"Come on below, and wait until they shove up the flooring," he
whispered.

The doctor's son understood, and with caution, so as not to make
any noise, the two chums came down out of the tiny loft, bringing
with them the pail and the tin can of awful-smelling flour paste.

It was absolutely dark below, but they could plainly hear Ham and
Carl working on the loose boards of the floor near the river end
of the boathouse. Thither they made their way, Snap with the pail
and Shep with the can, both ready for action.

Slowly one board was lifted and pushed aside and a second followed.
Then two heads appeared in the gloom.

"Robbers!" cried Snap.

"Burglars!" yelled the doctor's son.

"Shoot them!"

"Don't let them get away alive!"

Then with a vigorous throw Snap landed his pail of stuff full
upon the head of Ham Spink. Splosh! it struck the dudish youth
squarely in the face and ear. Another splosh followed, and Carl
Dudder was likewise decorated.

"Hi! wow!" spluttered Ham. "I---Oh, what a smell!