366 UNIVERSITY OF VIRGINIA PUBLICATIONS 



sulphide unless conditions were imposed which would probably give rise 

 to the formation of ionizable sulphur compounds. The addition of free 

 sulphur caused no difference in the results obtained. Dilution with kero- 

 sene had no effect. 



4. Under conditions which give rise to the formation of ionizable sul- 

 phides (both from sulphur bearing oil and from added elementary sulphur) 

 precipitates of vanadium sulphide are formed as in (1) and (2) above. 



5. Mixtures of petroleum and vanadium sulphide (both the precipi- 

 tated and finely pulverized ore) became gradually more and more viscous 

 and finally yielded a brittle and asphalt-like mass when exposed to the air 

 or to oxygen gas. This asphalting process required several months when 

 the quantity of oil was great enough to protect the interior portions from 

 the oxygen, but was quite rapid (few days) when oily masses of precipi- 

 tated vanadium sulphide were left exposed on the filter paper or asbestos 

 mat in a Gooch crucible, and when a paste of natural ore and oil was left 

 in the open. 



6. Oily masses of vanadium sulphide ore yielded a liberal quantity of 

 free sulphuric acid when exposed to the air — sufficient to destroy the paper 

 container of the sample. 



7. The process of asphalting which the samples of petroleum underwent 

 in this investigation seemed to involve partial oxidation of the petroleum, 

 because no thickening of the oil nor asphalting occurred when oxygen was 

 excluded. In an experiment in which the temperature was slowly raised 

 the mixture exploded and a portion of the resulting mass was seen to be 

 glowing with flameless combustion, strongly suggestive in appearance of 

 the oxidation of carbonatious matter with potassium nitrate. 



Along with the sulphide ore in the Peruvian deposits there is much 

 vanadium oxide ore. Strata of vanadium ore and asphalt occur one above 

 another, sometimes in contact and again separated. 



Vanadium as an "oxygen carrier" is well known and extensive use is 

 made of this property in some cases, in the manufacture of certain dyes, 

 for example. 



Vanadium sulphide is not soluble in water. Small quantities of very 

 finely divided ore (100-mesh) became incorporated or dissolved when 

 mixed and allowed to stand some time in contact with petroleum. 



The presence of an alkali sulphide caused part of the vanadium to appear 

 as a water soluble salt of thiovanadic acid, as was expected. 



Hence the association of petroleum with vanadium compounds, and of 

 asphalt with vanadium ores may occur in the following way: 



