Indian Forest Records. 
6 
[Vol. IV. 
Pure freshly distilled turpentine oil is a colourless, limpid, 
mobile liquid, which is neutral to the test paper. It has a peculiar 
odour, which varies according to the age. The sharp odour observed 
in old oils is believed to be due to the presence of an aldehyde, 
which is formed by the action of the atmospheric oxygen on the oil. 
Turpentine oil is volatile at ordinary temperatures and becomes 
slightly resinified by long contact with air. 
Crude turpentine oil gives a faintly acid reaction due to small 
quantities of free formic and acetic acids present. It has, there¬ 
fore, to be rectified with lime for certain purposes. Even pure oil, 
which has not been kept in well-closed vessels, shows an acid reac¬ 
tion due to the oxidation products formed. 
Solubility .—Turpentine oil dissolves with difficulty in alcohol, 
especially in dilute alcohol. The solubility, however, in this 
reagent increases with age, owing to the formation of readily 
soluble oxidation products. A good turpentine oil in general 
requires 5—9 parts of 90 per cent, alcohol to effect a clear solution. 
Ether, chloroform, carbon bisulphide, benzene, petroleum ether, 
glacial acetic acid and the fatty oils dissolve turpentine oil in 
almost all proportions. 
Turpentine oil is extensively employed for dissolving fats, 
resins, caoutchouc and is used in the arts for the preparation of 
varnishes and paints. 
Boiling point .—The greater portion of good turpentine oil (75— 
80 per cent.) boils between 155°—163° C. 
Rotatory power .—The several varieties of turpentine oil have 
different rotatory powers, some being dextro-rotatory or dextro¬ 
gyrate, others laevogyrate. The French turpentine oil is invariably 
strongly la3vogyrate while the American is generally dextrogyrate 
and seldom lsevogyrate. The optical activity of the American oil 
as determined by Dr. Armstrong isaD*=+9° 3(T to +14° 17' 
and that of French turpentine ctD = - 30° to - 30° 30k 
Specific gravity .—The specific gravity of a good turpentine oil 
is always between 0'8G2 and 0'872 at 15*55° C. The oil of com¬ 
merce, however, is sometimes found to have a greater specific 
gravity than the latter limit. 
(X D is the observed angle of rotation with sodium light in a 100 mm. tube. 
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