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JI:IX;IN<; OF AND TKSTIN<:  MOI.TKN  IRON.         ^71
.1 spherules of iron arc ejected from all parts of the surface t- height of tlw <>r six feet, and sometimes higher, when they in- un<! separate with a slight hissing noise or explosion into a* many particles of brilliant lire, forming oxide of iron.
;ic blast funiaeeman can often tell very closely the ;tde " an iron will show by analysis when cold, "by ippraraiuv when lluid, and whate.ver ])ractical pals a foundtT can ntili/.c will, at sonic time or r, prove very hcni'iieial, especially in tv air fur-
" workings and lon^ " heats" in cupolas, for with latter there is a chance j*iven, if at the first im,;s iron proves itself radically \vrontf Lhroii^fh rrnu's in figuring analyses, or in char^in^* the
etc., to alter the charges in order t<> change the tile " of the metal before a heat is finished.ich can be termed hard iron and also can be strong and weak, have peculiarities very pronounced to distinguish them from soft grades or No. i irons. In the ladle, such irons will, when "hot," show a smooth, bright appearance, with hardly a break on the surface, and as the mass becomes cool or "dulls down," it presents a dull, hazy, plastic appearance, which, if disturbed by a skimmer or rod, will act as if it were covered with an oxide or scum. While hot, it will often boil in the ladle .as if bubbles of gas were escaping from below. It also emits many sparks, which is the chief characteristic phenomenon of hard iron and cannot be better explained than in the language of Tomlinson, who says: