i 4 THE POPULAR SCIENCE MONTHLY. 



appears to have a purely physical basis. We know that the agree- 

 ableness of simultaneous tones depends partly on the relative 

 frequency of recurring correspondences of the vibrations pro- 

 ducing them, and partly on the relative infrequency of beats, and 

 we may suspect that there is a kindred cause for the agreeableness 

 of successive tones ; since the auditory apparatus which has been 

 at one instant vibrating in a particular manner, will take up cer- 

 tain succeeding vibrations more readily than others. Evidently 

 it is a question of the degree of congruity ; for the most congruous 

 vibrations, those of the octaves, yield less pleasure when heard in 

 succession than those of which the congruity is not so great. To 

 obtain the greatest pleasure in this and other things, there requires 

 both likeness and difference. Recognition of this fact introduces 

 us to the next element of sensational pleasure that due to con- 

 trast; including contrast of pitch, of loudness, and of timbre. In 

 this case, as in other cases, the disagreeableness caused by fre- 

 quent repetition of the same sensation (here literally called " mo- 

 notony ") results from the exhaustion which any single nervous 

 agent undergoes from perpetual stimulation ; and contrast gives 

 pleasure because it implies action of an agent which has had rest. 

 It follows that much of the sensational pleasure to be obtained 

 from music depends on such adjustments of sounds as bring into 

 play, without conflict, many nervous elements : exercising all and 

 not overexerting any. We must not overlook a concomitant 

 effect. With the agreeable sensation is joined a faint emotion of 

 an agreeable kind. Beyond the simple definite pleasure yielded 

 by a sweet tone, there is a vague, diffused pleasure. As indicated 

 in the Principles of Psychology, 537, each nervous excitation pro- 

 duces reverberation throughout the nervous system at large ; and 

 probably this indefinite emotional pleasure is a consequence. Doubt- 

 less some shape is given to it by association. But after observing 

 how much there is in common between the diffused feeling aroused 

 by smelling a deliriously scented flower and that aroused by list- 

 ening to a sweet tone, it will, I think, be perceived that the more 

 general cause predominates. 



The division between the sensational effects and the percep- 

 tional effects is of course indefinite. As above implied, part of 

 the sensational pleasure depends on the relation between each tone 

 and the succeeding tones ; and hence this pleasure gradually 

 merges into that which arises from perceiving the structural con- 

 nections between the phrases and between the larger parts of mu- 

 sical compositions. Much of the gratification given by a melody 

 consists in the consciousness of the relations between each group 

 of sounds heard and the groups of sounds held in memory as hav- 

 ing just passed, as well as those represented as about to come. In 

 many cases the passage listened to would not be regarded as hav- 



