10 Chemical Examination of American Minerals. 



analysis in the first place, and then satisfy myself with staling 

 the general results of each particular analysis, without enter- 

 ing into any details. 



My methods were originally founded on a careful study of 

 the analytical papers of Klaproth and Vauquelin. Their 

 methods were a good deal improved, by repeating many of 

 the excellent analyses given more lately to the public by 

 Stromeyer and Berzelius. A careful examination of the pro- 

 perties of the various bodies usually found in minerals, natu- 

 rally suggested new, or at least improved processes. But it 

 is the perfection to which the atomic theory has been lately 

 brought, which has conduced more than any thing else, to the 

 accuracy introduced into the modern analyses of minerals. 



In choosing a specimen for analysis great attention is re- 

 quisite ; for unless the mineral be pure, or nearly so, the 

 labour is thrown away. If possible, it should be in crystals, 

 and every portion exhibiting the least trace of foreign matter 

 should be rigidly excluded. Even with every attention to 

 the purity of the specimen selected, the results obtained are 

 frequently such, as to lead to the suspicion that foreign matter 

 had existed in our mineral. In such cases it is of great im- 

 portance to repeat the analysis upon a specimen from a dif- 

 ferent locality, and, if possible, from a difierent species of 

 rock ; for it is not likely that the same kind of foreign mat- 

 ter should exist in two minerals extracted from rocks of dif- 

 ferent species. Thus, if we were to analyse two amphiboles, 

 the one from a calcareous rock, the other from a greenstone 

 rock, though both might be impure, yet the particular impu- 

 rity would probably be different in each. We might expect 

 a contamination of calcareous matter in the former, and of 

 silica and alumina in the latter case. 



Stony minerals, as far as their chemical analysis is concern- 

 ed, may be divided into three sets. 



1. Those which are soluble in nitric or muriatic acid. 



