"You have seen things at sea that puzzled you?" Merry asked, knowing that he was making a center shot.

"Who said that I'd ever been to sea? And s'pose I have? I ain't worried people to death about it and broke up another man's business. There ain't a thing in this. This ain't out at sea, ye know!"

The landlord seemed to have the peculiar feeling that only ghosts that sailed or walked the briny deep were worthy of consideration.

"Explain it, then!" Merriwell demanded. "You can make us feel that nothing strange happened last night if you will explain the thing."

"You was just dopey!" the captain argued. "Your nerves was shook up from bein' in the water so long, and the skeer of the collision."

Though there seemed no use to make an investigation, Merriwell began one immediately. He felt sure that Barney Mulloy was somewhere in Glen Springs.

"I know that I saw him!" was his persistent declaration.

"And heard him walk!" added Hodge. "I can swear to it."

"Yes. And though the thing is so strange, it makes me feel better, for I am sure now that Barney is not dead."

"But he looked like a ghost!" Bart admitted. "I'm with you, though, to the end in this thing. We'll go to the bottom of it."

Questioning the people of the village yielded no better results.

Everybody agreed that no person answering to the description of Barney Mulloy had been in Glen Springs. Some of them were even more nervous and indignant than the landlord, for almost the sole remunerative business of these people was the keeping of summer boarders, and they feared that gruesome reports about the place would drive guests away.

"Mr. Hodge and I are coming back here to-night," Merriwell said to the landlord. "Perhaps we shall bring some of these friends with us. It seems useless to continue the investigation now, and I want, besides, to ask some questions at Sea Cove. The launch is all ready to return to Sandy Hook, and the officer in command says that his orders require him to return there without further delay. But we will come back to-night."

The landlord's face did not give the proposition an eager welcome, though one of his business tenets was never to turn a guest away.

So the launch steamed away to Sandy Hook, leaving Glen Springs and its strange and unsolved puzzle behind.

Frank only partly enjoyed the trip.

But for that seemingly impenetrable mystery, the trip to Sandy Hook, with the visit of inspection which followed, would have been jolly.

However, there was so much to be happy and thankful for, anyway, that the spirits of the party partook largely of the brightness of the day.

The run of the speedy launch up the coast was pleasant, and at Sandy Hook they found their fellow students awaiting them, and were given a right royal welcome by Captain Isaac Heath, the officer in charge of the proving-grounds.

"Say, fellows, this is great!" Danny warbled, as Captain Heath escorted them to where the big guns were. "I always did like big guns!"

"You're such a big gun yourself!" sneered Bink, under his breath.

"Binky, if my brain caliber required no more than a number five hat, as yours does, I'd sing low about big guns!"

"Number five hat? Why----"

"This ten-inch breech-loading rifle takes a charge of one hundred and ten pounds of Dupont smokeless powder and a projectile weighing five hundred and seventy-five pounds," Captain Heath was explaining, as they stopped in front of the big seacoast defender.

"Say, they're going to fire it!" Bink gasped.

"Of course, you idiot! Did you think it was going to fire them?"

"Better stand on your tiptoes and stick cotton into your ears," Browning warned, as the big gun was quickly made ready for hurling its terrible projectile.

"Wh-what if the dinged old thing should bub-bub-burst?" Gamp anxiously asked.

"We should have to

"'Ask of the winds, that far around!

With fragments strewed the sea!'"

was Danny's comforting answer.

Dismal and Rattleton retreated a step or two, as did Elsie Bellwood. But Inza stood her ground as bravely as Merriwell himself.

Then, before more could be said, the big cannon boomed forth its volume of deafening sound, making the very walls shake. Danny tumbled backward, then picked himself up and felt over his person very carefully.

"Am I all here?" he anxiously queried.

All watched the direction in which the huge shot had been fired, but it fell miles away. Merriwell and a few others, provided with strong gla.s.ses, saw it drop into the sea. The captain was talking again.

"The instruments record an initial velocity of one thousand feet per second, with a pressure of twenty-four thousand pounds."

"I've been under greater pressure than that," Danny chirped.

"When you were shot?" Bink asked. "All guns, big and little, are under pressure when they are shot."

"I'll put your throat under pressure when we get away from here!" Bink threatened.

"This is a twelve-inch rifle, loaded with one hundred and thirty pounds of powder and a projectile of the same weight as the first."

The party had moved to a new point, and Captain Heath was again talking.

Other guns were fired, after the discharge of this one; the last shot being sent from a twelve-inch rifle with a charge of four hundred and seventy-five pounds of Dupont brown prismatic powder and a projectile weighing one thousand pounds.

The roar, the jar, and the vibration were like that of a miniature earthquake. Captain Heath's calm voice was heard again, after a short silence.

"The velocity was two thousand and eighty-eight feet per second, and the pressure four thousand pounds. This pressure is ten thousand pounds too high. The powder is too quick, and will be condemned."

After this there was an examination of the guns and carriages, with a lecture by Lieutenant Bell; an examination of the gun-lift battery and the hydraulic lifts, and the wonderful Buffington-Crozier disappearing-carriages, and a look over the site of the new artillery post to be known as Fort Hanc.o.c.k. Then luncheon was served.

In spite of the many interesting things which he had seen and to which he had listened, Merriwell could not get his thoughts away from Barney Mulloy. He had already obtained consent for the party to be taken on the launch to Sea Cove and Glen Springs at once, after luncheon. Thinking of these things and with his head full of the plans for discovering the secret of the happenings at Glen Springs, he walked round the works again, viewing the emplacements and the big guns, but with his thoughts far enough away from the things on which his eyes rested.

Suddenly he was attracted by a cry. It seemed to come from the air, and it made him think of the apparition and the ghostly footsteps. But when he glanced up he saw Danny Griswold's head protruding from the muzzle of a large coast-defense cannon. Merriwell was astonished, though such a piece of recklessness was just like Danny. It was not that Frank feared any peril to Danny from the gun, but the officers and gunners would be indignant, no doubt, if they caught the little joker playing hide-and-seek in that way with one of their pets.

"I'll give him a scare," he thought. "He is getting altogether too fresh."

"Danny Griswold, that gun is loaded, and they are going to fire it!"

Merry cried, with well-simulated fear.

Danny's red head came farther out, like the head of a tortoise issuing from its sh.e.l.l.