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LOSS   OF    IKON    IIV   OXIDATION    IN   CUPOLAS.           319
This table, it was contended, showed the remarkable accuracy attained with even such small heats. Mr. Uehling in explaining the reason why chilled pig would not waste as much as the sand pig, said it was due to the fact that a slight format ion of oxide of iron in the case of the sand pig would immediately cause a slagging action, the iron thus being absolutely lost, whereas in a chilled pig the oxide coming in contact with incandescent carbon, fuel would be reduced back to iron again. Here also, lie said, would come the advantage of plenty of fuel to keep the ilame as constantly up to the reducing action as possible.
The following data was first presented by the author
before the Western Found rymen's Association April 18, 1^94. Iron is lost by being carried off with slag as well as by oxidation in a cupola. The author was led into an investigation of this subject on account of the peenliarities in slag foaming which came from three successive large heats, and was never known to occur before in the cupola used. In analy/.ing the slag to discover, if we could, the eanse of the slag foaming, we also took note of the iron it. contained. The slag coming from one of the foaming heals, when analysed, was found to contain an oxide of iron equivalent to 26.80 percent, metallic iron. In addition, to this there was i.c;7 percent, of very fine shot iron in the sample of slag selected, whieh was an average of the whole heat. Tin's, no doubt, was from droppings of melted iron, which elsewhere t han at the slag hole would have greatly found its way to (he bottom and constituted part of the liquid metal to br drawn off at. each tap. The fine shot5   "      "         u the heavier or sandless gray roll iron. While this is shown as such, it doeslate obtained.        .           ,      '    S<> Ibs,	sy Ibs	<jl Ibs	fi Ibs