XIV PREFACE. 



But though mineralogy thus pursued, fully rewards her 

 devotees, its numerous connected inquiries and pursuits con- 

 fer upon it, also, a high and deserving interest. 



To the chemist who proposes to extend his knowledge 

 to the productions of the mineral kingdom, this science be- 

 comes indispensable in order to enable him to know what he 

 has analyzed, or how to distinguish and describe the body 

 whose composition he has studied. To the geologist also, 

 it is a collateral study of no small importance ; since the 

 discrimination of many rocks, and the description of all, 

 depend upon a knowledge of no inconsiderable number of 

 mineral species. 



Of connected inquiries, however, the most fertile and 

 highly interesting, is that arising out of the regular forms as- 

 sumed by crystals, where, considering the absence of the 

 living principle, a most surprising mixture of simplicity and 

 complexness exists. To trace out the geometrical and nu- 

 merical laws by which the secondary forms are derived from 

 a few fundamental solids, though essential as a part of de- 

 terminative and descriptive mineralogy, still leaves out of 

 the question numerous, shorter and more beautiful modes of 

 treating the subject, in consequence of the circuitous route 

 by which it is necessarily effected in popular treatises. The 

 invention, therefore, of new and more scientific methods 

 of studying the geometry of crystals will always afford en- 

 tertainment and delight to those who possess the adequate 

 mathematical knowledge. The theoretical consideration 

 of the shapes possessed by the elementary particles as con- 

 nected with the same subject, though without any positive 

 means of verification and utility in the practice of mine- 

 ralogy, will afford to such inquirers a pleasing occupation. 



