i NOTES ON SCIENTIFIC RESEARCH. 71 
total to 100 g. To 5 cc. of this reagent he adds 1 drop of the oil to be tested, 
shakes thoroughly, and allows the mixture to stand for a quarter of an hour at 
ordinary temperature, but protected against daylight; he then heats it for 5 minutes 
on a boiling water-bath and finally shakes it with chloroform after cooling. The 
colorations during the three treatments are noted and compared with the indications 
of the tables mentioned below, or with samples of oils already known. When shaking 
with chloroform, the colouring matter passes into this, and different shades may then 
more easily be recognized. Cerdeiras tested in this way 42 different essential oils. 
He gives the results in the form of tables, in which are indicated: the colouring of 
every oil shown after a quarter of an hour, id. after 5 minutes’ heating on a water-bath, 
and the colour of the chloroform after shaking out. 
Quantitative estimation of camphor in camphorated alcohol. 
In order to determine the contents of camphor in camphorated alcohol, W. B.D. 
Penniman and W. W. Randall‘) pour an exactly measured quantity of this preparation 
into a flask with graduated neck (Babcock’s milk bottle), adding an aqueous solution 
of calcium chloride (d 1,37) until the liquid comes up to the neck. They then add 
exactly 1 cc. of light petroleum (b. p. 40 to 60°) and fill up with calcium chloride 
solution until the top graduation mark is reached. After the flask has been shaken 
_ thoroughly, it is put into a centrifugal machine for about 5 minutes. Should the cal- 
cium chloride solution still not be clear after this, the process is repeated. The 
increase in volume of the ether zone corresponds to the amount of camphor contained 
in the camphorated alcohol. In the same manner the contents of essential oils in 
essences, such as peppermint or lemon essences, may be determined. 
Quantitative estimation of aldehydes. 
M. Tiffeneau*?) recommends the use of melubrin (sodium phenyldimethylpyrazolone 
amidomethanalsulphonate) for the quantitative estimation of aldehydes. He describes 
the determination of benzaldehyde in cherry-laurel water and of heliotropin (m. p. 2) in 
commercial preparations. In this latter case he proceeds as follows: 0,20 g. of helio- 
tropin are dissolved in 1 cc. of 96 p.c. alcohol, and a solution of 1,5 g. of melubrin 
in 4cc. of water is then added. The next day, the deposit is collected on a weighed 
filter, dried and weighed. Tiffeneau thus found, as an average for two tests, 0,42 g. 
of piperonylidenaminopyrine, which indicates that the heliotropin used was 94,3 p.c. 
It still remains to be decided whether this result is due to lack of purity in the 
preparation or to defects of the method of testing. 
As to colour reactions of vanillin see page 61 of this Report. 
Determination of eucalyptol according to Dodge’s oxidation method. 
In our Report of April 1913 (page 62) we discussed a method proposed by 
F. D. Dodge for determining eucalyptol in eucalyptus and cajuput oils. It is based 
upon the fact that cineol is comparatively stable under the action of potassium per- 
manganate, and is carried out as follows: the volatile oil in question is shaken with 
a5 to 6 p.c. solution of potassium permanganate, which is gradually added under 
cooling with ice-water, until there is an excess of it. The quantity of the eucalyptol 
1) Journ, Ind. Eng. Chemistry 6 (1914), 926. — *) Bull. Sciences pharmacol. 21 (1914), 71. 
