Dumke is a name that appears in Brandenburg, Germany and also in Poland. I was born in Deutsch Krone, Kreis Schneidemuehl, Pomerania, Gerany. Now known as Walcz, Pila, Poland, after 1944. The name Henry would have been Heinrich. The Dumke's, according to MY mother, came from Bavaria, Germany, to get free land in Pomerania prior to 1800. Suggest you narrow your search. There are also Dumke's in Canada (distant relatives, I think) and a Meta Dumke in California whom I met when we embarked in New Jersey in July 1954 (but my dad said at that time, she's no relation to my German family).