274 Dr, Thornson's Answer to the Review, Sfc. [April, 



Genus V. — Red Manganese, 

 Sp. 1. Silicate of manganese. 



Genus VI. — Sparry Iron. 

 Sp. 1. Carbonate of iron. 



Now I appeal to every reader whether a chemist could adopt 

 such an arrangement. All minerals are probably saline com- 

 pounds, and Berzelius has gone a considerable way to prove 

 this ; but 1 do not consider mineralogy as yet ripe for a true 

 chemical arrrangement. Much labour must still be bestowed 

 upon the chemical analysis. I have been occupied with the 

 zeohtes occasionally for more than a year, and the 14 or 15 

 minerals which I have already analyzed have given me much 

 additional information — enough to enable me to arrange my own 

 cabinet ; but not to publish a systematic arrangement of even 

 the zeolites. I would still allow the Wernerian arrangement to 

 remain, were I to pubUsh a new edition of my System to-morrow. 

 By the united exertions of chemists in every part of the world, 

 a true natural arrangement of minerals will, by degrees, be 

 accomphshed. ^uifestina lente is an excellent adage, of which 

 the Reviewer would do w^ell to avail himself. 



The only other point to which I think it will be necessary to 

 allude is, the animadversions of the Reviewer on my chapter on 

 the analysis of minerals. He has pointed out one or two typo- 

 graphical errors, and invented as many more. This chapter 

 was written nearly 20 years ago, and consists chiefly of speci- 

 mens of the mode of analyzing minerals taken from the best 

 analysts. Since that time I have repeated more than once 

 almost every analysis contained in it. I could certainly have 

 improved it somewhat ; but to have given accurate formulfe for 

 the analysis of every mineral is still beyond our power. A pre- 

 cise knowledge of the atomic weight of every constituent of the 

 mineral kingdom is an essential preliminary. This I have been 

 acquiring only since my sixth edition was published. Even at 

 present my knowledge is incomplete, some very essential atomic 

 numbers being still wanting. We He under very great obliga- 

 tions to Klaproth, and Bucholz, and Vauquelin, for their nume- 

 rous analyses of minerals. They have greatly enlarged our 

 knowledge of the mineral kingdom ; while they have invented 

 many methods of analysis, which have added much to the 

 resources of the practical chemist. But we still require more 

 accurate methods than those with which these chemists were 

 satisfied, before we can acquire that precise knowledge of the 

 composition of minerals which is requisite for an accurate che- 

 mical arrangement. Towards this desirable object, I have 

 turned a great deal of my attention, and have contrived a variety 

 of methods for bringing the art of anpAlysis to the requisite 



