no 
Professor Moling General Reflections on 
which are essentia] to every science. The second reason is, that 
Chemistry was imagined to be sufficient for all those purposes, 
which it is the peculiar duty of Natural History to perform. 
Without entering here upon any discussion regarding the im- 
propriety of this latter reason, it will be enough to observe, that 
experience itself has already shewn its insufficiency. Chemists 
have not yet succeeded in determining the species in Mineralogy 
by chemical means alone, which, nevertheless, is the conditio 
sine qua non : nay, the accuracy or incorrectness of such a de- 
termination cannot be properly judged of, but by comparing the 
results of chemical analysis with the species already determined , 
according to the principles of Natural History ; for, from such 
a comparison we find, that some of the bodies extracted are 
mechanically blended with the normal composition, that others 
are accidental, others isomorphous, and so on. Experience has 
long ago demonstrated, that these considerations must not be 
slighted in determining the chemical species, otherwise we should 
find ourselves involved in all kinds of contradictions. If, there- 
fore, this matter should ever come to be settled in Chemistry, as 
has already been effected in Natural History, it could only hap- 
pen through the assistance of, or by comparison with, the re- 
sults of the Natural History determination. 
But, even supposing that the chemical determination of the 
species, and that obtained by the processes of Natural History, 
should entirely coincide, and that it were practicable to infer the 
one from the other with perfect securit}^ so that the species in 
Natural History might be exactly replaced by the species in Che- 
mistry ; yet the latter science could not be employed in the place 
of the former, for determining the objects of its own inquiries* 
and of those of other sciences. For it is sufficiently evident, 
that for this end such properties should be selected as are pe- 
culiar to them in their natural state, or with which they have 
been endowed by nature at the period of their formation ; not 
such properties as can* be observed and judged of only while 
they abandon this state, or after they have lost it altogether, 
and have been decomposed. In Zoology and Botany, there would 
be every reason to oppose such a proceeding with the utmost 
vigour, and still more so in Mineralogy. For, in the animal 
and vegetable kingdoms these properties are changeable, with- 
