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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1908 Excerpt: ...irons nearly free from silicon. Indeed, it seems to me that this is all that can be done, because our data are too scanty to permit us to make a series of inferences, a first as to silicon-less irons, a second as to those with a moderate quantity of silicon, a third for those with somewhat more, and so on. § 47. Solubility at 500. Case 14 of Table I. indicates that the solubility falls to zero somewhere above 500. Here castiron containing initially 0.25 per cent, of graphite and 2.71 per cent, of agraphitic carbon, though it underwent no change on staying for 3 hr. at 500, had the whole of its combined carbon changed to graphite when held for 3hr.at 600 and cooled slowly. From the fact that no combined carbon changed to graphite at 500, in spite of the initial presence of 0.25 per cent, of graphite to act as a nucleus to start graphitization, I infer that it is probable that graphitization will not occur at temperatures as low as 500. Hence I infer that the complete change of the 2.71 per cent, of combined carbon into graphite, which occurred in the heating to 600 and cooling thence, must have occurred before the temperature had sunk as low as 500, and hence that the solubility must have sunk to zero at some point higher than 500. § 48. Indications that the solubility may be very low at a relatively high temperature. There are two facts which support the belief that the solubility falls nearly or quite to zero at a temperature at least moderately high. Of these, the first is the familiar one that many commercial cast-irons are practically free from agraphitic carbon, even if their cooling is not very slow.51 The cooling of the cast-iron in the sand mold in the casting-house of the iron blast-furnace is rarely extremely slow. In general, the pigs a...