“What did you find out, Hugh?” questioned Bud.

“Not a single cloud to be seen in all the sky!” said the other impressively.

“Whew! that seems queer, doesn’t it?” faltered Bud.

“And it must be almost down to freezing, into the bargain,” added the patrol leader.  “I’ve seen lightning before, in February even, but always during a thaw.  Fact is, boys, I can’t believe that it was either lightning or thunder we saw and heard.”

“But, Hugh, what could it have been then?” demanded Ralph.

“If we were nearer the granite quarries, I’d say they had set off an extra big blast.  You know we sometimes hear a faraway boom over home.  Sound travels many miles when there’s a sub-strata of rock like a ledge to act as a conductor.”

“Yes, but then I understood work had stopped there for the season the Saturday before Thanksgiving,” volunteered Bud.  “Still, they may be doing some blasting, just to keep things moving as long as the snow holds off.  If that was a blast of dynamite, it must have been a stunner to make the earth quiver so much.”

Hugh made no reply.  Plainly he was deeply impressed with the mysterious nature of the unannounced explosion.  And when once Hugh started to find out what things meant, he seldom let the matter drop until he had accomplished his purpose.

Bud also went to the door and looked out, his curiosity having been duly aroused.  Hence he did not hear Ralph make a significant admission.

“Now that I come to think of it,” the other remarked, “for the last two nights I can remember hearing a distant, dull sound that I thought was a heavy blast off in this quarter.  I chanced to be outdoors each night about ten o’clock.  It’s come much earlier this time, it seems; but, anyhow, that is getting to be a regular nightly performance I wonder if they are working over in the granite quarries?  I’m something of a sticker when anything bothers me like this, and for three cents I’d take a turn over that way to-morrow just to satisfy my mind.”

“I was wondering whether those two men you saw could have had anything to do with that queer crash and flash?” suggested Hugh slowly.

“Ginger!  I wonder now!” exclaimed Ralph, who apparently had not thought to connect the pair of strangers with the mysterious goings-on.  “But they didn’t seem to have anything along with them at that time.  I remember seeing the taller man take something out of his pocket and examine it, Hugh; and at the time it struck me the shiny object looked mighty like one of these modern automatic pistols.”

Hugh shook his head as though, try as he would, as yet he could see no way of solving the puzzle.  Just then Bud came back, having fixed the door the same way he had found it, with the loose board used as a prop to keep it in position.

“Just as you said, Hugh,” he announced, “it’s clear as a bell, with a young moon hanging low in the western sky and the stars shining like all get-out.  No siree, thunder never yet was heard on a night like this.  So I guess it must have been a blast.  They do say dynamite shakes the ground a heap more than powder, because its force is always directed downward.  If you put a cartridge on top of a big rock and fire it, the boulder is shattered to pieces.  Powder you’ve got to put underneath every time.”