242 M. Viard on the Electro -chemical Deportment of Oxygen. 



These are the principal experiments known to me, which tend 

 clearly to show the influence of oxygen in batteries. 



Independently of the facts just cited, and of some others to 

 be afterwards mentioned, many other phenomena, involving 

 certainly the presence of oxygen, may be found in the memoirs 

 of Porret, Marianini, (Ersted, Sturgeon, De la Rive, Becquerel, 

 Faraday, Vorsselman de Heer, Poggendorff, Ed. Becquerel, 

 Schroder, Adie, Beetz, &c. I have made many experiments 

 upon the effects produced by agitating the plates immersed in 

 the liquids, by elevating the temperature of one of the plates, by 

 the ebullition of the liquids, and by exposing the one, or the 

 other, or both plates to the action of the atmosphere. Almost 

 all these phenomena vary with the nature of the liquids and the 

 plates, and consequently they did not appear to me at all capable 

 of illustrating the electro-chemical deportment of oxygen. 



Above all, if we reflect on the varied manners in which these 

 phenomena present themselves, the insufficiency of the experi- 

 ments, on which all explanations are sought to be based, will be 

 evident ; and then it will be understood why it has here been 

 deemed necessary so often to repeat, upon the metals and differ- 

 ent electrolytes, the fundamental experiments which show the 

 mode of action of the gas upon the electrolytes. 



As liquids, I have used water, the sulphates of potash, soda, 

 magnesia, zinc and copper, chloride of sodium, sulphuric acid, 

 and hydrochloric acid. 



As metals, — zinc, iron, copper, silver, platinum, and the amal- 

 gam of potassium. 



And as in all such experiments as are cited in the present 

 memoir analogous results were obtained without encountering a 

 single exception, I believe the suggested law to be a general 

 one. 



§ I. — On the Currents which are produced when two metallic plates 

 of the same nature are immersed in the same electrolyte , in pre- 

 sence of different quantities of oxygen. 



The currents first examined were such as are produced when 

 two plates of the same nature are immersed in two separate por- 

 tions of the same electrolyte, which differ from each other only 

 in the quantity of oxygen therein dissolved. 



The apparatus used (Plate IV. fig. 1) consists of two tubes, 

 each open at the top, but closed at the bottom by a piece of 

 bladder, both being sustained in the interior of a glass vessel by 

 means of the same cork. The vessel is filled with the electrolyte 

 to be operated upon, the two tubes are also filled with the same 

 liquid, but the portion poured into one tube differs from the 

 portion poured into the other by the quantity of oxygen or atmo- 



