The slag was quite liquid and flowed very well at all times. However, there was a marked variation in the amount at different tappings. This, I am satisfied, was not due to irregular work on the furnace, but may be accounted for in the following manner. The residue (not screened or weathered to any extent), consisting approximately of one-half coal and coke, was very bulky, and while there was about 35 per cent. of it on the charge by weight, there was over 50 per cent. of it by bulk, not including slag and coke. In feeding, therefore, it was a difficult matter to mix the whole of it with the charge. Several different ways of feeding the furnace were tried. The one giving the most satisfactory results was to feed nearly all of the residue along the center of the furnace, in connection with the lime-rock, coarse ore and coarse iron ore, and the fine and easy smelting ores along the sides. The slag was spread uniformly over the whole furnace, while the sides were favored with the coke. The charge would drop several inches at a time, going down a little faster in the center than on the sides. It is possible that a small proportion of the residue in connection with the easy smelting, leady, neutral ore, iron ore and lime-rock formed the type of slag marked No. 1. ───┬───────┬──────┬─────┬──────┬─────┬─────┬──── │ SiO₂ │ FeO │ MnO │ CaO │ ZnO │ Pb │ Ag ───┼───────┼──────┼─────┼──────┼─────┼─────┼──── 1 │ 33.7 │ 34.1 │ 1.0 │ 16.5 │ 7.5 │ 0.9 │ 0.7 2 │ 31.0 │ 36.1 │ 1.2 │ 16.0 │ 9.6 │ 1.3 │ ───┴───────┴──────┴─────┴──────┴─────┴─────┴──── This being tapped with a good flow of slag, the charge would drop, bringing a proportionately large amount of residue in the fusion zone which formed the type of slag marked No. 2. There was also a marked variation in the slag-shells from different pots. The above cited irregularities of course exist to a certain extent in any blast furnace. AVERAGE ANALYSIS OF MATERIALS SMELTED NAME ROW NAME ROW Mo. iron ore A Roasted matte[15] F Lime rock B Barrings G Mo. galena C Coke ash H Av. of beds D Coke[16] J Residue[14] E