502 STUDIES IN ADVANCED PHYSIOLOGY. 



HARMONY. 



A succession of notes varying in pitch and possibly 

 other properties is spoken of as a melody. Melodies need 

 conform to no especial physical rule, but are almost wholly 

 determined by the likes or dislikes of the composer. A 

 pleasing melody to one is not necessarily so to the next. 

 A much more definite arrangement of notes occurs in har- 

 mony. By harmony is understood the consonance of two 

 or more sounds. Any two sounds when sounded together 

 are by no means necessarily harmonious. In fact, if the 

 sounds were selected at random the chances would be very 

 much in favor of their proving discordant to the ear. Har- 

 mony is dependent upon the consonance of definite specific 

 sounds, and is, at least with the majority of civilized people, 

 the same for all persons. Every normal ear hears as a pleas- 

 ant sound the consonance of a note and its octave. Every 

 player on the piano knows that C and G produce a pleasant 

 effect when sounded together; that the same is true of C 

 and E, or C and F, confining ourselves in this illustration 

 to the key of C. C and B produce a discord, C and G^ are 

 displeasing. We have now to determine what physical 

 property it is that determines the consonance or dissonance 

 of notes. In doing so it is necessary to bear in mind that a 

 consonance or dissonance is first determined by the ear, 

 apart from any physical considerations of the sounds in 

 question. A person who knows not the first elements of 

 the nature of sound may be perfectly able and is perfectly 

 able to feel the pleasurable effects of certain combinations 

 of sounds, and the displeasing effects of others. The proper 

 chords on a piano or in an orchestra please the ears of the 

 attuned or untuned alike, within large limits. The determi- 

 nation of the physical nature of harmony, therefore, consists 

 merely in determining the relations of notes which have been 

 previously selected by the ear as harmonious. 



When, now, notes which are harmonious are examined 

 experimentally, it is soon established that the physical basis 

 of harmony is the simple matnematical ratio of tJie number 



