18 Obfervations on ‘Tron and Steel. i, 
tity of fuel made ufe of. Mr. Collier afferts, that the fecond p 
ftate of the metal only contains it; and although he admits 
of a third ftate of crude iron, manufactured with a ftill larger 
proportion of fuel, he takes no notice of the variable confe- 
quence, viz. an extra combination of carbon. Query, Can it 
be faid with propriety, that crude iron holds carbon in folu- 
tion, when it can be feparated from it by fimple mechanical 
divifion ? f 
It is to be withed that Mr, Collier had furnifhed an ana- 
lyfis of thofe ores, found in the neighbourhood of Sheffield, 
which he fays contain phofphat of iron, and from which 
they derive their cold fhort quality: if the property of form- 
ing cold fhort irons is a proof of the exiftence of phofphat of 
iron-in the ore, then I know of no ores that do not contain 
it; as J have never feen crude iron that could not be con- 
verted into cold fhort iron, at pleafure, by the management 
of the procefs of malleability. I would not with to deny - 
the exiftence of fiderite—] cannot—for it is already an efta- 
bhfhed truth ; but I cannot fubferibe to its being the exift- 
ing, alterative principle in the ore, which contaminates the 
iron, and renders it brittle when cold; unlefs I am cé@n- 
vineced, by its having been precipitated from the ore, before it 
came in contaét with combuftion. The great Lavoifier him- 
felf appears to have been uncertain, whether the fubilance 
called fiderite was a binary combination or not: hence he 
claffes it among the phofphurets, and expreffes his doubts of 
the oxygenation of the phofphorus. Mr. Chaptal, however, 
im experiments, which I fuppofe have been made pofterior 
to Mr. Lavoitier’s publication, has proved it to be a real 
folution of iron in the phofphoric acid. What I contend 
for is this, that the fiderite of iron may be an unknown com- 
bination, formed during the procefs of making the iron mal- 
leable. At iome future period I fhall enter more at large 
into what I conceive to be the exifting caufes of cold and 
fhort hot irons, and adduce experiments for their fupport. 
The 
