Steam:
Its Generation and Use

Pittsburgh, Pa., and elsewhere, these boilers are fired with the waste gases of the blast furnaces with marked success. The combustion of the gas is perfect; the boilers develop mach more than their rated capacity ; and the dust contained in the gas has given no trouble. The manager of the Lucy Furnace says : ‘They are very free steamers, easily cleaned, and will do a given amount of work on very much less gas than our cylinder or two-flue boilers. They have cost nothing for repairs.” WEIGHT AND VOLUME OF AIR. A cubic foot of air at 6o° and under average atmospheric pressure, at sea level, weighs 536 grains, and 13.06 cubic feet weigh one pound. Air expands or contracts an equal amount with each degree of variation in temperature. Its weight and volume at any temperature under 30 inches of barcfmeter may be found within less than one-half of one per cent, by the following formula, in which W = weight in pounds of one cubic foot, V — volume in cubic feet, per pound, Babcock & Wilcox Boilers over Puddling Furnace. In rolling mills doing the heaviest and most irregular kind of work, the success of these boil- ers has been equally encouraging, and, in a number of the Bessemer Steel Works, they are supplying steam to reversing engines rolling steel ingots in two high trains, while several large plants supply power for rolling rods, bar iron, rails and beams, and drawing wire. The names of many extensive Iron and Steel Works, in some of which large plants have been in use for years, will be found in the list of references. and t absolute temperature, or 460° added to that by the thermometer, — t + 460. w-^°- v=-T- r 40 For any condition of pressure and temperature the following formulas are very nearly exact: W 2.71^. . V--T- ' . .t 2.71 V/> — 460 7 2.71/ 1 in which p is pressure above absolute vacuum. The same formulæ answer for any other gas by ( hanging the co-efficient.