Professor Haussmann on Metallurgic Crystallography . 847 
with justice, be said of metallurgical processes, unless the re- 
sidua were just as accurately examined as the ores. From 
the following observations, I think it may be proved, that com- 
binations are formed in determinate proportions, by the aid of 
chemical elective powers, in scoriae as well as in other metallur- 
gical formations ; and that some combinations occur in scoriae 
which are regulated by the same principles in different metal- 
lurgical processes. By these observations, I hope to be able to 
bring together some new information in regard to the crystalli- 
sations of scoriae, which has not hitherto been discovered by an 
investigation of the regular forms of artificial glasses. 
The tendency which appears in glass to assume a regular 
form, by a slow process of cooling, has been long noticed. In 
this point of view, the observations of James Keir are very va- 
luable ; and to these we may add the observations of Reaumur, 
and of many later writers, who have explored nature, and pub- 
lished accounts in regard to what is called the Devitrification of 
Glass. The same tendency to crystallisation is observed in the 
fibrous texture, which is apparent in glass when slowly cooled; 
a similar tendency is also observed in scoriae, produced in me- 
tallurgical processes. I have more frequently met with this ten- 
dency in scoriae ejected from the bottom of deep iron furnaces, 
where, in addition to the fibrous texture, the other common pro- 
perties of glass, namely transparency and lustre, are combined, 
though in a less degree ; and, in the perfectly formed glass, a 
silky or resinous lustre is observed, instead of its own proper lus- 
tre. In the iron-founderies of the Hartz, I have occasionally 
seen green scoriae, with a curved fibrous texture, and possessing 
various shades of lustre. In many founderies of Norway, Swe- 
den, and Germany, I have found lapidoidal scoriae, of various 
grey colours, of a fibrous texture, with the fibres diverging. 
Scoria, produced in the fusion of cupreous minerals, at Fall- 
lun in Sweden, very frequently acquires, by being slowly cool- 
ed, a fibrous texture, which passes into a radiated texture ; 
the exposed surface shews also a tendency to a hexangular 
prismatic formation, in the same manner as has been ob- 
served in common glass by Keir. This scoria obviously 
appears in the process of cooling to possess the power of 
central attraction and crystallization, both in mutual co-opera- 
