154 



The Philippine Journal of Science 



Table VI. — Analyses of residue after completion of solubility determi- 

 nations. 

 [Numbers indicate percentages.] 



Lesson ignition 



Silica (Si02)- - 



Alumina (AI2O3) .-- - 



Iron oxide (Fe203) .-- --- 



Calcivun oxide (CaO) 



Magnesium oxide (MgO) 



Sulphuric anhydride (SO3) 



Sodium and potassium oxides (Na20, K2O) 



14.26 

 2.36 



45.12 

 1.86 

 0.35 

 0.44 



28.64 

 34.57 

 13.40 

 3.17 

 45.45 

 2.65 

 0.18 

 0.50 



25.26 

 32.36 

 10.30 

 5.16 

 49.00 

 2.20 

 0.53 

 0.32 



26.24 

 33.10 

 10.12 

 4.80 

 48.90 

 2.27 

 0.25 

 0.54 



Comparing this with Table III it may be noted that the re- 

 moval of calcium by solution has considerably raised the per- 

 centage of aluminium, silica, and magnesium in the residue. 

 The percentage of iron remains about the same, but the per- 

 centage of sulphuric anhydride and alkalies is less because of 

 the high percentage of each of these going into solution. 



The next point investigated was the effect of a larger volume 

 of water per gram of cement. Would this affect speed of solu- 

 tion or the final quantity of constituents in solution ? The same 

 volume of water was taken in each case, but less cement — 

 2, 1, 0.5, 0.25, 0.1 gram, respectively. The volume of water 

 present per gram of cement was then calculated and, neglecting 

 the decimals, the values are shown in Table VII. 



Table VII. — Effect of the volume of water on velocity of solution and total 

 amount of calcium dissolved in twenty-four hours.'' 



Volume 

 of water 

 per gram 

 of ce- 

 ment. 



I. 



II. 



III 



. 



IV. 



Time re- 

 quired 

 for con- 

 stant re- 

 sults. 



Daye. 



e. c. 



a. 



Per cent. 



0. 



Per cent. 



g. 



Per 

 cent. 



a. 



Per cent. 



432 



0. 1282 



29.84 



0. 1432 



32.12 



0. 1519 



34.37 



0. 1535 



34.52 



12 



864 



0. 1537 



35.14 



0. 1857 



41.63 



0. 1816 



41.07 



0. 1816 



40.84 



12 



1,727 



0. 1993 



45.60 



0.2407 



63.96 



0.2444 



55.27 



0.2334 



52.48 



1 



3,454 



0.2707 



61.92 



0. 2934 



65.79 



0.2934 



66.36 



0. 2690 



60.48 



1 



8,635 



0.4038 



92.41 



0.3907 



87.68 



0. 4038 



91.36 



0. 3855 



86.65 



1 



■ The first column under each number shows calcium dissolved per gram of cement ; the 

 second shows the percentage dissolved of the total calcium present (in 1 gram of cement). 

 With 432 and 864 cubic centimeters of water, respectively, the solution continued to increase 

 for a number of days, but with the other three volumes, the results were constant after the 

 first twenty-four hours. 



