— 102 



Lemon Oil {Aetheroleum Citri). Bright yellow ; di 5 o 0,855 to o,86i 1 ); 

 a D20° -(-58 to — (— 65 ; usually not quite clearly soluble in 5 parts of 

 spiritus cone. Oil of lemon should only have a slight deposit and give 

 no strongly acid reaction. 



*) Pure oils of less than 0,857 sp. gr. are very rare, and we have only on very 

 exceptional occasions observed a sp. gr. so low as 0,856, never one below that figure. 



Menthol (Mentholum). Colourless, brittle crystalline needles, almost 

 insoluble in water, readily soluble in spiritus cone, ether, chloroform 

 and fatty oils; m. p. 43 01 ); b. p. 212 02 ); 0,1 g. menthol, when heated 

 on the water-bath, should evaporate without leaving a residue. 



*) The m. p. lies between 43,5 and 44,5°. 



2 ) Menthol boils at 217 when the mercury column of the thermometer is 

 wholly surrounded by the vapours. See Introduction. 



Mustard Oil {Aetheroleum Sinapis). Colourless or pale yellow; 

 di5o 1,016 to 1,02 5 *); «d ±o°; soluble in any proportion in spiritus 

 cone, ether, benzene and carbon disulphide. On distillation the bulk 

 should pass over between 147 and 152 , and the sp. gr. of the first, as 

 well of the last, fraction should not differ materially from that of 

 the original oil; thiosinamine and sulphuric acid tests; ferric chloride 

 reaction; isothiocyanallyl content 82,3 to 100 % 2 ). 



*) We have found pure oils to have as low a sp. gr. as 1,014. 



2 ) The present edition of the Pharmacopoeia prescribes a test which differs 

 from the older method to this extent that the mustard oil is no longer to be left 

 standing with the ammoniacal silver solution for 24 hours at normal temperature, but 

 only for 1 hour at a temperature of about 75 . See our Report April 1908, 70. 



Peppermint Oil [Aetheroleum Menthae pipefitae) 1 ). Colourless, 

 yellowish or faintly yellow green; diso 0,90 to 0,92; «d to the left; 

 1 part of oil should give a clear, or at most a faintly opalescent 

 solution with 3 to 4 parts of spiritus dil. Iodine reaction 2 ). 



1 ) English as well as American oil answers these requirements. 



2 ) Reactions of this kind are out of date and purposeless. 



Rosemary Oil {Aetheroleum Rosmarini). Colourless or bright 

 greenish yellow; d^o 0,90 to 0,92; « D to the right; soluble in 0,5 parts 

 of spiritus cone. 



Sandal Oil {Aetheroleum Santali). Bright yellow, somewhat viscid; 

 faintly acid reaction; di 5 o 0,975 to 0,985; «D20° — 1 7 to — 20 *) soluble 

 in any proportion in spiritus cone, and in from 5 to 6 parts of dilute alcohol. 



1 ) As we have been able to observe in our own, normal distillates, the rotation 

 is occasionally a little less. Compare Report October 1905, 64. 



Thymol (Thymoluni). Colourless, transparent crystals, soluble in 

 water (1 100 parts), glycerin (100 parts) and very readily in spiritus cone, 

 ether and chloroform, also soluble in fatty and essential oils and in 

 soda solution; m. p. 50 to 5 2 , b. p. 228 to 230 01 ). When solid 

 thymol sinks in water; in tho molten state it floats upon it; 0,2 g. of 



