SOUND 



the sounds in the world, and understanding 

 perhaps only a quarter of those that reach us. 

 We may say that it would be of little use to 

 us as long as we have eyes, but we must not 

 forget that there are times when our eyes 

 themselves are of very little use. In the dark, 

 for instance, hearing will tell us much more 

 than seeing, and if we have trained ourselves 

 properly we should then rely on sound rather 

 than sight. 



Sound is a sensation which comes to us 

 from a distance ; not always from a great dis- 

 tance, and not always from the same distance. 

 If we shut the window of our room, a sound 

 from outside becomes much fainter. One day 

 we can clearly hear the neighbouring church 

 bells, another day they are quite indistinct. 

 We may be kept awake one night by the noise 

 of trains, and the next night forget that we are 

 near a railway. Such differences as these are 

 found to depend on the wind and the other 

 conditions of the atmosphere, and show us, 

 what indeed we probably already had realised, 

 that sound is something which usually travels 

 through the air. In order to find out the nature 

 of this something, let us examine an object which 

 is making a sound, say a gong or bell which has 

 been struck, or a fiddle-string which has been 

 played. If we touch one of these things lightly 

 with the tips of our fingers we can feel it tremb- 

 ling, but almost at once the touch of the finger 



(43) 



