206 ^^6 Philippine Journal of Science ms 



limited kilometers of railroad, it is likely that only some locality 

 near water transportation could be considered. 



Fuel. — The high price of imported coal at present prohibits 

 its use in burning brick. Therefore, if a factory is to be 

 operated on an economical basis, it is desirable to locate it near 

 a deposit of Philippine coal or other available fuel. 



It would be very expensive to locate a large number of deposits 

 and obtain samples for the investigation except in conjunction 

 with other work. Thus far no systematic survey devoted ex- 

 clusively to brick materials has been made. Most of the samples 

 have been obtained at very little cost by members of the Bureau 

 of Public Works and of the Bureau of Science who were in the 

 field on other lines of duty. The Director of the former bureau 

 has kindly sent a circular letter to all district engineers, request- 

 ing them to keep a lookout for shales and clays and to send 

 samples of any promising material to the Bureau of Science. 



RESUME OF PREVIOUS WORK AT THE BUREAU OF SCIENCE 



Systematic investigation of Philippine clays was started at 

 the Bureau of Science by Cox.* According to the author, his 

 object was — 



rather to show in a preliminary way the geological distribution and quality 

 of clays on Luzon, than to pronounce on their economic value. 



In the course of his work he examined more than thirty 

 samples of clays, making chemical analyses and physical tests. 

 Study of his paper clearly reveals the general character of the 

 clays of Luzon. Some of the clays had already been used by 

 Filipinos and Chinese in the manufacture of brick and pottery. 

 The author says: 



The common clays of Luzon are already [1907] used in several places in 

 the manufacture of brick and crude pottery. For example, the brick- 

 kilns at Mandaloyon and the one near San Pedro Macati, on the Pasig 

 River near Santa Ana, each of which employs from ten to twenty laborers, 

 turn out from one to three thousand bricks a day per kiln. * * * No 

 sand is added to it before molding, but the whole bank is broken down, 

 mixed by the tread of carabaos, and used for the bricks. This makes the 

 composition slightly different * * * but tests of the shrinkage and 

 tensile strength show that its physical properties remain almost unchanged. 



In his second paper ^ the same author says : 



This investigation was undertaken at the request of the Bureau of 

 Education to enable it to choose a clay for use in the pottery school, the 



*Cox, Alvin J., This Journal, Sec. A (1907), 2, 413. 

 'Ibid., Sec. A (1908), 3, 377. 



