290 DISCOURSE ON THE STUDY 



CHAP. IV. 



OF THE EXAMINATION OF THE MATERIAL CONSTITUENTS 

 OF THE WORLD. 



Mineralogy. 



(325.) THE consideration of the history and struc- 

 ture of our globe, and the examination of the fossil 

 contents of its strata, lead us naturally to consider 

 the materials of which it consists. The history of 

 these materials, their properties as objects of philo- 

 sophical enquiry, and their application to the useful 

 arts and the embellishments of life, with the charac- 

 ters by which they can be certainly distinguished 

 one from another, form the object of mineralogy, 

 taken in its most extended sense. 



(326.) There is no branch of science which pre- 

 sents so many points of contact with other depart- 

 ments of physical research, and serves as a connect- 

 ing link between so many distant points of phi- 

 losophical speculation, as this. To the geologist, 

 the chemist, the optician, the crystallographer, 

 the physician, it offers especially the very ele- 

 ments of their knowledge, and a field for many of 

 their most curious and important enquiries. Nor, 

 with the exception of chemistry, is there any which 

 has undergone more revolutions, or been exhibited 

 in a greater variety of forms. To the ancients it 

 could scarcely be said to be at all known, and up to 

 a comparatively recent period, nothing could be 



