weight, why does it hurt so when we
bump into anything? And when you throw anything, like the Doctor did
Perkins, why does it hit as hard as ever?"

"It's mass or inertia or something like that. A thing has it everywhere,
whether it weighs anything or not. Dick explained it all to me. I
understood it when he told me about it, but I'm afraid it didn't sink in
very deep. Did you ever study physics?"

"I had a year of it in college, but it was more or less of a joke. I
went to a girls' school, and all we had to do in physics was to get the
credit; we didn't have to learn it."

"Me too. Next time I go to school I'm going to Yale or Harvard or some
such place, and I'll learn so much mathematics and science that I'll
have to wear a bandeau to keep my massive intellect in place."

During this conversation they had prepared a substantial luncheon and
had arranged it daintily upon two large trays, in spite of the
difficulty caused by the fact that nothing would remain in place by its
own weight. The feast prepared, Dorothy took her tray from the table as
carefully as she could, and saw the sandwiches and bottles start to
float toward the ceiling. Hastily inverting the tray above the escaping
viands, she pushed them back down upon the table. In doing so she lifted
herself clear from the floor, as she had forgotten to hold herself down.

"What'll we do, anyway?" she wailed when she had recovered her position.
"Everything wants to fly all over the place!"

"Put another tray on top of it and hold them together," suggested
Margaret. "I wish we had a birdcage. Then we could open the door and
grab a sandwich as it flies out."

By covering the trays the girls finally carried the luncheon out into
the main compartment, where they gave DuQuesne and Perkins one of the
trays and all fell to eating hungrily. DuQuesne paused with a glint of
amusement in his one sound eye as he saw Dorothy trying to pour ginger
ale out of a bottle.

"It can't be done, Miss Vaneman. You'll have to drink it through a
straw. That will work, since our air pressure is normal. Be careful not
to choke on it, though; your swallowing will have to be all muscular out
here. Gravity won't help you. Or wait a bit--I have the control board
fixed and it will be a matter of only a few minutes to put in another
bar and get enough acceleration to take the place of gravity."

He placed one of the extra power bars in the chamber and pushed the
speed lever into the first