M. Viard on the Electro-chemical Deportment of Oxygen. 249 



needle rested almost stationary. Passing from the first to the 

 second pair caused a strong deviation of the needle ; and this 

 initial deviation, although it grew rapidly more feeble, indicated 

 again that the presence of oxygen rendered the plate negative. 

 These experiments succeeded easily with marine salt and with 

 sulphuric acid. 



It is probable that by operating with platinized platinum, 

 more powerful currents, and always in the same direction, might 

 be obtained ; for with sulphuric acid and two plates of platinized 

 platinum, one of which was placed in oxygen, Beetz could not 

 only observe a current, but could even deduce therefrom the 

 electromotor force*. 



All the currents of which we have hitherto spoken may be 

 very well explained according to the ideas of Faraday. If, for 

 example, we immerse in water, on the one hand, a naked copper 

 plate, on the other a copper plate covered over with oxygen, and 

 connect both by a conducting wire ; then, under the united in- 

 fluence of the first and the oxygen which adheres to the second, 

 certain particles of the electrolyte will be polarized (fig. 5), that 

 is to say, will take up a certain direction, and present at their 

 extremities contrary electricities ; afterwards the several polarized 

 molecules will react upon themselves and upon the other mole- 

 cules of the circuit, and produce a general state of polarization 

 which will continue to increase. This is exactly the same as 

 would occur in a complete circuit formed by two small magnets 

 a and a!, and two pieces of soft iron b and V (fig. 6) . At length, 

 when the polarization has attained a certain degree of complete- 

 ness, electricity passes from each molecule to the next following 

 throughout the circuit, and at the same time the copper com- 

 bines with the oxygen of the first molecule of water, the hydrogen 

 of the first molecule with the oxygen of the second, and so on, 

 until finally, the hydrogen of the last molecule of water combines 

 with a free molecule of oxygen. We shall here insist upon the 

 hypotheses, that polarization is anterior to the current and to all 

 chemical decomposition ; that it is the result of chemical affinity, 

 and subsequently of the mutual reaction of the polarized par- 

 ticles; that certain effects of tension are produced before all 

 decomposition and before all chemical combination. 



I am consequently of opinion that oxygen acts in the batteiy 

 by its affinity for the hydrogen of water ; that alone, it would 

 produce no action, but that the separation of the elements of 

 water is effected under the simultaneous influence of the free 

 oxygen upon the hydrogen of the water, and of the metal upon 

 the oxygen of the water. 



* Poggendorff's Annalen, vol. lxx. 



