THK MKI/I'INc; POINT OF CAST IRON. 351
above 2,600 degrees P. In this way the results noted in the tables below were obtained.
" It took much patience, a loss of a few samples, and a number of broken tips to accomplish all this, but on the whole the results given are as good as could be gotten under the conditions prevailing. The coke burning up would let the iron drop a little, and a failure to adjust the pyrometer to suit (the opening being closed by a piece of sheet iron, to prevent undue cooling by air drawn in), meant a break in the tip, which, while not affecting the results, caused subsequent delay and trouble.
"The following general observations were made. The white irons held their shape, the iron running from the sides and bottom freely, leaving smooth surfaces. The gray irons became soft, dropped in lumps, leaving a ragged surface. Fcrro-mangancse samples became soft and mushy, exhibiting a consistency of putty before finally running down. Perro-tungsten behaved in the most marked way. As it melted it aeted like white iron, but instead of chilling quickly it ran through UK: coke, coining down the spout in thin streams like white hot quicksilver, only setting after collecting in a pool in the pan of sand. (The above description of melting points of white and gray irons was verified by other members, though under different conditions.) The cupola was fluxed heavily with flu or spar to take care of the ash, for it was a case of a furnace full of incandescent coke and only one piece of iron in it."
The following tables give the results. For inciting points of other metals than shown in. this chapter, see Table 134, page 593.nald, of the Crescent Steel Co.which runs back, parallel to the platinum wire, to the terminal box. Both wires are covereda short time, compared to that generally occupied in ordinary shop practice. The longer heated or semi-molten iron remains in contact with incandescent fuel or is exposed to gases, the more sulphur will be absorbed — up to the limit of the iron'sding its mate.. 2111 3Os i m. mi 3os 3OS. 3111. im ^os Jill l^S i in.