328 COMBUSTION. 



This defect in the theory has given rise to another, which has been proposed 

 by Sir Humphry Davy. According to this theory, the phenomena of affinity 

 are the consequences of bodies existing in different states of electricity. It is 

 known that bodies when oppositely electrified attract each other, and when 

 similarly electrified repel each other. If the molecules of two bodies be oppo- 

 sitely electrified, and be so placed that they can act on one another, their ef- 

 fects will be attraction, the energy of which will be increased in a rapid pro- 

 portion with the diminution of their distance. The more intensely one is posi- 

 tively electrified, and the other negatively, with so much the greater force will 

 they combine, and the phenomena of combustion will be exhibited in their 

 union. Oxygen is in an intensely negative state of electricity, and hydrogen 

 intensely positive. Hence they combine with a great evolution of heat. 



