CHAPTER XVI. 



SOUND. 



Difficult problem in Science. Prof. Tyndall's explanation not satisfactory. 

 Sound vibrations and light vibrations. Sound generates heat. 

 How long fifty organs would take to heat St. Paul's Cathedral! 

 Sound in summer and winter. How we hear fifty sounds at the 

 same time. Echoes. New theory of Sound. A sympathy between 

 the mineral atoms of matter. Iron a better conductor than wood. 

 If a man has sympathy why should not an atom ? Dancing flames. 

 Tyndall's new theory of Sound. Experiments at the South 

 Foreland, England. Vapour in layers. 



AN explanation of the phenomenon of Sound we consider to 

 be one of the most difficult problems in science, and the 

 manner in which it has been explained by Prof. Tyndall, and 

 others, is far from satisfactory. For instance he says, sound, 

 light and heat, are all caused by the vibrations of the atoms of 

 the atmosphere. But sound, light and heat, all travel at 

 different rates of speed, and in order to surmount this difficulty 

 he says : " they all vibrate different ways," a most empirical 

 and yet safe assertion, for it is beyond the power of any 

 experimenter, or microscopist to demonstrate how atoms vibrate. 



Again he says : " Sound generates heat." " Every sonorous 

 vibration which speeds through the air of this room and wastes 

 itself upon the walls, seats and cushions, is converted into the 

 form with which the cycle of actions commenced : namely 



