IV 



Grand 

 provinces 



INTRODUCTION. 



inadequate to the subject, to carry this species of metaphor 

 too far, some lesser divisions must be borrowed from the 

 nature of the objects, as they present themselves to the 



observer. 



I would propose, therefore, in the present advanced state 

 of the science, that the mineral kingdom be considered as 

 divided into three provinces : 1. PETRALOGY, or the know- 

 ledge of rocks, or stones which occur in large masses. 



2. LITHOLOOY, the knowledge of gems and small stones. 



3. METALLO&Y, or the knowledge of metals. Each of these 

 branches is even at present so important, and offers such 

 numerous topics of disquisition and research, that in the 

 course of no long period a professor of each will appear in 

 universities ; and each might occupy the sole pursuit of an 

 author who is zealous to make discoveries, or to compose 

 complete and classical works. One of the chief causes of the 

 slow progress of the science is, that it is too wide for one 

 mind j and as zoology has been divided into ornithology, 

 ichthyology, entomology, &c. so mineralogy, to be duly stu- 

 died, should have grand subdivisions. 



These provinces may again be viewed as divided into DO- 

 MAINS, corresponding with the Orders of some writers and 

 the Genera of others, as the Provinces supply what was called 

 Classes. This term DOMAIN is preferred to District, &c. as 

 it not only implies a subdivision of a province, but, in another 

 acceptation, a ruling or preponderating power, strictly appli- 

 cable in mineralogy, where it is often the preponderance, 

 and not the universality, which imparts the denomination. 

 Thus in the siliceous, calcareous, and other domains, it is only 

 understood that the denominating portion preponderates, 

 as few or no rocks are pure, and unmixed with other sub- 

 stances. 



Petralogy, a province of mineralogy, may therefore be re- 

 garded as divided into Twelve Domains j of which the first 

 six, being distinguished by the substances themselves, may 

 Substantial, be called SUBSTANTIAL : while the remaining six, being distin- 

 guished by circumstances or accidences of various kinds, may 



Domains. 



