I'm interested in concertina history, and the harmonica and concertina are both in the 'Free Reed' family, which only came into being after some Vietnamese 'Shengs' were brought to Europe around 1820 and shown at some of the 'Great Exhibitions'. I've recently found a few concertina snippets related to the American Civil War on the CSS Alabama Society site (www.css-alabama.com). You might find some information and useful links there.
Good Luck!