It is probably a Rudge. The backbone is of unique construction. On most highwheel bicycles the rear forks have a lug that is fitted into the lower end of the backbone tube which normally was seamless tubing and swaged to form the taper. It was then brazed together with a pin running through it. On the Rudge racer, to cut down on weight, the backbone and rear forks were all one piece of sheet metal that was stamped and rolled to shape. I can't imagine the dies that were required to do this work. Incredible.