Although the results given in Table 11- cannot be considered as final

JL-LIUS STIEGLITZ.

1112

Although the results given in Table 11-cannot be considered as final and will need confirmation, they indicate one or two rather interesting points. I t will be noticed that the silica, soluble in hydrochloric acid, increases with the increzse in the temperature at which the clinker is produced. T h e silica, soluble in sodium carbonate, however, reaches a maximum in sample No. 14, burned at 13j2". T h e total insoluble residue after treatment with sodium carbonatc, usually reported as "unclecomposed silicate," is smallest (0.54 per cent.) in this same sample. The amount of undeconiposed silicates secms t o increase ivith rise i n temperature above 13j2', and the proportion of silica given off 01: treating these undeconiposed silicates with hyh-ofluoric acid, is zbout one-half their Tveight. These results would go to indicate that probably all of the original silicates were converted into readily decomposable basic silicates by the time zc temperature o l 13j 2 ' ivas reached, and that the increased amount of unclecomposed silicates found in the high numbers may be due to the more acid silicates left i n the magma, from which the tricalcium silicate or other true cement-forming material has separated.

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