IRON MANUFACTURE. 517 
ute, the blast taken in 82 minutes will be that given by 22 x 82 = 
1804 strokes; and allowing 104.8 cubic feet to the stroke, there’ results 
189,000 cubic feet of air per ton of iron made, calculated from the 
capacity of the engine. 
The exact number of strokes of the engine is, of course, not a 
matter easily ascertained, and hence the above is only an approxima- 
tion as far as the engine calculation is concerned, but it serves to show 
the manner of calculation; if the analysis of the gas is made, the cal- 
culation controlled by the actual amount of carbonic acid in the gas, 
becomes exact on all sides. Knowing the blast entering the furnace, 
the gases can be closely calculated in volume; 176,000 cubic feet of 
blast would furnish about 211,000 of gas. The weight of this gas can 
be also exactly found, and will be given further on. 
The working of these charcoal furnaces, in regard to economy of 
fuel and yield of ore, may be illustrated by the following table, the 
figures for which were taken from the books of the companies. It will 
be seen that the consumption of fuel for the ton of iron produced is 
from 220 to 123 bushels. These furnaces represent all varieties of out- 
line and temperature of blast. 
The following table was kindly furnished by a charcoal furnace 
company at Ironton, Ohio, and gives results extending over a number 
of years, and is here inserted as of interest: 
= Ss 
! a |e 
eval covet dead falta 
Year. i 8 5 og 
Oo mo 
2 = OO Zour 
2 se & § ce 
o) a) eo =| 
H H <q PQ 
TERE. cclckal Aon ce ee a rere 11,3; 2,332 | 2.28 1.558 
NSC UPeees set occ seeeaccseasen sescescouesiussesecuceeaeuess 13.91 2,685 2.35 1.42 
SOS uses ee creme on eccse cs cocine seu etesce rete vetincasen 124 2,049 2.38 1.38 
SOO) roses cttcecuome Clee cesses clcsese atocaidledsssleseaNermsecs 125 4,011 2.38 1.42 
MNS OMreieest: sce taces voce cen sodte skies sub shnedsscneacees 13 2,899 2.68 1.48 
WS UMeerrescecasce eel, Wtiaeecdececsisesdesteseeseneedaesons 12.65 2,778 2.28 1.43 
MSU Baeae nes waccoe est wuets so seeuteececuenesss soeweseeees 124 3,219 2.24 1.53 
LS OMe ok tatascen owns siecacish socenivechoxereesecdses 12 2,634 2.53 1.69 
ES Aree coc setec ee ee cecta ee ecu eeu cue edeseunkteeed 16% 3,083 2.58 1.46 
LG Oieeeriecrecccecaaneccascsrcesessscresseesiesesec aces acces 143 2,978 2.57 1.43 
TRA 0) odocoG Be SeOOCC OCR EAR CBSA CISAR SEAS ACEC A GRATE 15.03 3,081 2.15 1.45 
