After dining with Mendelssohn, I went with him to the Berlin pianoforte maker, Schönemann, who has brought here his new invention of octaves. By a pressure of the pedal you can add an octave to each note; a key-board on a diminutive scale can be screwed on to any piano, and enables the player to span two octaves, but this is at the cost of tone, and altogether the invention is yet in its infancy. Still, we amused ourselves alternately by playing octave passages, eight times doubled; what good are D.'s bravuras after this?