and Reduction of Iron Ores, 233 
particles being exposed in contact witli carbonaceous matter. 
The ironstone, when washed, and perfectly freed from this sub- 
stance, was of a greyish-blue colour, adhesive to the tongue, 
possessed of a metallic taste, and when pulverised, deflagrated 
in flame. 
400 grains of the common roasted ironstone, for the sake of 
comparison, were fused alone, and aflbrded a dense, shining, 
opaque glass, without any metallic separation. 
400 grains of the cemented deoxidated ore were reduced to 
the same size, and fused under the same circumstances, from 
which resulted a prismatic coloured button of iron, v/eighing 
120 grs., or BOyj^r cent. The marked diflerence betw'een these 
two results I also attributed to the presence and absence of 
oxygen in the two ores. 
In another experiment, I find that 4281 grs. of the same 
ironstone in pieces, were exposed for twenty-four hours in con- 
tact Avith coke-dust, to a heat, that, by the pyrometer, indicated 
of Wedgwood: loss in weight equal to 43 per cent.^ so 
that fourteen hours of longer exposure and double the tempera- 
ture, had only produced a further deoxidation of 1 per cent. 
beyond that obtained in the first cementation. The pieces of 
ironstone were noAV completely metallic, compact, and brighten- 
ed under the file. 
300 grains of this deoxidated ironstone, yielded by fusion per 
.9c, a mass of soft malleable iron, Aveighing 113 grains, or 37| 
per cent. 
300 grains, to AAdiich were added 15 of coke-dust, yielded by 
fusion 103 of iron, or 54 J per cent. ; 5 grains of coke Avere 
found in the crucible unacted upon, so that 10 grains of coke 
were employed in reviving the additional 50 grains of iron. 
200 grains of roasted ironstone Avere fused per se in a black 
lead crucible ; 49 grains of iron, or 24J per cent. Avas the re- 
sult. 
200 grains of ironstone, deoxidated at 09°, Avere similarly ex- 
posed, and fused, from Avhicli resulted 92 grains of iron, or 46 
per cent. 
These details, I think, clearly shew, that there is some pon- 
derable matter in the ironstone after roasting, Avhich is removed, 
by lieating it in contact with carbonaceous matter, and Avhich, 
