157 



Oil of Prunus AlUyU'daluS. The fat-oil (almond-oil) is 

 obtained by pressing the seeds. — Yellowish, mild, thinner than 

 olive-oil; of 0'920 density; becomes thickish at — 10°, at — 16° 

 white and at — 21° of butter-consistence; contains more olein than 

 olive-oil; dissolves in 25 parts cold and in 6 parts hot alcohol, in 

 any quantity of ether ; does not dry. 



The volatile oil, Oil of Bitter Almondsr^C^ He O2, does not 

 exist ready formed, but is produced from amygdalin, when in con- 

 tact with water and emulsin, together with hydrocyanic acid. Of 

 plants, yielding those two products, many ai*e known in the order 

 of Rosacea (see Amygdalin). The oil, obtained by distillation, is 

 freed from hydrocyanic acid by shaking with potash-ley or 

 hydrated iron-suboxyd and water or mercury-oxyd and water; 

 then poured off and rectified. — A colourless, thin oil of peculiar 

 obour and burning aromatic taste; of 1"043 density; boils at 

 180°; dissolves in 30 parts water, readily in alcohol and ether; is, 

 by keeping at the air, converted into benzoic acid; solidifies under 

 the influence of ammonia slowly to a ciystalline mass (hydi*o- 

 benzamid). 



Oil of QuerCUS. Obtained by distilling the fruit (acorns) of 

 Q. robur with watei*. — Of butter-consistence and peculiar, strong- 

 smell; lighter than water. 



Oil of Reseda luteola. Obtained by pressing the seeds. — 

 Dark- green, thin, of nauseous taste and smell; of 0"935 density; 

 remains liquid at — 15°; dries readily. 



Oil of Reseda Odorata. Obtained from the flowei-s by ex- 

 traction with ether. — Is yellowish, thickish through the admixture 

 of wax; lighter than water; of a most pleasant odour. 



Oil of Ricinus rr Castor Oil. 



Oil of Rosa. Obtained by aqueous distillation from the 

 flowers of various I'oses, especially from R. centifolia, R. Damas- 

 cena, R. Indica, R. moschata, and R. sempervirens. — Colourless, at 

 11°-16° of lamellar-crystalline appearance, fuses at 20° to 30°, has 

 a fragrant rose-odour and a mild, somewhat sweetish flavour; is of 

 0*870 density at 18°, and boils at 227°. It is a mixture of an 

 inodorous stearopten=:Ci6 Hie, fusing at 32° to 35°, distilling un- 

 decomposed at 280°-300°, and an oxygenised elseopten, which is 

 the odoriferous pi'inciple. [According to R. Baur, the elseopten is 

 convertible into the stearopten by treating with zinc, hydrochloric 

 acid, and alcohol.] 



Oil of Rosmarinus ofRcinalis (rosemary). Obtained from the 

 leaves and flowers by aqueous distillation. — Colourless or yellow- 

 ish, tastes and smells of the herb, somewhat camphorlike; of 

 0"886-0-933 density; dissolves readily in alcohol. It is a 



