Lafayette College economist Howard Bodenhorn has studied patterns of criminal sentencing in mid-19th-century Pennsylvania, and the National Bureau of Economic Research has put an abstract of his working paper #14283 on the web. In short,
The observed disparities [in sentencing] in the mid-nineteenth century . . . are different than modern disparities. Instead of longer sentences, African Americans and recent immigrants tended to receive shorter sentences, whereas more affluent offenders received longer sentences. The results are consistent with other interpretations of the period as the "era of the common man."(Gee, I wonder what kind of era we're living in?)
If that makes you want to read the whole thing, you'll either have to pay $5 or get next to an academic database.
Check his list of publications on the web site for leads on some more offbeat angles on genealogy, such as "Single Parenthood and Childhood Outcomes in the Mid-Nineteenth Century Urban South" and "Colorism, Complexion Homogamy and Household Wealth: Some Historical Evidence."