444 ' SMITH AND EDDINGFIELD. -T 



SiHca:^At one place on the Military Cut-off there is' "a deposit of 

 loose siliceous - sinter; -whiGh could be used in the making of sand-time 

 brick, for pottery glazing, or for glass. 



Sand-lime brick. — Eecently a large sample of the soft siliceous sinter 

 from the "Military Cut-off" road was sent to TV. C. Eeibling of the 

 chemical laboratoy, Bureiau of Science, who mixed it with lime and made 

 the material iato sand-lime bricks. Although the work as yet is only 

 preliminary, he has obtained encouraging results. 



Mr. Eeibling's work shows the possibility of the manufacture of good 

 bricks in Baguio, of these materials, and also the possibility of using Port- 

 land cement with greater economy on the Benguet road. Although some 

 Tarlac sand was used in making these briquets there was no need of it 

 as the Baguio sinter is practically nothing but silica (94 per cent). 

 Wherever a fairly pure sand and lime are available this process can be 

 used. 



Glass sand and pottery glazing. — There is the possibility of using this 

 sinter for tss'O other purposes, namely, for glass and for pottery glaze. 

 The present high price of glassware in the Philippines, particularly 

 window-pane glass, would seem to indicate a profitable undertaking in 

 this direction. 



Brick clay. — A good clay for making common red brick exists at several 

 points. The best locality is in Trinidad Valley. Another is ia tlie hollow 

 just below the Hotel Pines, but as this tract will be used as a park it will 

 be out of the question for this purpose. A pit deeper than the present 

 stream level will be needed to secure the clay in Trinidad Valley, as the 

 material above this level carries too much gravel. One sample which we 

 procured from the bottom of the large stream not far from the south end 

 of the valley is grayish yellow and verv' plastic. When tested by Alvia 

 J. Cox of the laboratory of inorganic chemistn-, of the Bureau of Science, 

 very satisfactory results were obtained, showing that there is, of a cer- 

 tainty, materials available for the manufacture of clay bricks in addition 

 to sand-lime bricks. 



It may at once be arg-ued that brick construction is not quite suited 

 to an earthquake country. As opposed to this idea, we can cite the ex- 

 perience in San Francisco. It is the opinion of more than one contractor, 

 that a reinforced-concrete structure is apt to be permanently warped 

 during an earthquake, and hence not the best type of construction. This 

 is not the case with bricks on a steel frame. 



Eoad metal. — For several reasons I have reserved the discussion of this 

 heading for a future article. A number of abrasion and cementation 

 tests have been completed on a variety of rocks from this region. 



