Professor Hausmann on MetaJlurgic Crystallography . 163 
accurately traced. I am indebted to Bernstejnius, superintend 
ant of the cobalt-work at Carlshaven, for a mass of this re 
siduum, so conjoined with charcoal, as to have the appearance 
of being conglomerated with it, and mixed also with arsenicated 
nickel, and arseniceous nickel, a decomposition of the former. 
In this specimen a slow process of cooling by charcoal leads to 
the formation of more perfect crystals. I have been able to 
ascertain with accuracy the following crystallizations : 
1. A regular pctaedron, deeply truncated on the apices 
2. A regular octaedron, truncated on the apices, and bevelled 
on the edges of the basis. 
3. A regular octaedron, truncated on the apices, and on 
the edges of the bevelment on the basis. 
4. A regular octaedron, in which the apices and the lateral 
edges are truncated. 
As the metallic residuum, arising from a preparation of cobalt- 
glass, runs into and mixes with native arsenicated nickel, it 
would be cf consequence to compare their several crystallisations. 
But the crystallisations of native arsenicated nickel are still 
problematical. A remarkable specimen, in which I had an op- 
portunity of observing the crystalline form, appeared to exhibit 
cubes with truncated apices. This form coincides with those 
crystallisations which are found in the artificial arsenicated nic^ 
kel ; it in ay therefore be referred to a regular octaedron. 
2. Graphite. 
i ‘ ' ■ ‘ v . 
Graphite is a crystalline composition, containing a small quan- 
tity of iron, and a large quantity of carbon. Although the pro- 
portion in which these component substances are connected toge- 
ther is undoubtedly ascertained, yet pf this proportion chemists 
differ very much in their opinions. Graphite, both in its native 
and artificial state, deserves repeated chemical examination, par- 
ticularly with a view of ascertaining whether or not the artificial 
graphite agrees in composition with the native. 
Graphite is plentifully produced by the fusion of iron, from 
minerals that do not contain manganese, by the addition of a 
quantity of charcoal. In crude iron it occurs in small scales ; 
but by increasing the quantity of charcoal, it exhibits larger cry- 
stals. In this state it is found imbedded in crude iron, or in the 
.* i ' . 
