ALCOHOL.
308. Fermented Liquor.
Experiment 130.--Introduce 20 cc.of molasses into a flask of 200
cc, fill it with water to the neck, and put in half a cake of
yeast. Fit to this a d.t., and pass the end of it into a t.t.
holding a clear solution of lime water. Leave in a warm place for
two or three days. Then look for a turbidity in the lime water,
and account for it. See whether the liquid in the flask is sweet.
The sugar should be changed to alcohol and CO2. This is fermented
liquor; it contains a small percentage of alcohol.
309. Distilled Liquor. Experiment 131.--Attach the flask used in
the last experiment to the apparatus for distilling water (Fig.
32), and distil not more than one-fifth of the liquid, leaving
the rest in the flask. The greater part of the alcohol will pass
over. To obtain it all, at least half of the liquid must be
distilled; what passes over towards the last is mostly water.
Taste and smell the distillate. Put some into an e.d. and touch a
lighted match to it. If it does not burn, redistil half of the
distillate and try to ignite the product. Try the combustibility
of commercial alcohol; of Jamaica ginger, or of any other liquid
known to contain alcohol.
310. Effect on the System.
Experiment 132.--Put a little of the white of egg into an e.d. or
a beaker; cover it with strong alcohol and note the effect.
Strong alcohol has the same coagulating action on the brain and
on the tissues generally, when taken into the system, absorbing
water from them, hardening them, and contracting them in bulk.
311. Affinity for Water.
Experiment 133.--To show the contraction in mixing alcohol and
water, measure exactly 5cc.of alcohol and 5cc.of water. Pour them
together, and presently measure the mixture. The volume is
diminished. A strip of parchment soaked in water till it is limp,
then dipped into strong alcohol, becomes again stiff, owing to
the attraction of alcohol for water.
312. Purity.--The most important alcohols are methyl alcohol and
ethyl alcohol. The former, wood spirit, is obtained in an impure
state by distilling wood; it is used to dissolve resins, fats,
oils, etc., and to make aniline. It is poisonous, as are the
others.
Ethyl alcohol, spirit of wine, is the commercial article. It is
prepared by fermenting glucose, and distilling the product. It
boils at 78 degrees, vaporizing 22 degrees lower than water, from
which it can be separated by fractional distillation. By
successive distillations of alcohol ninety-four per cent can be
obtained, which is the best commercial article, though most
grades fall far below this. Five per cent more can be removed by
distilling with CaO, which has a strong affinity for water. The
last one per cent is removed by BaO. One hundred per cent
constitutes absolute alcohol, which is a deadly poison. Diluted,
it increases the circulation, stimulates the system, hardens the
tissues by withdrawing water, and is the intoxicating principle
in all liquors.--It is very inflammable, giving little light, and
much heat, and readily evaporates.
Beer has usually three to six per cent of alcohol; wines, eight
to twenty per cent. The courts now regard all liquors having
three per cent, or less, of alcohol, as not intoxicating. In
Massachusetts it is one per cent.