9,66 Dr. Beddoes’s Observations on the Process for 
pressing upon them ; the elastic fluids could not either tra- 
verse the solid surface so freely as a liquid, and perhaps, as I 
am disposed to believe, they could not traverse it at all. The 
malleable skin seems close in its texture, and the porosity of 
the rest might arise from the generation of just air enough to 
produce an internal expansion. In the puddling operation, it 
is of the most material consequence to keep the mass in con- 
stant agitation. Thus the parts are thoroughly blended, the 
attraction of cohesion is a good deal counteracted, and there 
can be no pieces hide-bound, if I may so express myself. This 
last, perhaps, is the greatest advantage derived from the labour 
of the workman . 
4. I was asked by one of the most ingenious and profound 
philosophers of the present age, why I had neglected the ac- 
tion of the atmospheric air in the theory of the conversion of 
iron ? It is simply because its action upon the metal seems, in 
practice, pernicious ; I consider its presence as an evil, though 
a necessary one, according to the present modes of working ; 
I was also anxious to try this opinion by the test of experi- 
ment, and you see it has been fully confirmed. In the last 
experiment, part of the iron was completely converted, and in 
some others it seemed approaching fast towards nature, as the 
manufacturers express it. It is, indeed, very possible to con- 
ceive a way in which air might be beneficial ; that is, if it 
could be applied so as to burn the charcoal merely ; but at 
present, for one grain of charcoal which it converts into car- 
bonic acid air, it converts many of iron into finery cinder ; 
and as I have formerly shewn, this is not the way in which 
iron is actually converted in the reverberatory, and probably 
not in the finery, furnace. 
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