and the confirmation of this first impression at once
drove away all other thoughts, and brought back all the ideas of escape
which he once had cherished.

The boat was admitting the water, certainly, yet she certainly did not
leak quite so badly as before, but was floating far better than she had
done on the night of his trial. What was the meaning of this?

Now, the fact is, he had not noticed the boat particularly during the
last few days. He had given it up so completely, that it ceased to
have any interest in his eyes. Raising his signal, building his house,
and exploring the island had taken up all his thoughts. Latterly he
had thought of nothing but his dinner. But now the change in the boat
was unmistakable, and it seemed to him that the change might have been
going on gradually all this time without his noticing it until it had
become so marked.

What was the cause of this change? That was the question which he now
sought to answer. After some thought he found a satisfactory
explanation.

For a number of days the boat had been admitting the water till she was
full. This water had remained in for an hour or more, and this process
of filling and emptying had been repeated every tide. The atmosphere
also had been wet, and the wood, thus saturated with water so
frequently, had no chance of getting dry. Tom thought, therefore, that
the wooden framework, which he had constructed so as to tighten the
leak, had been gradually swelling from the action of the water; and the
planks of the boat had been tightening their cracks from the same
cause, so that now the opening was not nearly so bad as it had been.
Thus the boat, which once had been able to float him for a quarter of
an hour or more, ought now to be able to float him for at least double
that time.

Tom watched the boat very attentively while the tide was up; and, when
at length it began to retreat, and leave it once more aground, he
noticed that it was not more than half full of water. If any
confirmation had been needed to the conclusions which he had drawn from
seeing the improved buoyancy of the boat, it would have been afforded
by this. Tom accepted this with delight, as an additional circumstance
in his favor; and now, having become convinced of this much, he set his
wits to work to see if some plan could not be hit upon by means of
which the boat could once more be made sea-worthy.

Tom's indefatigable perseverance must have been noticed