- 8 4 - 



by expression is yellowish and turbid 2 ), separating off stearoptene 3 ) 

 at — 20°, possessing a very pleasant odour; the distilled oil is colour- 

 less and has a less pleasant odour; d 15 o below i; « D to the right 4 ); 

 soluble in ether and 95 per cent, alcohol, forms only cloudy solutions 

 with 85 per cent, alcohol. 



*) Distillation of the oil is quite irrational, as such oils rapidly deteriorate and 

 then acquire an unpleasant pungent odour. 



2 ) At ordinary temperature lemon oil is mostly clear; a possible turbidity is 

 caused by slimy or vegetable wax-like constituents. 



3 ) The separation called "stearoptene" consists of substances of the character 

 of vegetable wax. 



4 ) More precise data would here be very much to the point. The specific 

 gravity of good lemon oil obtained by expression lies between 0,857 and 0,861 (15 ) 

 and the rotation between +58 and -|- °5° ( at 20 ° Q. 



$) Of 95 per cent, alcohol about 1 vol. is required to form a solution. 



Menthol [Mentol). Colourless needles; di 5 o 0,89; ^ to the left; 

 melting point 42 01 ); boiling point 208 02 ); scarcely soluble in water, 

 readily soluble in alcohol, ether, chloroform, and fatty oils; volatilises 

 without residue. 



1 ) Melting point 42 to 43 . 



2 ) Boiling point 21 2° (760 mm). 



Mustard Oil [Esencia de mostaza negro). Colourless or yellowish; 

 when exposed to the air, decomposition occurs with red or brown 

 coloration; d^o 1,018 *); boiling point about 148 02 ); readily soluble 

 in alcohol, ether, and chloroform; should not contain any fatty oil; 

 a solution of 1 part mustard oil in 5 parts alcohol must not be coloured 

 red or blue by ferric chloride. 



*) The specific gravity of mustard oil at 15 fluctuates between 1,014 and 1,025. 

 2 ) On distillation the bulk of mustard oil passes over between 148 and 153 . 



Neroli Oil [Esencia de azahar). Colourless 1 ), in course of time 

 yellowish; di 5 o 0,85 to 0,90 2 ); «d to the right; neutral 3 ); when at 

 rest, separation of a white crystalline mass, which dissolves with diffic- 

 ulty in alcohol. Taste aromatic, not bitter 4 ). 



*) Neroli oil is never colourless, but right from the first yellowish; in course 

 of time it becomes reddish-brown. 



2 ) The specific gravity lies between 0,870 and 0,880. 



8 ) Oils containing ester show almost always a minute content of free acid. 



4 ) The after-taste is somewhat bitter. 



Peppermint Oil {Esencia de menta piperita). Colourless or 

 yellowish green; d^o 0,89 to 0,92; a D to the left; acid reaction; 

 readily soluble in alcohol. 



Rosemary Oil [Esencia de romerd). Colourless 'or yellowish; 

 di 5 o 0,88 to 0,91 x ); «d to the left 2 ); neutral reaction; soluble in every 

 proportion in 85 per cent, alcohol 3 ). 



