— 93 — 
Lavender Oil (Essenza di lavanda). Colourless or pale-yellow^); 
d^go = 0,885 to 0,895; soluble in alcohol in every proportion. 
^) Only rectified lavender oils are colourless, which, however, are inferior. 
Comp. Report October 1894, 30. 
Menthol. Colourless. Melting point 42° to 43°, boiling point 
212^; almost insoluble in water, very readily soluble in alcohol and 
ether; menthol should dissolve without colouration in a mixture of i cc 
acetic acid, with 3 drops concentrated sulphuric acid and i drop nitric 
acid. When evaporated on a wather bath, 0,1 gm. menthol should leave 
no weighable residue. 
Mustard Oil (Essenza di senape). Colourless, gradually yellowish 
with reddish tinge; the artificial oil has the specific gravity 1,020^), 
the natural oil 1,018 to 1,025; boiling point 148° 2); readily soluble in 
alcohol, ether, and carbon disulphide, very sparingly in water (i : 1000); 
when a few drops of oil are boiled with alcoholic potash solution, and 
subsequently diluted with water, a violet coloration occurs when sodium 
nitroprusside is added; the solution of 0,5 cc oil in 2 to 3 cc alcohol 
must not be coloured red or violet by a drop of ferric chloride sol- 
ution (test for phenol). 
^) For the artificial oil, also certain limits of value should be fixed, as here 
also slight fluctuations cannot be avoided. The specific gravity of allyl isosulpho- 
cyanate lies between 1,020 and 1,025. 
^) The statement with regard to the boiling point does not agree with the 
facts. A good mustard oil is required to boil chiefly between 147° and 152°, and 
the first as well as the last portion should have a specific gravity not appreciably 
differing from that of mustard oil itself. 
With regard to the other points specially to be observed in the determination 
of the boiling temperature, compare eucalyptol, note 2, page 92. 
Orange-blossom Oil (Essenza di fiori d' arancio amaro). Colourless^), 
under the influence of air and light yellow to reddish; d-^^o == 0,872 
to 0,890 2); soluble in I to 2 parts alcohol, when more solvent is added 
opalescence^); when the oil is shaken with a concentrated solution of 
sodium bisulphite, it should acquire a red colour^); the blue fluor- 
escence of the oil becomes more pronounced when alcohol is added. 
^) Freshly distilled neroli oil also is not colourless, but yellowish. 
^) The specific gravity fluctuates between 0,870 and 0,880. 
^) The statements respecting the solubility relate to alcohol of 80 ^/^ by volume, 
as neroli oil makes a clear solution with 90 alcohol in every proportion ; a slight 
opalescence in consequence of separation of paraffin occurs also in this case after 
some time. 
^) This test is of no value for judging the oil. 
Peppermint Oil (Essenza di menta). Colourless, straw-coloured, or 
greenish; on exposure to air the colour becomes gradually yellow and 
the oil viscid; d^go = 0,890 to 0,920; soluble in an equal part of 
alcohol; the oil solidifies between — 8° and — 20°, with separation 
