Iron. 
82 
touched by the lire. The effects produced by iron-stone 
in this state are exactly similar to those experienced in the 
former, arising from the same cause, but existing as the 
result of two opposite extremes. 
I confess it is much easier to point out the faults of an 
established mode of practice, than to substitute one, which, 
though it might unite some superior advantages, yet 
might not combine an equal number upon an extended 
scale. I have frequently considered the subject, and 
have as often been impressed with the truth of its impor- 
tance in the manufacturing of iron. At some future period 
I may submit to the manufacturers of iron a double me- 
diod of preparing iron-stones for the blast-furnace ; in 
which, certainty of operation would be obtained, and in 
the end most probably a degree of economy insured equal 
to that of the present mode. 
I would effect this by exposing the iron-stone stratified 
with a small proportion of coals, in simply constructed 
ovens, entirely covered on the top, except a few small 
funnels to carry off the smoke and disengaged vapours ; 
die ignition to be occasioned by a current of flame passing 
under a flue in the bottom of the furnace, and conveying 
combustion to the sub -stratified coals. As this opera- 
tion could be conducted to a physical certainty by means 
of damping the furnace instantaneously, as soon as the va- 
pour, &c. had ceased, or as soon as complete ignition had 
pervaded the contents, (the duration to be determined by 
the nature of the iron-stone,) the results in this case could 
at all times be depended upon, and the present irregular 
products avoided. A second method of depriving iron- 
stones of their volatile mixtures would be to expose them 
to a considerable degree of heat, in contact with the dust of 
pit-coal coaks— as being the most economical— shut up 
from the admission of external air. This would not only 
deprive them of their acid water, but would also un- 
