276 GEOLOGICAL SURVEY 
say, that from 55 to 65 per cent. of the combustible matter placed in the furnace, is carried off in the 
form of gaseous matter, so that only the remainder of the heating value of the fuel is actually con- 
sumed in the process of smelting. 
To economise this vast loss, a simple plan is adopted; in the upper part of the furnace, where the 
fuel is not yet ignited, a cylinder of iron is placed, and sustained by stays, a short distance from the 
brick work ; the gases meeting with less resistance here, than in passing through the solid materials 
placed in the furnace, they rush into this empty space between the cylinder and brick work. Flues 
lead from this space into iron chambers, where they unite, and from this the gas is delivered by 
nozzles into the puddling and other furnaces; the chimney of the furnace being sufficient to draw 
in the gases from the chamber; and in this way the fuel consumed in the high furnace is found suf- 
ficient for the conversion of the ore into bar iron. 
There is some difference in the quality of the iron produced by the hot and cold blast, but it is too 
trifling for comparison with the vast saving of fuel effected, especially when we consider the quality 
of the ores of this region, and that charcoal is the only fuel used. 
There seems to be a tenfency, at some of the works, to return to the old Catalan forge or bloom- 
ery, and certainly if such a retrograde movement be at all admissible, it is here, where we have the 
ores best adapted to this primitive mode. The black, granular magnetic ores, that, when broken, 
present a dull, and not a metallic lustre, are composed, for the most part, of the protoxide, and are 
easily reduced, because they contain, as already stated, less oxygen. 
Mr. Swann, the superintendent of the King’s Mountain Iron Works, has applied, with great appa- 
rent success, the hot blast to these forges. The air is heated by surrounding the forge with a con- 
torted tube, through which the air is blown. 
The result of this operation, as compared with that of the high furnace, is sufficiently remarkable 
to be presented here. 
Cost of blooms* from 3000 lbs. of pig iron, by the cold blast high furnace. 
For producing 3,000 lbs. pig, at 1 cent, - - - - - - $30 00 
180 bushels charcoal, at 4 cents, - - - - - - - 7 20 
Refining, &c.  - - - - - - - - - - 5 00 
Total - - - - - - - - - - - $42 20 
3,000 lbs. of pig will make 2,000 Ibs of blooms, and these, when rolled, produce 1,666 Ibs. of bar 
iron. By this process, then, the production of 2,000 Ibs. of blooms costs $42 20. 
Cost by the hot blast bloomery, of the same. ° 
Raising and carriage of ore for 2,000 Ibs. of blooms, — - - - - $9 00 
200 bushels charcoal, at 4 cents, - - = = = : : 8 00 
Cost of blooming, - - : : : : 3 = é - 666 
Washing ore, - - = - = : : Es. “ 1 00 
Total, - - “10 hts - - - - - =) (=!) 16 91G24 66 
Here, then, it seems that the entire cost of the blooms, by the hot blast forge, is not as much, by 
six dollars, as the bare cost of the production of the pigs, by the high furnace. The only item 
* The term blooms is applied to the iron prepared for the rolling mill. 
