Ciro Santilli @cirosantilli 37

As the various lines in the spectrum were identified with different quantum jumps between different orbits, it was soon discovered that not all the possible jumps were appearing. Some lines were missing. For some reason certain jumps were forbidden. An elaborate scheme of ‘selection rules’ was established by Bohr and Sommerfeld to account for those jumps that were allowed and those that were forbidden.

Bo Ya was good at playing the qin. Zhong Ziqi was good at listening to the qin. When Bo Ya's will was towards high mountains in his playing, Zhong Ziqi would say, "How towering like Mount Tai!" When Bo Ya's will was towards flowing water in his playing, Zhong Ziqi would say, "How vast are the rivers and oceans!" Whatever Bo Ya thought of Ziqi would never fail to understand. Bo Ya said, "Amazing! Your heart and mine are the same!" After Zhong Ziqi died, Bo Ya broke his Guqin because he thought that no one else can understand his music.