318 TENTH ANNUAL REPORT OF 



current tliiis produced must be proportional to tlie difference of the two 

 affinities." * ^ * * ^ * * * * * 



" It need hardly he mentioned, that other than metallic bodies can 

 also be placed at either end of a continuous series of electrolytic 

 molecules to polarize them. According to the chemical relation wliich 

 such bodies manifest for the anion or kation of an electrolyte, its 

 molecules will be polarized in the latter or the former direction. 



" If, for instance, chlorine be brought in contact with one of the 

 ends of a series of particles of water, the chemical equilibrium of 

 this molecule will be destroyed, and its hydrogen side will be directed 

 towards the chlorine. If the end of a platinum wire be placed in 

 contact vnih chlorine, and the other end of the same wir-e .vfith any 

 particle of water of the same series, a current must arise, passing 

 from this end of the platinum wire through the water to the chlo- 

 rine, while the latter combines chemically with the hydrogen of the 

 water. 



" On the contrary^ a non-metallic substance being placed at the end 

 of a continuous series of molecules of water, having a chemical 

 attraction for the anion of this series, polarization of the particles of 

 water will occur, and it will be opposite to that which chlorine occa- 

 sions in the case mentioned above. 



" Such a substance, for instance, is sul])hurous acid, which tends to 

 unite with the oxygen of the water. This tendency is sufficient to 

 polarize the particles of water, and under favorable circumstances to 

 set the current in motion. 



*■' By placing at one end of a series of molecules of water, a body 

 which has a chemical affinity for the anions, and at the other end a 

 substance having affinity for the kations of the molecules, it is evident 

 that this series will be under a double polarizing influence, and the 

 electro-motive forces coming into play will mutually increase each 

 other. A series of such electrolytic molecules, having, for instance, 

 chlorine at one of its ends and sulphurous acid at the other, if closed 

 by a conductor forming a voltaic circuit, must generate a current 

 stronger than that which appears in the cases where chlorine alone 

 or sulphurous acid alone are used, other things being the same. 



'' It is hardly necessary to remark^ that my hydrogen and platinum 

 battery, as well as Grove's new gas pile, are voltaic arrangements, 

 which, although presenting some peculiarities, belong to the class of 

 combinations described above." 



Schonbein finally describes the so called hyper-oxkh haUery. By 

 immersing in water a clean platinum jilate, and one furnished with a 

 covering of hyper-oxide of lead, a current will arise as soon as the 

 two metal plates are put in metallic connexion ; and the positive cur- 

 rent will pass from the clean platinum plate, through the liquid to the 

 other covered with the hyper-oxide of lead. 



The formation of the current, as well as its direction, is easily 

 explained. 



It is well known that half of the oxygen in the hyper-oxide ex- 

 hibits a great tendency to separate and combine with oxidable bodies. 

 Schonbein has, moreover, shown that this second portion of oxygen in 

 the same hyper-oxide has a greater affinity for oxidable substances 



