Cludsen's Concave Keyboard
Cludsen's Concave Keyboard, 1910
About 1780, Neuhaus, a piano maker of Vienna, constructed a concave-formed keyboard for his pianos. He aimed to follow the inclination of the human arm to move in a semicircle. This same idea was later tried by Cludsam of Germany, who obtained patents on such a keyboard and seriously attempted to promote it.
From the book Pianos and Their Makers
by Alfred Dolge