Your lucky day. I happened to see your posting. I'm descended from a long line of Melchers. I'm an Artist, Composer and writer. You have a painting by Jan Hermanus Tilmes Melcher who lived in Amsterdam. He was b.1847 and d.1920 as you say. He or his family was probably from Germany, but I haven't checked. His paintings are worth at about $3,000 up ( auction value). Depends on size etc. The Melchers although not a large family have many Artists.Many more than any family I know. I hope that you enjoy it and protect it. A great gift for your family one day.