OIL. 
Names. Coiour rh ty / Confiftency at 60°. Freezes at 14°, Odour, 
Nutmegs : - None. 948 Like butter, Very pleafant. 
Anifeed - - None Becomes folid at 50° Very ftrong. - 
Thyme - - Brown Cryitallizes Like camphor. 
pike - - Yellow 936 Very ttrong. 
Lavender - - None. Thin liquid. Very agreeable. 
Origanum - - . OF Very ftrong and acrid. 
Wormwood - - Green. 
Camomile - - Blue 
Hops - - - Green. Like butter. Like the flower. 
Parfley - - Green. 
Bergamotte = - - Yellow Not oily. Is folid at 23°, Very pleafant. 
Cardamom - - None. Oily 
ace - - Oily. Agreeable. 
Rofes - - None. 
Peppermint - - Green Thin liquid. Very agreeable. 
i - - None he Shas al 
Pepper - - None Like butter. Very a 
When the volatile oils are recently diftilled they evaporate 
they ‘have been expofed to the air for fume time they do not 
un c ; 
he effential oils, efpecially the more volatile of them, de- 
mofpheric air very completely, as was firft afcer- 
when in a clofe newly ond room 
The ation of oxygen upon thefe neg is very confpi- 
cuous. They become vifcid, and affume ellow colour. 
The colour becomes deeper, more seal; if it is expofed 
to the fun, and the oil ultimately affumes the form of refin. 
In thick oils another change takes"place ; 
Thefe cryftals, which have been occafionally miftaken for 
camphor, are flightly foluble in hot water, and more fo in 
alcohol; to which they communicate the property of red- 
dening vegetable e blues ; when gently heated, they {weil and 
cry ftallize in needles by cooling ; — heated by the blowpipe 
they evaporate, but do not inflame ; from thefe properties 
they have been confidered as an a very analogous to the 
benzoic. Some effential-oils afford real camphor by evapo- 
ration, as Proutt has ewn. See Campnor. ) if the mafs 
e 
If the furface of 
the heat of a ftove for a certain time, the oily part evapo- 
rates, eae a hard coating, which does not foften at a heat 
2 
» forming water, 
eaves a ee Ts lefs iy drapes. and in confequence 
more 
The a oils “from the great quantity of phd 
they contain, take fire with great facility, an 
copious white flame, producing much foot. If the produés 
of combuttion be colleéted, they will be found t- coll 
water and carbonic acid, derived from the carbon and hy- 
a of the oil, with the eel Sa = the atmofphere. 
y this means that we are to expect an analyfis of 
thefe “fabltances, an objet which hus on yet been accom. 
plifhed, but which is very defirable. 
The volatile oils do not undergo any change with hydro- 
gen or eee 
phu which they acquire a brownifh colour. 
Seal {mell. This falphurized oil aon ut on diftillation 
rar sae hydrogen; it is often called * balfam of 
fulphur 
It is faid that thefe compounds are decompofed by heat 
with a violent effervefcence, which is fuppofed to arife from 
the fulphur co ei ng with the hydrogen, forming ful- 
phuretted hydro 
Camphor, which’ may be deemed a concrete volatile oil, 
combines with phofphorus by arabe is compound 
may afterwards be diffole ed in moft of the volatile oils. The 
folution is lumiro ous when er to the air, fo as to tell 
the hour of the night. 
Water has ie ous upon the volatile oils. ‘The water, 
however, diffulv much as gives it a ftrong tafte of the 
oil. a ie oil is firft dropped upon fugar, and this put , 
into reater yore is — ed. Advantage is 
frequently pine of this arma 
hey are mottly Soluble i in saieoka ad ether, though in 
limited proportions. 
The 
