Excellent Research Sources
I thought I'd put this list together of the places I use to research these old tools, just in case anyone wants to conduct similar research.
Google Books - Excellent source for old magazine / publication articles, books, advertisements, etc. (HINT: USE the search tools at the top of the page when searching for specific date ranges, etc.)
Worldcat - Searches hundreds, if not thousands of library archives for online editions, editions in their holdings, etc.
Patents from 1790 - 1836 - "The X-Series Patents"
Commissioner of Patents Reports - 1849 - 1864 - These contain every patent issued yearly.
Google Patents - Perhaps even better than USPTO Patent Search
USPTO Patent Search - Good for newer patents, cumbersome and "iffy" for patents older than 1972
USPTO Patent Application Search - I'm putting this here for posterity, no good for older applications.
USPTO Trademark search (TSDR - Documents)
USPTO Trademark Search (TESS - Much less reliable but shows history of ownership)
Newspapers.com - This site adds thousands of pages of content every day and, while it is a pay site, it is an excellent resource for research.