104 
Iron, 
the principle of its reduction. The oxygen of the iron- 
stone is longer in being removed : this requires an addi- 
tional period of contact. To procure this, the furnace 
must be heightened to 35 or 40 feet, and the descent of 
the materials protracted to three days. 
It will be proper to exhibit the comparative effects pro- 
duced by the char of pit- coal and that of wood. The fol- 
lowing particulars will serve as data to make a calculation 
of the relative effects of the tw 7 o different fuels with a char- 
coal furnace of 26 or 27 feet high, 9 feet wide at the boshes, 
and blown by two inch and three quarter pipes placed 
along side of each other at the tuyere of the furnace. To 
make forge-pigs with this furnace, the following propor- 
tions have by experience been found requisite for each 
charge : 
2 sacks of charcoal of 1 121b. each * 2241b. 
7 measures of well dried Lancashire ore, each 1121b. 784 
Raw iron-stone - ~ - 56 
Limestone - - - 14 
In 24 hours 18 of the above charges would have been 
consumed, and nearly 3 tons of forge-pigs produced. 
The total quantity of char used for the 
quantity would be - - - 2 x 18 = 36 cwt 
The total quantity of iron ore - - 7x18 = 126 
■ — of iron-stone - | X 18 = 9 
— — — — - — ■ of limestone - -J X 18 = 2|- 
We find therefore that 12 cwt. or 13441b. of the char- 
coal of wood, produces of forge pig-iron 22401b. or 1 
ton ; and that 126 cwt. of Lancashire ore 4. 9 cwt. of 
iron-stone, yielded of metal 60 cwt. This quantity, by an 
easy mode of calculation, will be found to be at the rate of 
44*4 per cwt. 
When carbonated crude iron was produced, the charge 
was, 200 cwt. of wood char, 5 cwt. of ore, 1-2 cwt. of 
iron-stone, 14 lb. of limestone. 
The weekly quantity was always diminished in pro- 
