The crude oil had specific gravity at 150 C. = 0.9026; rotation aD - 10.3°; refractive index at 20° = 1.4703, and was soluble in 1 1/4 volumes 70 per cent. alcohol. The saponification number for the esters and free acid was 3.7.

On rectification, 1 per cent, distilled below 173° C. (corr.). Between 173-188°, 85 per cent. distilled, and between 188-215°, 10 per cent. distilled. These fractions gave the following results: -

The cineol, determined by the phosphoric acid method in the crude oil, was 22 per cent., and in the first fraction, 27 per cent. (O.M.).

The very high solubility for an oil containing that amount of cineol indicated that alcohols might be present; a portion of the crude oil was, therefore, acety-lated in the usual way; the "saponification number for this acetylated oil had then increased to 22.4.

Material of this species for distillation was also obtained from Monga, N.S.W., in July, 1898. The yield of oil at that time of the year was 3 per cent., but as this was the winter it was less abundant in the leaf, although richer in cineol. Similar constituents were present as in the Moss Vale oil, and on rectification the fractions were in agreement with those of the previous sample.

The specific gravity of the crude oil = 0.9012, and of the first fraction 0.8956. The optical rotation of the crude oil was aD - 12.2°, and of the first fraction aD - 13.6°. The cineol in the crude oil determined by the phosphoric acid method was 32 per cent. (O.M.). The crude oil was soluble in 1 1/2 volumes 70 per cent. alcohol, as in the previous case.

As illustrating the general characters of commercially distilled oils of this species, the following list is given. There was no doubt as to the authenticity of these samples as submitted to us.

The localities represent a considerable area of country. They were all crude oils, and the cineol was determined by the phosphoric acid method.

As the yield of oil from this species was so large, it was thought desirable to undertake experiments in order to determine whether an oil richer in cineol could be obtained by distilling the leaves in a special manner. We were indebted to the Australian Eucalyptus Oil Company, of Sydney, for assistance in deciding this question. This company was distilling oil from this species at Moss Vale, N.S.W., and the product from one tank was collected for us, by separating the whole of the oil that came over during the first, second, and third hours of distillation respectively. The ordinary square 400-gallon iron-tank, so extensively used in this industry, was employed for the purpose. It was at once seen that the oil which came over during the first hour was much richer in cineol than either that of the second or third hours. The quantitative determinations of the cineol were all made by the phosphoric acid method, and consequently are a little lower than the true content, although comparative.

First-hour Oil. Specific gravity = 0.9126; optical rotation aD - 9.2°; cineol = 38 per cent. (O.M.).

Second-hour Oil. Specific gravity = 0.902; optical rotation aD - 12.5°; cineol = 15 per cent. (O.M.).

Third-hour Oil. Specific gravity = 0.898; optical rotation aD - 21.0°; cineol was present in very small quantity.

Phellandrene was present in all three samples, but was more pronounced in the oil distilling during the second and third hours.

A consignment of the commercially distilled crude oil from this species, containing the whole of the oil obtainable from the leaf, gave the following results: - Specific gravity = 0.905; optical rolation aD - 11.3°; cineol = 27 per cent. (O.M.).

The above results were such that it was thought advisable to carry the experiments further. A tank was specially prepared for us by the Company, and the oil distilling during the several hours kept separate. The oil was distilled in April, 1899. The weight of leaves taken, collected as for commercial oil distillation, was 320 lbs. The weight of the whole oil obtained was 11 1/4 lbs., equal to 3.5 per cent. Of this 8 lbs. came over during the first hour = 71 per cent.; 2 lbs. during the second hour = 18 per cent.; 12 ozs. during the third hour = 7 per cent., and 7 ozs. during the fourth hour = 4 per cent.

The greater portion of the cineol came over during the first hour, the oil collected during that period containing more than 30 per cent. of that constituent. The second hour oil contained considerably less cineol, and had a secondary odour suggesting citral. Only a very small quantity of cineol was found in the third-hour oil, and it could hardly be detected in the fourth-hour oil.

In June, 1899, a second investigation was undertaken, 400 lbs. of leaves and terminal branchlets being distilled, from which 14 lbs. of oil were obtained, equal to 3.5 per cent. Of this 9 lbs. came over during the first hour = 64 per cent.; 3 1/2 lbs. during the second hour = 25 per cent.; 1 lb. during the third hour = 7 per cent., and 8 ozs. during the fourth hour = 4 per cent.

The greater portion of the cineol in the oil came over during the first hour; a considerably less amount during the second hour; a very small quantity during the third hour, and only a trace could be detected in the fourth hour oil.

Other determinations were made in June and July of the same year, but as the results were quite concordant, it is unnecessary to tabulate the figures.

The above investigations resulted eventually in the oil of E. Australians being distilled commercially in this way, and the "first-hour oil" from that species was placed on the market as such, and sold as a first-class pharmaceutical Eucalyptus oil, the product which came over later being utilised for other purposes. (See under that species in this work.)

It was thus shown that by collecting apart the product distilling during the first hour, the greater portion of the cineol in the oil was obtained in this way. It was possible to stili further enrich it by fractionation, collecting apart the portion distilling below 1750 C. (uncorr.), discarding the fraction containing the volatile aldehydes. The product obtained in this way from the mixed first and second hour oils gave the following results: - Specific gravity = 0.896; optical rotation aD - 10.4°; cineol = 43 per cent. (O.M.).