ime is known to the
chemists as sulphate of lime. Do not forget that this last form is never
to be used on sour lands. We shall therefore not consider it further.

Air-slaked lime is simply quicklime which has taken from the air a gas
called carbon dioxide. This is the same gas that you breathe out from
your lungs.

Water-slaked lime is quicklime to which water has been added. In other
words, both of these are merely weakened forms of quicklime. One hundred
pounds of quicklime is equal in richness to 132 pounds of water-slaked
lime and to 178 pounds of air-slaked lime. These figures should be
remembered by a farmer when he is buying lime. If he can buy a fair
grade of quicklime delivered at his railway station for $5.00 a ton, he
cannot afford to pay more than $3.75 a ton for water-slaked lime, nor
more than $2.75 for air-slaked lime of equal grade. Quicklime should
always be slaked before it is applied to the soil.

As a rule lime should be spread broadcast and then harrowed or disked
thoroughly into the soil. This is best done after the ground has been
plowed. For pastures or meadows air-slaked lime is used as a
top-dressing. When air-slaked lime is used it may be spread broadcast in
the spring; the other forms should be applied in the fall or in the
early winter.

SECTION LXVII. BIRDS

What do birds do in the world? is an important question for us to think
about. First, we must gain by observation and by personal acquaintance
with the living birds a knowledge of their work and their way of doing
it. In getting this knowledge, let us also consider what we can do for
our birds to render their work as complete and effective as possible.

Think of what the birds are doing on every farm, in every garden, and
about every home in the land. Think of the millions of beautiful wings,
of the graceful and attractive figures, of the cunning nests, and of the
singing throats! Do you think that the whole service of the birds is to
be beautiful, to sing charmingly, and to rear their little ones? By no
means is this their chief service to man. Aside from these services the
greatest work of birds is to destroy insects. It is one of the wise
provisions of nature that many of the most brilliantly winged and most
enchanting songsters are our most practical friends.

Not all birds feed on insects and animals; but even those that eat but a
small amount of insect food may still destroy insects that would have
damaged fruit and cro