W. Skey. — On the Mineral Oils of New Zealand. 255 



an appearance of uniformity for the first seven distillates, at the 8th, 9th, 

 and lObh, or when about half the oil has been drawn over, these distillates 

 drop very considerably in density, or from -938 to '930, "898, and -908. 



I may state that the temperature of the contents of the retort could not 

 have been lower at this stage than at the one just previous. 



We may properly attribute this reversion of density to the splitting up of 

 some oil or oils in the retort into oils lighter and heavier than themselves ; 

 and this view is supported by the fact that these two distillates afforded me, 

 to successive fractional distillation, oils very much lighter than any which 

 I could obtain by treating in a similar manner the first distillates of the crude 

 oil. Thus, half an ounce of the lightest oil I obtained from the first four 

 distillates had a specific gravity of "8574 at 60° Fah., while the same quantity 

 obtained from the ninth and and tenth distillates had a specific gravity of 

 •7706 at 60° Fah. The latter sample has a much lighter and more agreeable 

 odour than the other. 



The heaviest oil I could obtain from this petroleum had a specific gravity 

 of -964. 



Those oils having higher specific gravities than "950 solidified at 12° Fah. 



The last portion of the oil distilled over solidified in the condenser. This 

 portion, on being examined, yielded whitish crystals, which fused at a 

 temperature of about 170° Fah. They are therefore, no doubt, naphthaline. 

 I do not think this substance exists in the crude oil ; it is most probably a 

 product of some change wrought upon it by the heat employed in the process. 

 Probably the light oil — that with a specific gravity of '770 — -and this napthaline 

 are formed simultaneously. 



To test the applicability of this oil for illuminating purposes I took a 

 further quantity of it, and retorted over 40 per cent. I then treated the 

 distillate with 3 per cent, of sulphuric acid, shook the mixture well about, 

 washed away the tariy mattei'S resulting, and agitated the oil with 2 per cent, 

 of soda of the strength generally used for purposes of this kind. The oil 

 removed from the soda was then re-distilled until oil equal to 30 per cent, of 

 the quantity originally taken had distilled over. This oil had a sjjecific 

 gravity of "904. Its colour was a pale yellow. It burns in a kerosene lamp 

 with a dull sluggish flame of small volume, and I question whether it can be 

 made to substitute the kerosene now used here. 



The fact, however, is an important one, that by a course of fractional and 

 apparently destructive distillation, the petroleum in part breaks xip into a 

 series of oils considerably lighter than any present in the natural oil, and into 

 heavy oils, naphthaline, and tarry matters. By the employment of apparatus 

 appropriate for such a process as this, it is not improbable that a portion of a 

 certain charge of this oil could be so far improved as to be capable of use for 



