Page:Transactions NZ Institute Volume 15.djvu/481

a mawkish but not unpleasant odour, being very different in this respect from most rock oils, and is especially free from all traces of sulphuretted hydrogen. Minute flakes of a white 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. Boils at 340° Fahr., and does not appear to evaporate at ordinary temperatures. Vapour inflames at 260° Fahr.; does not contain paraffin. Very valuable as a lubricant on account of its low freezing and high volatilizing points.

2. Poverty Bay.—A true paraffin oil. Opalescent and thickly interspersed with minute flaky particles of a white colour; by warming the oil gently these particles subside, and the oil manifests the following characters: translucent in masses of considerable thickness; colour, red by transmitted and blackish-green by reflected light; flows readily and gives off the usual odour of crude petroleum. Its boiling-point at 30 ins. barometric pressure varies from 289° to 291° Fahr. The temperature at which the vapour inflames is from 230° to 233° Fahr., and sp. gr. from .864 to .871 at 60° Fahr. Passes into a jelly-like mass at 50° Fahr., owing to the quantity of paraffin dissolved in the oil.

3. Manutahi, Waiapu River.—Is the lightest natural mineral oil known in the colony. Colour, pale brown; nearly or quite transparent; does not manifest a green-black colour by reflected light; flows with great freedom; has the odour of kerosene; sp. gr. .8294 at 60° Fahr.; burns well in a kerosene lamp for some time. Contains only traces of paraffin, and does not acquire any increased consistency when the temperature is lowered to 8° Fahr.

For details concerning the constitution of these oils I must refer the reader to the paper above cited, and also to another by the same author (Trans. N.Z. Inst., vol. xi., p. 469).

Dopplerite.—A mineral grease resembling dopplerite was collected by Dr. Hector from Waiapu in 1872, and during 1880 a specimen of the same mineral was forwarded to the Colonial Laboratory for examination on the supposition that it was ozokerite or native paraffin.

This substance is of a soft greasy nature, brownish-yellow colour, and possesses a strong odour of paraffin. It burns readily with a smoky flame, leaving a large quantity of ash, and consists, according to Mr. Skey (Trans. N.Z. Inst., vol. xiv., p. 398) of 3.1 per cent. oils; 9.3 per cent. paraffin 26.9 per cent. earthy matter; 11.3 per cent. water; and 49.4 per cent. oxygenated hydro-carbons.

Ozokerite, CH.—This mineral is mentioned by Dr. Hector (Jurors' Rep. N.Z. Ex., 1865, pp. 267, 438) as occurring in the brown coals of Dunstan, Otago. We have, unfortunately, no specimen of this.