34 Proceedings of the Royal Irish Academy. 



the percentage present of the slowest ion increases with the time ; but whether 

 this is due partly to the reason here suggested, or whether it can be sufficiently 

 explained by the more rapid loss of the more mobile ions, we are not yet in a 

 position to say. Further work is also required in the direction of measuring 

 the mobilities at shorter intervals after the spraying and the bubbling through 

 mercury. 



In this discussion we have dealt only with the five groups of ions which 

 occur both in the experiments with water and with mercury, the slowest of 

 these ions being the well-known large ion of Langevin. The other groups 

 of ions found in the spraying of distilled water contain the ordinary small 

 ion and at least two classes of even greater mobility. These ions are now 

 being further investigated by a different and more convenient method, and 

 we must postpone further discussion for the present. It would appear that a 

 fuller knowledge of the different groups of the more mobile ions that occur 

 in these experiments shoixld help to elucidate the nature of the ordinary small 

 ion, while a study of the slower groups can hardly fail to add to our knowledge 

 of the Langevin ion. 



