little cracking sound of these sparks was a kind of baby thunder.

So he thought that he would try to catch a little bit of lightning.
Perhaps he could put it into one of the little bottles used to hold
e-lec-tric-i-ty. Then if it behaved like e-lec-tric-i-ty, he would
know what it was. But catching lightning is not easy. How do you think
he did it?

First he made a kite. It was not a kite just like a boy's kite. He
wanted a kite that would fly when it rained. Rain would spoil a paper
kite in a minute. So Franklin used a silk hand-ker-chief to cover his
kite, instead of paper.

[Illustration: Franklin's Discovery.]

He put a little sharp-pointed wire at the top of his kite. This was
a kind of lightning rod to draw the lightning into the kite. His kite
string was a common hemp string. To this he tied a key, because
lightning will follow metal. The end of the string that he held in his
hand was a silk ribbon, which was tied to the hemp string of the kite.
E-lec-tric-ity will not follow silk.

One night when there was a storm coming, he went out with his son.
They stood under a cow shed, and he sent his kite up in the air.

[Illustration]

After a while he held his knuckle to the key. A tiny spark flashed
between the key and his knuckle. It was a little flash of lightning.