OF NATURAL PHILOSOPHY. 29V 



more imperfect than its descriptions, or more in- 

 artificial and unnatural than its classification. The 

 more important minerals in the arts, indeed, those 

 used for economical purposes and those from which 

 metals were extracted, had a certain degree of 

 attention paid to them, for the sake of their utility 

 and commercial value, and the precious stones for 

 that of ornament. But until their crystalline forms 

 were attentively observed and shown to be deter- 

 minate characters on which dependence could be 

 placed, no mineralogist could give any correct ac- 

 count of the real distinction between one mineral 

 and another. 



(327.) It was only, however, when chemical 

 analysis had acquired a certain degree of precision 

 and universal applicability that the importance of 

 mineralogy as a science began to be recognized, and 

 the connection between the external characters of 

 a stone and its ingredient constituents brought into 

 distinct notice. Among these characters, however, 

 none were found to possess that eminent distinct- 

 ness which the crystalline form offers ; a character, 

 in the highest degree geometrical, and affording, as 

 might be naturally supposed, the strongest evidence 

 of its necessary connection with the intimate con- 

 stitution of the substance. The full importance of 

 this character was, however, not felt until its con- 

 nection with the texture or cleavage of a mineral 

 was pointed out, and even then it required numerous 

 and striking instances of the critical discernment of 

 Haiiy and other eminent mineralogists in predicting 

 from the measurements of the angles of crystals 

 which had been confounded together that differ- 



