SO Professor Mohs’s General Reflections on 
minerals. This is the most important part of terminology ; nay ? 
we may safely maintain, that, without this property , minera- 
logy itself could not exist as a science, — that is to say, it could 
not form part of Natural History. Crystallography has been 
considered by naturalists from so many different points of view, 
that it is perhaps worth while to examine what it should be, as a 
part of mineralogical terminology. Every one who has for any 
time been occupied with the examination of minerals, must have, 
no doubt, observed, that certain minerals possess certain crystal- 
line forms, while others are excluded from them. If we distin- 
guish between simple and compound forms, we discover that the 
varieties of one and the same species assume various, sometimes 
a great many, simple forms ; and that the compound forms in 
which they likewise occur, contain either these simple forms 
themselves, or such as are in a certain connexion with them, 
dependent not only upon the kind, but also upon the relative 
dimensions of the forms. Crystallography is not intended to in- 
vestigate the reason why the property of assuming certain forms 
is innate in certain species, or why these forms are united with 
several other properties, if we consider the productions of nature 
merely as the bearers of these properties ; because nothing can 
be inferred with regard to these inquiries from the mere obser- 
vation of natural-historical properties. The only object of crys- 
tallography is, to examine the circumstances and relations under 
which several of these forms may appear in connection with each 
other, in one and the same individual, or at least in varieties of 
the same species. It is this consideration which renders crystal- 
lography of so much importance to Natural History, and contains 
the reasons why it should be treated more at large in the termi- 
nology of that science. It may be effected by purely geometri- 
cal processes, by which we obtain a certain connection among 
some of the forms (of which, however, it is only necessary to con- 
sider the simple ones), while between others no such connexion 
is manifested; — a circumstance that enables us to establish ge- 
neral ideas of them, so highly useful and applicable in Natural 
History, that, notwithstanding the introduction of mathematical 
considerations, it would remain doubtful whether it might be 
possible without them to arrive at any thing deserving the name 
2 
