Mr Musliet on the Deoxidaimn 
in the after fusion, affords a very striking and very different re- 
sult. I am aware that it may be urged, that this ponderable 
matter may not have previously existed in the ironstone, but 
have become united to it in the process of roasting ; and that the 
contrast in the above experiment, to have been more complete, 
ought to have been made with the ironstone in its raw or native 
state. In answer to this, I have, in the first place,, to remark, 
that no reliance can be placed on experiments made with raw 
ironstones, and carbonaceous matter, reduced to the necessary 
degree of fineness : The instantaneous expulsion of 30 per cent, 
of volatile matter, occasions such an agitation in the crucible, 
that part of the ore and carbon is unavoidably lost. In the 
second place, I submit, that it is exceedingly improbable, in an 
operation which may be performed in two minutes, in a heat 
which would not raise the slightest scale of oxide upon pure 
malleable iron, that any combination of oxygen can take place 
with iron not in a metallic state, the particles of which are more 
or less sheltered, by the presence of a quantity of earthy mat- 
ter, equal to that of the metal. 
The ironstone subjected to the foregoing experiments, when 
roasted, yielded 44 per cent, of iron, and lost in roasting 32 per 
cent.^ so that the ore in its native state contained 33 per cent, of 
iron. After the rate of 40 per cent.^ this would furnish us with 
a quantity of oxygen equal to 13.2 per cent.^ united originally 
with the iron. Now, the ponderable matter got rid of by the 
cementation, in the experiment at 28° of Wedgwood, was the 
difference between 32 and 42, or 10, and in that of 69°, the 
difference was equal to 11° ; a coincidence sufficiently near to 
warrant the conclusion, that the iron of our ironstone is not 
only in the state of an oxide, but that the dose amounts to 40 
per cent, at least ; for it cannot for a moment be supposed, that 
any process of cementation confined to an inferior range of tem- 
perature, could separate^ from the ore the last portions of oxy- 
gen, which it is even probable resist the higher temperature, 
and more perfect operation of the smelting furnace. 
That a greater portion is removed in a smelting temperature, 
is proved by the following experiments : 
934 grains of raw ironstone in pieces, were placed in contact 
with pounded charcoal of wood, and exposed for four hours to 
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