16 
[Assembly 
cies with that of its varieties, as well as the characters which serve 
to unite them into genera find families, in order that they may be 
easily recognised. 
Mineralogy thus characterized, derives its principal aid from 
physics and from chemistry. The celebrated Beudant has well 
observed, that " if the successive discoveries of crystallography 
have had the effect of raising mineralogy from the empyricism to 
which it was consigned, the progress of chemistry has really ele- 
vated it to the rank of the exact sciences; and such is now its po- 
sition with regard to these two sciences, that it is impossibie for it 
to make any positive advance without the powerful aid which 
they afford." Thus also Dr. Thomson remarks, " that mineralo- 
gy is so closely connected with chemistry, and so dependent on it 
for specific distinctions, that it would be highly injurious to it, and 
therefore very unwise to attempt to deprive it of so important an 
all}*. It would be nearly the same as it the astronomer were to 
announce that his science was independent of mathematics, and 
were therefore to insist upon banishing that indispensable auxilia- 
ry from his sublime science." And to these, I may add the opin- 
ion of Dr. Buckland in his recent Bridgevvater Treatise, who just- 
ly places many distinct departments of science in a similar relation 
to geology; for says he, We now approach the study of the na- 
tural history of the globe, aided not only by the higher branches 
of physics, but by still more essential recent discoveries in mine- 
ralogy and chemistry, in botany, zoology and comparative anato- 
my. By the help of these sciences, we are enabled to extract 
from the archives of the interior of the earth, intelligible records 
of former conditions of our planet, and to decipher documents 
which were a sealed book to all our predecessors in the attempt 
to illustrate subterranean history." 
From what has now been said, it will be manifest, that although 
mineralogy, like zoology, botany and comparative anatomy, is 
connected with geology, and is of great assistance to the geolo- 
gist, its objects are sufficiently distinct, and when as in the pre- 
sent instance, chemistry is expressly made its auxihary, its utility 
cannot well be questioned. 
Such being my views of the nature of the work committed to 
mc, and being sensible of its importance and of the labor which 
its completion would require, I need not say that I have addressed 
