210 



The Philippine Journal of Science 



1916 



SOURCE AND DESCRIPTION OF SAMPLES 



1. About 600 meters north of Mabolo barrio, Cebu. Brown; good working 



qualities. 



2. Pasig River, near San Pedro Macati. Brown; sticky. 



3. Laguna Province, on the shore of Laguna de Bay, between Lumbang 



and Pagsanjan^ Gray; plastic. 



4. Masbate, white clay; analysis corresponds closely to kaolin. 



5. Calapan, Mindoro. Dark brown ; contaminated with stone. 



6. Camansi, Cebu. A brown shale. 



7. Near Jaro River, about 3 kilometers from Iloilo. Dark brown; slightly 



contaminated with stone. 



8. Rio Grande de la Pampanga, Matamu barrio, Arayat, Pampanga. Dark 



brown; contaminated with sand. 



9. Bangued, Abra subprovince, Ilocos Sur. A light red clay. 



The chemical analysis of each sample as received is given in 

 Table II. 



Table II. — Analyses of clays.^ 



[Numbers give percentages.] 



Determinations, b 



No. 1. 



No. 2. 



No. 3. 



No. 4. 



No. 5. 



No. 6. 



No. 7. 



No. 8. 



No. 9. 



Loss on ignition . 



6.11 

 74.63 

 13.17 

 2.14 

 1.44 

 0.72 



13.84 

 51.00 

 20.60 

 6.36 

 2.91 

 2.31 



20.94 



44.00 



26.66 



4.34 



1.15 



0.86 



27.30 

 37.80 

 34.20 

 0.40 

 trace 

 trace 



16.21 



46.20 



27.56 



3.50 



2.80 



2.50 



44.35 

 24.90 



11.37 

 2.59 



13.45 



51.64 



19.52 



6.06 



4.14 



3.74 



10.72 

 66.10 

 18.24 

 6.92 

 3.74 

 2.64 



14.66 

 51.90 

 24.20 

 7.14 

 0.54 

 0.79 



Silica (Si02) - - 



Alumina (AlaOs) 



Ferric oxide (Fe203) 



Calcixun oxide (CaO) _ - 



Magnesia (MgO).- - 





■> Most of these analyses were made by F. D. Reyes, inorganic chemist. Bureau of Science. 

 * Alkalies were not determined. 



Methods of testing a raw clay. — There are a great many- 

 physical tests that can be applied to clays, but some of them 

 are of doubtful value. In this work only those which are most 

 important were chosen. In general, these are well known.^^ 



Water of plasticity. — The clay is ground, put through a sieve 

 having about 8 meshes per centimeter (20 per inch), and then 

 mixed with sufficient water to give the right consistency. After 

 a little experience this consistency can be determined by the 

 working qualities of the clay. A small pat is made on a square 

 of glass which has been previously weighed. The pat is dried at 

 room temperature for several days and then for one day in an air 

 oven at 105 to 110°C. It is removed from the oven and allowed 

 to cool in a desiccator. The loss in weight is calculated to per 

 cent on the basis of the dry weight. Clay of the same con- 



" I am indebted to Prof. A. V. Bleininger, of Ohio State University, for 

 a number of suggestions, which have proved helpful in carrying out the 

 physical tests. 



