INVISIBLE COLOR BOOK
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Wails-
Gui Fiddle
or Banjo Strinm
Rubber Ball
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The Weather Ball
or
Hydrometer
by
Edward Thatcher
The Weather Ball pictured above it a very useful and
Interesting toy to make. Change In the weather cause the
ball to turn, so that If It Is going to rain, the ball will turn
around toward the word Wei, and If It has been raining and
it Is going to clear, the ball will awing toward the word
Dry. , The reason (or this action Is very simple. There Is
always more or less moisture In the air,, whether we can
see It In the form of rain or not The ball Is suspended
from the wooden framework by a piece of fiddle or banjo'
sinner. These strings are made from the Intestines of
eertain animals (not the wire strings sometimes used for
hese Instruments, of course; do not try to use these).
When the air beoomes moist, the fiddle string absorbs
moisture, which causes It to swell and to twist slightly,
thus turning the ball. When the moisture dries out of the
air. If. of course. dres out of the fiddle string also, causing
It to shrink and also twist, thus turning the ball the other
way i By making and watching the Weather Ball you may
become quit a weather prophet and mystify all your
friends. -
To make the Weather Ball you will need a short piece
pf a fiddle or banjo string about 5 Inches long, one rubber
ball SV or 3 inches In diameter, a small cork, some fiat
pieces of wood for the framework, eight small nails and
one large one.
Make the wooden framework first The piece of wood
which is used fpr the base C should be about 1 Inch thick
and Inches square. The two side supports B, B should be
m, ?f thln wod about 1 Inch wide and S Inches long.
Cigar-box wood will do very nicely for these. The top
piece A should be about 1 inch square and 4 Inches long.
Ah',11""h.uy larB"er han the mall end of the cork O.
which Is to be pushed In It. should be bored through the
center of the piece A. as shown The frame should then b
nailed together
Make a hole In the rubber ball for on end of the fiddle
string. A simple way to do this Is to shove a large needle
In an old penholder, heat the needle red hot and then push
it through the rubber to burn a hole A hole may be burned
through the cork In the same way Tie a small knot In
one end of the fiddle string Pour some alcohol In a small
cup and soak the fiddle string In the alcohol for a few
minutes to remove the rosin, eta. Then push the knot at
the end of the string through th hole In the rubber ball.
to that the ball will be held at the end of the string. Push
the other end of the fiddle string up through the hole In
piec A and then through the hole In the cork. Slip the
cork In place, pull up on the fiddle string until the ball
swings clear of the base and then tie a knot In this end of
the string to hold the ball in place Drive a nail In the
base C. so that It forms a pointer, as shown at D Paint
the wooden framework and the ball as you like, but do
not paint the fiddle string
Set the Weather Ball on the porch where it Is shielded
from the sun. wind or rain, but where the air may circu
late freely about It Make a chalk mark on the ball oppo
site the pointer and then after an hour or so see which way
the ball has turned, and notice the state of the. weather and
mark the ball accordingly, after which the words "wet" and .
"dry" may be painted on. as shown In th picture.