LINING AND DRYING OF FURNACES.
Methods of lining- a furnace and the shape of the bricks have as much to do with the life of the lining as other qualities defined in this chapter. It is very expensive to line a modern furnace, and when completed it should give, at least, a continuous service of two years with hard ores and three years with soft ores, and this length of service may often be doubled. When it is stated that 450 tons of fire-brick and 60 of fire-clay, or a heavily laden train of about twenty-five cars of material, are necessary to line such a furnace as seen in Fig. 10, the magnitude of such a job, as compared with lining even our largest cupolas, can be readily perceived. Bricks for a furnace are largely made to order, so as to neatly fit its curves, slant, or circle which the form of the shell or inside of the lining, etc., may exact. This is done so as to have all joints fit as closely as possible without cutting bricks or filling in the clay. Bricks of a softer quality than those used for the stack portion of the furnace are desired for the hearth and bosh, as the former are exposed to greater destruction from friction, while those in the hearth and bosh portion are chiefly subjected to the action of heat. Such a quality, if used in the stack portion, though its composition is best able to withstand the heat, would soon wear away by the's lot is by no means one any need envy, for he shares very fairly the troubles and dangers he has who " meddles with hot iron."n some of the many coolers which are built in the furnace lining to preserve its life. In the furnace shown these are placed in layers about thirty inches apart in height, and has about two feet of space between them. vSome furnaces have them built much closer than this, both in heighte metals are jf|V