Electricity of Drops. 

 This is shown by the following table : — 



351 



Substance. 



Deflexion when 



drops fall 



through air. 



Deflexion when 



drops fall 

 through coal- 

 gas. 



Deflexion when 



drops fall 



through 



hydrogen. 



Water 



230 + 



110+ 



200 + 



360- 



325- 



70- 



310+ 



40+ 



15- 



5- 



95 + 

 8 + 

 200+ 

 360- 

 330- 

 133- 



25- 

 125- 



35 + 

 395- 

 580- 



10- 

 150- 

 130- 



70- 



Eosine in water 



Potassium permanganate 

 Phenol in water 



Absolute alcohol 



Methyl violet in alcohol. . . 

 Phenol in alcohol 





When drops fall through sulphuretted hydrogen, the de- 

 flexion of the electrometer is very small whatever be the 

 nature of the drop. I am inclined to attribute this to the 

 absorption of the gas by the water of the solution; the drops 

 absorb so much gas that they may be regarded as pretty 

 strong solutions of sulphuretted hydrogen, and it is consistent 

 with what we have seen of the behaviour of solutions of salts 

 or acids that a strong solution should be electrically neutral. 

 This explanation is supported by the fact that, whereas to get 

 the hydrogen effect it is necessary to take the greatest pains 

 to exclude the air, we can get the effect produced by sul- 

 phuretted hydrogen when a good deal of residual air remains 

 in the gas surrounding the drops. I also found that when 

 water in which sulphuretted hydrogen had been dissolved fell 

 in drops through air, no electrical effect was produced. 



When solutions of rosaniline and methyl violet fell through 

 chlorine, the drops had a slight positive charge; the same drops 

 when falling through air or hydrogen had a negative charge : 

 the solutions were quite bleached by the chlorine. When 

 chlorine water falls through chlorine, no electrification is 

 produced. 



Discussion of the Results. 



The preceding experiments show that the electrification 

 developed by the drop depends (1) on the nature of the 

 gas surrounding the drop ; (2) on the nature of the drop 

 itself. On the drop side of the surface of separation of the 

 drop and the gas there is a coating of one kind of electricity 



