Dick considers Mr. Greyson, the first patron figure he encounters in the novel, to be an immensely wealthy man. When the businessman invites him to Sunday lunch, Dick uses hyperbole to express Mr. Greyson's wealth and the honor of the invitation:
Dick was as much astonished at this invitation as if he had really been invited by the Mayor to dine with him and the Board of Aldermen. Mr. Greyson was evidently a rich man, and yet he had actually invited two boot-blacks to dine with him.
This is an example of hyperbole because the reader understands that Mr. Greyson does not have the same social status as the mayor. He's probably not even as wealthy as it seems, since Dick, who comes from poverty and is unused to luxury of any kind, isn't the best judge of such things. The fact that Mr. Greyson personally teaches Sunday school and lives in a brownstone rather than the enormous mansions that New York's 19th-century elite built for themselves suggests that he's part of the larger class of affluent bourgeoisie. Dick's idea of Mr. Greyson's importance is inaccurate, but it accurately conveys his own sense of awe and intimidation at the prospect of dining with the businessman's family.
While Alger is often associated with "rags-to-riches" tales, his characters usually aspire to and achieve moderate wealth and an upper-middle-class lifestyle. This focus on entering the middle class rather than becoming ultra-wealthy may reflect Alger's attempt to reach a large audience and inspire readers with a theoretically achievable goal. It's worth noting, however, that Alger paints an extremely rosy portrait of social mobility in the 19th century. In fact, many Americans were trapped in poverty by social and structural conditions and would have found it impossible to ascend to Mr. Greyson's class status.
