7 8 THE CREATION OF MATTER 



equal. Periodic waves are those which follow each 

 other at the same intervals, that execute their oscillations 

 in the same time. When the waves succeed each other 

 with sufficient rapidity, and at the same intervals of time, 

 they make music to the ear. When they follow each 

 other at irregular intervals, they produce a noise that 

 grates on our sense of hearing. It matters not from 

 what source the force originating the motions comes ; if 

 they be periodic, they are musical ; if unperiodic, they are 

 unmusical. From the finest instrument a confused jangle 

 may be made to issue. 



All simple sounds are periodic and musical. A noise 

 is always composed of two or more simple sounds super- 

 posed on each other irregularly. A resonator is an 

 instrument made to re-echo one tone, and one tone only. 

 It will select, and respond to, and so reveal the presence 

 of that tone, if it be in any combination of sounds. If 

 it be not present, the resonator will be silent. Apply 

 resonators to a noise, and they will show what notes are 

 mingling in confusion in it, and that the components are 

 pure and true and pleasant as music. Make a noise with 

 a piano by striking its keys anyhow, and it is easy to see 

 that each key struck makes a musical sound, and that it is 

 their irregular mingling that makes the unpleasantnesses. 

 Every simple sound is thus seen to be in all respects 

 perfect. It is pleasant to the sense. It is in finest 

 harmony with the perceptive power. Its wave vibra- 

 tions, which strike the tympanum, are periodic. To and 

 fro the particles oscillate, always passing the same point 

 in the same interval. The order that is in all material 

 particles, and in their sensibility to force, is thus beauti- 

 fully exhibited. Their forms and characteristics, in their 

 relationships to each other, are such that they are 

 naturally fitted for executing perfect motions. Struck 



