200 ANNUAL OF SCIENTIFIC DISCOVERY. 



when a circuit is closed, the gases contained in the tubes of each pair 

 diminish in volume, the hydrogen twice as rapidly as the oxygen, so 

 that the re-composition of water is effected in each element. Many 

 eminent philosophers Faraday among others have directed their 

 attention to this subject, and their experiments pro"ve that the proba- 

 ble cause of the disengagement of electricity is the combination of the 

 oxygen dissolved in the liquid with the hydrogen adhering to the pla- 

 tinum by the intervention of this metal. The oxygen adhering to the 

 second sheet is therefore only opposed to the polarization that would 

 be produced by carrying over this sheet, the hydrogen that precedes 

 from the decomposition of the conducting liquid. Therefore the plat- 

 inum, like other solid bodies employed under some circumstances, 

 instead of this metal, is only the medium that determines the combina- 

 tion of the gases, and permits the circulation of electricity. It appears 

 from this that the nature of the conducting liquids, must have an 

 influence on the development of electricity, and the new results that 

 are found mentioned in that part of the treatise of M. Edmond Bec- 

 querel, which speaks of the action of hydrogen on the chloride of gold 

 as well as in that entitled " electric current developed," confirm the 

 truth of this assertion. The following experiment is corroborative of 

 the first : If a tube of very small diameter, filled with hydrogen gas 

 be placed in a vessel containing a concentrated solution of chloride of 

 gold, at the end of a few days the temperature not having sensibly 

 varied, the level of the chloride of gold, inside the tube will be very 

 little different from what it was at first. Then introduce a piece of 

 platinum wire, one part in the gas and the other part with its extremity, 

 immersed in the chloride of gold ; the gas is seen slowly to diminish in 

 volume, and even at the end of a certain time to disappear completely, 

 when the platinum wire rises to the top, but at the same time as the 

 hydrogen gas disappeared, gold is precipitated in the metallic state on 

 that part of the platinum wire immersed in the chloride. It is to be 

 observed that the liquid does not contain, in solution, any platinum, 

 therefore it is not acted upon by the neutral chloride of gold, at least 

 as far as analysis proves ; moreover, the exterior air is not an agent in 

 the manifestation of the phenomenon, since it is produced likewise in 

 close vessels. To be able to judge of the different results obtained, 

 M. Becquerel gives the following conclusions: 



1st. Platinum wire that does not reduce a neutral solution of chlo- 

 ride of gold, may acquire this property when the solution is placed in 

 contact with hydrogen gas, and the wire immersed partly in the gas and 

 partly in the solution ; gold is precipitated in the metallic state on that 

 part of the wire immersed in the liquid, and the gas is absorbed while 

 the deposit is going on. 



2d. This action is manifested equally in close vessels not exposed 

 to atmospheric influence. As the liquid, after the reaction, does not 

 contain any platinum in the solution, it results that the metal under- 

 goes no alteration - - that it only serves as a conductor, and it acts 

 only by its pressure. These experiments appear to prove that in 



