— 72 — 



boiling point about 180 ; soluble in every proportion in alcohol, also 

 in an equal volume 70 per cent, alcohol 5 ); test for absence of chlorinated 

 products. 



*) Comp. note under benzaldehyde. 



2 ) Such a content of hydrocyanic acid cannot always be guaranteed. 



3 ) The specific gravity given is for a temperature of 15 , but it should be 

 taken into consideration that even in the case of absolutely normal oils, it often 

 amounts to 1,070; for 25 the following figures apply: 1,038 to 1,063 (comp. table). 



4 ) Occasionally a feeble optical activity is also observed. 



6 ) Of 70 per cent, alcohol, 1 to 2 volumes are required to dissolve the oil. 



Cajeput Oil (Oleum cajuputi). Colourless or greenish; cineol - 

 content at least 55 percent, by volume 1 ); d25o 0,915 to 0,9252); laevorot- 

 atory, «D25° not above — 2 03 ); soluble in every proportion in alcohol, 

 also in 1 part 80 per cent, alcohol. 



*) The estimation of cineol is accomplished by means of phosphoric acid in 

 the following manner: 10 cc. oil are dissolved in 50 cc. petroleum ether, and to 

 the well cooled solution (freezing mixture) is gradually added, whilst stirring, concent- 

 rated phosphoric acid, until the white compound separating off acquires a yellowish 

 (or reddish) shade. The crystalline mass is then filtered off with a suction pump, 

 washed with petroleum ether, pressed to remove the last liquid portions, and decom- 

 posed with water. The cineol separated off is estimated volumetrically and the 

 percentage calculated. 



"We have again convinced ourselves by estimations of mixtures of a known 

 cineol-content, that this method does not always give reliable results. This applies 

 specially to oils less rich in cineol; for example, in mixtures of 50 per cent., the 

 content of cineol found was up to 8 per cent, too littie, although we endeavoured 

 by different small improvements, to avoid sources of error as much as possible. 

 For this reason, the cineol-estimations can only lay claim to approximate accuracy. 



2 ) As lower limit of value, 0,913 is to be recommended (comp. table). 



3 ) With pure distillates, we have observed rotations up to — 2° 40'. 



Camphor (Camphord). White, transparent mass; d 2 so 0,990; « D to 

 the right; melting point 175 ; boiling point 204 . 



Caraway Oil (Oleum can). Colourless or pale yellow; d25© 0,905 

 to 0,915*); a D25°-t~7 to 4~8o°; soluble in an equal volume alcohol, 

 and in 3 to 10 volumes 80 per cent, alcohol. 



x ) The specific gravity given applies to a temperature of 15 ; it should read: 

 d 25 o 0,899 to 0,909 (comp. table). 



Cassia Oil 1 ) (Oleum cinnamomi). Yellowish or brownish; content 

 of cinnamic aldehyde at least 75 per cent, by volume; d25o 1,045 to 

 1,055 2 ); a 25° between — i° and -J- i°; soluble in 2 volumes 70 per 

 cent, alcohol. 



1 ) Only the rectified oil answers the requirements given. 



2 ) The upper limit of value given is slightly too low; it should be 1,059 

 (comp. table). 



Chenopodium Oil (Oleum chenopodii). Colourless or yellow, 

 d25o about 0,965 to 0,985*); laevorotatory, a D25 o not above — 5° 2 ); 

 soluble in 5 volumes 70 per cent, alcohol. 



