Perfumes and their preparation

by George William Askinson

Fig. 18.

This procedure is very cumbrous and tedious and therefore had better be modified thus: In an air-tight box K (Fig. 19) we place a larger number of glass plates g covered with lard drawn into fine threads by means of a syringe. This box is connected with a smaller one K₁ which is filled with fresh flowers and provided with openings below and above, O and O₁. The latter, O₁ communicates by a tube with box K, at whose upper end is a tube e terminating in an exhaust fan so that the air must pass through the apparatus in the direction indicated by the arrows. A small fan V driven by clockwork will answer. The air drawn from K₁ is laden with odors and in passing over the fat as shown by the arrows gives them up completely to the fat. The use of this apparatus has very important advantages: the absorption is effected rapidly, requires little power, and the flowers do not come at all into contact with the fat which therefore can take up nothing but the odors present in the air.

Fig. 19.

Instead of charging the fat with odors by either one of the methods here described, carbonic acid can also be employed with advantage, by means of the apparatus illustrated in Fig. 20. The large glass vessel G contains pieces of white marble M upon which hydrochloric acid is poured at intervals through the funnel tube R. A current of carbonic acid is thus developed, which passes through a wash bottle W filled with water, then through the tin vessel B containing fresh flowers, and finally into a bottle A filled with strong alcohol and set in cold water, after which it escapes through the tube e. The carbonic acid absorbs the aromatic vapors from B and leaves them in the alcohol which absorbs them. (G, R, W are made of glass, B of tin.)

Fig. 20.

Extraction.

This method is based on the fact that some volatile liquids such as ether, chloroform, petroleum ether, or bisulphide of carbon possess the property of rapidly extracting the aromatic substances from flowers; when they are evaporated at a gentle heat they leave the pure odors behind. In our opinion this process is the best of all for the perfumer and it is to be regretted that it is not more generally used.

As a rule we employ either petroleum ether or bisulphide of carbon (see above, pp. 65, 66) because these products are cheaper than ether or chloroform.