various important subjects in Mineralogy. $1 5 
duced the essential circumstances and causes of formation. A 
number of salts, and other bodies, obtained by the aid of Che- 
mistry, would in that case be excluded, and considered as artifi- 
cial productions, although the part which art, or the controul of 
man, takes in their formation, is entirely limited to the mere 
production of those circumstances, under which nature may ex- 
ert, in producing those new combinations, the same powers which 
enter into action, when the other bodies are produced. The 
properties considered in Natural History have been so imperfect- 
ly observed or investigated in these bodies, that, on this account, 
they could not be made use of in the construction of systems ; 
and yet they are among those, from the examination and deter- 
mination of which, according to the principles of Natural History, 
Chemistry would derive the greatest benefit, and more especially 
in its endeavours to fix the idea of the chemical species. The 
knowledge of these bodies would also be highly useful in Mine- 
ralogy, because the frequent opportunities which they afford for 
the application of the fundamental principles and general ideas 
of their science, would materially assist in demonstrating the ge- 
nerality of the former, and the reality of the latter, in order to 
convince those who require a still greater compass of information 
than that which at present exists. 
Natural History attends most particularly to those very pro- 
perties which have been so much neglected in these bodies, and 
even in many which have exclusively been called minerals. It 
considers bodies in that state in which they have been placed by 
the completed action of those powers by which they were pro- 
duced. This state is here called the natural state of a body. 
It is the compass or simultaneous existence of the properties de- 
nominated natural-historical properties , because they alone form 
the object of natural-historical consideration. If one or more of 
these properties may have been lost, then the body itself has been 
removed from its natural state, and has ceased to be a fit object 
of natural-historical investigation. This circumstance deserves 
to be well attended to, in order to separate such natural produc- 
tions as are decomposed, from such as still remain in their na- 
tural state, which is likewise done in Zoology and Botany ; be- 
cause experience has already sufficiently shewn, that the neglect 
of this difference has been productive of the greatest errors. 
