IRON MANUFACTURE. | 515 
carbonates of lime and magnesia, and 4.16 per cent. silicious matter and 
alumina, or in pounds furnished to the slag. There is as follows: 
SHGOWE MEKKRET? OH INTODEEROLG).4655000080000000000b00007500000N40080 bodon00G0D00000 30.4 lbs. 
Gimerandenniacnexiaroislimestonmelenicsietsccee scene sti crek cesses cele cocecee 389.1 “ 
MoO CMotrO MmipliMMEStOM Eyer ten aesccccecnnueceter er otes tesenes ness eeees eens 419.5 lbs. 
e ORE ee iscr senna nee aca ctoneen eee sceiiycutee est aoe ceenleed wssens 1662.0 “ 
‘ hel (EOP pEraceTits)) Mean senseceh ees ose aeacee oeacaos oe 42.6 “ 
Rotalislacstorminesmatenialseescspeeecsecssseesceaeees 2124.1 lbs. 
Deducting the silica, etc., absorbed by the iron (23 per cent.), it 
appears that for each ton of iron made the furnace makes about 1.05 
tons of slag. 
Owing to the hot throat of the furnace, and the short stack, it is 
probable that all the carbonic acid expelled from the limestone is con- 
verted into carbonic oxide. Assuming this to be the case, and also that 
about one-third the carbonic acid produced from the reduction of the 
iron ore by the gas is similarly reduced, the following account may 
be stated : 
Carbon in fuel per ton iron made (2.808 lbs. & .90 per cent.) = 2.554 lbs. 
Carbon required to reduce 304 lbs. carbonic acid in the lime- 
SCOTS Pee eee Nee ee ceases Ve cncnk sew coo suschsanesiecacestietacs vere’. 83 lbs 
One-third carbon required to reduce the carbonic acid from 
LINELO ESTE CUILCETOM cesar settee hacia dcteeets dosanaeaesnee cece eessch ess 20) 
Carbon lost in going through the furnace............. . 284 lbs. 
(CRA avo TH TROT, (GD JOE CSIWMES)) c50c0000000000900090005608400008 uo ™ 
Carbon to be deducted from the fuel used................-+0 354 Ibs. 
Or carbon actually burnt at tuyeres <%...............ceccececeees 2200 “ 
To burn this amount of carbon to carbonic oxide, 2933 lbs. of 
oxygen, or 176,000 cubic feet of air nearly, would be required at normal 
barometer and temperature. 
This then is the amount of blast needed to make one ton of pig- 
iron. To compare this with the blast engine record, it appears that one 
ton of iron would be made in 7/5 day, or 82 minutes. 
The capacity of each blast cylinder is 52.4 cubic feet nearly, or of the 
two about 104.8 cubic feet; hence this amount of air is taken in to the 
blowing apparatus at each stroke. Assuming 11 double strokes per min- 
