Ionization by Spraying. 387 



the other set of air, but both must consist o£ the liqiud, or of 

 liquid and air together forming clusters of molecules and 

 carrying a charge. In this respect also, niy results are in 

 agreement with Aselmann's, who found that the large slow 

 ions, whether positive or negative, consisted of masses about 

 equal in size, all consisting of salt solution, or of salt solution 

 and air together. 



In figure 5 are drawn more curves, obtained when the air- 



Fis:. o. 



current carried spray to the electroscope for half a minute. 

 The curve for chloroform is given both for positive ions, 

 indicated by dots, and for negative, by crosses, corresponding 

 to negative and positive charges to the central insulated 

 cylinder. This curve emphasizes the similarity of the two 

 kinds of ions. 



The curve (fig. 5) for phenetol is typical of those obtained 

 for benzine, toluene, and turpentine. Their total ionization 

 effects are small compared with water. 



It is not possible to give precise values to the relative 

 ionizing powers of different liquids, because the numbers 

 obtained must vary with the nature of the apparatus used, 

 and the strength of the air-current applied. But I have made 

 a large number of observations, and taken the mean values, 

 and the results are shown in Table II., with the number of 

 positive ions from distilled water as standard. With different 

 experimental conditions these numbers will appear on a 

 different scale, but the general order would not be materially 

 different. I have endeavoured, without great success, to 



