PROCEEDINGS 



01' 



r H i: R () Y A E I R I S EI A C A D E M Y 



PAPERS READ BEFORE THE ACADEMY 



I. 



THE NATURE OF THE IONS PRODUCED BY PHOSPHORUS 

 By PROFESSOR J. A. McGLELLAND, D.Sc, F.R.S., 



AND 



P. J. NOLAN, M.Sc. 



Reail Februauy 10. I'liblislied October 3, 1919. 



Before the discovery of the large ion many observers investigated with 

 conflicting conclusions the electrical conductivity of air in the neighbourhood 

 of phosphorus. E. Bloch.^ in a paper which contains a history of the work 

 on this subject up to 1904, showed that the conductivity imparted by the 

 phosphorus was due to large ions. The mobility of the ions varied witli the 

 rate of drawing air over the phosphorus into tlie electrical measuring apparatus. 

 The lowest mobility, which was obtained with the slowest air current, was 

 ■00029 cm. per second. He was of opinion that all the ions observed in an 

 experiment were not of the same mobilit)', and that his mobility numbers 

 were means. His experiments lead him to think tiiat the ions are charged 

 dust particles. L. Bloch- found that tlie ioiiisalion of tlie air by tlie phosphorus 

 took place in the i-egion of the phosphorescence, and that ozone was formed 

 in the same place. He decided that the phosphorescence is just like an 

 ordinary flame which accompanies the combustion of phosphorous oxide into 

 phosphoric oxide, and tliat ionisation liy phosphorus is a particular case of 

 ionisation by flame. He pointed out that the fact that higher mobilities are 

 obtained if the ions are examined at shorter times after formation has also 

 been observed in the case of flame ionisation. 



In previous papers' the nature of the ionisation produced by bubbling air 



1 E. Bloch : Ann. de Chem. efc de Phys , vol. iv (1905). 

 - L. Bloch : Ann. de Chem. et de Phys., vol. xxii (1911). 



^ McClelland and Nolan : Pioc. Roy. Iiisli Acad., vol. x.wiii, Sec. A (1910), and 

 vol. xxxiv. Sec. A (1918). 



R,I,A. PBOC, VOL. XXXV, SECT. A. [1] 



