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tion. No matter if the pendulum of a large clock should 

 move through an arc of only a degree, or if it should move 

 through an arc of ninety degrees would the number be 

 changed, but it is of course evident that when moving 

 through ninety degrees the stroke is more intense than 

 when moving through one. 



If a tuning-fork by means of a point at its vibrating ends 

 could be allowed to trace its vibrations on a revolving drum 

 the intensity of the sound would be pictured to the eye by 

 the height of its waves. Intensity, therefore, is usually 

 explained by saying that it is that property of a sound which 

 depends upon the amplitude of the vibration. Loudness in 

 sound is brightness in the case of light. 



2. Pitch. We readily distinguish sounds as higher or 

 lower, and we speak of bass, alto, tenor and soprano parts 

 when we haVe these distinctions in mind in the case of 

 singing. This highness or lowness, or, in other words, the 

 pitch of a sound, depends upon the number of vibrations 

 per given time, of which the sound is composed. For in- 

 stance, sixteen, or more generally thirty-two vibrations per 

 second is the lowest note audible. Middle C on a piano 

 (French pitch) is 256 vibrations per second, while the 

 upper C on the piano has over 2,000 vibrations to the 

 second. Pitch is expressed in another way, by stating that 

 it is that property which depends upon the length (not 

 height or amplitude) of the vibrations. This is but saying 

 the same thing in another form. In a note which has 2,000 

 vibrations per second the individual waves must be much 

 shorter than in a note that has but 32. Just as in a chain 

 having 100 links to the foot, the individual links must be 

 much shorter than a chain having but three links to the 

 foot. Evidently the number of links and the length of the 

 individual links express the same thing. 



Other things being equal, the pitch which a sounding 

 body will produce will in the case of tuning-forks or vibrat- 

 ing tongues depend upon the length of the fork or tongue, 



