He had two witnesses to this claim, Willet and John O. Walton, both of 1940 East Somerset Street in Philadelphia. Willet knew my third great-grandfather for 40 years and John for 20. I'm guessing that John was Willet's son. I wonder what their relationship was to my third great-grandfather. This document does not state that.
Also listed on here is the address for my third great-grandfather's lawyer, 2711 North 6th Street (6th and Lehigh Avenue). The law office was just over five miles from his home.