I wonder if he came from Yorkshire. I keep looking at this:
Name: Samuel Porritt
Event Date: 30 Jul 1785
Event Type: Baptism
Parish: Birstall, St Peter
Father's name: Joseph Porritt
http://search.ancestry.co.uk/cgi-bin...iv=1&ml_rpos=6
My Samuel's daughter, Mary, my 2x-great-grandmother, named her two sons Joseph and Samuel.