SPECIFIC GRAVITY. 153 



oscillates within very wide limits. Even if we disregard for a mo- 

 ment the semisolid oil obtained from Kodoung well No. 23, in which 

 the hydrometer stuck, we see that the specific gravity varies with- 

 in the limits :— 



0*9722 (88°F.) =0-9834 and (6o°F.) 

 0-8484 (89°F.) -o-86oo and (6o°F.) 



the former being observed in pit well No. 691, the latter in the 

 Kodoung well No. 53. The Yenangyoung petroleum belongs therefore 

 to the very heavy oils, a fact which has already been noticed by pre- 

 vious observers. But the figures seem to demonstrate, that within 

 the area of the Yenangyoung oilfield the heaviest liquid petroleum 

 hitherto known has been found. The heaviest petroleum mentioned 

 by B. Redwood comes from Barbadoes, and has a specific gravity of 

 0*957, which is considerably exceeded by several samples of the 

 Yenangyoung oil. 



It may be mentioned, that the examination of these various 

 qualities of petroleum have shown that the Yenangyoung oil forms no 

 exception to Hofer's rule K The lighter coloured the oil, the smaller 

 its specific gravity. The oils of low specific gravity, exhibit in 

 transmitted light a fine dark reddish colour, which changes into dark 

 brown in heavier oils, and is almost perfectly black in the heaviest 

 varieties. 



Among these 72 samples of oil, examined with regard to their 

 specific gravity, we find that — 



7 or 9-8 / o 



have a 



sp. 



gr. 





• 



below i6°B. 



6 or 85 „ 



n 





11 



above 



• 



i6°B. but below 20°B. 



12 or 17-0 „ 



it 





11 



»• 



. 



20°B. „ 25°B. 



21 or 29*5 ,, 



>» 





11 



i» 



• 



25°B. „ 3o°B. 



25 or 35'i „ 



11 





11 



11 



• 



3o°B „ 35°B. 



These figures seem to demonstrate, that notwithstanding the 

 high specific gravity of some varieties of the petroleum, the very 

 heavy oils are decidedly in the minority. Oil having a specific 

 gravity between o* 8750 and o* 8484, takes the largest share, but is 



1 Das Erdol (Petroleum) und seine Verwandten, Braunschweig, 1888, page 29, 



( J 99 ) 



