to the Contact of Gases with Liquids. 



65 



yet it carried with it the greater part of its charge, as the fol- 

 lowing notes of the experiment prove. The high-resistance 

 Daniell gave a deflexion of 72 divisions either way. 



Zinc dropped into acid. Cover placed on beaker, 

 4 flat zincs placed over aperture 



Spot conies to rest and returns 



Effervescence ceasing 



Quadrants short-circuited 



Time. 



3 23 



25 

 27 

 28 

 29 

 30 

 31 

 32 

 33 

 34 



3 35 

 3 36 



37 

 39 

 42 

 43 



Reading. 



365 



364 

 363 

 358 

 343 

 333 

 333 

 343 

 353 

 363 

 373 

 383 

 383 

 413 

 413 

 368 



On examining the perforated zincs used in this experiment, 

 each was found to have either spray or condensed vapour de- 

 posited on it, but the quantity on the lowest one was greater 

 than that on any of the others. I was not, therefore, clear as 

 to what part the spray played in the matter, and I set myself 

 to consider what experiments I could make to clear up the 

 point. Eventually I decided to make the following two, 

 which I submit as decisive : — 



(a) Every one has noticed that when hydrogen escapes 

 from a generator containing acid and zinc, particles of the 

 former are projected with considerable force from the vessel. 

 I easily succeeded in catching these particles, or some part 

 of them, on the metallic part of a proof-plane. I then touched 

 the electrode of the insulated quads with the proof-plane, and 

 found that the charge produced a deflexion to the left, indi- 

 cating that the spray was of the same sign as the generator, 

 and consequently opposite in sign to the charge carried by the 

 gas. It also appears from this experiment that electrical re- 

 pulsion among the particles themselves constitutes part of the 

 force which causes their flight through the air. 



(b) The bottom of a metallic goblet was perforated with 

 holes about ^ inch in diameter. It was then attached, mouth 

 downwards, to the electrode of the insulated quadrants. A 

 hydrogen-generator containing zinc and HC1 was placed under 

 it in such a position that the evolved gas passed right through 



Phil. Mag. S. 5. Vol. 29. No. 176. Jan. 1890. ' F 



