446 Richardson and Mackenzie — Natural Najphtha. 



results, the fraction at the top of the tube has a lighter gravity 

 than that at the bottom, and that the saturated hydrocarbons 

 come to the top while the unsaturated are lower. Also when 

 water is added to the fuller's earth containing the petroleum, 

 the oil is displaced, but about one-third of the oil remains in 

 the earth. 



Day and Gilpin* have carried this work further and have 

 obtained similar results with clay. They have pointed out its 

 application to the accumulation of petroleum in different 

 places. 



We have in this Cuban oil an exact confirmation of these 

 experiments by nature. It will be remembered that from 

 the oil well there was obtained naphtha, water and emulsion. 

 The history of this naphtha may be very briefly told. At some 

 depth, considerably below 1500 feet, a crude petroleum filtered 

 up through this rhyolitic clay,f the upper part of the clay 

 stratum by fractionation containing the lightest naphtha. 

 Saline waters then came in contact with this upper clay layer, 

 displacing two-thirds of the oil contained in it and forming 

 with it the emulsion. In Trinidad asphalt, as shown by one of 

 us4 we have an exactly similar case of a permanent emulsion 

 of bitumen, water and mineral matter. 



To summarize briefly, we have examined a naturally occur- 

 ring white naphtha from the province of Santa Clara, Cuba. It 

 occurs at a depth of 1560 feet in black quartz and green ser- 

 pentine with water and an emulsion of oil, w T ater and rhyolitic 

 clay. It contains practically no unsaturated hydrocarbons, but 

 a mixture of paraffins and naphthenes. Over 50 per cent dis- 

 tills between 100°-125°, and very little above 150°. It was 

 undoubtedly formed by the upward filtration of a heavy pe- 

 troleum through the clay stratum, similar to the fuller's earth 

 nitrations of Gilpin and Cram, and the light naphtha in the 

 upper part of the stratum was afterwards partly liberated by 

 saline waters, the oil remaining in the clay forming with water 

 the emulsion. 



Our thanks are due to Mr. L. W. Page of the Office of 

 Public Roads for the examination of the clay, and to the 

 Cuban American Sugar Company, the owners, for permission 

 to publish these resulis. 



New York Testing Laboratory, 

 January 31, 1910. 



*Ind. Eng. Chem., i, 449. 



f It may be stated that the drillers are confident of finding a heavy 

 petroleum at greater depths. 



% Richardson, Proc. Am. Soc. Test. Mat., vi, 509. 



