Scoria
The cinder and slag rejected after the reduction of metallic ores, or the superfluous matter of metals in fusion. See SLAG. Scotch Pig Iron is a brand of iron that in the past has been highly esteemed by founders almost everywhere for its softness and fluidity, as well as for the particular quality of retaining its heat when melted for a much longer time than most other irons. This remarkable iron is made from ores and coal eminently adapted to the production of No. 1 irons. The particular quality of fluidity which it possesses is owing to the presence of a large proportion of phosphorus; but many of these brands are high in both manganese and combined carbon, which renders their use for strong castings that have to be tooled very undesirable. When these irons have been low in the latter-mentioned elements and correspondingly high in silicon and graphitic carbon, they have been unquestionably successful as softeners; but the following comparison of a cheap No. 2 American with a high-grade Scotch iron will show that our domestic brands are far superior as softeners--a fact that is becoming more widely known by foundrymen, as the decreased imports testify. This shows the softening element, silicon, to be much higher in the American brand--while phosphorus, manganese, and combined carbon, all hardening, are almost absent by comparison with the Scotch. See SOFTENERS; SILICON. Silicon. Phosphorus. Manganese. Sulphur. Graphite. Com. Carbon. American No. 2. 3.81 .49 .15 .04 3.26 .04 Scotch No. 1. 1.70 1.10 1.83 .01 3.50 .40