378 



INDOOR RECREATION 



sense of equilibrium, and if their semi-circular canals are 

 not in excellent condition, they cannot enter this arm of 

 government service. 



Music and noise. We are all aware of differences in the 

 sounds that come to the ear which cause us to say, " This 

 is noise," or " This is music." These differences are due 

 to definite pitch relations and periodic movement of sound 



The musical scale. 



waves. The beating of a tom-tom and the monotonous 

 chant of a savage in his war dance are periodic, and have 

 a definite pitch, but they are not pleasing to our ear, 

 hence they cannot be classified as music to us, although 

 to the savage who makes them and enjoys them, they are 

 music. 



The musical scale. Our music is built up on a series 

 of sounds having definite ratios of vibration. This is 

 called the musical scale. A study of the diagram below 

 shows the staff, with the names of the notes or letters 



