114 
Philippine Journal of Science 
1919 
Table I . — Analyses of raw materials. 
[Numbers give percentages.] 
Lime- 
stone. 
Silic 
1 . 
ate. 
Loss on ignition _____ _ _ _ _ __ ___ 
42. 88 
5.77 
3.24 
0. 68 
53.76 
61.35 
Iron oxide (Fe203) - ___ _ 
0.30 
6. 84 
4. 82 
Aluminium oxide (AI 2 O 3 ) _ __ _ _ _ _ __ 
0.34 
22.88 
18.46 
Calcium oxide (CaO) _ _ _ _ _ _ . _. 
54. 72 
5.41 
5. 22 
Magnesium oxide (MgO) __ _ __ __ _ 
0.56 
1. 88 
2.72 
Sodium oxide (NasO) ... - - 
0.60 
1.65 
2.26 
Potassium oxide (K 2 O) ' - 
trace 
1.84 
1.95 
Sulphuric anhydride (SO 3 ) - ------ 
trace 
trace 
trace 
On analyzing a number of samples by the four methods men- 
tioned above and calculating all results to percentage calcium 
carbonate, the agreement was not satisfactory. The analyses of 
ten samples are shown in Table II. Most of these were prepared 
in the laboratory from samples of the raw materials, dried and 
ground to pass a 200-mesh sieve. These are only a few of many 
comparative analyses that have been made from time to time. 
Table II. — The analyses of raw mix by several methods. 
[Numbers give percentages.] 
Sample No. 
By titration 
with potas- 
sium perman- 
ganate. Total 
calcium is cal- 
culated to cal- 
cium carbon- 
ate. 
By calcimeter. 
Total carbon 
dioxide is cal- 
culated to cal- 
cium carbon- 
ate. 
By acid-alkali 
titration. Total 
alkalinity is 
calculated to 
calcium car- 
bonate. 
Matter insolu- 
ble in hydro- 
chloric acid 
with density 
of 1.125. 
1 
54.40 
51.25 
53.03 
22.30 
2 
62.30 
59.42 
61.31 
17.25 
3 
66.50 
64.00 
65.35 
16. 10 
4 
76. 80 
76. 00 
76.26 
11.20 
5_ 
77.80 
77.25 
76.30 
21.68 
6 
78. 00 
77. 00 
76.30 
21.82 
7_ 
79.60 
78.63 
78.88 
11. 04 
8 
83.00 
83.08 
81.71 
8. 10 
9 
84. 40 
84.17 
83.22 
7.00 
10 
86. 50 
86.00 
85. 14 
6.70 
CAUSES OF ERROR 
In any analytical procedure certain errors of the process it- 
self — such as inexact calibration of apparatus, slight solubility 
of precipitates, difficulty of complete washing, and the like — can- 
