Introduction to the Study of Mineralogy. AG\ 



. The second class will be formed of the substance?; which 

 I call eartky, i. c. of those which admit no acid among 

 the earths that enter into their composition. I do not 

 think that we are as yet sufficiently acquainted by analysis 

 with the number and proportions of these earths in a part of 

 the substances in question, to be able to subdivide this class 

 into genera. Thus, I shall content myself with presenting 

 the series of the species it contains, taking advantage only 

 (in order to arrange the terms of this series) of analogies or 

 differences which the knowledge we already possess admits 

 of our perceiving among them. 



Let us hope that the chemistry of minerals, which since 

 the days of Cronstadt and Bergman has made so great pro- 

 gress, will at length attain a point of perfection which will 

 place this class, and even certain parts of subsequently de- 

 scribed classes, upon a level with the first. We have seen 

 for several years discoveries succeed each other rapidly. 

 Klaproth has furnished us with zircon, uranium, titanium, 

 and tellurium. To Vauquelin we are indebted for glucina 

 and chrome. — Analyses made by one person have been ve- 

 rified by others. What may not science gain by this for- 

 tunate concurrence ? 



But if the second class still leaves any thing to desire re- 

 lative to the regularity of the whole, I flatter myself that I 

 have at least contributed to perfect it in its details, not only 

 by a more exact division of the substances which constitute 

 the species, but also by the care which I have taken to 

 apply this name only to those substances which really de- 

 serve it, and to those which have a type susceptible of a pre- 

 cise determination*. Thereby we exclude from the method, 

 and throw into a separate appendix, the argils, marls, and 

 every other similar aggregate composed of fragments bor- 

 rowed from different species, and consequently possessing 

 mixed characters. 



I comprehend under a third class the common name of 



* Thus the beryl and emerald are ranged in one and the same species . 

 the zeolite, on the contrary, is divided into four different species : the strahi- 

 stein of the German mineralogists, into two forms very distinct from each 

 •ther. 



coml ust ill* 



