W. SxEv.—On the Mineral Oils of New Zealand. 255 
an appearance of uniformity for the first seven distillates, at the 8th, 9th, 
and 10th, 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 а 
product of some change wrought upon it by the heat employed in the process. 
Probably the light oil —that with a specific gravity of *7 70—and this napthaline 
are formed simultaneously. 
То 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 sulphurie acid, shook the mixture well about, 
washed away the {атту matters 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 specific 
gravity of 904. Tts 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 up 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 
