The sun glistened on the bright brass and nickel parts, and glinted from the gleaming barrels of the quick-firing guns.

“That’s enough!” Tom called to the men below, who were paying out the ropes from the windlasses.  “Hold her there.”

Tom, Ned, Lieutenant Marbury and Mr. Damon were aboard the captive Mars.

Looking about, to see that all was in readiness, Tom gave orders to load the guns, blank charges being used, of course.

The recoil apparatus was in place, and it now remained to see if it would do the work for which it was designed.

“All ready?” asked the young inventor.

“Bless my accident insurance policy!” exclaimed Mr. Damon.  “I’m as ready as ever I shall be, Tom.  Let ’em go!”

“Hold fast!” cried Tom, as he prepared to press the electrical switch which would set off the guns.  Ned and Lieutenant Marbury stood near the indicators to notice how much of the recoil would be neutralized by the check apparatus.

“Here we go!” cried the young inventor, and, at the same moment, from down below on the ground, came a warning cry: 

“Don’t shoot, Massa Tom.  Don’t shoot!  Mah mule, Boomerang—­”

But Eradicate had spoken too late.  Tom pressed the switch; there was a deafening crash, a spurt of flame, and then followed wild cries and confused shouts, while the echoes of the reports rolled about the hills surrounding Shopton.

CHAPTER X THE NEW MEN

“What was the matter down there?”

“Was anyone hurt?”

“Don’t forget to look at those pressure gauges!”

“Bless my ham sandwich!”

Thus came the cries from those aboard the captive Mars.  Ned, Lieutenant Marbury and Tom had called out in the order named.  And, of course, I do not need to tell you what remark Mr. Damon made.  Tom glanced toward where Ned and the government man stood, and saw that they had made notes of the pressure recorded on the recoil checks directly after the guns were fired.  Mr. Damon, blessing innumerable objects under his breath, was looking over the side of the rail to discover the cause of the commotion and cries of warning from below.

“I don’t believe it was anything serious, Tom,” said the odd man.  “No one seems to be hurt.”  “Look at Eradicate!” suddenly exclaimed Ned.

“And his mule!  I guess that’s what the trouble was, Tom!”

They looked to where the young bank employee pointed, and saw the old colored man, seated on the seat of his ramshackle wagon, doing his best to pull down to a walk the big galloping mule, which was dragging the vehicle around in a circle.

“Whoa, dere!” Eradicate was shouting, as he pulled on the lines.  “Whoa, dere!  Dat’s jest laik yo’, Boomerang, t’ run when dere ain’t no call fo’ it, nohow!  Ef I done wanted yo’ t’ git a move on, yo’d lay down ‘side de road an’ go to sleep.  Whoa, now!”