180 - - REPORT—1845. 
essential to the reduction and smelting of the ore. In furnaces fed with char- 
coal, the gaseous fuel has been collected and applied without any great diffi- 
culty, by building into the wall of the furnace a cireular channel supplied in 
the inner part with a grating so as to prevent its obstruction by the materials 
introduced into the furnace. The gases stream freely through this channel, 
even though the furnace is left entirely open, and though the pressure is so 
inconsiderable as scarcely to affect a water manometer. The great pressure 
of blast used in English furnaces led us to the conviction that in them the 
column of gas must be much more compressed, and we have confirmed this 
opinion by a series of measurements on a water manometer attached to the 
tube through which the gases were collected for experiment. The pres- 
sure of the gases expressed by the height of the column of water at various 
depths is as follows :-— 
5feet . . . O12 inch. 
Oo be ee et OS | gs 
Loe AS eral ae pag ai ma 
LBM ees OO 5 
Oye ek ee POUL ay 
<2 get lls Sean i a | a ae 
Ee oe a eh UL 99 
This table proves that even in the highest portion of the gaseous column, 
the pressure is considerably greater than in that region of the furnace from 
which the gases are withdrawn in Germany. 
Hence it follows that hot-blast furnaces fed with coal are peculiarly well- 
adapted for the economy of gaseous fuel, which may be conducted from the 
furnace and applied without in any way interfering with its operations. 
We have already shown, on the very lowest calculation, that at least 81°54 
per cent. of valuable fuel must escape from the mouth of the Alfreton furnace. 
Now as about fourteen tons of coal are used in that furnace every twenty-four 
hours, it follows, according to our experiments, that 11°4 tons of coal are lost 
every twenty-four hours by escaping in the form of gases still capable of 
being used as excellent fuel. 
We have previously shown, that the temperature capable of being attained 
by the combustion of these gases is 3083° Fahr. (1695°-2 C.), and, by using a 
blast sufficiently heated, this could easily be raised to 3632° Fahr. (2000° C.). 
Now as Pouillet has shown that cast iron melts at 2192° Fahr. (1200° C.), it 
follows that the gases of hot-blast furnaces fed with coal, when burned with 
hot air, would yield a temperature more than sufficient to melt iron. 
The gases of our furnaces fed with coal contain a very valuable consti- 
tuent, which is entirely absent from the charcoal furnaces of the continent. 
This substance is ammonia, which is present in such abundance, as to be 
sensible to the smell in the gases collected from the deeper parts of the fur- 
nace. We have therefore devoted our special attention to this valuable in- 
gredient, and have arrived at the conclusion that it is possible to economise 
it in the most simple manner. The ammonia may be obtained in the form 
of sal-ammoniac, if the gas previous to its application as fuel be conducted 
through a chamber containing muriatie acid. In collecting the ammonia in 
this manner, there need be little fear of any considerable deposition of tar, 
for the product of distillation flows back upon red-hot coal, and is so com- 
pletely decomposed, that the tube, thirty feet long, used by us for a period of 
twelve hours in collecting the gases, scarcely contained a trace of tar, although 
its temperature was not sensibly higher than that of the surrounding air. 
