OILS/VOLATILE 457 



residuum, -whilst an oil mixed with any of the above substances leaves a translucent 

 etain upon the paper. If fat oil be present, it will remain undissolved, on mixing the 

 adulterated essential oil with thrice its volume of spirit of wine of specific gravity 

 0-840. Kesinous matter mixed with volatile oil is easily detected, being left in the 

 alembic after distillation. Oil diluted with spirit of wine forms a milky emulsion on 

 the addition of water ; the alcohol is absorbed by the water, and the oil afterwards 

 found on the surface, in a graduated glass tube, will show by its quantity the amount 

 of the adulteration. 



Oil of bitter almonds is prepared by exposing the bitter-almond cake, from which 

 he bland oil has been expressed, in a sieve to the vapour of water rising within the 

 still. The steam, as it passes up through the bruised almond parenchyma, carries off 

 its volatile oil, and condenses along with it in the worm. The oil which first comes 

 over, and which falls to the bottom of the water, has so pungent and penetrating a 

 smell, that it is more like cyanogen gas than hydrocyanic or prussic acid. This oil has 

 a golden yellow colour ; it is heavier than water ; when much diluted, it has an 

 agreeable smell, and a bitter burning taste. When exposed to the air, it absorbs 

 oxygen, and lets fall a heap of crystals of benzoic acid. Perfumers formerly employed 

 a great quantity of this oil in scenting their soaps. But nitro-benzole is now used, 

 instead of the essential oil of bitter almonds, in flavouring. See BENZOLE ; NITKO- 

 BENZOLE. A similar oil is obtained by distilling the following substances with water : 

 the leaves of the peach (Amygdalus Pcrsica), the leaves of the bay-laurel (Primus 

 lauro-ccrasus), and the bruised kernels of cherry- and plum -stones. All these oils 

 contain hydrocyanic acid, which renders them poisonous, and they also generate 

 benzoic acid, by absorbing oxygen on exposure to air. 



Oil of anise-seed is extracted by distillation from the ' seeds ' of the Pimpindla anisum, 



Oil of bergamot is extracted by pressure from the rind of the ripe fruit of the Citrus 

 bergamia. 



Oil of cajeput is prepared in the Moluccas, by distilling the dry leaves of the 

 Melaleuca cajeputi. Cajeput is a native word, signifying merely a- white tree. This oil 

 is green ; it has a burning taste, a strong smell of camphor, turpentine, and savine. 



The oil of caraway is extracted from the seeds (cremocarps) of the Carum carui. 



The oil of cassia, from the Cinnamomum cassia, is yellow passing into brown. 



The oil of chamomile is extracted by distillation from the flowers of the Anthemis 

 nobilis. It has a blue colour when quite fresh, but becomes yellow by exposure ; it 

 possesses the peculiar smell of the plant. 



Oil of cinnamon is extracted by distillation from the bark of the Laums cinnamomum. 

 It is produced chiefly in Ceylon from the pieces of bark unfit for exportation. It is 

 distilled over with difficulty, and the process is promoted by the addition of salt water, 

 and the use of a low still. 



The oil of cloves is extracted from the dried flower-buds of the Caryophyllus aroma- 

 ticus. It is colourless, or yellowish, has a strong smell of the cloves, and a burning 

 taste. It is one of the least volatile oils. 



The oil of elder is extracted by distillation from the flowers of the Sambucus nigra. 



Oil of fennel is extracted by distillation from the seeds of the Ancthum Fceniculuw. 



Oil of juniper is obtained by distilling juniper berries along with -water. These 

 should be bruised, because their oil is contained in small sacs or reservoirs, which 

 must be laid open before the oil can escape. It is limpid and colourless, or sometimes 

 of a faint greenish yellow colour. 



The oil of lavender is extracted from the flowering spike of the Lavandula vera. 



OH of lemons is extracted by pressure from the yellow peel of the fruit of the 

 lemon or Citrus limonum. 



The oil of mace lets fall, after a certain time, a concrete oil under the form of a 

 crystalline crust, called by John myristicine. 



The oil of nutmegs is extracted chiefly from mace, which is the inner epidermis of 

 these nuts. 



The oil of orange-flowers, called neroli, is extracted from the fresh flowers of the 

 Citrus aurantlum. When recently prepared it is yellow ; but when exposed for two 

 hours to the rays of the sun, or for a longer time to diffuse daylight, it becomes of a 

 yellowish-red. It is very fluid, lighter than wa!:er, and has a most agreeable smell. The 

 aqueous solution, known under the name of orange-flower water, is used as a perfume. 



The oil of parsley is extracted from the Apium Petroselinum^ 



The oil of pepper is extracted from the Piper nigrum. 



The oil of peppermint is extracted from the Mcntha piperita. 



The oil of pimento is extracted from the envelopes of the fruit of the Eugtnia 

 pimento, which afford 8 per cent, of it. 



The oil of rhodium is extracted from the wood of the Convolvulus scoparius. 



