250 PHYSIOGRAPHY. 



cies, and to the general arrangement of the species, such an arrange- 

 ment that they may in like manner, serve the purpose of charac- 

 ters. Neither of these plans entirely answers the purpose ; and 

 those who wish to become acquainted with minerals, or to acquire 

 some knowledge of their natural properties, are still under the ne- 

 cessity of proceeding upon the old empirical method. They must 

 content themselves with a superficial and broken sort of knowledge, 

 to which they themselves do not attach any security; whereas the 

 systematic way of proceeding leads to information, that is solid, con- 

 nected, and as complete as possible. 



. 124. OBJECT OF PHYSIOGRAPHY. 



The object to which Physiography refers, in the mine- 

 ral kingdom, in as far as it produces a MERE description, is 

 the INDIVIDUAL. 



Any description, containing the indication of all the properties, 

 will suffice for determining a particular individual. In the animal 

 and vegetable kingdoms, homogeneous individuals are in most cases 

 at the same time identical, excepting their sexual differences ; or 

 at least the deviations occurring in their single characters may be 

 considered as merely accidental. One individual, therefore, or in. 

 the case of an existing difference in the sexes, two of them, will 

 represent the whole species. In the mineral kingdom, the homo- 

 geneous individuals in most cases differ so widely from each other, 

 that a description of the one does not by any means apply to an- 

 other ; one, or a few of them, therefore, cannot represent the whole 

 species, nor can their description be substituted instead of the de- 

 scription of the species. The description of all the varieties of a 

 species does not produce a clear idea of the species itself; because 

 the species is not a single body, but the assemblage of all the ho- 

 mogeneous individuals or varieties. Individuals, only, therefore, 

 (or compositions of individuals) admit of being described; and this 

 is effected by indicating all their natural properties. In enumera- 

 ting these, it is important to adopt some order of succession, which, 

 for the sake of the greater perspicuity, should remain unaltered. 

 All prolixity should be carefully avoided : every superfluous word, 

 every ambiguous expression, in short, every thing foreign to the 

 purpose should be rejected ; and such terms employed as are ex- 

 plained in the Terminology. Abbreviations of frequently occurring 



