PATCHOULI. 305 
distilled over *, and was found to be a hydrocarbon analogous to 
that from cubebs; but towards the end the thermometer rose 
much higher and the distillate became of a deep blue colour, owing 
to the presence of an intensely blue matter termed ‘azulene’ or 
‘cerulein,’ which is also found in the oils of Calamus aromaticus, 
Achillea Millefolium, Matricaria Chamomilla, Artemisia Absinthum, 
and in a small quantity in the oils of Bergamot and Ceylon 
Lemon-grass.” The analysis of this remarkable fluid shows its 
formula to be C,,H,,;0. Its boiling-point is 576° F., and its sp. 
gr. ‘910. There are but few liquids which give a coloured vapour 
when boiled, but azulene is one of them. Its vapour is blue. It 
is soluble in alcohol, fatty and volatile oils, and many other liquids, 
to which it imparts its colour, but not in water. It is very per- 
manent, and bears a temperature of 700° to 800° F. in a sealed 
tube without alteration, and none but the strongest acids aided by 
heat will break up its constitution. It is most intensely blue, 
appearivg almost black when in a concentrated state. It is not 
decolorized by sulphurous acid, sulphuretted hydrogen, or bromine- 
water. It does not attach itself to animal charcoal, nor does it 
dye wool, cotton, or silk. It has been found to exist to the 
extent of 6 per cent. in pure oil of patchouli. 
Oil of patchouli contains a camphor called “ Patchouli camphor.” 
It crystallizes in regular hexagonal prisms, melts at 59° C., and 
boils at 296° C. Its composition is C);H,,O. It was investigated 
by Gal + and by Montgolfier ¢. It is considered to be an isomer 
of camphor of cubebs and of concrete oil of cedar. The conditions 
most favourable to the formation or deposition of this body are 
little known, but it has been remarked that it forms or separates 
more rapidly in samples of oil which have been desiccated by 
chloride of calcium. This camphor not having any commercial 
value, its formation is undesirable, but as it results from a simple 
molecular change, it may be difficult to prevent it; however, it is 
possible that the presence of a small quantity of water in the oil 
may at least retard it. A sample of oil filled up to the cork, 
* This seems strange, considering the way in which it can be fractionated 
when distilling directly from the leaf, and leads to the conclusion that although 
his samples may not have been adulterated, they were not intact, and that the 
finer and most volatile portion may have been abstracted from them. 
+ Bull. Soc. Chim, 1869, p. 304. 
t~ Comptes Rendus, 1877, p. 88. 
