— 29 — 
H. von Soden and W. Rojahn^) have been able to isolate from 
the hydrocarbons of an oil of clove stems, naphthalene 2), a body which 
up to now had not been detected as a constituent of an essential oiL 
Oil of Copaiba, Oil of copaiba has been adopted officially only 
by the British Pharmacopoeia, and it is there required to have a 
specific gravity of 0,900 to 0,910, Isevorotatory power, and solubility 
in an equal volume of absolute alcohol. The degree of Isevogyration 
is not given, but in the article ''Copaiba", i. e. copaiba balsam, it 
is stated that the essential oil, contained up to 40 per cent in the 
balsam, must have a rotatory power of — 28° to — 34^. That 
this condition is evidently due to an error is a matter to which 
F. W. Short^) has first called attention; Parry, as appears from a 
recently published communication^) by him, is also of opinion, that 
many oils of copaiba, although unadulterated, do not possess such a 
rotatory power. According to our own experience, the extreme limits 
within which the rotator v power may fluctuate, should be taken as 
— 7^ and — 35°. 
But, according to Parry, much adulterated copaiba balsam has^ 
especially in recent times, been placed on the market, from which 
either a dextrogyrate (up to -|- 28^) oil is obtained, or one which 
is very strongly Isevorotatory ( — 50° to — 60^). If such oils are 
to be judged, it may always be taken for granted that they are 
adulterated; the change in the rotatory power in the first-named case 
would lead to the conclusion that so-called African copaiba balsam 
had been added, whilst in the second case it might be assumed that 
gurjun balsam had been mixed with the material used for distillation. 
Oil of gurjun balsam, also called East Indian copaiba oil, would no 
doubt, when added to copaiba oil, raise the latter's specific gravity, 
whereas the oil of African copaiba reduces the solubility in absolute 
alcohol required by the British Pharmacopoeia. 
Cypress Oil. In the cohobation of the distillation waters there 
is here also obtained a very volatile, yellow-coloured distillate, in 
which can be detected without difficulty methyl alcohol, diacetyl, and 
furfurol, bodies which have already been found repeatedly in distil- 
lation waters. They were identified in the usual manner: methyl 
alcohol by the acid oxalate; diacetyl was separated as monophenyl- 
hydrazone, or osazone; and furfurol was recognised by its boiling 
point, its colour-reaction with aniline and toluidine, and was also 
^) Pharm. Zeitung 47 (1902), 779. 
^) The same substance has been found by the authors in the essential oil from 
the bark of a storax. 
^) Pharra. Journ. 64 (1900), 54. 
^) The Chemist and Druggist 62 (1903), 332. 
