Esters of the character of amyl-eudesmate and amyl-phenylacetate have, so far, only been found in a very few Eucalyptus oils. They appear to be present in greatest amount in that from E. aggregata, and it was from this species, collected at Fagan's Creek, near Braidwood, New South Wales, that oil was distilled in which amyl-eudesmate was first detected. (See paper by one of us, Proc. Roy Soc, N.S.W., 34, 1900, 72.) The yield of oil from E. aggregata is, unfortunately, almost the least of any, and consequently it was difficult to obtain sufficient oil for complete investigation.

In 1909 material of E. aggregata was forwarded from Rydal, New South Wales, many miles from the previous locality, but even less oil was distilled from this than from the Fagan's Creek leaves.

In 1920 we procured fresh material from Rydal, but were still more unfortunate, as oil did not distil in sufficient quantity to enable it to be collected, and attempts to extract the oil from the leaves directly with ether were not more satisfactory. We were desirous of obtaining the oil of this species in some quantity because the investigation of the Rydal material had resulted in the separation of a second solid acid which was different from eudesmic acid, and had the characters of phenylacetic acid. It is thus possible that two esters of amyl alcohol occur in the oil of this species, or else the Rydal trees are not quite identical with those growing at Fagan's Creek. The identity of the amyl-alcohol was, however, proved in the oils from both localities. When further investigation on the oil of this species and its esters is undertaken it would be well to procure material from both the above localities, and collected during the spring or early summer months, as at that period of the year the maximum amount of oil might be expected to occur. 400 lb. of leaves and terminal branchlets from Fagan's Creek gave only 2 1/2 oz. of oil, equal to 0.04 per cent., while that from Rydal gave a yield of 0.038 per cent.

The saponification number for the Fagan's Creek oil was 112.2, and for the Rydal oil 119.5.