MINERALOGY ; WITH A CLASSIFICATION OF SILICATES. 27 



and third editions of this work, however, in 1844 and 1852, Shepard, while retaining 

 with slio'ht modifications the classes and orders of Mohs, abandoned the characteristic 

 specific names of the latter for the trivial names generally accepted. The natural-history 

 system of Mohs was also adopted in the first and second editions of his " System of Miner- 

 alogy," by J. D. Dana, in 183T and 1844. He, however, devised a Latin terminology for 

 the orders, as well as a binomial Latin nomenclature for the genera and species. 



§ 7. In abandoning the natural-history system in his third edition, in 1850, Dana 

 returned to the trivial nomenclature. Referring to these changes, its author declared in 

 the preface to a fourth edition of his System, in 1854, his opinion that " the system of 

 Mohs, valuable in its day, had subserved its end, and that in throwing off its shackles for 

 the more consistent principles flowing from recent views on chemistry, the many difficul- 

 ties in the way of perfecting a new classification led the author to an arrangement which 

 should serve the convenience of the student, without pretending to strict science." 



A so-called " purely chemical mineral system " had been proposed by Berzelius as 

 early as 1815,' and had meanwhile found favour with chemists. Towards this, the difii- 

 culties of the natural-history method in mineralogy directed Dana, who, in the preface to 

 his second edition, in 1844, gave "besides the natural classification, another placing the 

 minerals under the principal element in their composition;" adding that "various improve- 

 ments on tlie usual chemical methods have been introduced, which may render it accept- 

 able to those who prefer that mode of arrangement." The chemical scheme then given by 

 him was, as he informs us, taken almost entirely from Rammelsberg's treatise on Chemical 

 Mineralogy, then recently published. In 1850, in the latter part of his third edition, Dana 

 put forth a new chemical classification "in which the Berzelian method was coupled 

 with crystallography;" while in his fourth edition, in 1854, he maintained that " the classi- 

 fication of minerals must flow directly from the principles of chemistry," and accepted 

 what he now called the Berzelian System, which, as his readers are aware, is retained in 

 his fifth and last edition, that of 1868. 



§ 8. The views of Berzelius, as adopted and modified by Rammelsberg, Naumann, Dana 

 and others, now prevail among students of mineralogy, with whom the results of the chemi- 

 cal analysis of species are generally considered as of paramount significance ; while hard- 

 ness, specific graA'ity, crystalline form, and optical characters assume a secondary value in 

 classification, and are regarded as important chiefly in connection with determinative 

 mineralogy. The conception of a true natural method which, although but partially 

 understood, was at the basis of the system of Mohs, has been lost sight of; the order 

 which the naturalist finds in the organic is no longer apparent in the inorganic world, 

 as presented in modern mineralogical text-books ; and this state of things has contributed 

 not a little to the comparative neglect into which systematic mineralogy has of late 

 years fallen. 



As to the complete divorce between physical and chemical characters in the study 

 of mineral species, maintained by "Werner, Mohs and his followers, there seems to have 

 underlaid it the notion of framing a system which, as in botany and zoology, shall be 

 available for the purposes of determination without the destruction of the individual. 

 It is to be noted however, that characters dependent upon chemical differences, such as 



' Berzelius, Nouveau Syatèine de !Minei;il(igie, Paris, 1819. 



