from the time they are started until the interior lin ing is worn out, and the furnace has to be "blown down" to receive a new lining. Since the stopping of a furnace and the building up of the inner lining are extremely costly, it becomes a question whether the best economical results are obtained by driving the furnace at a moderate �peed, and thereby prolonging its life, or driving at extremely high pressure, with a view to securing a very large annual output, and making repairs at

more »

... ingly frequent intervals. British practice favors the first method, American the second; our ironmasters believing that since" a lin ing is good for so much pig, the sooner it makes it the better." The difference in practice is shown by the fact that whereas the largest Middlesbrough furnaces, with a capacity of 36,000 cubic feet each, produce only 950 tons of pig iron per week per furnace, the Duquesne furnaces, with a capacity of 25,000 cubic feet, have pro duced 4,200 tons per week. Of course, the life of the American furnaces, working under this terrific pres· sure, is very much shortened, lasting on an average only four years, as against one case where the lining of a British furnace lasted eighteen years. Another broad distinction between British and American furnaces is sententiously expressed by The Times correspondent, when he says" nothing seemed to me more notable at the Duquesne Works than their loneliness." He further says: "Had it not been for the su bdued hum, characteristic of a furnace in blast, one might have thought that the works were shut down," -so complet�ly had mechanical appliances taken the place of hand labor. In the production of steel ingots, rails, plates, etc., from the mine to the mill, the Ameri· can instinct for labor-saving has been followed even to detail. From the iron mine in Minnesota to the ship ment of the finished product on the cars at Pittsburg, the American iron master does not expect any hand labor to appear in the whole process of manufacture, the single exception being the filling of the buckets which take the ore out of the ship on the lakes, for' which spadework is employed. Of course, as has been suggested above, one great ad· vantage enjoyed by American steel manufacturers is the extraordinary richness and accessibility of the iron ore in the Lake Superior region, immense masses of which lie on the slopes of the hills, covered only by a thin layer o[ suriaee soil. A railway track, quickly laid over the surface oftl1eground, brings into operation a steam shovel which, digging up lhe ore at the rate of five tons to the shovelful, at five strokes will fill a 25·ton ore car, and will load a train of cars at the rate of 600 tons an hour. The significance of such work as this, III connection with mines so extensive and rich, will be morf' fully appreciated when we remember that in the Mesaba range alone there are in sight 400,000,000 tons of iron ore. •••••