LAGUNA CLAYS. 



Physical properties. 



387 



Water 

 added 

 to give 

 a work- 

 able 

 paste 

 (percent 



total 

 weight). 



26.6 



Tensile strength. 



Shrinkage (per cent). 



Color. 



Air dried, 3 de- 

 terminations 

 averaged. 



Burned.'' 



Air. 



Fire 

 at cone 

 No. 9. 



Total. 



Air dried. 



1 



Burned with 



free acces.s 



of air. 



Kilos 



per 



square 



centi- 

 meter. 



Pounds 



per 

 square 

 inch. 



Kilos 



per 



square 



centi- 

 meter. 



Pounds 



per 

 square 

 inch. 



1.61 



23.3 



2.95 



42 



1.6 



9.6 



11.2 



Cream 



Pale lilac. 



" Crackles to a certain extent. 



Some of the natives state that they have made excavations as deep as 

 four meters, but although they worked regularly in these deposits they 

 showed such timidity about entering the pits that I doubt if they often 

 go deeper than the holes which were open during my visit. 



The information gained from the chemical and physical tests of this 

 deposit indicate the usefulness of this material for making certain grades 

 of pottery. 



The deposit below Point iilipasio in the region of Calamba is at an 

 altitude of 210 meters and has apparently been very little, if ever, worked. 

 It is on the dry side of the mountain and the weathering has taken place 

 very much more slowly; moreover the deposit is quite hot and the heat 

 soon dries out the water which is perhaps the chief desintegrating factor 

 in a tropical country, this prevents further action. In some places the 

 basal rock is scarcely decomposed at all, at others there is a thin layer 

 of completely weathered, grayish clay, while in still others there are 

 pockets probably of no great extent, of a good quality of kaolin. 



One of these at the base of the deposit was sampled and investigated 

 in the laboratory. The data and results are as follows : 



Chemical analysis. 

 [Figures give percentages.] 



Silica 

 (SiOo). 



Alu- 

 mina 

 (AI2O3). 



Fluxes. 



Loss on 

 igni- 

 tion." 



Water 

 (H,0) 

 below 

 110". 



Tita- 

 nium 

 oxide 

 (TiOo). 



Total 

 fluxes. 



Total 

 iron 



given as 

 oxide 

 ferric 



(Fe.03). 



Lime 

 (CaO). 



Mag- 

 nesia 

 (MgO). 



Soda 

 (Na,0). 



Potash 

 (KoO). 



43.16 

 i>43.77 



38.64 

 i>39.20 



1.19 



n.20 



0.09 



bo.og 



0.14 

 '0.14 



0.08 

 "0.08 



0.02 

 ■■0.02 



14.55 

 i>14.75 



1.42 

 '0.00 



1.54 

 i>].56 



1.52 

 '1.53 



' Mostly water above 110° 



^ Recalculated free from water below 110°. 



