Chin-noung, successor of Fo-hi, was also a good ruler; his chief works in music seem to have been some alterations in the _Che_ (a sort of _Kin_) and he was able by his playing to turn the heart of man, from intemperate life, to celestial truth. Hoang-ti, the next emperor, had music scientifically investigated and established natural rules to the art. The reign of Hoang-ti is supposed to have been about 2,600 B. C. In his day music though practised, was not understood in its natural elements. The Chinese even at that day, based all other sciences on music, and sought to make this art (in a mystical and hyperbolical way) the foundation of all others. The emperor therefore ordered Ling-lun to give his attention to the development of the laws of music. The fables on the subject of his researches are innumerable; he travelled to the north-western part of China and took up his abode on a high mountain, near which was a large growth of bamboos. Ling-lun took a bamboo, which he cut between two knots; he removed the pith, and blowing in the tube, a sound resulted which was of the exact pitch of the human voice when in its normal state. Not far off was the source of the Hoang-ho, and Ling-lun found that the tone of his tube was similar to the sound given by the waters of that river in bubbling from the earth; thus was discovered the first _Lu_, (or Li) the fundamental tone. Ling-lun was pursuing his investigations further, when the Foang-hoang appeared with its mate and perched upon a neighboring tree. The male bird sang in six different tones, while the female also used six, but different from the preceding. The first note of the mystical Foang-hoang, was precisely in unison with the reed which Ling-lun had cut from the bamboo. On ascertaining this, the fable continues, Ling-lun cut twelve pieces of bamboo and pitched them according to the notes of the two songsters; he found by alternating the sounds of the male with the female bird, that he had a chromatic scale. The six tones of the male were called the _li-yang_ (masculine tones) the other six _li-yn_ (feminine tones), and throughout all Chinese music, the distinction between the male and female tones of the scale still exists. This was the first Chinese discovery of the proportions of sound, the first step in the science of Acoustics, and though covered over with fable and allegory, it really preceded the discoveries of Pythagoras by many centuries; Ling-lun went back to the emperor’s court and there measured and fixed the pitch of the Chinese scale forever. Bells were also made of the official pitch, that it might easily be perpetuated.