323 



different ? However, look in Br\isb, on p. 69 ; you will find them there 

 united not only in the same class, or the same group, but, as it were, in 

 the same family, standing side by side as closely allied species. For 

 what reason ? do you ask. Because both of them are fusible. Nor must 

 you believe that the}' have the same degree of fusibility ; far from it. 

 Bismuth will fall in drops in the ordinary flame of a gas jet ; but Mag- 

 netite, the strongest heat to be procured by the skillful management of 

 the blow-pipe will scarcely round its thinnest edges. Another cause 

 has brought these two minerals together, and nothing can illustrate 

 better the scientific poverty of that system. Though Bismuth and 

 Magnetite are two of the most easily characterized species, having very 

 remarkable properties of their own, no group in the division of fusible 

 minerals could be made to comprehend them, so they were left, and had 

 to fall together under this scientific title, " Not belonging to the fore- 

 going divisions." Of course, if we consider that Professor Brush 

 intended his work for the use of those who are unacquainted with 

 chemistry, we cannot throw any blame on him, nor slight the wonderful 

 amount of erudition necessary to compile that work ; for it is evident 

 that the author had to be himself more than ordinarily conversant with 

 the mysteries of chemistry to bring out those tests, so ingeniously con- 

 trived that even the uninitiated may, by their wse, come to practical 

 and sure conclusions. But it is no less true that the method is worse 

 than useless to impart to the student that method of scientific research, 

 more precious by far than all the skill he may acquire in determining 

 particular minerals. 



Sjme miy deduce from the foregoing remai'ks that T am opposed 

 to the study of Determinative Mineralogy in an elementary course. 

 They are mistaken. On the contrar}'-, they will presently see, when 1 

 propose my own system, what an important pUce I give to the deter- 

 mination of minerals. In fact, one of the greatest defects I find in the 

 present system of most of the best books is the virtual exclusion of the 

 determinative part of the science. For, as fai* as my humble experience 

 reaches, I perceive that it is imi)ossible to give to the students any taste 

 for the rocky science till you put specimens into their hands to analyse. 



I have been so long dwelling upon the actual system and showing 

 its shortconiino[s that little time is left me now to expose the svsteui 



