Professor Haussmann on Mctallurgic Crystallography. 161 
the length of an inch, cutting each other at various angles, and 
thus forming little cells ; and, by a more accurate examination 
of these folia, I have often found the entrance of the plates to 
have the form of a regular octaedron, although their complete 
regularity of formation may not always be observed. 
The folia of crude iron have a vivid brightness, and, when 
observed by the naked eye, appear almost smooth, but, by the 
help of the microscope, we perceive in them pinnated grooves, 
which, running over the whole surface of the folia, prove the 
tendency of the particles to crystalline formation. This pheno- 
menon is in like manner observed in other foliated metals artifi- 
cially produced, and sometimes also in natural substances, such 
as in native silver. 
h. Copper .— The crystalline form of copper is well known. 
Native copper is observed to be frequently crystallised, as also 
that which is artificially produced by cementation. For the 
most part it occurs as a regular octaedron, in various forms. 
Crystalline copper is also sometimes produced by a dry prepara- 
tion in metallurgical processes. I am indebted to the kindness 
of Henserus, a promising student, for a specimen of crude 
copper (schwarz kupfer) produced in the foundry of Reichels- 
dorf, which possesses the same elements of octaedral crystal- 
lisation, as we found in crude iron described above, except that 
the small particles are more numerous, and more closely con- 
nected together. 
We now take occasion to notice a very remarkable cupreous 
production, found in foundries, and which deserves our most 
particular attention ; namely, capillary copper, ( pili cuprini ,) 
which occurs in cupreous mixtures, where, the surface being first 
of all cooled by water, it is found in the cavities. This sub- 
stance lias been observed by Swedenborg. Stone mostly com- 
posed of copper, contains, besides other sulphuretted metals, 
sulphuret of copper, which is very closely connected with sul- 
phuret of iron ; we also meet with pure copper, which is not ob- 
servable when the mass is allowed to cool spontaneously, but, 
when suddenly cooled, appears in detached pili. This pheno- 
menon can be explained by the fact, that sulphuret of copper 
consolidates quicker than metallic copper ; thus the liquid, by 
vol. v. no. 9. JULY 1821. 
i, 
