369 



volatile acid had all conn- over. A portion of the distillate was exactly neutralised 

 with barium hydrate solution, evaporated to dryness, heated in air oven to render 

 the salt anhydrous, and finally igniting with sulphuric acid. 0-828 grams gave 

 0-754 grams barium sulphate : 91-06 per cent. A second determination gave 

 corresponding results. 



Barium acetate theoretically gives 91-37 per cent, barium sulphate, a result 

 which indicates that a very small amount of another volatile acid than acetic 

 was present in the oil as ester. When the barium salt was first decomposed the 

 odour suggested valeric acid as well as acetic, and as valeric acid ester is a common 

 constituent in Eucalyptus oils, it may thus occur in traces in the oil of E. Macarthuri. 



The remainder of the distillate was exactly neutralised with sodium 

 hydrate and evaporated to crystallising; well-formed crystals of sodium acetate 

 were thus obtained. 



The Terpincols of Eucalyptus Oils. 



IN a paper on Eucalyptus Australiana and its essential oil, read by us before the 

 Royal Society of New South Wales, December, 1915, it was shown that a consider- 

 able quantity of a high-boiling aromatic alcohol was present in the oil of this 

 species, and that it was concentrated to a considerable extent in that portion of 

 the oil which came over during the second and third hours of distillation, and 

 analysis showed that between 30 and 40 per cent, of the third hour oil consisted 

 of this alcohol. Considerable work has now been undertaken with this alcohol, and 

 it has been isolated from the oils of several species, with the result that it is now 

 shown to be terpineol, and to exist in Eucalyptus oils in both the dextro- and 

 laevo-rotatory modifications. 



Voiry had shown in 1888 that terpineol and its esters occurred in the oil 

 of E. globulus (Compt. Rend. 106, 1888, 1419). 



Dextro-rotatory terpineol has now been isolated from the oils of some of the 

 earlier members of the genus, viz., E. diversicolor and E. carnea; and the laevo- 

 rotatory terpineol from the oils of E. Australiana and E. phellandra. The terpineol 

 isolated from the oil of the latter species had a higher laevo-rotation than had that 

 of the former. It may be supposed, therefore, that terpineol similarly with 

 geraniol runs through the whole genus, occurring in larger or smaller amounts 

 in the oils of the several species, sometimes in the free condition, and as terpinyl- 

 acetate or terpinyl-butyrate. 



The alcohol has so far been found to occur in the liquid form, but was 

 crystallised when subjected to considerable cold for a sufficiently long period. 

 The solid form when purified melted at near 35 C , and had the characteristic 

 lilac odour of terpineol. 



In the first edition of this work the oil of E. phellandra (known at that 

 time as a form of E. amygdalina), although containing only about 30-40 per cent, 

 of cineol, was shown to be exceedingly soluble in 70 per cent, alcohol. This 

 peculiarity for an oil in which phellandrene occurs in some quantity is now known 

 to be chiefly due to the presence of the terpineol. The species E. Australiana was 

 not discovered until many years later. 



When the crude oil of either E. Australiana or E. phellandra was treated 

 with phosphoric acid on a watch glass and the cake of cineol phosphate allowed 

 to remain in the open for two or three days, crystals eventually appeared in the. 



