518 GEOLOGY OF OHIO. 
It will be seen that the consumption of charcoal in the Hanging 
Rock region is large. The reasons for this may be found in several 
causes—the imperfect roasting of the ore, the low grade of the ore, and 
the dimensions and lines of the furnaces. The furnaces of the Hanging 
Rock region are short, and probably promote the escape of gases over- 
charged with carbonic oxide. To investigate this matter the analyses 
and figures given before will be used as a basis for a calculation of the 
heat requirements and fuel consumption of the furnaces. Analysis of 
the gas would be necessary to settle the questions involved, but a partial 
examination may be made as follows: referring to the former calcula- _ 
tion, 1 ton of pig-irop containing 1,880 pounds metallic iron was made 
with about 2,250 pounds of carbon; of this 70 pounds went into the iron, 
leaving 2,180 pounds as fuel, from the combustion of which the heat of 
the furnace is maintained, with the addition of what heat the hlast 
supplies. 
The heat requirement of the furnace does not admit of exact 
calculation, but it can be approximately determined per ton of iron as 
follows : 
(A.) Reduction of iron ore: This has been carefully investigated 
by Bell, Gruener and others, and the accepted result may be taken at 
about 1,800 units per unit of iron, or for 0.94 of a ton, 1,692 units, 
the unit taken being the heat required to heat one ton of water, 1° cen- 
tigrade ; this ton unit will be used to avoid large numbers, the relation 
being the same, whether the ton or pound be used. 
(B.) The heat required in fusion of iron and slag: The heat 
represented by a unit of iron, at the temperature of the furnace, is de- 
termined by Bell and others to be about 330, and by a unit of slag, 550. 
This gives— 
HOY Ue Com OLA rOT se sears hace dees tek Ee een eae 330 units. 
Flor: 1.05 slagy css scsascsasteel a tocceeseones a acacceste sonteoescesasineteneces Hy 
Lo) 71] Dus RR ERE OR ARE ORES oer bcouh 9072.8 
(C.) For reduction of silicon, manganese, etc: The expulsion of 
the carbonic acid from the limestone, and the evaporation of 8 per cent. 
of water from the charcoal, will require a total of 650 units. 
(D.) The loss through walls of furnace, etc., will be smaller than 
in the iron mantle furnaces, but assuming the figures found for such 
