64 Scientific Proceedings, Royal Dublin Society. 



flats, and to be but little less distinct in E b with three. Let us 

 then compare the keys of A and A b as the best representatives of 

 the two classes in major keys. 



Now the first thing to observe is, that the tones of the scale 

 which in the key of A are on the black notes are the tones 

 which in the key of Ab are on the white notes, and vice versa. 

 In fact — 



In A, fa, do, so, re (the fourth, first, fifth, and 



second of the scale), are 

 on white notes ; 



and ti, mi, la (the seventh, third, and 



sixth), are on black; 

 while 



In Ab, fa, do, so, re, are on black notes; 

 and ti, mi, la, are on white. 



.This, without going farther, at once indicates that there should be 

 some difference of musical effect between these keys. And this 

 conclusion will be more fully borne out when we consider the 

 place of these notes in the principal chords. 



In the key of A, the major chords (the tonic dominant and 

 subdominant chords) have their end notes {i. e. the first and fifth 

 in each chord) on white notes, while the middle note in each (the 

 third) is on a black note. Hence, in playing in this key the end 

 notes of the major chords will be relatively strong, and the middle 

 note relatively soft. This of course gives a peculiar quality to 

 the chord. 



On the other hand, in Ab the end notes of the major chords 

 fall on black notes and are softened, while the middle note falls on 

 a white note and retains its strength. This gives a special quality, 

 differing from the former, to the major chords of Ab- 



The different provision made for the major chords in the two 

 keys is represented to the eye in the following diagram : — 



