lengthways for the person's heels
to rest against.

Any child can guide this bob, as all he has to do is to guide the
rudder right and left to go in the direction named. If he wants to
stop, he pulls up on the handle and the heel of the rudder will
dig into the snow, causing too much friction for the sled to go
any further.
--Contributed by Wm. Algie, Jr., Little Falls, N. Y.

** How to Make a Small Microscope [408]

Theoretically a simple microscope can be made as powerful as a
compound microscope, but in practice the minute size required by
the simple lens to give the highest power makes it almost
impossible to be used. However, a lens having a reasonable
magnifying power can be made in a few minutes for almost nothing.
Take a piece of glass tubing, heat one place in a hot flame, hold
one end and pull on the other and draw the heated place down to a
fine string as shown in Fig. 1. Take about 3 in. of this fine tube
and heat one end which will form a glass bead as shown in Fig. 2.
This bead is the lens. When in this form it can be used only in an
artificial light coming from one direction, but if you take a
piece of

[Illustration: Lens Formed by Heat]

cardboard and bore a hole in it a little smaller than the bead on
the glass tube which is forced into the hole, Fig 3, you can use
this mounted lens in ordinary daylight. In this case a mirror must
be used to reflect the light up through the lens. It is difficult
to see anything at first, as the lens must be held very close to
the eye, but in practice you will soon learn to see the object as
it appears enlarged.

If you soak a little dried grass or hay in water for a few days
and look at a drop of this water, germs in various life forms can
be seen. The water must be put on the lens. One thing to remember
is that the smaller the lens, the greater the magnifying power.
--Contributed by Daniel Gray, Decatur, Illinois.

** Freezing Pipes [409]

The water in hot water supply pipes will freeze quicker than water
that has not been heated. This is because the air, which is a poor
conductor of heat, has been driven out by the heat.

** How to Carry Books [409]

Almost all school children carry their books with a strap put
around and b u c k led very tight. This will make dents in the
cover where the board overlaps the body of the book. If the strap
is left loose, the books are liable to slip out. Place the cover
of one book between the cover and fly