HO The Philippine Journal of Science ms 



The presence of such a proviso fails to eliminate the possibility 

 of a personal motive or prejudice in selection. Furthermore, the 

 rejection of all cements except those of established reputation 

 would practically place the consumer at the mercy of present 

 manufacturers. 



On October 30, 1912, the cement specifications of the Govern- 

 ment of the Philippine Islands were again changed by Executive 

 Order No. 75, and now they conform to the 1912 specifications of 

 the United States Government. As there are no vital differ- 

 ences between the latter and the specifications of the American 

 Society for Testing Materials, the change can not be regarded 

 as beneficial. 



During these six years, the quality of the cements received 

 was equally as unsatisfactory. The records of this Bureau 

 show that : 



(1) The best products received from different manufacturers 

 varied considerably in character and efficiency. 



(2) While in certain instances different shipments from the 

 same mill showed a remarkable uniformity in quality, in others, 

 we have met with sound and unsound, slow and quick-setting 

 cements, and cements which developed both low and high 7-day 

 tests, the value of which was no criterion of the ultimate 

 strength. 



(3) At times several shipments showed an apparent inten- 

 tional decrease in efficiency. New cement factories, especially, 

 have been known to submit very good material at first, and then, 

 as soon as their product had gained a suitable reputation, to 

 cut down grinding and burning expenses and market an inferior 

 product. 



The differences between different brands of high-grade cement 

 is readily accounted for. I have inspected many large plants in 

 Asia, Europe, and America, and have found adequate reason 

 in local conditions for the peculiarities of many products which 

 laboratory tests had revealed. The quality of the best product 

 from any mill depends more or less upon the nature of the raw 

 materials used, the processes of manufacture employed, and the 

 influences of various factors on the cost of production. For 

 instance, a uniform shipment, whether good or bad, was always 

 associated with large storage bins for the ground cement. On 

 the other hand, the cement received from one factory, where 

 the storage capacity was so limited that the cement was packed 

 almost as soon as it left the grinder, usually showed considerable 

 variation between successive samples taken from the same ship- 

 ment. It is evident that variations in the product of the grinders 



