THE ODOUR OF ROSE. 51 
form, filtered, pressed, and washed with the same solvents (in 
which it is practically insoluble). The washed bisulphite com- 
pound, now free from residual oil, is freed from ether by exposure 
to the air for a few hours. At this stage it has the appearance of 
wax orsoap. To liberate the aldehyde, the dry mass is mixed 
with crystallized sodic carbonate, in the proportion of 450 grammes 
of the former to 350 grammes of the latter, in a large flask. 
Steam is then admitted into the mixture, which now liquefies, and 
yields a distillate of about 250 grammes. 
On fractionating this oil, the first portion, amounting to 75 c.c., 
is limpid and colourless, boils between 177° and 180°, and has a 
lemon-like odour. The second portion, a somewhat thicker oil 
amounting to 120 c. c., and boiling between 222° and 224°, is of a 
slightly greenish colour, and has a pleasant rose-like odour *. 
Another observer, Kremers (Proc. Amer. Pharm. Assn. 1887), 
found that the sodium bisulphite compound could be decomposed 
by dilute sulphuric acid at a gentle heat, and the sulphur dioxide 
removed by dry potassium carbonate. The aldehyde thus obtained 
being a viscid yellow liquid, possessing a geranium-like odour. 
As before cbserved, otto of rose and rose-water, obtained by 
distillation, do not give an idea of the true odour of rose, the most 
delicate fragrance being destroyed by contact with boiling water, 
In a manufacturing way the fragrance of the rose m its integrity 
is more nearly obtainable by subjecting the separated petals to the 
process of “ maceration” in pure grease, and finishing off the 
product by the process of “enfleurage;” the perfume being 
ultimately extracted from the grease by a solvent. Many flowers 
whose perfumes are destroyed by heat are submitted to these 
processes. 
In the first process, when oil is used, it is the very finest olive- 
oil produced by the trees in the neighbourhood of Grasse, or that 
part of the coast. This is put into copper vats holding about 50 
gallons; 1 ewt. of flowers is added and well stirred in. After an 
immersion of some hours, and in some cases a whele day, the 
flowers are strained out by means of a large tin sieve. The oil is 
treated with several successive charges of flower until sufficiently 
impregnated. It is then clarified by filtration through paper or a 
* American Chemical Journal, xi. p. 457. 
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