214 Miscellanies. 



15. Miner alogical systems. — The following is the substance of the re- 

 marks by Prof. Whewell in his History of the Inductive Sciences, Vol. 

 Ill, p, 526. In speaking of Mohs's system and of its failure, he says, the 

 design of giving to all minerals names in accordance with bis system was 

 too bold to succeed. A new nomenclature truly was needed ; but an im- 

 proved classification ought to have furnished an improved nomenclature, 

 as in botany by Linnreus. Mohs had not prepared his verbal novelties 

 with the temperance and skill of the great botanical reformer. He called 

 on mineralogists to change the name of almost every mineral with which 

 they were acquainted, and the proposed appellations were mostly of a 

 cumbrous form. Berzelius contrived a purely chemical system, on the 

 electro-positive principle, both as to minerals and elements. Mitscherlich's 

 isomorphism showed that minerals with very different electro-positive ele- 

 ments could not be distinguished. Berzelius then assumed the electro- 

 negative character of the formative element as the basis of his system, 

 viz. all sulphurets together, all the oxides, and all the sulphates. Gmelin, 

 in 1825, assumed the same fundamental principle, and took account of 

 the number of atoms or proportions ; e. g. the silicates were simple, double 

 — quintuple, as pitchstone — sextuple, as pearlstone, &c. Nordenskiold 

 assumed the same bases, but regarded also crystalline form. Beudant 

 proceeded on the electro-negative principle, and on Ampere's circular 

 arrangement of elementary substances. 



Such schemes exhibit rather a play of mere logical faculty, exercising 

 itself on assumed principles, than any attempt at the real interpretation 

 of nature. Both these attempts by Mohs and Berzelius failed because 

 there was no coincidence between them. A chemical arrangement and 

 a natural history system should agree, and thus verify each other. The 

 interior and the exterior systems should be type and antitype, else they 

 are not successful 



He then proceeds to give other reasons, Berzelius's electro-positive 

 principle was soon found false. Why should not the electronegative 

 prove so also ? The former is isomorphous and the latter too ; e. g. arse- 

 nic and phosphoric acids. How do we know that the external properties 

 depend on electrical properties? The composition of all minerals, even 

 ot those most analyzed, is not yet certain ; and this ancient notion of the 



K 



composition of a species," is unsettled by isomorphism. The constancy 

 of the angles also is rendered doubtful by plesiomorphism. The optical 

 properties, yet so imperfectly known, are somewhat arbitrary and capri- 

 cious. The chemical and optical mineralogists have been obliged fre- 

 quently of late to separate species which had been united, and to bring 

 together those which had been divided. Every thing shows that classifi- 

 cation is still to begin. Afxity of characters for the foundation of spe- 

 cies is not yet knotcn. The natural history classifiers assume that they 

 can discover the relative value and importance of those characters. The 



