"I hope we get to a better place soon," said Jack, just before they sealed themselves up in the projectile to travel to a new spot.
As distance was comparatively small on the moon, for her diameter is only a little over two thousand miles and the circumference only about six thousand six hundred miles, the Annihilator could not be speeded up. If it went too fast, it would soon be off the moon and into space again.
Accordingly the Cardite motor was geared to send the big craft along at about forty miles an hour, and at times they went even slower than that, when they were passing over some part of the surface which the professors wished to photograph or observe closely.
They did not rise high into the air, but flew along at an elevation of about two hundred feet, steering in and out to avoid the towering peaks 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 fairly stalled the Annihilator.