242 



The Philippine Journal of Science 



will be the most desirable for a red lead paint. With these 

 mixtures, the resulting paint does not set as in the case of lin- 

 seed u or lumbang bato oils ; it does not dry into a paste in the 

 container as in the case of mixtures 6 and 7 ; and a better paint 

 is obtained than can be secured with linseed or lumbang bato 

 oils alone. 



Moisture-excluding property. — To determine the moisture- 

 excluding property of films, 14 pieces of suitable size and shape 

 were fastened with Canada balsam over the mouths of 200 cubic 

 centimeter bottles containing drying agents. One set of bottles 

 was half filled with concentrated sulphuric acid, another set 

 with calcium chloride. The test pieces were cut from the same 

 films as those whose tensile strength was recorded in Table IV. 

 The moisture-excluding property of linseed and lumbang oils 

 as determined by the increase in weight of the bottles of drying 

 agent is shown in Table VI. 



Table VI. — Moisture experiment. 



[Numbers express percentage gain in weight. The calculations were based on the original 

 weights of concentrated sulphuric acid and calcium chloride.] 



Oils used. 



Per 



Absorbent. 



Number of days. 



cent. 



5. 



10. 



40. 





100 

 50 

 50 



100 



100 

 50 

 50 



100 





0.24 

 0.37 



0.42 

 1.07 



0.45 

 0.69 



1.67 

 2.53 



Do 



f — -do 



CaCl2 



Lumbang 





2. CO | 6.98 



Do 



Lumbang 



Do 



(-;— " " 



1.14 

 1.18 



2.15 

 2.18 



7.52 

 7.76 



Table VI shows that the moisture-excluding property of lum- 

 bang bato red lead paint films are not as high as those of linseed 

 oil red lead paint films. The moisture absorption with calcium 

 chloride was relatively higher than with sulphuric acid. 



Similar tests were conducted with the films made from mixtures 

 of lumbang bato and lumbang banucalag oils whose strength 

 was shown in Table V. In this test 25 cubic centimeter bottles 

 half filled with concentrated sulphuric acid were used. The 

 results obtained are shown in Table VII. 



" Cf. Holley, C. D., Analysis of Paint and Varnish Products, 

 and Sons, New York (1912), p. 222. 

 " Gardner, op. cit., p. 83. 



John Wiley 



