A sonic switch was the answer. A complete melody which, when played through, would actuate his invention. The new sound system would then be coupled to the old piano and a twenty-third century instrument would be in operation. A piano, but more than the piano, beyond it. To himself Danny called it a meta piano. The requirements of the actuating melody, the key that would operate the sonic switch, were simple. It had to be a melody that was never played. Something that had never been recorded in pre-music robot days, or one of which no record had survived. Danny could read music, an accomplishment he'd taught himself. He visualized a printed score he had once seen in a museum. He ran over it once in his mind and he played it on the piano. The blank tape that was a part of sounds were impressed on the his device. The melody was keyed in; thereafter, when it was played once, his invention would be ready for operation. A time lapse would switch it off. Danny arose and walked out of the enclosure. His work as an inventor was done. His accomplishments as a musician were just beginning. * * * * * The next two years Danny learned the instrument. Each time he switched it on with the key melody, playing until it was time to go, and then leaving, secure in his knowledge that the passage of time would disconnect his invention. He grew more assured of his technique, expanding and developing it. He had been good before. How much he now knew there was no way of gauging. He had no audience whose reaction he could test. Of course there were the usual evening concerts. One night he sat in the balcony listening aimlessly. He let conversations flow past without actually hearing them. Background noise, an essential part of the scene at Music Hall. Without knowing why, he became disturbed. Something was happening. He listened more closely. Several times he heard it mentioned. And no one but himself ought to know that. For the first time he glanced at the program he'd taken on entering. He read through it with profound unease. "Tonight's audience will participate in the most exciting musical event of the past generation. A new record has been found. The robot piano master, Horowitz Rubinstein Paderewsky Art Tatum Rozenthal will have a new technique added. Jelly Roll Morton will be integrated into the composite musical personality. "The record was found several months ago during the excavation of a twentieth century slum. Shattered into several hundred pieces, at first it was not recognized. A keen student of music investigated, and, as a result of modern research was able to restore it to the original condition. "Transposed to the brain of the robot master, the work is presented tonight for the first time in several centuries. Flee As A Bird To The Mountain...."