~8. Alcohol~ (al´-co-hol).--All of you know something about alcohol.
Perhaps you have seen it burn in a lamp. It will burn without a lamp, if
we light it. It is so clear and colorless that it looks like water. The
Indians call it "fire-water." Alcohol differs very much from foods. It
is not produced from plants, as fruits and grains are; neither is it
supplied by Nature ready for our use, as are air and water.

~9. Fermentation.~--When a baker makes bread he puts some yeast in the
dough to make it "rise," so the bread will be light. The yeast destroys
some of the sugar and starch in the flour and changes it into alcohol
and a gas. The gas bubbles up through the dough, and this is what makes
the bread light. This is called _fermentation_ (fer-men-ta´-tion). The
little alcohol which is formed in the bread does no harm, because it is
all driven off by the heat when the bread is baked.

[Illustration: FERMENTATION.]

~10.~ Any moist substance or liquid which contains sugar will ferment if
yeast is added to it, or if it is kept in a warm place. You know that
canned fruit sometimes spoils. This is because it ferments. Fermentation
is a sort of decay. When the juice of grapes, apples, or other fruit is
allowed to stand in a warm place it "works," or ferments, and thus
produces alcohol. Wine is fermented grape-juice; hard cider is fermented
apple-juice.

~11.~ Beer, ale, and similar drinks are made from grains. The grain is
first moistened and allowed to sprout. In sprouting, the starch of the
grain is changed to sugar. The grain is next dried and ground, and is
then boiled with water. The water dissolves the sugar. The sweet liquid