118 



Philippine Journal of Science 

 Table V. — Typical aiialysis. 



1919 



Constituent. 



Calcium oxide combined as calcium carbonate -. 



Calcium oxide in other compounds 



Carbon dioxide combined as calcium carbonate . 



Carbon dioxide in other compounds 



All other constituents 



Acid-soluble portions of silicate 



Percent. 

 42.08 



1.23 

 32.99 



0.46 

 23.24 



Equiva- 

 lent to 

 calcium 

 carbon- 

 ate. 



Percent. 

 75.05 



2.19 

 75.05 



1.37 



0.65 



The square represents the composition of a sample of raw 

 mixture having the analysis given in Table V. The calcium 

 oxide combined as calcium carbonate and the carbon dioxide 

 combined as calcium carbonate are drawn to scale. The calcium 

 oxide and the carbon dioxide in compounds other than calcium 

 carbonate are exaggerated five times to make them more easily 

 seen on the diagram, and the rectangle representing all other 

 constituents is made proportionally smaller. The rectangles /, 

 g, h, and i at the right of the square represent the results that 

 would be obtained by analyzing the sample by four different 

 methods. The shaded portion of each rectangle shows the con- 

 stituents on which the result is based, and the total area (ex- 

 cept in i) shows the calcium carbonate content as calculated 

 from this result. In / the total calcium, in whatever way com- 

 bined, is determined and calculated to calcium carbonate. This is 

 taken as correct, since we are concerned only with the calcium 

 present and not with the carbon dioxide. In g the total carbon 

 dioxide, in whatever way combined, is determined and calculated 

 to calcium carbonate. With respect to the carbon dioxide, the 

 result is slightly too high, because it includes the carbon dioxide 

 not combined as calcium carbonate. However, the calcium pres- 

 ent in the silicates is omitted. In h the total carbon dioxide is 

 likewise included ; but, in addition, a portion of the calcium and 

 of the iron and aluminium in the siliceous materials have acid- 

 consuming power. Theoretically, the analysis of this sample 

 would be as follows : 



Calcium carbonate. 

 Per cent. 



By permanganate titration 75.05 -f- 2.19 s= 77.24 



By calcimeter 75.05 + 1.37 ss 76.42 



By acid-alkali titration 75.05 + 1.37 + 0.65 e= 77.07 



