Page:The New International Encyclopædia 1st ed. v. 09.djvu/631

HARMONY. 575 HARMONY. voices, as under (b). (2) The leading tone can never be doubled. As the leading tone always =^ demands the progression of a seniistep upward into the octave, it is clear that a doubling of this tone would necessitate the faulty progression of open octaves. ( 3 ) Chords nuist not progress so as to produce an inhannonic relation. This means tliat a tone of one chord cannot appear cliromatic- ally altered in the next chord, except in the same voice. For instance, if g appears in one chord in the tenor part, a gjf or gb can be introduced in the succeeding chord onh/ in the tenor jiart. In the following example the faulty progression under (a) is corrected under (b) (ex. 12). (4) often also the fifth, seldom the third. In two- l)art writing some interval must be omitted, and this is almost always tlic llftli. The number of parts is not restricted. There .ire compositions' for as many as twenty-four, and even thirty-two parts. Of course it requires absolute mastery to liandle such a number of parts. Anticipations, Suspension, Resolution. Tones may also appear in other chords than the ones to which they belong. When one or more voices proceed to tones of the next chord, while the remaining voices sustain the harmony of the first chord, anticipation occurs. Husiicnxion takes place when one or more voices liold the tone of the previous chord when the other voices have already proceeded to the harmony of the next chord. As the tones thus held do not belong to the chord with which they are sounded, they cause a dissonance. All dissonances require reso- ^ 1 „ a — e — b ^ — ^ — ' — P) — ^ — l<^)r-S ^ -V 1 — ?r: ">•• -^ & S '■^ — ,& — ?r3 J:- -^ S — Ti '^- 'C-- '^.. EX. 12. The interval of the seventh is never to be doubled ; neither is any augmented or diminished interval to be doubled, for all such intervals are dissonant, and hence are sufficiently prominent if they occur in only one voice. With respect to one another, the different voices Parallel. Contrary. lution into consonant chords. Anticipation oc- curs upon either the strong or weak beat of a bar; suspension only on the strong beat. Sus- pension, moreover, requires preparation, i.e. the tone suspended must occur in the previous chord as an essential element. The preparation takes Oblique. 1 1 1 U may proceed in parallel, contrary, or ohlique mo- tion. The motion is parallel if both voices either rise or fall together; contrary when one rises and the other falls ; oblique when one remains on the same tone, while the other either rises or falls (e.x. 13). With respect to the number of voices place upon the weak beat, while the suspension itself occurs upon the strong beat (ex. 14). Passing Notes and Changing Notes. By passing notes are meant notes of short duration that do not affect the harmony, but only serve as a connective element between chords, as in Suspension. EX. 16. employed, a distinction is made between two-part, three-part, four-part, etc., writing. The kind most generally used is the four-part. As a triad contains only three tones, it is evident that in four-part writing one of the intervals must be ex. 15 (passing notes marked*). A changing note is one that lies a second above or below a tone belonging to a chord. Whereas passing notes occur always in passages progressing by steps, changing notes generally proceed by skips, as doubled. This is generally the fundamental tone, ex. 16 shows (changing notes marked*)