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 by this time. To make the best of circumstances; to stand face to face with misfortune, and shrink not; to meet the worst with equanimity, and grasp eagerly at the slightest favorable change,—such was the character that Tom had shown during his experience of the past. Now, once more, he grasped at this slight circumstance that appeared to favor his hopes, and sought to find some way by which that half-floating boat could be made to float wholly, and bear him away to those shores that were so near by. Too long had he been submitting to this imprisonment; too long had he been waiting for schooners to pass and to bring him help; too long had he been shut in by a fog that seemed destined never to lift so long as he was here. If he could only form some kind of a boat that would float long enough to land him on the nearest coast, all that he wished would be gratified.
As he thought over this subject, he saw plainly what he had felt very strongly before—that the boat could not be sea-worthy unless he had some tar with which to plaster over the broken bow, and fill in the gaping seams; but there was no tar. Still, did it follow that there was nothing else? Might not something be found upon the island which would serve the purpose of tar? There must be some such substance and perhaps it might be found here.
Tom now thought over all the substances that he could bring before his mind. Would clay do? No; clay would not. Would putty? No, and besides, he could not get any. What, then, would serve this important purpose?
Tar was produced from trees. Were there no trees here that produced some sticky and glutinous substance like tar? There was the resin of pine trees, but there were no pines on the island. What then? These fir trees had a sort of sticky, balsamic juice that exuded plentifully from them wherever they were cut. Might he not make some use of that? Suddenly, in the midst of reflections like these, he thought of the gum that is found on spruce trees—spruce gum! It was an idea that deserved to be followed up and carried out. Thus far he had never thought of spruce gum, except as something which he, like most boys, was fond of chewing; but now it appeared before his mind as affording a possible solution of his difficulty. The more he thought of it, the more did it seem that this would be adapted to his purpose. The only question was, whether he could obtain enough of it. He thought that he might easily obtain enough if he only took the proper time and care.
With this new plan in his mind, Tom retired for the night, and awaked the next morning by the dawn of day. It was still foggy; but he was now so resigned, and was so full of his new plan, that it did not trouble him in the slightest degree. In fact, he was so anxious to try this, that the sight of a boat landing on the beach, all ready to take him off, would not have afforded him an unmixed satisfaction.
He took his tin dipper, and went up at once into the woods. Here he looked around very carefully, and soon found what he wanted. He knew perfectly well, of course, how to distinguish spruce trees from fir, by the sharp, prickly spires of the former, and so he was never at a loss which trees to search. No sooner had he begun, than he was surprised at the quantities that he found. To an ordinary observer the trunk of the spruce tree seems like any other tree trunk—no rougher, and perhaps somewhat smoother than many; but Tom now found that on every tree almost there were little round excrescences, which, on being picked at with the knife, came off readily, and proved to be gum. Vast quantities of a substance which goes by the name of spruce gum are manufactured and sold; but the pure gum is a very different article, having a rich, balsamic odor, and a delicate yet delicious flavor; and Tom, as he filled his pan, and inhaled the fragrance that was emitted by its contents, lamented that his necessities compelled him to use it for such a purpose as that to which this was destined. After four or five hours' work, he found that he had gathered enough. He had filled his pan no less than six times, and had secured a supply which was amply sufficient to give a coating of thick gum over all the fractured place. The tide, which had already risen, was now falling, and, as soon as the boat was aground, and the water out of her, Tom proceeded to raise her bows, in precisely the same manner as he had raised the boat on a former occasion.