they know that a fire burned up half of the town in that smoke-hazed september of 1951 , but they do n't know that it was set , and they do n't know that the boy who set it graduated valedictorian of his class in 1953 and went on to make a hundred thousand dollars on wall street , and even if they had known , they would not have known the compulsion that drove him to it or the way it ate at his mind for the next twenty years of his life , until a brain embolism hustled him into his grave at the age of forty-six .