l at this, and he assisted Frank in
perfecting the figure in Merriwell's bed.

"There," he finally whispered, with satisfaction, "that would fool
Lieutenant Gordan himself."

They donned trousers and coats, and prepared to leave the room in their
stocking feet.

Bart opened the door and peered cautiously out into the hall.

"Coast is clear," he whispered over his shoulder.

In another moment they were outside the room. Along the corridor they
skurried like cats, their feet making no noise on the floor.

Frank was still entirely unaware of their destination, but, as they had
not taken their shoes, he knew they were not to leave the building.

Frank cared little where they went, but he realized Hodge was leading
the way to a remote part of the building, where the rooms were not
entirely taken, as the academy was not full of students.

All at once, Bart sent a peculiar hiss down the corridor, and it was
answered by a similar sound.

A moment later they scudded past a fellow who was hugging in a shadow
where the lights did not reach.

"Who's that?" whispered Frank.

"That's the sentinel," replied Bart.

Then they came to the door of a certain room, on which Hodge knocked in
a peculiar manner.

A faint sound of unbarring came from behind the door, which quickly
opened, and they dodged into the room.

As yet there was no light in the room, and, still filled with wonder,
Frank asked:

"Was that the regular sentinel out there, Bart?"

"That was our sentinel," was the reply.

"But where are the regular sentinels? I did not see one of them."

Faint chuckles came from several parts of the room, and Hodge replied:

"At a certain hour each night the duties of the regular sentinels take
them away long enough for me to get out of my room and in here. See?"

"They must be in the trick?"

"The most of them are. When it happens that one is not, we have to
look out for him, and dodge him. To-night those on duty on this floor
were all fixed."

Then somebody cautiously struck a match, by the flare of which Frank
saw several fellows were gathered in the room.

A lamp was lighted, and Merriwell looked around. Besides Bart, he saw
Harvey Dare, George Harris, Wat Snell and Sam Winslow.

"Hello, Merriwell, old man," some greeted, cordially, but cautiously.
"Glad to see Hodge has brought you along."

Frank was instantly seized by an unpleasant sensation--a foreboding, or
a warning. Harris and Snell were not