THE VOICES OF NA TURE. 
I2 9 
LECTURE VI. 
THE VOICES OF NATURE AND HOW WE . HEAR THEM. 
E have reached 
to-day the mid- 
dle point of our course, and here we will make a new 
start. All the wonderful histories which we have been 
studying in the last five lectures have had little or 
nothing to do with living creatures. The sunbeams 
