74 Proceedings of the Royal Irish Academy. 



the rate of falling off being then in both cases greater than would be given by 

 these equations. 



5. The mobiUty of the large ions is the same under aU circumstances, and 

 the same in any mass of flame-gas. The mobility must, therefore, be in- 

 dependent of the charge. 



C. The formation of the nucleus seems not to be affected by the charge. 



In conclusion I wish to express my indebtedness to Professor ilcClelland 

 for his advice and encouragement during the work. 



