22. * Nelson: The Solid Bitumens of Leyte 619 



On distilling, the rock commences to emit gases at tempera- 

 tures above 300° C. ; these gases are only partly condensable and 

 are due to the breaking up and decomposition of paraffin hydro- 

 carbons of high molecular weight into hydrocarbons of lower 

 series. Distilled hydrocarbons represent about 70 per cent of 

 the total weight of the rock ; noncondensable gases, about 3 per 

 cent ; and the residue consists of the remaining 27 per cent which 

 has become carbonized. The distillate, which is a mixture of 

 solid and liquid hydrocarbons, constitutes a vaselinelike or butter- 

 like grease, leaving a greasy spot on paper. It acts as a perfect 

 mineral lubricant. Alcohol dissolves only the liquid oil, leaving 

 the solid hydrocarbons behind as a yellow wax. 



The ethyl acetate insoluble (asphalt) portion of the bitumens 

 is always hard; it dissolves in benzene and, on evaporation of 

 the solvents, deposits at the bottom of the vessel a brilliant black 

 lacquer which scarcely adheres to the vessel. On heating, it 

 does not melt, but softens at high temperatures. 



The ethyl acetate soluble (paraffins) extracted from the bitu- 

 mens presents a hard waxy substance, dark brown when seen 

 in large masses, but reddish yellow when observed in thin layers. 

 Solutions in all solvents present a very marked fluorescence. 

 The ethyl acetate soluble being a mineral wax, it is very impor- 

 tant to ascertain whether it consists of ceresin or of paraffin hy- 

 drocarbons. Its melting point, 60 to 61° C, is at the limit of 

 that of paraffins and ceresin hydrocarbons, but its extraordinary 

 capacity for crystallization and some of its physical properties, 

 particularly its brittleness, indicate that it consists mostly of 

 paraffin. 



Leyte pure bitumens are essentially mineral waxes and must 

 be classified as such, in spite of the admixture of 10 per cent 

 (on the average) of ethyl acetate insoluble asphaltenic elements. 

 The only varieties of natural mineral waxes hitherto known were 

 those slightly metamorphosed residues of paraffinaceous petro- 

 leum which contain practically no asphaltenic ingredients, such 

 as ozocerite, montan wax, hatchettite, and scheererite. It would 

 be quite impossible to classify this rock as montan wax, hatchet- 

 tite, or scheererite ; the following circumstances make it difficult 

 to classify it as ozocerite either. Ozocerite is subjected indus- 

 trially to a process of refining which consists in heating it with 

 about 20 per cent by weight of concentrated sulphuric acid to 

 280 to 300° C. until the evolution of sulphur dioxide fumes ceases. 

 Concentrated sulphuric acid attacks and destroys unsaturated 

 hydrocarbons and resinous matter, while volatile hydrocarbons 



