Iron . 
85 
matter almost invisibly interposed betwixt their interstices. 
If the heat is urged still further, the iron, now malleable, 
begins to take up a portion of the carbon from the charcoal, 
and the metal then commences its change toward steel. 
During any part of the process, should air come in 
contact with the ore, by previously destroying the sur- 
rounding charcoal, an immediate oxydation of the iron 
takes effect, proportioned in its increase of weight to the 
stage of the operation at which it is effected. The ore has 
then passed into a friable, bulky, and unmetallic state. 
In de-oxygenating iron-stones, with an intention of dis- 
covering and of establishing an analogy as to the quan- 
tity of oxygen contained in the respective classes of stones, 
I was frequently led to conclude, that argillaceous and 
calcareous iron-stones contained less oxygen than iron- 
stones where a greater proportion of silex predominated. 
Though by far the greater number of experiments per- 
formed on this subject were in favour of such an infer- 
ence, yet I have at times experienced my arrangement 
palpably contradicted, without being able to solve the 
obtruding difficulty. I shall not however despair, in most 
cases, to reduce to certain invariable inherent properties, 
and external characteristic forms, the various iron-stones 
in the manner in which I have arranged them, and conso- 
nant to the results obtained from them in the process of 
manufacture. The utility of such an arrangement, found- 
ed upon experiment, must be obvious and striking : it 
will give certainty and value to the various products of the 
manufacturer, as it will in the end systematize the manu- 
facture itself, and reduce it to rules guided by principle, and 
not by the aberration of a false or misinformed judgment. 
From many experiments I have made with all the va- 
rieties of iron-stones found in this country, I shall sub- 
join the treatment of one of each class, highly marked 
with the predominating earths, that an accurate opinion 
may be formed of the phenomena exhibited in this part 
of the process. 
