DIFFERENT KINDS OF PIG IRON, ETC. 145
the casts of iron into different piles, according to the grade of the pig iron by fracture. The most open pigs went into piles as a No. i iron, the smaller grained as Nos. 2, 3, and 4 and upward, according as the grain decreased in size. The greatest care was exercised in thus grading iron, not only because it was believed that the size of the grain revealed the grade, but also because the £' grader '' had a reputation to sustain in making his various piles of even grain, and the furnace-man was anxious to have every piece of the open grained iron collected by itself; for No. i iron brought him more money than a No. 2. With the advent of selling by chemical analysis all this was changed. The graders were replaced by the chemists, and the iron as it comes from a furnace cast is now thrown into one pile or car, and neither furnaceman nor progressive founder as a rule pays any attention to the color or the size of the grain of iron in the pig. The different brands are now generally piled, by progressive furnace-men, according to the percentage of silicon and sulphur the iron contains, as they now concede these to be the elements or metalloids that vary the grade of any iron made from like ores, fuel, and fluxes — a system which was advocated by the author in earlier writings-, and the first edition of this work.
The different brands of pig iron are classed as foundry, charcoal, bessemer, gray forge, basic, silvery or ferro -silicon, mottled, and white iron.
Foundry iron is made with coke or anthracite fuel. Its silicon generally ranges from i.oo to 4.00, sulphur .01 to .05, manganese from a trace to 1.50, phosphorus from .20 to 1.50, and is a class of iron used in the construction of chilled as well as unchilled castings. analysis which may be given is simply an average of the whole, generally taken from the two ends andith the uncertainty of furnace workings when in urgent need of ten hundred jon of iron; and Sir........................ 2,720 "