and Reduction of Iron-Ore.^. SS5 
a cementing heat of 40°, which was then gradually Increased to 
1S0% at which it remained for nearly eight hours. The result 
was a complete separation of the iron and earthy matters from 
each other, in the shape of globules ; the former in the state of 
grey crude iron, the latter in that of glass possessed of some 
transparency. They weighed collectively 484 grains, the loss 
450 grains, being equal to 48.19 per cent If 32 is taken 
from this, being the loss sustained in the operation of roasting, 
the quantity of matter removed by the cementation will be 
16.19; so that in these three experiments by deoxidation, the 
loss in weight has been analogous to the temperature, viz. 
tn 28“ of Wedgwood, loss 42 per cent. 
In 69“ . ditto, 43 
la 120“ ditto, 48.19. 
And the quantities of oxygen passed off in the state of car- 
bonic acid or carbonous oxide, will be represented by the num- 
bers 10, 11, 16, 19. 
H<»ving arrived at similar conclusions in experiments by de- 
oxidation with roasted ironstones, I insert the following as illus- 
trative of this coincidence. 
Some pieces of ironstone that had lost in roasting 29 per 
^ent.y were exposed for fourteen hours to a heat increasing to 
120° of Wedgwood, at which it was stationary for several 
hours. 
Tlie ironstone originally w'eighed 
After cementation, it was found resolved into 
- 
749 grains. 
Crey cast-iron globules, 
- 
SIS grains. 
Crlass globules. 
- 
217 
592 
Loss in oxygen - - « 
Iron obtained - - - , 
Glass, very transparent. 
20.9 
50.0 
29.1 
100.0 
Loss 
157 
This experiment was repeated, subjected to a longer but in- 
ferior temperature. The quantity of volatile matter lost, was 20.6 
per cent. A few small globules of cast-iron had exuded, and ap- 
peared upon the surface of the masses ; but no separation had 
