Professor Haussmann on MetalJurgic Crystallography . 159 
to the largeness of the grains, and less so, according as the tex- 
ture of the iron is assimilated to the texture of steel. Although 
I cannot agree with the opinion of Epicurus, as handed down to 
us by Lucretius, and of more recent atomists, that iron owes its 
hardness and strength to barbed particles, yet I perfectly rely 
upon those observations and experiments, which prove that the 
crystalline tendency of the texture is different, according to the 
various degrees of tenacity possessed by bodies in a given rela- 
tion. Iron does not possess any great tenacity, except in a par- 
ticular state of crystalline texture, and this tenacious texture is 
obtained by a violent compression. We generally find the crys- 
talline texture to be more perfect, in proportion as it is less te- 
nacious ; and heated iron, which possesses a very small degree 
of tenacity, exhibits a very strong tendency to crystallisation. 
Nor does it appear an improbable supposition, that the elements 
of various crystalline forms are to be found in the various de- 
grees of flexibility possessed by iron. But this subject does not 
admit of being more particularly explained in this place. 
There are two principal varieties of crude iron, capable of be- 
ing distinguished, namely, crude iron, vulgarly so called, and 
steel. If the first variety is produced from a carbonaceous mix- 
ture, it contains more or less of graphite. In the latter variety, 
on the contrary, carbon is more equally distributed through the 
whole mass; and if it is produced from minerals containing 
manganese, it generally retains a certain quantity of the manga- 
nese. In this variety, the tendency to crystallisation is much 
stronger than in the former, where the crystalline tendency is 
less, according to the quantity of graphite which it contains. 
Yet in crude iron, vulgarly so cal led, when allowed to cool slow- 
ly, there appears to be sometimes produced imperfect oc- 
taedral crystals ; but it is an imperfect formation, occurring 
also in other metals, and which Grignonus, in a passage 
quoted p. 476. tab. 13. fig. 1., has described and sketched. 
But, as has been justly observed by Romeus Insulanus, this 
metallurgian was mistaken, when he believed the fundamen- 
tal figure of the crystal to be a rhomboid. In these imperfect 
crystallisations found in crude iron, the elements of a regu- 
lar octaedron are distinctly observed. The small particles are 
joined together by three planes, cutting each other at right 
