Is there a way to track the history of this patent? It was my Great Grandfather's and we never knew he held a patent. I'm interested in learning more, such as whether he ever sold the patent/technology to a company or another person.
You can go to the PTO website and do a search, or do a more user friendly search via google at: google.com/patents . Just search your great grandfather's name and if he does have a patent in his name, it should pop up. Assuming it's quite old, the patent text may be distorted if google tried to read the text which was on paper at the time. In that case, google should also link to the source documents at the PTO in which you can then see the original document scans.