John has been browsing the family history magazines in the local library, and pointed out to me an article on Knitting Ancestors by Penelope Hemingway in the current issue of Family Tree. Amongst other interesting bits of knitting history, it has a wonderful early photograph of two Cornish girls knitting (ganseys, I think). You can see and read all about the photograph on her blog, The Knitting Genealogist. She dates it to the early 1870s, and has done some census research to show that the two girls became professional knitters.
She has also just started publishing a series of articles in Yarn Forward, also called The Knitting Genealogist.
In the Family Tree article, I found the snippets of information on the history of knitting interesting for their own sake, but it would be wonderful to find professional knitters in your own family tree. It's not likely to happen to me, though - although I'm from Yorkshire, I don't have any connections with the Dales area, which was well-known at one time for its skilful knitters. All the ancestors that I have been able to trace came from further south - Derbyshire and the Midlands. My own knitting genealogy only goes back to my Grandma, as far as I know.