METALS. 
671 
never to have revived ; for even so late as the year 1747. 
Mr. Mason says in the Phil. Trans. several attempts have 
been made to run iron ore with pit coal, but he thinks it 
had not then succeeded any where, as no account of its being 
practised had been published ; but Mr. Ford from iron ore 
and coal, both got in the same dale, makes pig iron brittle or 
tough as he pleases ; there being cannon thus cast so soft 
as to bear turning like wrought iron. 
Oflate years, coke has been used extensively in England, 
for smelting iron ores ; particularly the clay iron ore. 
which lies in beds between the coal itself. As these fur 
naces are usually blown by machines moved by steam en 
gines, these iron works can be established in places where 
there is no stream of water. Coke requiring a stronger blast 
than charcoal to excite a great heat, it is very usual to have 
two blast holes. 
Fig. 297, represents the vertical section of a coke high furnace at 
Koenigshutte, in Silesia; and fig. 298, is the plan of the same. In these 
figures, e is the internal lining of the fire room, which is 50 feet high, 
and 12 feet wide at the boshes, while the crucible is only 2 feet wide, and 
8 feet high. G, are the archways of the twyer or blast pipe. H, is the 
archway of the tymp. I, are strong iron bars to support the main mass 
of the furnace, over the archways of the two twyers and the tymp. K, 
are strong iron hoops, which bind the furnace, and prevent its bulging 
or cracking. V, is the mouth of the furnace ; «, is the trough to convey 
the metal to the moulds when the furnace is tapped; and y, are the cast 
iron pipes, by which the blast is conveyed from the blowing machine to 
the twyers, which are not placed exactly opposite to each other. 
In the smelting house where this furnace is used, the ore 
is a mixture of about 72 parts of brown iron stone, and 28 
of common clay iron stone, to which are added about 20 of 
lime stone : 100 of the mixed ore produce about 33 of cast 
iron. The blast used, is 1220 cubic feet of air by the 
minute, with a pressure of five feet of water. The furnace 
is generally worked for 40 weeks, and then requires the fire 
to be blown out in order to repair the crucible. The average 
produce is 423 Cwt. of iron by the week; each 100 pounds 
of which require the consumption of 308 pounds of ore 
243 pounds :8 of coke weighing 31 pounds •4 by the cubic 
foot, and 68 pounds of limestone. 
In a work at Gravenhorst, where meadow iron ore is 
smelted, the height of the furnace is 36 feet, its breadth at 
the boshes, 9 feet 1, and the weekly produce of iron, is 225 
Cwt. of cast iron, every 100 pounds of which requires the 
consumption of 290 pounds :8 of ore, 69 pounds of lime 
stone, and 417 pounds :5 of coke. 
At Creusot, in France, furnaces of about 40 feet in height