12. Modern music differs from ancient in two radical points: Tonality, or the dependence of all tones in the series upon a single leading tone called the Key; and Harmony, or the satisfactory use of combined sounds. This part of music was not possible to the ancients, for want of correctly tuned scales, and the selection of the proper tone as key. The only form of combined sounds which they used was the octave, and rarely the fifth or fourth. The idea of using other combined sounds than the octave seems to have been suggested by Aristotle, about 300 B.C. The period from the Christian era until about 1400 A.D. was devoted to apprentice work in this department of art, the central concept wanted being a _principle of unity_. After the beginning of the schools of the Netherlands, about 1400, progress was very rapid. The blossoming time of the modern art of music, however, cannot be considered to have begun before about 1600, when opera was commenced; or 1700, when instrumental music began to receive its full development. Upon the whole, the former of these dates is regarded as the more just, and it will be so used in the present work. [Illustration] [Illustration: KING DAVID, PLAYING ON THE THREE-STRINGED CRWTH. (From a manuscript of the eleventh century now in the National Library, Paris.)] Book First. THE Music of the Ancient World. PRIMITIVE TYPES OF INSTRUMENTS, AND AN ARTISTIC MONODY, WITHOUT REAL TONALITY. CHAPTER I. MUSIC AMONG THE ANCIENT EGYPTIANS. By a curious fortune we are able to form an approximately accurate idea of the musical instruments in use in Egypt as long ago as about 4000 B.C. The earliest advanced civilization of which any coherent traces have come down to us was developed along the Nile, where the equable climate and the periodic inundations of the river raised the pursuit of the husbandman above the uncertainties incident to less favorable climates, while at the same time the mild climate reduced to a minimum the demands upon his productive powers for the supply of the necessaries of life. This interesting people had the curious custom of depositing the mummies of their dead in tombs elaborately hewn out of the rock, or excavated in more yielding ground, in the hills which border the narrow valley of the Nile. Many of these excavations are of very considerable extent, reaching sometimes to the number of twenty rooms, and a linear distance of 600 feet from the entrance. The walls of these underground apartments are generally decorated in outline intaglio if the rock be hard; or in color if the walls be plaster, as is often the case. The subjects of the decorations embrace the entire range of the domestic and public life of the people, among them being many of a musical character. One of the first discoveries of this kind was made toward the close of the preceding century, when Bruce, an English traveler, found in a tomb at Biban-El-Moulouk representations of two magnificently decorated harps played by