In addition, the blast-furnace uses a very cheap source of energy, coke, anthracite, charcoal, and even certain kinds of raw bituminous coal, and owing first to the intimacy of contact between this fuel and the ore on which it works, and second to the thoroughness of the transfer of heat from the products of that fuel's combustion in their long upward journey through the descending charge, even this cheap energy is used most effectively.
The next great improvement in blast-furnace practice came in 1811, when Aubertot in France used for heating steel the furnace gases rich in carbonic oxide which till then had been allowed to burn uselessly at the top of the blast furnace.
The first blast-furnace in the colony seems to have been owned by Governor Spotswood, and was built and operated at the head of the Rappahannock river about 1715 by a colony of German Protestants.
Each blast-furnace is now provided with three or even four of these stoves, which collectively may be nearly thrice as large as the furnace itself.
This pours into them the molten cast iron which it has just received directly from the blast-furnace.
- On its way from the blowing engine to the tuyeres of the blast-furnace, the blast, i.e.
A, Ladle bringing the cast iron from the blast-furnace.
The numerous converting mills which treat pig iron made at a distance will now have the crushing burden of providing in other ways the power which their rivals get from the blast-furnace, in addition to the severe disadvantage under which they already suffer, of wasting the initial heat of the molten cast iron as it runs from the blastfurnace.
Like the Siemens furnace, described in § 99, they have two distinct phases: one, " on gas," during which part of the waste gas of the blast-furnace is burnt within the stove, highly heating the great surface of brickwork which for that purpose is provided within it; the other, " on wind," during which the blast is.