Symbolism, Imagery, Allegory
For someone who's never actually in the novel, Bert Breen certainly makes an impression by way of his stuff. His barn is the strongest symbol in the book, but his money comes up a fair bit, too. That mystery money has got everyone curious for most of the book; those nasty Flanchers in particular are relentless, tearing through the house and yard in search of the money.
None of them find it. But Tom, using a bit of deducting reasoning and a late-night search, eventually does.
Critics Alethea Helbig and Agnes Regan Perkins argue "although the treasure hunt contributes suspense, it strains credulity and weakens the theme that hard work and determination can result in success" (Dictionary of American Children's Fiction, 1960-1984, Greenwood Press, 1986, pg. 51).
Valid point, scholars, but we're going to put another theory out there: the chest is a symbol of the rewards of hard work. Tom gets the money as a direct result of his careful observation, thoughtfulness, and tireless work.
What do you think? Is the money an important symbol of Tom's success, or is it an unnecessary narrative distraction?