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high, lest the zone of fusion be too thick. The running of blast furnaces with bituminous coal and light friable anthracite at many places has proven that high furnaces are not practicable for this purpose.
Under existing circumstances, therefore, the most promising outlook for the employment of brown coal in iron smelting would appear to be its use in the largest possible proportion with stone coal coke in the blast furnace process, and as producer gas in the further manipulations of the pig iron.
At Zeltweg, near Leoben, the Oesterreichisch-Alpine Montangesellschaft have two blast furnaces each of eighty tons capacity, fifty-five feet high, seventeen foot bosh, which have been run for many years with a mixed fuel of Silesian coke and raw brown coal from the mines in the vicinity. The lines of the furnace now in use are given in Fig. 5, with measurements in meters.
The amount of brown coal used is governed by the comparative cost of coke and coal at the furnace. When coke or freight rates are high, or brown coal decreases in price, a greater per centage of brown coal is used, but as stated before, the brown coal is sold at such a high figure as to prevent its being used to the extent which it would otherwise be. At times there are equal amounts of brown coal and coke used, and according to Prof. Kupelweiser, it has been found practicable to use a mixture containing as much as seventy per cent of brown coal; but the average of these furnaces, as furnished me by the secretary of the company, gives for different periods something over thirty per cent of brown coal used.
These furnaces have been in practical operation for more than ten years, and afford most positive proof that raw brown coal of proper firmness can be used advantageously in the blast furnace, in connection with coke, for the production of pig iron.
COKING.
Experiments in the coking of brown coal have been made at many different times both in Europe and America.
Speaking in general terms, it has not been found practicable to make a coherent coke suitable for metallurgical purposes from brown coal under the ordinary conditions observed in coking bituminous coal. It is true that once in a while a variety of brown coal is found which affords