Professor Haussmann on Metallurgic Crystallography .. 157 
1. Metallic Crystallisations . 
Metallic substances, in a state of crystallisation, exhibit a 
much greater uniformity than other crystalline bodies. In sul- 
phuretted, but more particularly in oxidised metals, we discover 
a beautiful variety of crystalline forms. According to the ob- 
servations which have been hitherto made, the original form of 
all metals seems to be a regular octaedron ; and the edge of the 
secondary crystalline forms, which surrounds this original form, 
does not possess any great extension. Mixtures do not appear 
to produce any change in the original form of metals ; they 
merely regulate variously the series of secondary forms. This 
is evident in mixtures of antimony with silver, and of silver with 
mercury. Were these opinions completely established, a more 
profound study of mineralogy would lead to conclusions of a 
very important and valuable nature. From thence it might 
perhaps be justly inferred, that the principle of crystalline for- 
mation in those metals mentioned above, lies deeper than in those 
metallic substances hitherto discovered ; that all metals are sub- 
jected to the same law of crystallisation, and hence that we have 
additional encouragement to hope for the discovery of a better 
method of decomposing metals. From them, also, we might be 
enabled to fix with much greater certainty upon that part in a 
substance which is characteristic and distinguishing of its na- 
ture ; and sometimes we might be led to point out the method 
of discovering substances by chemical analysis, which have not 
hitherto been detected by re-agents. These conjectures are 
placed ‘in a new light, by some observations which follow, 
with reference to metallic crystallisations produced by metal- 
lurgical processes. 
a. Iron .- — No metal in nature deserves a greater share of at- 
tention from mineralogists than iron, for none in nature is of 
greater importance. We are, however, so very far from having 
an accurate knowledge of this metal, that we are but little ac- 
quainted even with its regular external appearance. Haiiy ob- 
serves, that the crystallisation of native iron has the form of a 
regular octaedron. In the native iron which we sometimes find 
scattered through meteoric stones, I have observed crystals 
which had an octaedral appearance. This tendency in me- 
teoric iron to the octaedral form, clearly appears also by cor- 
