384 



cox. 



Physical properties. 



Water 

 added 

 to give 

 a work- 

 able 

 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- 

 metep. 



Pounds 



per 

 square 

 inch. 



Kilos 



per 



square 



centi- 

 meter. 



Pounds 



per 

 square 

 inch. 



33.7 







8.44 



120. 



4.65 



4.25 



8.9 



Light grayish- 

 white. 



Bluish-white. 







» Crackles considerably. 



These three samples taken together may indicate that the material 

 is still in the process of formation and that formerly only the pockets 

 of the best clay were sought and worked out. Both the chemical and 

 physical characteristics of these two samples indicate them to be suitable 

 for use in the manufacture of a good class of pottery, but probably a 

 large amount of sorting would be necessary in the mining of the clay. 



CALAUBA. 



Two kaolin deposits are known in the region of Calamba; one in tlie 

 Pajo Canon and the other below Point Alipasio, overlooking the Santo 

 Tomas Eoad. 



A pony trail on the right side of the canon leads to the former; it is 

 steep in places but fairly passable in the dry season. This deposit is about 

 two or three kilometers from the lake and at an altitude of about 200 

 meters. There are outcrops on both sides of the caiion, but like those 

 of Los Banos, they have been disturbed imtil definite information 

 regarding them is difficult to obtain. The natives say that on the right 

 side of the canon the clay is the whitest that has ever been found. I 

 made several borings at spots indicated by men familiar with the deposit. 

 Some samples were white, streaked with black, perhaps vegetable matter, 

 but one was uniformly white. Since it is claimed that the latter was 

 not an unusual pocket I have studied the sample in the laboraton', 

 obtaining the following data and results : 



Chemical analysis. 

 , [Figures give percentages.] 



Silica 

 (SiOs). 



Alu- 

 mina 

 (Al.Oj). 



Fluxes. 



Loss on 

 igni- 

 tion.' 



Water 

 (H„0) 

 below 

 110°. 



Tita- 

 nium 

 oxide 

 (TiOo). 



Total \ 

 fluxes. 



Total 

 iron 



given as 

 ferric 

 oxide 



(FejOs). 



Lime 

 (CaO). 



Magne- 

 nesia 

 (MgO). 



Soda 



(NaoO). 



Potash 



(K„01. 



55.99 

 i>57.4 



28.77 

 i>29.47 



0.89 

 I'D. 91 



0.18 

 *'0.19 



0.03 

 1-0.03 



0.08 

 bO.08 



0.09 1 11.59 

 i>0.09 j '■11.87 



2.42 

 "0.00 



0.91 



•■o.gs 



1.27 

 n.30 



' Mostly water above 110° 



» Recalculated free from water below 110.' 



