An average sample of a June distillate from old leaves gave the following results: - Specific gravity at 150 C. = 0.9218; rotation aD + 1.2°; saponification number = 191.8, representing 67.13 per cent, ester. Cold saponification during two hours' contact gave identical results. The crude oil was soluble in 1 1/2 volumes 70 per cent. alcohol.

From very many analyses made since the first announcement in 1900, the following may be selected.

The oil distilled towards the end of July from old leaves, contained a larger amount of ester than the June oil, as the saponification number was 202, equal to 70.7 per cent, geranyl-acetate.

A sample of the oil distilled early in September, from old leaves, contained still more ester, the saponification number, in the cold with two hours' contact, being 214, equal to 74.9 per cent, geranyl-acetate.

The average ester content for a consignment of 100 pounds of the oil of this species, distilled from old leaves at various times during the year 1902, was 62.8 per cent, geranyl-acetate, from determinations made at the Museum during that year.

Analyses were also-made with eight samples of the oil of this species which had been distilled at Wingello from old material during the year 1917. The average ester content for geranyl-acetate was 67.5.

The oil from the abnormal leaves contains even more geranyl-acetate than does that from the old leaves. This is shown from the following determination: - -Trees had been felled at Paddy's River, N.S.W., for oil production, in April, 1902, and in the following March, the young growth from the stumps of the felled trees (" suckers ") was distilled at the Museum. The yield of oil was 0.23 per cent. The ester value by cold saponification with two hours' contact was 221.4, equal to 77.5 per cent, geranyl-acetate.

This species readily lends itself to cultivation, and is now grown extensively at Emerald, Victoria, where the clippings from the young bushes have yielded up to 0.3 per cent, of oil. A sample of this oil which was distilled in the year 1913, from material twenty-two months old from the time of planting the seed, when analysed at the Museum, gave a saponification number by the cold treatment of 200.3, equal to 70.1 per cent, geranyl-acetate. The quality of this oil was excellent.

The vitality of this species is remarkable, and the continued reproduction of new material is quite equal to that of any other species of Eucalyptus.

Oil. from the Bark. - The distillers who extracted an essential oil from the leaves of this species of Eucalyptus were generally acquainted with the odoriferous nature of the bark, and were desirous that the quality of the oil should be determined.

We are indebted to Mr. W. J. Quigg, of Wingello, N.S.W., for forwarding in November, 1915, the freshly-stripped bark for distillation. It had been obtained from fair-sized trees, and ranged in thickness up to 1 1/2 inches. The odour of geranyl-acetate was distinctly noticeable on the freshly-cut edges, and when ground for distillation, had a very pleasant odour.

The yield of oil by steam-distillation from this ground bark was somewhat disappointing, as it did not exceed that obtainable from the mature leaves; but the statement has been made that at certain times of the year, the yield is greater than that obtainable from the leaves at the same period.

The results of the investigation on the oil from the bark show it to be identical in composition with that obtainable from the leaves, so that no separation need be made for commercial purposes. With trees of fair size, it should be profitable to steam distil the bark for its oil, that is, if it be considered necessary to cut down the trees in the process of manufacture. The growth of "suckers" from the stumps of the felled trees is, however, somewhat rapid, so that new material would soon be available, and, as shown above, an excellent oil is obtainable from this young foliaceous growth.

The bark was chopped into small pieces, coarsely ground in a mill, and steam-distilled. The yield of oil was equal to 0.12 per cent.

The crude oil was of a light amber colour, and had a distinct odour of geranyl-acetate. It gave the following results: -

The optical activity of the oil was due to the presence of a small quantity of dextro-rotatory pinene. The stearoptene eudesmol, which is a constant constituent in the leaf oil, does not appear to be present in the bark oil.

The saponification number for the esters in the cold with two hours' contact was 169.5, equal to 59.3 per cent. geranyl-acetate.

A portion of the oil was then acetylated in the usual way. The saponification number with this acetylated oil in the cold was 198.8, equal to 69.6 per cent, of ester. The saponification number had thus increased by 29.3, so that the free geraniol in the oil was 8 per cent.

A sample of crude oil from the bark of this species distilled in October, at Wingello, by Mr. W. J. Quigg, was also investigated at the Technological Museum. It contained a larger amount of ester than did the oil distilled by us, and had the following characters: -

The saponification number for the ester in the cold with two hours contact was 195, equal to 68.2 per cent, geranyl-acetate.

The saponification number for the acetylated oil, also in the cold, was 224, equal to 78.4 per cent. of ester, an increase in the saponification number of 29, representing about 8 per cent. of free geraniol in the crude oil.

A commercial sample of the bark oil of this species, presented to the Museum by De Meric Ltd., George-street, Sydney, had the following characters: -

Soluble in 1.2 volumes 70 per cent. alcohol.

The saponification number in the cold with two hours' contact was 169, equal to 59.2 per cent, geranyl-acetate.

This Eucalyptus is one of the very few species of the genus from which an essential oil can be distilled from the bark, and, so far as at present known, it is the only Eucalyptus bark of commercial value for oil production.