— 73 — 
a flocculent precipitate should be formed; identity-reaction with ferric 
chloride, and test for carbolic acid. 
^) For the boiling point the example of the German and Swedish Pharma- 
copoeias should be followed: 251° to 253°. 
Oil of Fennel {Foeniculi essentia). Colourless or yellowish; 
d^go = 0,965 to 0,975; at about 0° anethol crystals separate out, which 
dissolve again at -{~5°'^)^ completely soluble in an equal vol. alcohol. 
^) The separation of anethol may have to be brought about by inoculation with 
a small crystal of pure anethol. 
Oil of Lavender {Lavandulae esseittia). Colourless^), yellowish, 
or yellowish-green; d-^go = 0,885 to 0,895; soluble in three parts 70 per 
cent, alcohol; ester-content (determined after neutralisation of the acid) : 
at least 29,4 per cent, linalyl acetate^). 
^) Only the rectified oils are colourless, but these are inferior. Compare our 
Report October 1894, 30. 
^) For 2 grams oil a minimum of 13 cc. semi-normal potash solution is required, 
which would correspond to an ester number of 182 = 63,7 per cent, linalyl acetate. 
The minimum content of linalyl acetate (29,4 per cent.) corresponds to an ester number 
of 84, or a consumption of 6 cc. semi-normal solution for 2 grams oil. 
Oil of Lemon {Citri essentia), d-,^50 ===0,858 to 0,861; dissolves 
clear or with a slight turbidity in 5 parts alcohol; makes a clear mixture 
with carbon disulphide in every proportion^). 
The solubility tests have little value for lemon oil, but a statement of the 
rotatory power would be very useful in this place; good lemon oil at 20° should 
have an optical rotation of at least 58°, and at most -[- 65°. 
Menthol. Needle-shaped, colourless crystals; almost insoluble in 
alcohol, ether, and chloroform i); melting point 42° to 43°; boiling point 
2 1 2° 2) J the solution of 0,1 gram menthol in i gram glacial acetic acid 
should not colour when three drops sulphuric acid and one drop nitric 
acid are added; when evaporated on the water bath, 0,1 gram menthol 
should leave no weighable residue. 
^) This should clearly be: almost insoluble in water, readily soluble in alcohol, 
ether, and chloroform. 
^) The determination of the melting point would suffice for judging the menthol. 
Oil of Mustard [Sinapis essentia). Colourless or yellowish; 
d^50 = 1,020; boiling point 149°^); very sparingly soluble in water, 
readily soluble in alcohol, ether, and carbon disulphide. 
For the rest the tests agree with those of the German Pharmacopoeia, 
excepting that a somewhat higher minimum content of isothiocyanallyl 
is required. 
In this case also certain fluctuations in the specific gravity and boiling point 
should be admissible, and we therefore suggest the following test: dj^o = 1,016 to 
1,025; rnustard oil should boil chiefly between 147° and 152°, and the first as well 
as the last portions of the distillate should have no pronounced difference in the 
specific gravity from mustard oil itself. 
