ON ATTAR OF ROSE. 
291 
Geranium oil is mixed with attar in almost any proportion, from a few parts 
per cent, up to 80 or 90. The differences in congealing point are not quite in 
proportion to the relative volumes of the two oils which are mixed, apart from 
the variable properties of each ; and to calculate the amount of mixture that is 
required to suit a particular market, one has always to make some preliminary 
trials as to the congealing point. Thus it will be seen that the business of 
adulterating attar is somewhat troublesome, but honest dealing out of the ques¬ 
tion, it is very profitable. 
Many attempts have been made to discover some chemical reaction which 
would reveal the falsification of attar with geranium oil, but hitherto mostly in 
vain. As completely deceptive may be noticed Guibourt’s test with the vapour 
of iodine ; and also that with K I and starch. The author has had the oppor¬ 
tunity of preparing a standard attar of rose on the spot and was also in a posi¬ 
tion, such as scarcely another chemist ever was, for investigating the whole 
subject. Pure attar gives with iodine and with iodide of potassium and starch 
the same reactions as when it is mixed with geranium oil, and even those with 
pure geranium oil are hardly different. The proposed tests of 1S T 0 5 , N 0 4 and 
S0 3 are equally devoid of value. 
Among reactions such as these, there is not one of real importance for the re¬ 
cognition and determination of geranium oil when mixed with attar. The 
author has learnt to distinguish but one constant character for geranium oil, 
which is that of not diverting a ray of polarized light; whilst attar in a tube of‘ 
100 mm. rotates the ray 4° to the right. Here is the single handle for the ex¬ 
amination of a suspected attar. Considerable difficulties are certainly in the 
way of using such a test. The differences observable are very small, and the 
test is in fact applicable only in the case of very gross adulteration. In the use 
of a longer tube (say about 200 mm.) there are difficulties from the colour of 
the oil and its want of transparency. The author has recently made trials of 
another form of polarizing apparatus constructed expressly for the purpose 
which has enabled him to detect in attar of rose so small an addition of geranium 
oil as 5 per cent. ; but such an apparatus is somewhat exjoensive and much 
practice is required in order to use it effectively.* 
The author considers that an attar of rose which at a temperature of C. 
(54‘5° Falir.) in a thin glass tube does not congeal well in the space of 
five minutes ; and which has not moreover a dextrogyre rotatory power of 4°, 
should be returned to the seller; no matter how fine may be its odour. That 
there are attars which solidify at 10° C. (50° Fahr.) and yet are genuine (owing, 
for instance to faultily conducted or to repeated distillation) is just as true as 
that there are those which do the same at from 20° to 25° C. (68° to 77° Fahr.) 
and are yet of indubitable goodness. But these are exceptional as in the case 
of opium, certain indubitably pure samples of which have yielded respectively 2 
and 16 per cent, of morphia. 
To obtain attar of rose as far as possible free from adulteration, the author 
recommends that purchasers should address themselves to well-known and re¬ 
spectable firms, who possess whatever facilities exist for obtaining a genuine 
product; yet with all this, no firm would probably be willing to give an abso¬ 
lute guarantee in respect to such an article.f 
* The difficulties of employing polarized light for the discrimination of attar are, in my 
opinion, too considerable for the test to be at present of any practical value. I may refer 
to some experiments on the subject made in 1857 by my friend Dr. De Vry, the results of 
which by no means accord with those obtained by Dr. Baur. D. H. 
f To this excellent recommendation should be added another, namely that purchasers 
should be willing to pay a remunerative price for a good drug. Some years ago a quantity 
of attar of rose was consigned to a house in London, with directions that it should not be 
sold unless at a certain high price, but that if no purchaser could be found for it, a certain 
