PHYSIOGRAPHY. 249 



PART. V. 



PHYSIOGRAPHY. 

 . 123. DEFINITION. 



Physiography is the description of natural productions, 

 and consists in the enumeration of all their natural proper- 

 ties. It is intended to produce a distinct image of those 

 objects which we distinguish from each other by means of 

 the Characteristic, and denominate conformably to the rules 

 laid down in the Nomenclature. 



Physiography is not adapted to the purpose of distinguishing min- 

 erals. We cannot therefore, by its assistance, find the place of a giv- 

 en mineral in the system, or in other words, recognise it ; for it is 

 independent of that connexion among natural productions upon 

 which systems are founded, and considers them singly, every one 

 by itself. Physiography, therefore, cannot acquiesce in consider- 

 ing single characters or characteristic marks; but it must exhibit 

 them all, if the image it produces is meant to be a complete and 

 satisfactory one. Its difference from the Characteristic founded 

 upon these properties, is as obvious as the impossibility of substitu- 

 ting the one instead of the other. A description, therefore, is not 

 a character ; since the peculiarity of every character consists in its 

 being composed of a smaller number of characteristic terms that 

 may be observed in the objects characterized. 



The descriptions presuppose nothing but Terminology. It is per- 

 fectly indifferent what nomenclature is adopted in Physiography, 

 provided only the names and denominations to which the descrip- 

 tions of the species refer, answer the purpose of keeping separate 

 those objects, which really differ from each other. 



The system of Prof. Mohs, is the only one which has hitherto 

 presented a separate view of the Determinative and the Descrip- 

 tive parts of Mineralogy. The greater part of the mineralogical 

 works have given to the characters such an arrangement, that they 

 may at the same time represent the general descriptions of the spe- 



