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Volume 14, 1881
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Art. LXIV.—On the supposed Paraffin Deposit at Waiapu.

[Read before the Wellington Philosophical Society, 20th August, 1881].

You may be aware that a considerable quantity of a soft, greasy, combustible mineral occurs about ten miles south of Waiapu associated with the petroleum rocks of that district, and forming a rather extensive deposit there, and that the nature and value of this has been, and now is, a subject upon which professional opinion is exceedingly varied. Opinions being in this way, at the suggestion of Dr. Hector I have prepared this paper for the purpose of bringing the whole question before you in a concise manner.

So far back as the year 1872, a sample of this mineral was handed to me by Dr. Heetor, who collected it, and the partial investigation of it which I then made, showed that, except for clay and sand, which was, of course, foreign to the mineral, it was in principal part oxygenated hydrocarbons; among which I considered dopplerite, or a mineral greatly resembling it, was largely represented. I promised a fuller report upon it as soon as I had time to continue my examination, but before I could well do this a sample of an article averred to be “solid paraffin,” also from Waiapu, was forwarded to Dr. Hector by the Hon. G. Randall Johnson for analysis. This

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sample on examination proved to be very similar to the one already described, consequently made up in principal part of oxygenated hydrocarbons, and therefore a substance far removed from solid paraffin, and so very inferior in value to this mineral. But as I have said, professional opinion differs, and differs greatly in regard to these points. No doubt what have been taken for fair samples of it have differed somewhat in character, but still, as I conceive, hardly so much as to allow us to explain this divergence in the way indicated. It appears to me that this divergence of opinion is in greater part to be properly ascribed to the various methods of analysis employed in testing it.

The annexed table clearly shows the very great divergence there is in the results obtained by Mr. Dixon, of the Technical College Laboratory, at Sydney, Mr. Cosmo Newberry, Government Analyist, of Melbourne, and myself respectively:—

[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]

Dixon. Newberry. Skey.
Kerosene 17.5
Intermediate oils 9.8 3.1
Heavy oils 35.0 73
Paraffin 30.0 9.3
Carbon 7.7
Earthy matters 24 26.9
Water 3 11.3
Mineral 49.4
100.0 100.0 100.0

These results are certainly very discordant. It should be remarked, however, that Mr. Dixon's result could be got upon the sample I examined by washing out the earthy matter, drying the residue, and submitting it to a distillation which, towards the end, is destructive.

Mr. Newberry's results agree with mine pretty nearly as regards the earthy matter, but not, as you will observe, in respect to the water, while he has no representative of the 49.4 per cent. of carbonaceous matter which I find, and which is fundamentally different to either oil or paraffin, and also is of far less monetary value.

Assuming that the trial tests of this analyst have given results approximately correct, the analysis, when completed, will, he considers, give 63 per cent. of paraffin, as against 9.3 per cent. by myself, and 30 per cent. by Mr. Dixon. Mr. Newberry values the article at £28 per ton, after being cleansed; an estimate which is, I dare say, about right for this percentage of paraffin.

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Assuming my result to be approximately correct, you cannot avoid coming to the conclusion that the substance which exists in largest quantity in this mineral, has been all along mistaken both by professional analyists and those interested in the article for paraffin.

The precise nature of this substance is more a matter of scientific interest than of anything else. I intend, so soon as I can spare the time, to determine this, but I think that for the present I have done all that is required for economic purposes. I show that about half of the carbonaceous part of this “mineral grease” (as Dr. Hector terms it) is neither paraffin or oil. You can judge for yourself of this matter by inspecting what I have just obtained from this grease as separated from oil and paraffin.* You may notice that it is solid, brittle, and infusible—characters which do not belong to either of the substances which, I think, it has been mistaken for, viz., paraffin or oil. It is besides highly absorbent of water, and swells very much in this liquid, passing thereby into a gelatinous form. The mineral grease or supposed “solid paraffin” yields nearly fifty per cent. of this substance. Mineralogically it belongs to the class of combustible minerals known as oxygenated hydrocarbons, and I believe contains several of these bodies. It is obviously formed out of some of the constituents of petroleum by oxydation and absorption of water. Copies of the reports of the analyses to which I have just referred, are laid upon the table for your inspection.

[Footnote] * Sample was exhibited, as also one of the supposed paraffin mineral.

[Footnote] † Since this paper was read an examination of the Waiapu mineral grease has been made upon a large scale on the grounds of the Southern Cross Petroleum Company. The result of this, for comparative purposes, I here render centesimally:—

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Light oil 5.4
Kerosene 13.2
Lubricating oil 4.0
Paraffin 7.9
Balance not specified 69.5
100.0

[Footnote] It seems therefore that, as in my results, that constituent of the mineral which is the most valuable, and which has been asserted to be the most abundant, viz., paraffin, is present, but in minor quantity; the difference between my result and these, in respect to the paraffin, is only 1.4 per cent. The excess of oil over that which I indicated is doubtless derived by destructive distillation from the oxy-hydrocarbons present.