160 Professor Haussmann on Metallurgic Crystallography. 
angles, and cutting also the edges of a regular octaedron ; but 
the crystalline formation does not extend to these edges. The 
greater quantity of the mass is accumulated in the central part 
of the octaedral formation ; and in each of the eight tetrae- 
drons, which may bp considered as composing an octaedron, 
there is a greater or less cavity, so that the lines forming the 
edges, in which tetraedrons touch each other from without, are 
curved inwards. Nor do these curved edges form sharp lines, 
but they are themselves formed by a number of points going off 
from the three axes of the crystal, and having a direction to 
these axes, and to each other at right angles. These points, 
observed by a microscope, form more minute axes, from which 
lesser points go off at right angles. Many elementary octae- 
drons in such points are observed apparently laid over each 
other, so that the points of the lower octaedrons appeal* to 
rest upon the lower part of the upper octaedrons, and the di- 
mensions of these elementary octaedrons are contracted at the 
top, and being piled up one above another, the whole has a re- 
semblance to the elements of a very sharp octaedron, which has 
been observed by Romeus Xnsulanus in the passage quoted 
above. 
The strong tendency to crystallisation which appears in crude 
iron produced from ores containing manganese, admits of an ex- 
planation, partly from this circumstance, that generally it con- 
tains no graphite, which, having a stronger tendency to crystal- 
lise, impedes the crystalline formation of the iron ; but partly 
also from the combination of the iron with manganese, which, 
according to many analyses, bears a small proportion in quan- 
tity to the iron. For it appears to follow, from many experi- 
ments, that the tendency of metals in a mixed state to crystal- 
lise, is stronger than the tendency of the simple metals of which 
the mixture is composed. Nay, it appears to be a general law 
of Nature, that the crystalline tendency of inorganic bodies is 
greater in proportion as they are thoroughly amalgamated in 
their mixed state. 
Crude iron of the nature 'of steel acquires, while in the act of 
cooling, a foliated texture, which becomes more remarkable, ac- 
cording to the quantity of charcoal which is used for its pro- 
duction. There occur also on its surface crystalline folia, about 
