" Cub
proposed.

The run was made, with Cub in charge of the wheel and engine controls.
They circumnavigated the island with unsatisfactory result.

"That settles it," Bud declared. "If San Salvador had been like that,
Columbus would have made his first landing somewhere else!"

"Robinson Crusoe would never have found any footprints in the sand
there," Hal declared.

"Yes, we'll give it up for the time being," Mr. Perry declared. "We won't
try to scale any perpendicular banks, fifteen or twenty feet high, at
least, not to begin with."

"I tell you what we ought to do," Hal volunteered next. "Let's accept
this island as the center of probability."

"What in thunder is that?" Cub demanded.

"That's a good one on you, son," laughed the latter's father. "I thought
you were the highbrow of your bunch; but here's our subtle Tee-hee
putting a bit of clever phraseology over on you."

"Oh, I know what he means," Cub rejoined with a panicky haste to recover
lost prestige. "I was just giving him a dig. He's forever giving me one,
whenever I come along with anything of that kind."

"It indicates that his mind is maturing rapidly," said Mr. Perry.
"All right, Hal, we'll accept this island as a center of
probability--what next?"

"Why, let's cruise around about half a mile in all directions and pick
out those islands that look as if they might have concealed a prisoner
from view of passing boats."

"That's a good suggestion," said Mr. Perry. "Bob, start the boat again."

The inspection required about an hour, at the end of which they compared
notes and found that their island inventory disclosed the following
conditions:

Three possible places of concealment for the "Canadian Crusoe" had been
discovered. Two were small islands a short distance from each other in a
region of shallows and more or less hidden by rows of long slim islands.
No boat of greater draught than a canoe could make its way through the
intervening passages. In other words, these islands were virtually
isolated from all river traffic. The other possible place of concealment
was an island about five acres in extent, completely hemmed in by a group
of other islands, which were so overrun with rampant vegetation,
including bushes and trees, as to conceal the inner isle from any but the
most scrutinizing vision.

"That is the place we want to explore first," announced Mr. Perry as
reference was made to this retreat in the check-up.

"I agree with yo