e had done; and this friend had so much love for Ruth, so
much real grief for what she knew Ruth felt, that when young friends
came to play with her, she took care to beg that there should not be
_jam cake_.

THE AIR.

What is air? Look up and look round; _there_ is air, though it is not
to be seen. It fills all things. The glass jug which seems to be quite
void is still full of air.

[Illustration: THE LESSON ON AIR. Page 23.]

It is the air we feel when the wind blows. We do not see the wind, but
it can blow with such force as to throw down trees. When the wind blows
it makes ships sail on the seas to all parts of the world, and brings
them back home. It turns mills, to grind corn; and in some parts they
use the force of wind to do all kinds of work. The wind is but the air,
and it does all these things, though it is not to be seen.

But the air does more than this. If it were not for the air we could
not live. It is the air we breathe; and if the breath were stopt, we
all know that we should die. How it is that the air does this would
take a long time to tell, and you must learn a great deal more of such
things than you have yet done, to know why air keeps up life. But so it
is. The air is the breath.

It is the breath, too, that makes us warm and keeps us so; for if it
were not for the air we breathe, we should be as cold as stones.

The air it is that makes fire burn. The fire in the grate would soon go
out if it were not for the air. The flame in a lamp burns dim when it
has not so much air as it wants; and when the air is shut from the
flame it goes out.

Trees and plants could not live if they had not air. The birds fly by
means of the air, which helps to keep them up, while their wings flap
up and down. If there were no air, they could not rise from the ground
at all, nor could they live if they did not breathe.

It is the air which makes sound. We could not hear men talk, nor bells
ring, if the air did not bring the sound to our ears.

Of such great use is the air, though we can not see it, that no one
thing could move, or be heard, or live, if it were not with us and
round us.

SAIB, THE BLACK BOY.

In a far-off part of the world there is a place where the boys and
girls have not the white fair skins that boys and girls have here, but
whose skins are quite black, and whose hair is short and thick, like
black wool. Some of these poor things know not what it is to have a
home, th