320 
Iron . 
ed in the crude iron, the destruction of which, and the 
consequent malleabilization of the iron, constitute the uni- 
versal acknowledged principles of bar-iron making. 
From the imperfect dissipation of oxygen, and carbon 
in the process of giving malleability, arise the various qua- 
lities of malleable iron ; these may be arranged in the fol- 
lowing order 1. Hot- short iron 2. Cold short iron ; 
—and, 3, Iron partaking of none of these evils ; and so 
far it may be denominated pure malleable iron. 
1. Hot- short iron is possessed of an extreme degree of 
fusibility when in contact with a high degree of heat, and 
is incapable of receiving the weight of a small hammer 
without dissipating ; it is, however, possessed of an ex- 
treme degree of softness and ductility when cold, and may 
then be bent or twisted in almost any direction. Various 
reasons have been assigned for this destructive property in 
hot-short iron, I am of opinion, that it arises from the 
iron containing a small portion of concrete carbon, not ex- 
tirpated during the operation of rendering the iron mallea* 
ble ; and that in proportion to the quantity of carbon uni- 
ted, so will be the shortness or fusibility of the iron : this 
Variety of iron is always of a dark coloured unmetallic frac- 
ture, 
2d, Cold-short iron is possessed of the property of with- 
standing the most violent degree of heat, without exhibit- 
ing the least indication to fusion ; it remains firm under 
the heaviest hammer, and is capable, while hot, of being 
beat into any shape : when cold, however, it is brittle, and 
possessed of a small degree of tenacity : its fracture is al- 
ways clear and large .grained, of a light blueish colour. A 
small portion of iron dissolved in the phosphoric acid is 
now believed to constitute the cold-short principle of iron. 
Besides the difficulty of conceiving how an acid could 
exist in the v iolent and long continued heats of the refine^ 
ry, the puddling and balling furnaces, wherein the metal 
