156 Professor Haussmann on Metallurgic Crystallography . 
watery solution of that substance. The compact artificial gale- 
na or lead-glance, formed in melting-furnaces, cannot be distin- 
guished from what is naturally produced in mines. Pseudo- 
galena , which is sometimes produced in melting-furnaces, bears 
every resemblance to that which occurs in metallic veins, except 
that, in the former, there may be observed a certain porousness, 
which is not found in the latter. We cannot, however, certain- 
ly conclude, that the specimens of galena and pseudo-galena, 
which occur in metallic veins and strata, are produced by 
one and the same process, namely, by sublimation . In the 
upper parts of the metallic vein which occurs in the mine 
of Andreasberg, called Catherina Neufang, there is found 
a compound containing arsenic, friable silver-glance, scoria- 
ceous yellow orpiment or sulphuret of arsenic, and scoria- 
ceous arsenical acid, which exhibits the appearance of being 
an igneous production, and which bears a very close affinity 
to some varieties of arsenical argentiferous lead, occurring in 
mixtures, which also are produced by heat, but which has been 
formed on the wet way, by a process of decomposition in the 
vein itself. These facts ought to make us cautious of ascribing 
to similar formations, uniformly one and the same cause. 
Crystalline formations are by far the most remarkable of all 
those that proceed from inorganic bodies, because in these the 
operating powers act with the precise regularity of mathematical 
principles. Although, however, we admire this regularity of 
operation, and although we have made some discoveries of the 
mathematical connexion which subsists among the crystalline 
forms of Various mineral substances, yet, it must be confessed, 
that Our knowledge of the theory respecting the formation of 
crystals is very limited. We are strongly induced, therefore, 
to cultivate a more intimate knowledge of this department of 
science ; and we trust, that, in our investigations concerning the 
formation of crystals, we shall derive no inconsiderable assistance 
from metallurgical processes. In the observations which follow, 
I venture to present to the public the first specimen of crystal- 
lisations, formed by metallurgical processes ; and in this per- 
formance I hope to receive the more indulgence, as the train of 
observations which I pursue has not hitherto been entered upon. 
