Keywords: Patent DE204721, page 3.png en Detailed sketches of breast-mounted carrier pigeon camera with two lenses invented by Julius Neubronner de Detailskizzen von Neubronners Brieftaubenkamera mit zwei Objektiven Screen shot of PDF file from European patent server Julius Neubronner 1852 “1932 1907 PD-old-75 Pigeons in aerial photography Patent drawings Cameras of Germany |