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Music is essentially rhythmical. Sound without rhythm is 

 noise. The ear is gratified when the sounds succeed each other 

 at definitely recurring intervals. The pendulum swinging before 

 us has its own special rate of vibration. So long as it is as it is, 

 and where it is, it will vibrate at the same rate and no other. 

 This principle is of general application and musical instruments 

 are based on it. The columns of air in the pipes of an organ 

 have their own determined and definite periods of vibration. 

 Dr. Draper showed many experiments illustrating this. 



The drawing of a violin bow over a string presses the string 

 slightly out of its position, the string springs back again, and 

 these motions produce a noise pleasant or otherwise, according 

 to the regularity of their recurrence. The musical note produced 

 by rubbing a finger over the edge of a glass bowl, the air in the 

 bowl responding to the vibrations in accordance with its own, the 

 singing of a rifle bullet as it passes through the air, the singing 

 of a tea kettle produced by the bubbles of steam rising through 

 the water and bursting, are all instances of the same 

 rhythmical motion. The note produced by a metallic plate 

 which has been struck is beautifully shown by the figures into 

 which sand strewn on its surface is thrown. The higher the 

 note the more complex the figure, because of the more frequent 

 the vibrations. 



How is it we hear each other talk ? The tongue so often 

 spoken of as an unruly member, is not, strictly speaking, the 

 organ of speech. People have been known to talk after their 

 tongues have been removed. The apparatus by which the sound 

 of the voice is really produced is the larynx. Through the 

 aperture termed the glottis the air is continually passing. The 

 size of this aperture is determined by the vocal cords. It is this 

 which determines the character of the sound we utter. The 

 vibration of the air thus produced reaches the delicate membrane 

 within the ears of those listening to a voice, these are passed on 

 to the nerves of the brain, and the voice is heard. These vibra- 

 tions are at the rate of from one to three hundred per second, 

 both in the person transmitting, and, of course, in the ear of the 

 one receiving the sound. 



Music can be appreciated by people who are deaf. Beethoven 

 was deaf for a great part of his life. He used to sit with a 

 stick pressed against the piano, the other end against his teeth, 

 and he could hear the sounds produced by his instrument. 

 Think of the multitudinous wave systems crossing each other in 

 a room during a concert. From the vocal organs of the men 

 proceed waves of from six to 12 feet in length. The higher 

 voices of the women produce waves from 18 to 36 inches long. 

 Each instrument in the orchestra emits its own peculiar waves. 

 They are all again reflected from the walls of the room, and 



