The Laevo-rotatory Pinene. - The crude oil of E. Iævopinea, from Rylstone, N.S.W., distilled a few days after collection, gave the following results: -

On rectification 2 per cent. came over below 157° C, this portion contained the usual amount of acid water and some volatile aldehvdes.

Continuing the distillation: -

On again distilling that portion which came over between 157 and 1640 C, the following results were obtained: -

The third and final rectification, again taking the first fraction, gave 50 per cent. of an oil boiling between 157 and 158° C. This gave results as follows: -

Specific rotation taking density at 190 C. = [a]D - 48.63°. The refractive index at 200 C. for a specially prepared sample was 14660.

The boiling-point of this lævo-rotatory pinene was thus a shade higher than the dextro-rotatory form; this was shown to be due to the presence of a trace of cineol still remaining,

The same apparatus was employed for the whole of the distillations, and the results were obtained under exactly similar conditions, and upon a similar quantity of oil.

From the above results it will be seen that the several fractions of the two oils gave fairly concordant results, with the exception that the oil from E. Iævopinea boiled at a slightly higher temperature than that from E. dextropinea. Another sample was then prepared and the cineol removed by shaking with 50 per cent. resorcinol; the remaining pinene boiled at 1560 C., the same as that from E. dextropinea. The difference between the Eucalyptus pinenes is in their extreme opposite rotations, and while the specific rotation of the dextro-rotatory form is twice as great as that observed in the pinene from dextro-rotatory oil of turpentine, the specific rotation of the lævo-rotatory form is greater than that of the pinene from laevo-rotatory oil of turpentine.

The pinene from E. Iævopinea does not, however, show the highest specific rotation to the left. This was given by the pinene from E. phlebophylla; a sample of the pure pinene from that species having a specific rotation [a]D - 50.18°. This oil was distilled in August, 1919, from material collected at Braidwood, New South Wales.

The Eucalyptus pinenes are identical in appearance, being colourless, mobile liquids, and have a similar odour and other resemblances to the pinene from ordinary oil of turpentine; the odour was, perhaps, more distinctly shown with the dextro-rotatory form.

The nitrosoehlorides. - For the preparation of these compounds one volume of the pinene was added to one of amyl nitrite, and the mixture dissolved in two volumes of glacial acetic acid; this was cooled in a mixture of ice and salt, and concentrated hydrochloric acid and glacial acetic acid, in equal parts, slowly added while the blue colour remained; it was then allowed to crystallise in the freezing mixture. The crystals from both forms were identical in every respect and melted quite sharply at 103-104° C. The product from the dextro-pinene was heated with alcoholic soda, and the nitrosoterpene thus formed, when crystallised from alcohol, melted at 128-129° C.

The hydrates. - About 4 or 5 volumes of the pinenes were frequently agitated for two or three days with 1 volume of nitric acid (specific gravity 1.25) and half its quantity of alcohol; the solutions were then allowed to slowly evaporate in open vessels. Alter some days crystals were formed in some quantity with both forms. These were rhombic crystals, and when purified by recrystallisation from alcohol, melted at 116-1170 C. with elimination of water. On melting these terpin hydrates and taking the melting point of the terpins thus formed, it was found that both melted at 102-1030 C., and readily sublimed. The terpin hydrate from either form was soluble in boiling water, in alcohol, and in ether, and behaved chemically in exactly the same manner in every respect.

A vapour density determination of the pinene gave almost the identical figures required for the molecule CI0Hl6.

The monohydrochloride was prepared with the dextropinene; this had the odour and appearance of ordinary camphor and melted at 123-1240 C.

Crystalline bromides were not obtained by ordinary methods.

For the corresponding pinene from the oils of the closely-related genus Angophora, see paper by one of us, Proc. Roy. Soc, N.S.W., August, 1913.