58 J 



V. 



THE LAPvGE lU>fS Am) COimEXSATIOS-NUCLEI 

 FEOM FLAMES. 



By H. KEXXEDT, M.A., ILSc, 

 University College, Dublin. 



Bead JrsE 26. Published Octobek 3, 1916. 



Is previous papers,' Professor M'Glelland and the author have given the 

 results of observations on the large ions occurring in the atmosphere. These 

 investigations included a prolonged study under various conditions in the city, 

 and an examination of the air at a distance from the city, and free from the 

 artificial sources of large ions, such as flames, &c. The results were such as to 

 lead to the conclusion that the large ions occurring in the atmosphere of a city 

 are due for the most part, if not entirely, to the great number of sources of 

 combustion, which, as laboratory experiments prove, produce large ions of 

 exactly the same mobility as those occurring in the atmosphere. Attention 

 was also directed to the analogy existing between the results of the study of 

 atmospheric large ions and the work of Aitken on condensation-nuclei in the 

 atmosphere under various conditions, and it was suggested that the nuclei 

 measured by Aitken were not dust particles in the form of solid matter in a 

 very fine state of division, but were identical with the large ions and the 

 uncharged nuclei, from which large ions may be formed by ionizing the air 

 in which these nuclei occur. The atmospheric large ions and condensation- 

 nuclei, then, seem to be the same as those produced by flames. The mobility 

 of the large ions from flames has been already investigated. Its value is 

 found to be about 0003 cms. per second for an electric field of a volt 

 per em., and the mobilities of all the ions are the same. If the flame-gas 

 be deionized by an electric field when the gas has just left the flame, 

 nuclei are still formed, and they may be changed into large ions of the 

 same mobUity by ionizing the air in which they are contained. The relations 

 existing between the number of charged and uncharged nuclei at any time, 

 €md the nature and cause of the disappearance of ions and nuclei, seemed to 

 be a subject worthy of investigation, and the present paper is an account 



■' M'Clclland and £eimedy : Proc. Royal Irish Academy, toI. ttx, Sect. A, I>'o. 5. 

 Kennedy ; Proc. Royal Irish Academy, rol. ixxii. Sect. A, ^To. 1. 



