RADIATION. 209 



parts, the sea-waves, which cannot subside without pro- 

 ducing heat, finally resolve themselves into waves of ether, 

 thus regenerating the motion from which their temporary 

 existence was derived. This connection is typical. Nature 

 is not an aggregate of independent parts, but an organic 

 whole. If you open a piano and sing into it, a certain 

 string will respond. Change the pitch of your voice ; the 

 first string ceases to vibrate, but another replies. Change 

 again the pitch ; the first two strings are silent, while an- 

 other resounds. Now, in altering the pitch you simply 

 change the form of the motion communicated by your vocal 

 chords to the air, one string responding to one form, and 

 another to another. And thus is sentient man acted on by 

 Nature, the optic, the auditory, and other nerves of the 

 human body being so many strings differently tuned and 

 responsive to different forms of the universal power. 



Note. — The statements regarding the action of aqueous vapor, made 

 in sections 12 and 13 of this Lecture, have been controverted by the late 

 Professor Magnus, of Berlin. I therefore wish the reader to hold in sus- 

 pension his judgment of these two sections until new light can be thrown 

 upon the subject. This will soon be done. 



