1854.] OF THE ROYAL INSTITUTION. 44] 
bonic acid and carbonic oxide gases is not observable in the analyses of 
Bunsen and Playfair, which Ebelmen attributes to the circumstance 
that those chemists collected their gases through narrow iron tubes, 
which, becoming intensely heated and partially choked by the frag- 
ments of ore and fuel introduced by the rapid stream of gas, so modified 
the composition of the gases that the analyses, however carefully con- 
ducted, could not represent accurately the actual composition of the 
furnace gases. Ebelmen collected his gases through wide tubes, and 
from the lower part of the furnace, by piercing the solid masonry. 
According to Ebelmen’s analyses, the gases between the depths of 12 
and 45 feet are composed alinost entirely of carbonic oxide and nitrogen. 
The proportion of oxygen to nitrogen at 12 feet is as 29°9 to 100; 
in atmospheric air it is as 26°3 to 100 ; the difference amounting to 
3°6 represents the oxygen arising from the bed of fusion from the 
Tuyeres to this height. It arises from the reduction of the silicates 
of iron constituting the forge cinders, which takes place between the 
Tuyeres and the depth of 12 feet. Without wishing in the slightest 
degree to impugn the accuracy of Bunsen and Playfair’s analyses, 
it was considered that the conclusions of Ebelmen accord best with 
the general phenomena of the Blast-furnace, inasmuch as if the re- 
duction of the ore only takes place in the boshes as the former 
chemists suppose, there seems no reason why furnaces should not be 
built one half their present height, and the fuel consist entirely of 
coke. It is found, however, practically impossible to reduce ma- 
terially the height of the furnace; but this is at once intelligible, if 
we suppose that the oxide of iron is reduced principally in the cone, 
and that in its descent through the boshes to the crucible it acquires 
From the fuel that proportion of carbon which it requires to bring it 
to the state of fusible cast iron. It is very desirable, however, that 
this interesting chemical question should undergo further elucidation 
at the hands of some chemist properly skilled in the difficult subject 
of gaseous analyses. . 
The practical application of the furnace gases was lastly briefly 
alluded to. It was shown on the authority of Bunsen and Playfair, 
and from calculations deduced from data furnished by the posthu- 
mous papers of Dulong, that of the heat produced by the combustion 
of the fuel in a coal-fed blast furnace, only 18°5 per cent. is rea- 
lized in carrying out the processes of the furnace, the remainder 
81-5 per cent. being lost. This loss in well conducted establishments 
is no longer permitted. The gases are now collected at the mouth 
of the furnaces and conveyed by large pipes underneath the boilers 
of the engines and round the hot air stoves. The principle has been 
carried out in great perfection at Cwm Celyn: the pipes are six feet 
in diameter, and are lined with fire-brick ; and the gases from two 
furnaces only more than suffice for the supply of seven boilers, and 
for the hot blast for both furnaces, at a saving of full 10,000 tons of 
coal a year. [Drawings on a scale of one inch to the foot showing 
the entire arrangement were exhibited and referred to. } 
[H. M. N.] 
