ACCENT AND REGNANT HARMONY 143 



for treating all other chords in similar relations in 

 the same way have been derived by induction. 



The diatonics form a scale of eight tones in which 

 the same two tetrachords are disjunct. This scale 

 proceeds from the Tonic-centre of one tone-region to 

 the Tonic-centre of a contiguous region; in it the 

 two Tonics form lower and upper terminals. This 

 our familiar Major scale is as follows : — 



Do — re — mi -^fa — sol — la — ti Do 



I IV V I 



A consonant thread of harmony extends throughout 

 the range of pitch and connects all its components in 

 all regions. Of these threads I is the genus and 

 original, V and IV are relative. In the following 

 illustration the arrows indicate the whole range of 

 pitch. 



I— ^1 — ^iV 



i 



i 



The thread of the dissonant genus V9 extends from 

 one region into the next, and in each octave one such 

 thread intersects another thus: — 



