did not find any, though they dug holes until their
backs ached.

Then Margy said:

"Let's don't play this any more."

"What shall we play?" asked Mun Bun.

"Oh, let's see if we can find some wood and make little boats."

So they walked about the island looking for bits of wood. But none was
to be found. For wood floats; that is, unless it is so soaked with water
as to be too heavy, and all the pieces of wood that had ever been on the
island had floated away.

"I don't guess we can build any boats," said Margy. "Let's go back to
shore and get some wood, and then we can come back and sail boats."

"That'll be fun," said Mun Bun. "We'll go."

But when he and his sister started to wade back, they had not gone very
far before Margy cried:

"Oh, the water's terrible deep! Look how deep down my foot goes!"

Mun Bun looked. Indeed the water was almost up to Margy's knees now, and
she had gone only a few steps away from the shore of the island.

"Let me try it," said her brother. "I'm bigger than you."

He wasn't, though he liked to think so, for Margy was a year older. But
I guess Mun Bun was like most boys; he liked to think himself larger
than he was.

However, when he stepped out from the island, ahead of Margy, he, too,
found that the water was deeper than it had been when they started to
wade from the shore near Cousin Tom's pier.

"What makes it?" asked Margy.

"I--I don't know," answered Mun Bun. "I guess somebody must have poured
more water in the river."

"Lessen maybe it rained," suggested Margy. "Don't you know how Rainbow
River gets bigger when it rains?"

"It didn't rain," said Mun Bun, "or we'd be wet on our backs."

"No, I guess it didn't rain," agreed Margy. Then she cried: "Oh, look,
Mun Bun! Our island's getting awful little! It only sticks out of the
water hardly any now! Look!"

Mun Bun turned and looked behind him. As his sister had said, the island
was very much smaller.

"What--what makes it?" asked Margy.

"I--I don't know," answered Mun Bun. "But it is getting littler, just
like when you keep on sucking a lollypop."

And that is just what the island was doing. What Margy and Mun Bun did
not know was that the tide had turned, that it was rising, and that it
would soon not only make their island much smaller, but would cover it
from sight, leaving no island at all!

"Oh, the water's getting deeper," said Margy, as she took another step
and found it coming over her little kne