360 The Philippine Journal of Science 
not cause any serious loss in strength. In some instances there 
was an increase. 
The highest percentage of sulphuric anhy- 
dride, however, caused a decided reduction in strength. The 
three-year briquettes made with Cement E were cracked and 
partly disintegrated and could not be tested. 
TABLE 3.—Variation of percentage loss in tensile strength with the 
iron content, 
Tensile strength of 
five-year neat bri- 
° coaites, Saeees 
Ferric el Corre- 
evide sponding 
Cement. (Fez f Loss. loss for 
Os) Sodium sul- early 
m phide solu- period, 
Water.| tion con- 
taining 9. 
g. per liter. 
Lbs.per; Lbs. per \Lbs. per 
P. ct. | sq.in. sq. in. sq.in. | P. et. P, ct. 
Ba ee sa 1,12 546 446 100} 18,31 18. 56 
Be i eho ee ra, 1,34 457 897 60} 18.18 24.07 
WO ase csttnns BiG wecSesnk ase 1.38 597 447 150} 25.13 26.12 
Peete 5 Sake. ibe hed 659 445 214| 32.47 47,29 
