Patent and Trademark Resource Centers are excellent places to conduct research on historically significant patents, trademarks, inventions and inventors. PTRC librarians specialize in tracking down materials of this nature. The Orono PTRC has many books and other materials intended to assist historians, genealogists, and the like, in finding very old patents, trademarks and related information.
In addition, the Patent and Trademark Resource Center Association website has a listing of websites, databases, spreadsheets, and other tools specifically for conducting research of a historical nature.
Below (and in the column to the right) are some of the materials you can find at the Orono PTRC.