256 PHYSIOGRAPHY. 



ly, indeed, foreign to Mineralogy) ; this is arranged in a 

 systematic order, and forms an appendage to the collective 

 description of each species. 



The rules adopted in forming the general description, required 

 the omission of several facts relating to crystallography, the history 

 of the species as connected with its division into sub-species and 

 varieties by other writers, &c., information, nevertheless, which is 

 requisite to be understood: this will be collected together and placed 

 immediately after the general descriptions in a smaller type. 



The collective descriptions being thus rendered as complete as 

 possible, mineralogy, as a pure science, may be said to have dis- 

 i charged its duty ; and its species are now fit to be subjected to in- 

 vestigation in other sciences, each of which will produce a mass of 

 information concerning them, according to its peculiar nature. This 

 information the student in mineralogy will desire to become ac- 

 quainted with. He will seek, for example, to know the chemical 

 properties of the mineral, whose name and natural properties he has 

 just ascertained ; its geological position likewise, and its applica- 

 tion to useful purposes. To save him the inconvenience of consult- 

 ing other works in which this various knowledge is contained, the 

 results of the different sciences to which it belongs, are introduced 

 into the present treatise, and form the conclusion of the appendage 

 to the general descriptions. 



These results will be introduced in the following order : 1. Those 

 derived from Chemistry, as the properties of the species before the 

 blowpipe, or when acted upon by acids, one or more analyses by 

 the most celebrated chemists, to which will be added such facts as 

 are known concerning the artificial production of the species, by 

 mingling the ingredients in the proper proportions in our Laborato- 

 ries : 2. Geological information, or facts relating to the mode in 

 which the species occurs in nature, as the particular rock in which 

 it is engaged, the manner of its engagement, whether in veins, beds 

 or disseminated, &c. : 3. The Geographical distribution, which is 

 much less important than that of plants or animals, in which so 

 much depends upon climate, soil and other accidental circumstan- 

 ces ; American localities, however, are carefully designated : 4. 

 Application and uses of the species in the arts. To which is some- 

 times added another head for the purpose of introducing miscella- 

 neous observations, which do not, strictly speaking, fall under any 

 of the above provisions. 



END OF PART FIRST. 



