"No, let's get right to work," suggested Jack.

They got out their tools and started to repair the two pumps. It was
found that the Cardite motor was not badly damaged, one of the negative
electrical plates merely having been smashed by a piece of the broken
connecting rod of the air pump. It was only a short time before the
motor was ready to run again.

But it could not be successfully operated without the air and water
pumps, and it was necessary to fix them next. New gaskets were needed,
while an extra valve and some sliding gears had to be replaced.

"It's an all day's job," remarked Professor Henderson.

But many hands made light work, and even Washington and Andy were
called upon to do their share. By dinner time the work was more than
half done, and Professor Roumann, announced that he and Mr. Henderson
would finish it if Jack and Mark would take a look at the exterior of
the projectile, to see if any repairs were needed to that.

The boys found that some of the exterior piping had become loosed at
the joints, because of the jar of the sudden descent, and, taking the
necessary tools outside, while they stuck their life-torches upright
near them, they labored away.

At four o'clock the two lads had their task completed, and at the same
time Professor Henderson announced that the air and water pumps were
now in good shape again.