in a general sense, means the production of appreciable and varied sounds by the voice. In a more limited sense, it means different inflexions of the voice through intervals admitted in music, and consistent with the rules of melodic modulation. It is well known that these inflexions differ from those of the voice in speaking. In singing, harshness of vocal timbre (see Music) and falseness of intonation are much more frequently met with than the opposite qualities, especially among persons not trained to sing. Musical training, when applied to a person possessed of a naturally good quality of voice, and a good ear, produces effects that can hardly be imagined by those who have not watched them attentively. Upon the subject of vocal-training, the reader may consult any of the best treatises on singing. For some remarks on the mechanism of the human voice in singing, and the compasses of voices, see Music.

Singing of Birds. Birds may more correctly be said to whistle than to sing. This is shown by the structure of their vocal organs, as well as by the mechanism of the automation singing-bird of Maillardet. The power of singing is confined to the human race. In the notes of but few birds can distinct melodic intervals be perceived. The notes of the swall, the cuckoo, &c. as well as many of the notes of the blackbird, &c. constitute distinct melodic intervals, and are therefore susceptible of musical notation. Captive singing-birds may be taught tunes, as in the case of piping-bullfinches, &c. These last have even been taught to perform in concert. We have observed, among a number of piping-bullfinches, marked differences of musical ear. Some piped well in tune; others more or less out of tune.