280 FANNING. 
Mr. W. C. Reibling 2° states: 
Samples 3 and 4 can be combined to form an ideal mixture for the 
manufacture of Portland cement. Considering first their chemical composi- 
tion we find that a mixture of one part of sample 3 and 2.2 parts by weight 
of sample 4 will produce cement clinker of the following composition: 
Constituent. Per cent. 
CaO - 65.6 
SiO, 21.7 
Al.Os 7.0 
Fe.0; 3.1 
MgO 1.7 
According to European standards the hydraulic modulus should be 
about 2.0; that is, the content of calcium oxide should be twice as great as 
the sum of the percentages of silica, alumina, and ferric-oxide; the permis- 
sible variations ranging from 1.8 to 2.2. The hydraulic modulus of this 
mixture is exactly 2.0. Also, this mixture calculates almost identically with 
the formula obtained from the average American Portland cement, the 
latter being 1.10 CaO, 0.863 SiO., 0.074 Al.O:, 0.021 Fe.0; (allowing for the 
presence of 0.83 per cent CaO as sulphate), and the former 1.1 CaO, 0.363 
SiO., 0.116 Al.Os, 0.060 Fe-Os. 
The ratio of silica to alumina is 3:1. This ratio and the presence of a 
desirable quantity of fluxing material (3.7 per cent of Fe.0;) guarantees 
easy burning, the very small percentage of MgO (1.7) insuring no trouble 
from that source. 
Considering next the physical condition of these two materials, we find 
that they are both fairly soft and very finely grained; therefore, they can 
be ground into an impalpable powder at a low cost. The argillaceous 
material is free from irregularly distributed matter such as concretionary 
nodules of ferrous carbonate, calcium carbonate, etc., and would require a 
minimum amount of chemical work and would be an easily controlled raw 
mixture. 
The formation occurs in great thickness and is well adapted to 
easy quarrying. ‘The analyses made are so favorable as to war- 
rant further sampling and investigation. The splendid trans- 
portation facilities which can be developed in the Pangasinan 
area may make this region of merit equal to that of the other 
regions of the Islands now being investigated as possible sites 
for cement plants. 
* Chief, division of general, inorganic and physical chemistry, Bureau of 
Science. 
