254 



Transactions. — Chemistry. 



respect from most rock oils, and is especially free from all traces of sulphuretted 

 hydrogen gas. 



Minute flakes of a wliite substance float in the oil, and are gradually 

 deposited when it is allowed to remain quiet at a low temperature, nearly the 

 whole of this solid substance becoming dissolved when the oil is gently heated. 



The temperature at which the oil boils is 340° Fah., and it does not appear 

 to evaporate at ordinary temperature, for when exposed to the air it remains 

 unchanged, neither thickening nor acquiring a skin on the surface. 



Its temperature requires to be raised to 260° Fah. before its vapour inflames. 



This oil differs from petroleum oils generally in not containing paraflin. 

 In this respect it resembles a so-called surface oil occurring in Santa Barbara 

 County, California. These oils also agree in being of very similar density. 



Details of the results of the distillation of a small quantity of this oil have 

 been given in a special report by Dr. Hector, but since then I have had the 

 opportunity given me of operatijig upon larger samples, and I have thus 

 obtained further results which could not well be observed otherwise. 



A large quantity of the oil was distilled very slowly until 82 per cent, of 

 volume of the charge had passed over. The residual matter left in the retort 

 set very hard on cooling to 60° Fah. It had the appearance of pitch, and 

 vs^ould have yielded a further quantity of solid and liquid distillates if needed. 

 The density of the several portions of the oil obtained was as follows : — 



■NTn 



VOLTTME or 



Distillate 



SpEciric 



i>IO. 



UPON Charge. 



Gravity. 



1 



2 



per cent. 



•880 



2 



5-5 





•888 



3 



5-5 





•900 



4 



4 





•910 



5 



8 





•917 



6 



.. " ... 8 





•926 



7 



12 





•938 



8 



12 





•930 



9 



13 





•898 



10 



4 





•908 



11 



8 





•938 



82 



The total amount of oil distilled over was therefore 82 per cent, upon the 

 charge taken, and the amount of residual matter left, 1 8 per cent. This was 

 a kind of pitch, intensely black, and solidifying to a very hard mass at common 

 temperatures. By destructive distillation it would, of course, yield further 

 oily and solid products. 



On an examination of the columns just given, it will be observed that the 

 products of the distillation of this oil do not constantly increase in density as 

 the process of distillation goes on, but that, while they increase in density with 



