382 



cox. 



Physical properties. 



Water 

 added to 



give a 

 workable 



paste 

 (per cent 



total 

 weight). 



Tensile strength. 



Shrinkage (per cent). 



Color. 



Air dried. 



Burned. 



Air. 



Fire. 



Total. 



Air dried. 



1 



Burned with free 

 access of air. 



Kilos 

 per 

 square 

 centi- 

 meter. 



Pounds 



per 

 square 

 inch. 



Kilos 

 per 

 square 

 centi- 

 meler. 



Pounds 



per 

 square 

 inch. 



36.4 



>0.15 



>2.2 







14.0 



17.5 



31.5 



Dark red _ 



Verj" dark red. 







This clay on burning gives a very dense, hard body and a good paving 

 brick might possibly be manufactured from it by recomposing it to 

 increase its tensile strength and overcome its cracking in the air. 



MOUKT MAQUILING REGION. 



The clays of this region are the only true kaolins that I have seen 

 in Laguna Province. The knowledge of their existence dates back to 

 Spanish times, but their extent is not known. The outcrops in all of 

 these deposits have been very much worked over and in such a manner that 

 it is not easy to obtain very many particulars concerning them. The 

 laborer digs a hole through the overburden just large enough to admit 

 his body; when he reaches the kaolin he buiTOws it out in ever}' direction 

 as far as he can without danger to himself. When he has exhausted one 

 hole he goes a little farther and digs another. Sometimes the strippings 

 from the second hole have been thrown into the first and even when this 

 has not been done, since the deposits are in all cases on the mountain side, 

 slides and washes have filled all the old workings and it is impossible to 

 estimate either the amount of overburden or the extent of the deposits. 

 Only systematic boring or the uncovering of a large area can determine 

 this. 



LOS BANGS. 



This deposit is 6 or 8 kilometers from the lake, southeast of Los Banos 

 on the mountain side above Bagong Bola Creek. This is the only 

 deposit known to the natives and is reached by a verj' poor trail. The 

 highest point on the trail is about 370 meters, while the deposits are 

 about 350 meters above sea level. The natives say that no clay has been 

 taken from this point since Spanish times. One man informed me that he 

 formerly made e.xcavations here and that many of the pits were dug to a 

 depth of five rrieters. There are scores of holes partiality or almost 

 completely filled by wash ; their existence indicates that the deposit extends 

 over a considerable area. In several places there are appearances of an 

 outcrop, but closer examination shows them to be only excavated mate- 

 rial cast aside by the miners and proves that no superficial examination 

 can possibly reveal much regarding the thickness or extent of the deposit. 



I opened 'up two of the old pits which I thought perhaps representa- 



