distance. Though they were not aware of it at that moment, it was much
easier to walk on the moon than it was on the earth, for they weighed
only one sixth as much, and the attraction of gravitation was so much
less.

But suddenly Jack remembered that curious fact, and, stooping, he
picked up a stone. He cast it from him, at the same time uttering a
yell.

"What's the matter?" called Mark.

"Look how far I fired that rock!" shouted Jack. "Talk about it being
easy! why, I believe I could throw a mile if I tried hard!"

"It goes six times as far as it would on the earth," spoke his chum,
"and we can also jump six times as far."

"Then let's try that!" proposed Jack. "There's a nice level place over
there. Come on, I'll wager that I can beat you."

"Done!" agreed Mark, and they hurried to the spot, their very walking
being much faster than usual.

"I'll go first," proposed Jack, "and you see if you can come up to me."
He poised himself on a little hummock of rock, balanced himself for a
moment, and then hurled himself through space.

Prepared as he was, in a measure, for something strange, he never
bargained for what happened. It was as if he had been fired from some
catapult of the ancient Romans. Through the air he hurtled, like some