An Arizona woman hopes to learn the fate of the man who sketched a portrait of her father when they were WWII POWS in Krems, Austria; the Seadrome, a floating airport proposed during the 1920s to enable transatlantic flights, is investigated for a New Yorker who inherited photos of a Seadrome model from his grandfather; a New Jersey woman who has an unusual artifact: a live artillery shell that may date to a 1916 sabotage attack on a Black Tom Island, N.Y., munitions depot by a German spy ring.