NEW CONCEPTIONS IN SCIENCE 



formula, cherished through twenty years, expressed 

 a truth, there can be slight wonder that a work so 

 marvellously successful should breed large hopes. 



It was clear now that the beat of the heart is not 

 due to some mysterious influence of the still more 

 , mysterious nerves, as had so long been supposed. 

 It conies from the presence or absence of a minute 

 quantity of certain salts. The new chemistry 

 stepped in to show precisely how these may act. 



A lump of common salt dissolved in a vessel of 

 water makes the water a conductor of electricity. 

 Bits of metal joined to a copper wire dipped there- 

 in start an electric current. A lump of sugar so 

 dissolved has no such effect. This was for more 

 than half a century one of the deepest problems 

 of chemical philosophy. It remained so until the 

 distinguished Swedish physicist Arrhenius brought 

 forward evidence to show that the molecules of the 

 salts and acids are torn apart when they are dis- 

 solved, and apparently with tremendous force. We 

 are but on the threshold of a knowledge of the ac- 

 tions which take place in the molecular world ; in 

 some instances, as in the case here under view, it 

 seems as if these forces are so great that we have 

 scarce any means of coping with them. The effect 

 in dissolving the salts seems to be an enormous 

 electrical charge on the individual atoms. In the 

 tearing apart, one set is charged positively, the 



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