Read it through once

Tom did his humble comrade these various ill turns partly out of native viciousness, and partly because he hated him for his superiorities of physique and pluck, and for his manifold cleverness. Tom couldn't dive, for it gave him splitting headaches. Chambers could dive without inconvenience, and was fond of doing it. He excited so much admiration, one day, among a crowd of white boys, by throwing back somersaults from the stern of a canoe, that it wearied Tom's spirit, and at last he shoved the canoe underneath Chambers while he was in the air--so he came down on his head in the canoe-bottom; and while he lay unconscious, several of Tom's ancient adversaries saw that their long-desired opportunity was come, and they gave the false heir such a drubbing that with Chambers's best help he was hardly able to drag himself home afterward.