NATURAL CEMENT VERSUS BRICK; IWAHIG PENAL COLONY 



RAW MATERIALS 



By W. C. Reibling 



(From the Laboratory of General, Inorganic, and Physical Chemistry, 



Bureau of Science, Manila, P. I.) 



One plate 



INTRODUCTION 



Although this investigation deals primarily with the value of 

 certain raw materials which are available for the manufacture 

 of brick and natural cement at the Iwahig penal colony, many 

 of the results obtained and the principles discussed are universal, 

 as well as local, in their significance and value. This is especially 

 true 'of the data on the manufacture of natural cement by the 

 so-called artificial process. 



Results obtained by using fine coral sand as the calcareous 

 material, while especially interesting to this country, are none 

 the less valuable to the cement industry in general. They show 

 the economic possibilities not merely of the Iwahig sand, but also 

 of vast resources of similar coral and calcareous sands which 

 heretofore have been practically overlooked by cement producers 

 although already ground fine by natural forces. The artificial 

 method of manufacturing natural (or Roman) cements is com- 

 paratively new, although advocated by A. V. Bleininger^ many 

 years ago as a practical method of overcoming the lack of uni- 

 formity in the setting and hardening properties of natural 

 cements. 



BRICK MANUFACTURED AT IWAHIG 



The history of the manufacture of brick at the Iwahig penal 

 colony shows that the industry was started at the suggestion 

 of Governor Evans. He had experience with brick making at 

 Bontoc, and believed that successful results could be obtained 

 with the clay located a short distance from the colony on the 

 banks of Iwahig River. The Iwahig bricks are made from 

 an alluvial clay obtained near the junction of Malatgao and 

 Iwahig Rivers adjacent to the penal colony. At first, the clay 

 was pugged by a homemade mill turned by a carabao, and the 

 bricks were molded by hand. Now, the clay is taken directly 



^Bull. Geol. Siir. Ohio (1904), 4, 186. 



163 



