I have just found this thread and I am descended from the publishing Johnsons. Samuel born 1783 died 1868 was my great great grandfather. My website is a bit out of date as i have a lot more info but you may like to visit it at http://www.geocities.com/garthjh/johnsonfamily.
If Mona Christian has any details I would be fascinated to share information.

Many thanks, Garth