CHAPTER II. 

 DISCOVERY OF IONS: A NEW KIND OF PARTICLES. 



The fact that gases ordinarily possess but a slight elec- 

 trical conductivity may not seem particularly impressive, or 

 even the additional fact that this conductivity may be 

 vastly increased, until, indeed, they become very good con- 

 ductors. Yet this simple-seeming fact is destined above 

 all others to inform man of some cf nature's mcst carefully 

 guarded knowledge. Some facts, it may be observed, are 

 pregnant with the meaning cf a universe; and this is one 

 of them. 



Starting, then, with this apparently unimportant fact, we 

 may best begin our study with a candle flame. Bring the 

 candle up to the little charged electroscope. Observe that 

 the leaves collapse, verifying the fact previously stated , that 

 the gas in the neighbourhood of a flame is a conductor of 

 electricity. Knowing this, it is important to find out why. 

 And we discover the why in the properties of the conducting 



In the first place, the gases which come from the flame 

 retain their conductivity, even after they have got some dis- 

 tance away and have been cooled by the surrounding air. 

 It has been proved that such a gas will retain some con- 

 ductivity six or seven minutes after it has left the flame. 

 Fig. 9. You may prove it for yourself by drawing the 

 gas from the flame over the leaves of the electroscope 

 situated at some distance, under which conditions the 

 leaves collapse, thus showing that the gas retains its 

 (48) 



