ich is another reason," remarked Tom Reade, "why we're going to solve
the mystery of said explosions at the earliest minute that we can."

"One thing is certain," observed Mr. Prenter, with the nearest approach to
gloom that he had yet shown. "If you don't soon penetrate this grim
mystery, and find a way to stop these outrages, then the wall will be
destroyed more rapidly than you can build it."

"The outrages may cease after a while," suggested Harry.

"No," answered Reade. "As long as the unknown enemy feels that he can
harass us without much risk of being caught red-handed, just so long will
he go on with his outrages---unless we give in."

"Give in?" asked Mr. Prenter, with a rising inflection in his voice.

"Unless we give in," supplied Tom promptly, "by allowing gambling and
rum-selling to go on openly in our camp of workmen."

"Have you any notion of giving in to that extent?" asked Mr. Prenter.

"Not an idea!" retorted Tom Reade promptly. "It wouldn't be my way to
surrender to the Devil. I'll fight to the last ditch---unless your
company really prefers to have Hazelton and myself cancel our contract and
get out of this work. Do you?"

"_I_ don't want you to quit," replied Mr. Prenter positively. "I admire
fighting grit, and I want to see you keep hammering away at the work until
you win and the job is finished. The board of directors will stand with me
on that, if I can sway them. As for Mr. Bascomb, you mustn't take him too
seriously. He's a first rate fellow in a lot of ways, but there's no fight
in him, and he's a bit close-fisted, too. As for me, Reade, and as far as
I can speak for my fellow directors, go ahead, just the way you've started.
If you can find any way to hammer camp vice harder than you've been
hammering it, then go ahead and do some harder work with your little
hammer."

"I'll do it," promised Tom. "Now, Mr. Prenter, I don't believe anything
more will happen here to-night---perhaps not for two or three nights. So
I think the wisest thing for you to do will be to get back to the house and
get some sleep. The same for you, Harry!"

"What are you going to do?" Hazelton wanted to know.

"I?" repeated Reade. "For to-night I'm going to remain up, and be out here
around this threatened wall."

"Then that ought to be good enough for me, also," Harry suggested.

"Not much, chum. I'm going to take the night trick for the present, and
put on you the burden of all the day work.