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GRADING   PIG   IRON   BY   ANALYSES.                  149
2.75 to 3.00 per cent, of silicon and sulphur from .01 to . 04, with manganese below i. oo and phosphorus ranging from .30 to i.oo. Evidence of evils to come from the above practice of irregularity in grading pig iron by analysis can be found in Mr. Seymour R. Church's first edition of " Analysis of Pig Iron." In this work we find pig irons called No. i by their makers ranging in silicon from one-half of one per cent. (.50) to four per cent. (4.00). Furthermore, the wildest kind of confusion exists as to numbers and trade-marks, etc., supposed to designate the special qualities of the different grades of pig iron reported.
To correct this evil and to establish uniform methods for grading, the author presented a paper on the subject to the Pittsburg Foundrymen's Association, March, 1901: This paper embodied the table seen on page 152 and some of the arguments presented in this chapter. The Pittsburg Foundrymen's Association was so impressed with the importance of this work that a committee was appointed, with the author as chairman, to advance the work and carry it to the American Foundrymen's Association Convention at Buffalo, N. Y., June, 1901. To this end, circulars were issued regarding the work and replies requested as to opinion of the methods presented or suggestions for others. Fully two-thirds of the many replies received endorsed the author's method, shown in this chapter, and which differs only (Table 22) in permitting higher sulphurs in grades Nos. i to 3, whereas the original plan restricted it not to exceed .02 for No. i and .03 for Nos. 2 and 3. However, it should be born in mind that if sulphur reaches ".04 the silicon might often be required at the highest point of any oneled 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     "