scattered here and there. Occasionally they found themselves over
immense craters that seemed to have no bottom.

For two days they moved here and there, finding no further signs of
life, neither petrified nor natural, though they saw many strange
sights, and some valuable pictures and scientific data was obtained.

It was on the third day, when they were approaching the side of the
moon which from time immemorial has been hidden from view of the
inhabitants of the earth, that Jack, who was with Mark in the engine
room, while the two professors were in the pilot-house, remarked to his
chum: "Mark, doesn't it strike you that the water pump and the air
apparatus aren't working just right?"

"They don't seem to be operating very smoothly," admitted Mark, after
an examination.

"That's what I thought. Let's call Mr. Henderson. The machinery may
need adjusting."

Jack started from the engine room to do this, and as he paused on the
threshold there was a sudden crash. Part of the air pump seemed to fly
off at a tangent, and a second later had smashed down on the Cardite
motor. This stopped in an instant, and the projectile began falling.
Fortunately it was but a short distance above the moon's surface, and
came down with a jar, which did not injure the travellers.

But there was sufficient damage done to the machinery, for with the
breaking of the air pump the water apparatus also went out of
commission, and together with the breakdown of the Cardite motor had