in music. The Greeks had three different species of music; the diatonic, the chromatic, and the enharmonic. This last was esteemed by much the most agreeable and powerful of the three; but the difficulty of its execution rendered its duration short, and latter artists were upbraided for having sacrificed it to their indolence. It proceeded upon lesser intervals than either the diatonic or chromatic; and as the chromatic semitone is still less than the diatonic, the enharmonic intervals must have consisted of that semitone divided into parts more minute. In Rousseau's Musical Dictionary (at the word Enharmonique), the reader may see how that interval was found in the tetrachords of the ancients. It is by no means easy for modern ears, inured to intervals so widely different, to imagine how a piece of music, whose transitions were formed either chiefly or solely upon such minute divisions, could have such wonderful effects; yet the melody of speech, which rises or falls by intervals still more minute than the enharmonic, when properly modulated and applied with taste, has an astonishing power over the soul. As to the modern enharmonic system, we may likewise refer the reader to the same work for an account of its nature and use; though he will find it accurately and clearly explained by D'Alembert, in the Treatise of Music given in the present work, (art. 144, 145, 146.)