Hello Max,
Moselle in 1839 was a French "departement" as it is today. It is
situated in the Lorraine region (3 departements actually, I think)
neighbouring the Alsace region (two departements). Part of Lorraine (the
Moselle departement) and Alsace became German after the French-Prussian
war of 1870/71. They became French again after WW I.
I dont know anything about rootsweb search sites but you could write to
elsass-lothringen-l@genealogy.net
<mailto:elsass-lothringen-l@genealogy.net>.
Regards
Colette
www.llorca.ovh.org