GREY GUM AND ITS ESSENTIAL OIL. 277 
From 240 to 245°C. 4 ec. had been obtained 
The mercury then continued to fall although the heat was 
increased. We have thus obtained nearly 10 cc. boiling between 
240 and 261° C. from 50 ce. of original residues which represent 
from 800 to 1000 cc. of the original oil, so that these bodies are 
present to the extent of about one per cent. in the original oil 
taken collectively, and as we consider that the colour of the oil is 
partly due to these bodies, and as the colour is almost absent in 
some oils, we think that they are present in greater quantity in 
the older trees. 
The specific gravity of this distillate was found to be ‘9361. It 
was treated with acid sulphite of soda, when a small quantity of 
a crystalline compound was obtained, showing the presence of an 
aldehyde. The mixed bodies have somewhat the odour of cumin 
oil, which is much more pronounced in the regenerated substance. 
As cuminic aldehyde boils at 237° C., we think we are justified in 
stating that this substance is present in a very small quantity in 
this oil. 
The remaining body removed from the aldehyde has a very 
pungent odour, and when diffused sufficiently not at all unpleasant. 
This odour becomes less marked after some time, further altera- 
tion evidently taking place. It is of a deep orange brown colour, 
is an oil, and no signs of crystallisation are apparent. We hope 
eventually to obtain sufficient material to further investigate it. 
As there is a connection between the constituents of the species 
of the. genus Eucalyptus, we may perhaps obtain it in larger 
quantities from the oil of other species. We hardly think it can 
be closely connected with the other constituents of the oil, as the 
differences in boiling points are too distinct, very little oil being 
obtained between 193 and 240°C. 
As the levo-rotation of the oil increases the see appears 
to exist in less quantity. 
