On the Principles of Iron and Steel. 261 
have been affiened for this deftruétive property in hot fhont 
iron. I am of opinion, that it arifes from the iron contain- 
ing a fmall portion of concrete carbon, not extirpated 
during the operation of rendering the iron malleable; and 
that in proportion to the quantity of carbon united, fo will 
be the fhortnefs or fufibility of the iron: this variety of iron 
is always of a dark-coloured unmetallic fracture. 
ad. Cold fhort iron is poffeffed of the property of with- 
ftanding the moft violent degree of heat, without exhibiting 
the leaft indication to fufion; it. remains firm under the 
heavieft hammer, and-is capable, while hot, of being beat 
into any fhape: when cold, however, it is brittle, and pof- 
feed of a {mall degree of tenacity: its fracture is always 
clear and large-grained, of a light blueifh colour. A {mall 
portion of iron diffolved in the phofphoric acid is) now 
believed. to conftitute the cold ‘fhort principle of iron. 
Befides the difficulty of conceiving how an acid could exift 
in the violent and Jong-continued heats of the refinery, the 
puddling and balling furnaces, wherein the metal is fubje@ed 
to motion, frequently agitated, and extremely divided, how 
does it happen, that that iron on which the cold fhort prin- 
ciple is imprefled, becomes more and more cold fhort, by a 
continued expofure to the combination. of oxygen with 
caloric, either excited by blaft or the attenuated heat of a 
wind furnace? This fact would imply a generation of the 
alterative principle—which is indeed the cafe—but which 
cannot be admitted, if the cold fhort quality is attributed to 
the phofphat of iron; unlefs recourfe is had to the fuppofi- 
tion of a new combination of this metallic falt during the 
operation. . 
If highly oxygenated crude iron, of any manufacture, is 
“expofed to the aétion of a current of flame, after its fmall 
portion of carbon is burnt: out, and after the mafs has ex- 
hibited the proper fiens of malleability, it will pafs into the 
Atate of cold fhort iron; and this principle will exift in pro- 
portion to the length of the expofure ; or, in other words, in 
Vor. II, M proportion 
