The cave was an enduring and substantial joy.  It was a real cave, not merely a hole, but a subterranean marvel of deep passages and vaulted chambers that led away into bluffs and far down into the earth’s black silences, even below the river, some said.  For Sam Clemens the cave had a fascination that never faded.  Other localities and diversions might pall, but any mention of the cave found him always eager and ready for the three-mile walk or pull that brought them to its mystic door.  With its long corridors, its royal chambers hung with stalactites, its remote hiding-places, its possibilities as the home of a gallant outlaw band, it contained everything that a romantic boy could love or long for.  In Tom Sawyer Indian Joe dies in the cave.  He did not die there in real life, but was lost there once, and was living on bats when they found him.  He was a dissolute reprobate, and when, one night, he did die there came up a thunder-storm so terrific that Sam Clemens at home and in bed was certain that Satan had come in person for the half-breed’s wicked soul.  He covered his head and said his prayers industriously, in the fear that the evil one might conclude to save another trip by taking him along, too.

The treasure-digging adventure in the book had a foundation in fact.  There was a tradition concerning some French trappers who long before had established a trading-post two miles above Hannibal, on what is called the “bay.”  It is said that, while one of these trappers was out hunting, Indians made a raid on the post and massacred the others.  The hunter on returning found his comrades killed and scalped, but the Indians had failed to find the treasure which was buried in a chest.  He left it there, swam across to Illinois, and made his way to St. Louis, where he told of the massacre and the burial of the, chest of gold.  Then he started to raise a party to go back for it, but was taken sick and died.  Later some men came up from St. Louis looking for the chest.  They did not find it, but they told the circumstances, and afterward a good many people tried to find the gold.

Tom Blankenship one morning came to Sam Clemens and John Briggs and said he was going to dig up the treasure.  He said he had dreamed just where it was, and said if they would go with him and dig he would divide up.  The boys had great faith in dreams, especially Tom’s dreams.  Tom’s unlimited freedom gave him a large importance in their eyes.  The dreams of a boy like that were pretty sure to mean something.  They followed Tom to the place with some shovels and a pick, and he showed them where to dig.  Then he sat down under the shade of a papaw-tree and gave orders.

They dug nearly all day.  Now and then they stopped to rest, and maybe to wonder a little why Tom didn’t dig some himself; but, of course, he had done the dreaming, which entitled him to an equal share.