earthy or 

 metallic class, from the simple and obvious distinction of specific 

 gravity. He looks onlv at the grievous, and to him unpardon- 

 able, sin against arrangement according to chemical compos-ition, 

 of placing sulphate and carbonate of lead with sulphate and car- 

 bonate of barytes. 



1 need not enlarge on the advantages which would accrue from 

 a method such as that which Mr. Jameson attempts. By en- 

 abling any one to recognise a mineral at first sight, and give it 

 its proper place in the system, it removes the great deficiency of 

 mineralogy, and gives it that facihtv and precision which have 

 conferred such superiority on botany and zoology. To obtain 

 this great desideratum, what mineralogist woidd hesitate to make 

 some sacrifices, even in what may be considered as the just al- 

 liances of minerals, those derived from their composition ? And 

 even though he were obliged to place sulphate of lead with sul- 

 phate of barytes, would lie not think this amply compensated by 

 the advantages gained ? At least, while there is a propriety in 

 admitting the one system, there is an equal propriety in admit- 

 tifg the other; each having its peculiar advantages. 



As for the discrepancies which he seems so much to exult overj 

 they are so trivial as scarcely to deserve attention, when it is re- 

 collected that, in giving the general characters of a class, it is by 

 uo mean.s supposed that no mineral is to be included but what 

 acrrecs exactly with every one of them. It is sufficient if it cor- 

 rcponds in the greater number or the more important. 



Another thing which Mr. Brown finds fault with, is, that in 

 Vol. 55. No. 264. April 1820. Q Uic 



