The Dictionary of the Vulgar Tongue should make some good reading for anyone interested in early 19th-century slang. Though sometimes you have to go look up the definitions as well; for example, "TO FUNK. To use an unfair motion of the hand in plumping at taw." It's kind of like the jargon file, only without the hypertext.
In a similar vein, the Online Etymology Dictionary is pretty nifty as well.