Iron* 
PI 
in making the iron-stone pass into a 
state of malleability - - 2 s 5— 17*3 
Earths, viz. silex 9, lime 6, clay 3T, = - 18*1 
100 parts. 
In these experiments I wished to obtain results which 
would throw light upon the de-oxygenation of iron-stones, 
with a view to apply them to practice upon an extended 
Scale. I therefore used fresh ore, in order to present near- 
ly the same surface to the action of the heat, and to be 
able to judge of the results apart from each other. In tor- 
refaction, it frequently happens that the stone is reduced 
too small to enable us, by its subsequent treatment, to 
form a probable opinion of the tenacity, or otherwise, with 
which iron-stones hold their oxygen. The difference be- 
twixt returning into the crucible the same pieces deprived 
of their volatile mixtures, and operating upon fresh ore, 
cannot be great, especially when they are selected from 
fragments of the same mass, directed by an intimate ac- 
quaintance and thorough knowledge of the qualities indi- 
cated by their external forms. 
All iron-stones thus exposed to de-oxygenation be- 
come more or less saturated with carbon ; it forms a uni- 
on like carbon in steel, and its presence is only ascertain- 
ed when the iron-stone is dissolved in an acid, by rising to 
the top, and forming a line pellicle possessing lustre and 
various shades of colour. I have also at times detected 
crude carbon in the centre of pieces of ore one and a half 
inch diameter. To the remainder of this mixture, after 
the oxygen is taken up, ought to be attributed the natu- 
ral tendency, which most malleable iron made in this pro- 
cess, has of becoming red-short. 
The average of the results of the principal classes of 
iron-stones may serve for information on the products ob- 
tained, by treating those of equal quantities of mixture. 
