various important subjects in Mineralogy. 215 
ences, nor the means which they furnish, but upon the intellec- 
tual powers of man. 
It has very frequently happened, that errors committed in 
Mineralogy were discovered and rectified by chemists ; and it 
has from this been inferred, that Mineralogy is not sufficient of 
itself, but requires the support of Chemistry , at least for confirm- 
ing its results. The discussion of the general relations of the 
two sciences will form our more particular object at another 
time ; at present, we shall confine ourselves to the consideration 
of the inference mentioned above. Errors committed in deter- 
mining minerals, depend either upon the method used, or upon 
the incorrect application of it. It can scarcely be said, that Mi- 
neralogy, as it has hitherto existed, provides a method for this 
purpose ; because this would suppose it to be a science. Mi- 
nerals too frequently used to be determined, not by a philoso- 
phical and regular investigation of their properties, but by a 
superficial inspection ; and this being the case, even those most 
practised in the ready recognition of minerals, must unavoid- 
ably fall into errors, which it will be easy to discover, by the 
application of any constant test. If we make abstraction of 
the two great divisions of the species, which is one cf the most 
disadvantageous consequences of this looseness in the mode of 
procedure, we may rather feel surprised that no greater num- 
ber of errors should have been committed ; but this was owing 
to a natural instinct, rather than to any constancy of method fol- 
lowed in the determination of the species. These errors chiefly 
originate, in as far as they depend upon an erroneous applica- 
tion of the method, in the wish to determine individuals or va- 
rieties of minerals, that in reality are not determinable, because 
some one or more of their properties cannot be observed with 
sufficient accuracy, and in supposing them in consequence to 
form either distinct species, or varieties of a species to which 
they do not belong. If, by any circumstance, we are led to 
imagine some inaccuracy to have taken place, these errors will 
disappear of themselves. If the assertion, that Mineralogy can- 
not depend upon its own peculiar processes, had any foundation 
at all, it would require to be possible to demonstrate, that the 
natural-historical determination of a species, according to this 
method, is impossible. But this is itself impossible, since the 
