Primary and Secondary Results of Electrolyzation. 263 



present in large quantity, but is merely that of combination, 

 still secondary results often ensue : for instance, it is very 

 possible that in Sir Humphry Davy's decomposition of the 

 hydrates of potassa and soda, a part of the potassium pro- 

 duced was the result of a secondary action. Hence, also, a 

 frequent cause for the disappearance of the oxygen and hy- 

 drogen which would otherwise be evolved : and when hydro- 

 gen does not appear at the cathode in an aqueous solution, it 

 perhaps always indicates that a secondary action has taken 

 place there. No exception to this rule has as yet occurred to 

 my observation. 



779. Secondary actions are not confined to aqueous solutions, 

 or cases where water is present. For instance, various chlo- 

 rides acted upon, when fused (402.), by platina electrodes, 

 have the chlorine determined electrically to the anode. In 

 many cases, as with the chlorides of lead, potassium, barium, 

 &c, the chlorine acts on the platina and forms a compound 

 with it, which dissolves ; but when protochloride of tin is used, 

 the chlorine at the anode does not act upon the platina, but 

 upon the chloride already there, forming a perchloride which 

 rises in vapour (790. 804.). These are, therefore, instances 

 of secondary actions of both kinds, produced in bodies con- 

 taining no water. 



780. The production of boron from fused borax (402. 417.), 

 is also a case of secondary action ; for boracic acid is not 

 decomposable by electricity (408.), and it was the sodium 

 evolved at the cathode which, reacting on the boracic acid 

 around it, took oxygen from it and set boron free in the ex- 

 periments formerly described. 



781. Secondary actions have already, in the hands of M. 

 Becquerel, produced many interesting results in the forma- 

 tion of compounds; some of them new, others imitations of 

 those occurring naturally*. It is probable they may prove 

 equally interesting in an opposite direction, i. e. as affording 

 cases of analytic* decomposition. Much information regarding 

 the composition, and perhaps even the arrangement of the 

 particles of such bodies as the vegetable acids and alkalies, 

 and organic compounds generally, will probably be obtained 

 by submitting them to the action of nascent oxygen, hydro- 

 gen, chlorine, &c, at the electrodes ; and the action seems the 

 more promising, because of the thorough command which we 

 possess over attendant circumstances, such as the strength of 

 the current, the size of the electrodes, the nature of the de- 

 composing conductor, its strength, &c, all of which may be 



§ Annates de Chimie, torn. xxxv. p. 113. 



