The determination of rotations so far made, have shown the "first hour oii" to be usually slightly dextro-rotatory, although if the distillation be continued longer, the resulting oil may be slightly lævo-rotatory. This result appears to be due to the presence of some terpineol. Improvements in this method of first distillation will result in the production of a pharmaceutical oil from this species growing in other localities, and already at Burraga, in the Bathurst district, it is being so worked for pharmaceutical oils. An analysis of the oil from this district is given later.

In the first edition of this work, p. 275, we drew attention to some remarkable features shown by the oils of this group, particularly that of solubility in 70 per cent. alcohol, a result which placed the species in the class yielding Eucalyptus oils richest in cineol, thus practically predicting the present results. This high solubility is due to the presence of the alcohols terpineol and geraniol as well as to the cineol. That this is so is shown by the increased saponification numbers of the acetylated higher-boiling fractions, as well as from the results with the Nenigundah "second hour oil."

Yield of Oil. - The yield of oil from the Yourie-Tanto material agrees with that of this species from other localities, and our sample, distilled at the Museum, gave 4.4 per cent. for leaves with terminal branchlets, collected in the month of November. The material, which had dried somewhat, was weighed into the still and the amount of oil determined. These figures may perhaps be considered as the maximum yield. From a series of results obtained by Mr. E. McGrath, of Yourie, during the months of June, July, August, September and October, the differences of yield at various times of the year are well illustrated. Mr. McGrath uses a pair of tanks coupled together and worked simultaneously. These are the usual 400-gallon square iron tanks, fitted in the simple manner customary with the majority of Euca'yptus oil distilling plants in New South Wales, and fired directly.

Average yield of oil from the two tanks for all distillations.

The months of June and July are midwinter in Australia, when the oil is at a minimum.

The actual weight of green leaves with terminal branchlets packed into the tanks was not known, but if this be considered as 800 lb. per tank, which amount would probably be nearly correct, then for June an average yield of 2.5 per cent. was obtained: for July 3 per cent., tor August 3.2 per cent., lor September 3.4 per cent., and for part of October 3.3 per cent.

Analysis of the Oil. - The crude oil of the Yourie and Tanto material distilled at the Technological Museum, was of a very light lemon tint, had quite a pleasant odour, the volatile aldehydes not being at all pronounced. The oil contained a large amount of cineol. The reaction for phellandrene was not distinctive, and this terpene probably does not occur in the oil of this species at any time except in. traces.

The crude oil, which had been distilled right out, had specific gravity at 150 C. = 0.9157; rotation aD + 2.8°; refractive index at 20° = 1.4644; and was soluble in 1.2 volumes 70 per cent. alcohol. The saponification number for the esters and free acid was 8.9.

On rectification, 2 per cent, distilled below 1720 C. (corr.). Between 172-1930, 84 per cent. distilled; between 193-2200, 5 per cent. distilled, and between 220-2600, 5 per cent. distilled. These fractions gave the following results: -

The cineol was determined by the resorcmol method in the first fraction, and calculated for the whole oil; the result for the crude oil was 70 per cent. By the phosphoric acid method it was 66 per cent. The higher fraction contained a little piperitone (the constituent of peppermint odour), a small amount of ester, and free alcohols. A portion of the crude oil was then acetylated in the usual manner, when the saponification number had risen to 51.3. This result indicated the presence of alcohols in fair quantity, to which constituents the aromatic and somewhat characteristic odour of the oil was largely due. As the alcohol was chiefly terpineol there was about 12 per cent. of that constituent in the crude oil, assuming the whole alcohol to be that substance. The presence of the terpineol is more distinctly shown with the second and third hour oils, which were distilled and collected for us by Mr. Gough, of Youne. Geraniol is also a constituent in the oil of this species.

"First Hour Oil." - As previously mentioned, the commercial distillation of this species has resolved itself into a fractional separation during the primary distillation of the oil from the leaf.

The "first hour oil" is practically water-white, as are all the rectified oils of this group; it is rich in cineol, of good odour, and is fairly constant in composition. The average specific gravity of the "first hour oil" taken by Mr. McGrath for twenty-six distillations during the months of September and October was 0.919, the highest being 0.920, the lowest 0.917.

For the constants with the "first hour oil," see the table in the article "The comparative constancy of the oil products from individual species of Eucalypts."