~3.~ The vapor of alcohol will burn also, and under some circumstances
it will explode. On this account it is better not to try any experiments
with it unless some older person is close by to direct you, so that no
harm may be done. Alcohol is really a dangerous substance even though we
do not take it as a drink.

~4. An Interesting Experiment.~--We have told you that all fermented
drinks contain alcohol. You will remember that wine, beer, ale, and
cider are fermented drinks. We know that these drinks contain alcohol
because the chemist can separate the alcohol from the water and other
substances, and thus learn just how much alcohol each contains.

~5.~ If we should remove all the alcohol from wine, no one would care to
drink it. The same is true of beer and cider. It is very easy to remove
the alcohol by the simple process of heating. This is the way the
chemist separates it. The heat drives the alcohol off with the steam. If
the heating is continued long enough, all the alcohol will be driven
off. The Chinaman boils his wine before drinking it. Perhaps this is one
reason why Chinamen are so seldom found drunken.

~6.~ By a simple experiment which your parents or your teacher can
perform for you, it can be readily proven that different fermented
drinks contain alcohol, and also that the alcohol may be driven off by
heat. Place a basin half full of water upon the stove where it will soon
boil. Put into a glass bottle enough beer or cider so that when the
bottle stands up in the basin the liquid in the bottle will be at about
the same height as the water in the basin. Now place in the neck of the
bottle a closely fitting cork in which there has been inserted a piece
of the stem of a clay pipe or a small glass tube. Place the bottle in
the basin. Watch carefully until the liquid in the bottle begins to