VIBRATIONS OF MUSICAL NOTES. 351 



leasing effect than others. The most pleasing result 

 s attained when one note is just an octave above the 

 >ther, as c' and c", and consequently one produces twice 

 he number of pulsations of the other. Such a combi- 

 lation of two musical sounds which make an agree- 

 Me impression is called a concord. Next to the octave, 

 he most pleasing concords are produced by notes the 

 atios of whose numbers of vibrations are those given 

 >elow : 



i ATIO OF VIBKATIONS. 3:2 4:3 5:4 6:5 



U r 



EXAMPLE. 





g' and c' f and c' e f and c' g f and e' 

 NAME OF C Major Minor 



INTERVAL. I Fifth Fourth Third Third. 



From the number of holes in the different rows 



L , follows that the note ef is produced by f of the 



ibrations which produce c', the note g f by |, and the 



.ote c" by twice as many as c'. Three simultaneous notes, 



ke our c r , ef, cf , in which the ratio of the number of 



ibrations is as 4 : 5 : 6, constitute a ' perfect chord.' 



Whenever the disc is made to rotate with a con- 



tant velocity, though different from that previously 



issumed, other notes will be produced, but they will 



jave the same constant relation to one another, and the 



nportant result will be established that the difference 



ji pitch or the interval between two notes depends 



)lely upon the ratio of the numbers of vibrations 



hich produce them, whatever their absolute pitch 



; ay be. The number of vibrations made by the key- 



)tes in the successive octaves, that is, those correspond- 



g to Ci, (7, c', &c., may be determined experiment- 



ly. As has been shown, each note of the higher 



