76 Electrifications clue to Contact of Gases with Liquids. 



taining the acid should pass into it and be retained until it 

 got into the air by diffusion. The hydrogen in the half 

 Winchester quart was next forced through the acid by a 

 stream of water. The spot did not move. No electrification 

 was produced by the hydrogen bubbling through the acid. 

 The experiment was repeated with the remaining half Win- 

 chester quart of hydrogen, but with the same result. 



I had then to consider whether, in the face of this failure 

 to electrify the neutral gas, I could reasonably stick to my 

 theory of contact. I concluded that I could, and urge the 

 following as sufficient grounds for my decision : — 



I had proved beyond doubt that hydrogen holds a charge 

 with amazing tenacity, and that it only gives it up when each 

 molecule individually, it would appear, comes into contact 

 with a conducting body. Such contacts were also proved to 

 be most difficult to effect, and whatever difficulty exists in 

 discharging the gas, by bringing it into contact with other 

 substances, must also exist, and in a magnified form, when 

 one tries to make contact between the gas and any substance 

 for the purpose of charging. The difficulty of making real 

 contact is not a new one. In fact, I hold that when the 

 stream of hydrogen was forced through the pure acid, real 

 contact was not made. 



A very different state of things obtains when a piece of 

 zinc is thrown into a quantity of acid. Here each molecule 

 of hydrogen escapes from the chlorine into the acid separately, 

 and very likely takes its charge while in the nascent condition. 

 One cannot imitate the circumstances attending this condition 

 of things by any possible arrangement of delivery-tubes, 

 however small. 



If it is proved that hydrogen or gases in general, in their 

 nascent condition, take a charge when they come into contact 

 with acids or solutions of salts, the fact, I should think, cannot 

 fail to be of importance in the theory of the galvanic battery; 

 and if it is proved that to make electrical contact between a 

 gas and either metals or liquids is extremely difficult, what is 

 known as " the air effect " in connexion with that theory 

 appears to be negatived. 



In conclusion, I wish to acknowledge the help in making- 

 many of the experiments which I have received from Messrs. 

 Horsnell and Leach, students at present passing through the 

 college. 



St. Mary's College, Hammersmith, 

 November 1889. 



