to the Contact of Gases with Liquids. 71 



phur electrified by the grinding. Most instances of charged 

 bodies are connected with surfaces, but here appeared a case 

 where electricity pervaded an enclosed space. The only way 

 in which I could figure it in my mind in connexion with the 

 hydrogen was by furnishing each molecule of the gas with a 

 charge with which it could not part until, in the ordinary 

 movements of the molecules (according to the dynamical 

 theory of gases) each came into actual contact with the 

 moist inner surface of the flask containing the gas. This way 

 of looking at it enables one to understand the slowness with 

 which the electrified hydrogen becomes neutral ; and as the 

 time required to neutralize a vessel of gas of given shape and 

 dimensions must be a function of the average velocity of its 

 molecules at the existing pressure, suitable experiments may, 

 possibly, lead to a direct determination of this quantity. 



Musing over these experiments, the wet flask holding the 

 charged hydrogen appeared, to me, not to differ materially 

 from a soap-bubble blown with hydrogen from Zn + HC1. 

 If there be anything in the notion, such a bubble should con- 

 stitute a charged condenser with the binding charge com- 

 pletely enclosed. During the process of blowing it the 

 repelled charge would pass to earth through the wet delivery- 

 tube and generator. Figuring such a condenser floating 

 through the air, I speculated as to how it would behave itself. 

 As long as it remained in its integrity, no manifestation of its 

 electrical condition could be given. Should the film, how- 

 ever, get fractured its nature would display itself. The gas 

 containing the binding charge would instantly pass away, 

 leaving the bound charge free on the water composing the 

 shell, and it would pass to earth at the first opportunity. 



Accounts have been given from time to time of curious 

 bodies which make their way into dwelling-houses during 

 periods of electrical disturbance in the air. They are de- 

 scribed as gliding about, apparently examining nooks and 

 corners, and often going up the chimney exploding (as it is 

 called) on the way. Now if we consider a portion of elec- 

 trified air enclosed by a film of some substance such as water, 

 it would in most respects behave like a soap-bubble blown 

 with hydrogen from zinc and hydrochloric acid. Being of 

 nearly the same density as air, it would not rapidly ascend but 

 move about, impelled by every slight draught. It would be a 

 charged condenser, and the moment any rough or sharp 

 prominence fractured the film, the bound charge would pass 

 to earth, doing mischief in its track. Such an enclosure of 

 electrified air might possibly be effected by an abnormal dis- 

 tribution of heat similar to that indicated by the formation 



