The melting point of eudesmol is given by Semmler and Tobias as 78° C, but in all the samples of eudesmol we have prepared from the oils of different species of Eucalyptus, the melting point of the finally crystallised substance has been between 79.80° C. In some species the solid paraffin occurs, together with the eudesmol (E. Moorei for instance), and the melting point may thus easily be lowered. It may be removed by dissolving in alcohol, adding sufficient water to precipitate the paraffin, and filtering it off on a Buchner funnel by the pump.

When, however, the oil of E. Macarthuri was distilled under 10 millimetres pressure, the product thus obtained melted at 78°, and also at the same temperature when sublimed from the water bath, before recrystallising.

We are not aware from which species of Eucalyptus the eudesmol was obtained upon which Semmler and Tobias carried out their investigations, but from the specific rotations given above and also from the fact that the oil of E. Macarthuri is commercially distilled in Australia, the indications are that it might have been derived from that species.

The Monohydric Alcohols of the CnH2n +1 OH Series occurring in Eucalyptus Oils.

The abnormal solubility in alcohol shown by the oils of some species in which cineol is not pronounced, and phellandrene present in some quantity, points to the occurrence of an excess of alcoholic bodies not present in the more distinctly phellandrene-bearing oils of other Eucalypts. The comparatively high percentage of cineol in the oil of E. phellandra over those of E. dives, E. radiata and similar species, naturally assists this solubility, but that constituent is not present in sufficient amount to alone place the oil in the same class, as regards solubility, with those richest in cineol. The odour possessed by the oil of E. phellandra is somewhat aromatic, largely due to the presence of terpineol, and is perhaps characteristic of that species.

It was this peculiarity of solubility that induced us to carry out investigations in order to determine whether the earlier members of the monohydric alcohols were also present. The lower boiling aldehydes only occur in this oil in very small amount, and the peppermint ketone, piperitone, is not pronounced, so that those constituents cannot influence the solubility to any great extent. Both ethyl and amyl alcohols had previously been determined in a Eucalyptus oil (stated to be that of E. globulus) by Bouchardat and Olivier, and if no doubt exist as to the origin of the material worked upon by them, then these alcohols are more frequently present in the oils of the various species than has been supposed. Unfortunately, the products of the several species have not always been kept distinct. In the oil we obtained from E. cinerea, alcohols boiling below 100° C. did not appear to be present, and that species yields an oil belonging to the same group as that distilled from E. globulus.

Through the kindness of the Australian Eucalyptus Oil Company we were supplied with two litres of the water which first distilled on rectifying the oil of E. phellandra by direct distillation. The free acetic acid was first neutralised, and the water distilled, a Glynsky's fractionating column being used for the purpose.

The first distillation gave 88 cubic centimetres boiling between 70 and go° C, and 30 c.c. between go and 95° C. On again fractionating the portion distilling between 70 and 90° C, 15 c.c. came over between 70 and 760 C.; between 76 and 780 C. only a. very small amount was obtained; but between 78 and 79° C. no less than 26 c.c. distilled, and 5 c.c. more below 8o° C. Although containing a small amount of aldehyde, yet the greater portion of the fractions was found to be alcohols. As the lower boiling alcohols distilled off, the liquid remaining in the flask separated into two layers, the upper one having an oily appearance. The 30 c.c. obtained in the first "distillation, boiling between go and 95° C, were then added, when the oily layer again dissolved; on again removing the lower boiling alcohols the oily substance again separated. The upper layer, which consisted principally of the higher homologues, was investigated separately.

On again rectifying the 46 c.c. which distilled between 70 and 8o° C, 15 c.c. were obtained boiling below 760 C. This portion consisted principally of methyl and ethyl alcohols. The thermometer then rapidly rose to 780 C.; between 78 and 78.5° C. 15 c.c. distilled. This was found to consist mostly of ethyl alcohol; it was readily oxidised to acetaldehyde and then to acetic acid; it also formed ethyl acetate, and gave other chemical reactions for ethyl alcohol.

To prove the presence of methyl alcohol, the portion distilling below 760 C. was carefully oxidised, the acids distilled off in the usual way, and their barium salts prepared. The barium sulphate thus obtained was 95.18 per cent., indicating 13.56 per cent. of barium formate, and 86.44 per cent. barium acetate. The presence of formic acid was proved by its characteristic reactions, and an excellent silver mirror was obtained. Formic acid was also detected by M. Voiry in the oil of E. globulus (Compt. Rend. 1888, 1419). See also the article in this work on the free acids of Eucalyptus oils.

The liquid remaining in the flask, which had separated into two layers, was then distilled, and the portion which came over below 99° C. removed. On continuing the distillation, part of the "oily" layer came over with the steam, and partly separated again in the receiver. It was added to the upper portion still remaining in the flask. Valeraldehyde was shown to be present in this oily layer, and it was removed by combining it with acid sodium sulphite, and after separation oxidising it to valeric acid. The unacted-upon portion formed esters in the ordinary way, amyl-acetate being readily detected. On gentle oxidation the odour of butyric acid was obtained, but on energetic oxidation the acids formed were acetic and valeric. Ethyl alcohol could hardly have been present under the circumstances, so that the acetic acid shown to be present was apparently obtained by the oxidation of one of the alcohols. This points to the probable presence of iso-butyl alcohol existing as such in the original oil. Valeric acid was readily detected by its characteristic objectionable odour, when the salt was decomposed with sulphuric acid, and the formation of this acid points to the prior presence of amyl alcohol. Iso-amyl alcohol is a frequent constituent in Eucalyptus oils and is more pronounced in those intermediate between the pinene oils and those richest in cineol. A determination of the mixed barium salts of the oxidation product gave 86.8 per cent. barium sulphate, indicating 79.81 per cent. barium acetate and 20.19 Per cent. barium valerate. The results of this determination with the first distillate from Eucalyptus phellandra indicated that methyl, ethyl, iso-butyl, and amyl alcohols were present. Normal butyric acid has also been found in the oils of other species of Eucalyptus. (See the article in this work on the Butyl ester of butyric acid.) Although the presence of the above enumerated monohydric alcohols was thus demonstrated, yet they were not in sufficient amount to account for the exceeding solubility of the oil, a character evidently due to the influence of the higher boiling alcohols. (See the article on the Terpineols of Eucalyptus oils.)