The Philippine Journal of Science 



were variable. One sample (A) of 25.4230 grams gave the 

 following results : 





The volatile matter here consisted of liquid hydrocarbons 

 which are volatile at temperatures around 100°, particularly in 

 the presence of water. Without volatilization the bitumen con- 

 tent would be in the neighborhood of 10 per cent. 



A large sample of rock (B) weighing 273.5 grams was attacked 

 with hot dilute muriatic acid and extracted with benzene. After 

 volatilization of the solvent by prolonged heating at 100° C, the 

 extracted bitumen weighed 30.12 grams, or 11 per cent of the 

 crude rock. 



The bitumens of the two samples were treated separately with 

 boiling ethyl acetate for the purpose of separating the paraffi- 

 naceous ingredient, which is soluble, from the insoluble tarry 

 asphalt. The results were as follows : 



Soluble and insoluble ethyl acetate in Samples A and B. 



Ethyl acetate. 



1 1 — 



Insole. ! 



; A _..... ! t. 



shSj 



1 B -— 25.4131 



The bitumen of the impregnated rock is thus found to be con- 

 siderably richer in asphaltic constituent than is Leyte pure bitu- 

 men. Pratt's 4 supposition that Leyte bitumens are derived from 

 evaporation of paraffinaceous petroleum is evidently incorrect, 

 since paraffin-base petroleums could never have left residues 

 so rich in ethyl acetate insoluble as are Leyte bituminous rocks. 



The physical characteristics of the rock bitumen are totally 

 different from those of the pure bitumen. The rock bitumen is 

 extremely sticky and has the appearance of a heavy maltha of 

 viscous and semifluid consistency. Neither the penetration test 

 nor the ductility test can be made on such a substance. The fixed 



* Pratt, W. E., Philip. Journ. Sci. § A 10 (1915) 241. 



