264 POPULAR LECTURES AND ADDRESSES. 



perceptions in connection with the double sense 

 of touch the sense of temperature, and the sense 

 of force should time permit before I conclude. 

 But I must first say something of the other senses, 

 because if I speak too much about the senses of 

 force and heat, no time will be left for any of the 

 others. Well now, let us think what it is we per- 

 ceive in the sense of hearing. Acoustics is the 

 science of hearing. And what is hearing ? Hear- 

 ing is perceiving something with the ear. What 

 is it we perceive with the ear ? It is something 

 we can also perceive without the ear ; something 

 that the greatest master of sound, in the poetic 

 and artistic sense of the word at all events, that 

 ever lived Beethoven for a great part of his 

 life could not perceive with his ear at all. He was 

 deaf for a great part of his life, and during that 

 period were composed some of his grandest musi- 

 cal compositions, and that without the possibility 

 of his ever hearing them by ear himself; for his 

 hearing by ear was gone from him for ever. But 

 he used to stand with a stick pressed against the 

 \N piano and touching his teeth, and thus he could 



