62 Existence of Compound Radicals in Amphide Salts. 



easily understood, for the oxide of silver is one most easily re- 

 duced by hydrogen, and consequently one on which the action 

 of a hydrogen acid, as P0 3 -f-H 3 , or P0 7 +H 2 , would be most 

 completely exercised. 



"A remarkable verification of this theory has been recently 

 found in the decomposition of solutions of the oxysalts in water, 

 by voltaic electricity. It has been already explained (pp.314 

 et seq.) that it requires the same quantity of electricity to de- 

 compose an equivalent of any binary compound, such as iodide 

 of lead, chloride of silver, muriatic acid, or water. Now, if we 

 dissolve sulphate of soda in water, and pass a current of voltaic 

 electricity through that solution, we have water decomposed, and. 

 also the glauber's salt; oxygen and sulphuric acid being evolved 

 atone pole, and soda and hydrogen at the other. Here, on the 

 old view, the electricity performs two decomposing actions at the 

 same time, and, as it thus divides itself, its action on each must 

 be lessened, and the quantity of each decomposed be diminished, 

 so that the sum should represent the proper energy of the cur- 

 rent. On measuring these quantities, however, the result is to- 

 tally different, the quantity of sulphate of soda decomposed is 

 found to be equal to the full duty of the current, and an equiva- 

 lent of water appears to be decomposed in addition. It is quite 

 unphilosophic to imagine, that the strength of a current should 

 be thus suddenly doubled, and a simple and sufficient explana- 

 tion of it is found in the new theory of salts. The sulphate of 

 soda in solution having the formula NaSO 4 is resolved by the cur- 

 rent into its elements, Na and SO 4 , as chloride of sodium would 

 also be ; the sodium, on emerging at the negative electrode, from 

 the influence of the current, instantly decomposes water, and 

 soda and hydrogen, of each an equivalent, are evolved ; at the 

 positive electrode the compound radical So 4 also decomposes wa- 

 ter, and produces H.SO 4 and 0. The appearance of the oxy- 

 gen and hydrogen is thus but secondary, and the body really de- 

 composed by the current is only Na So 4 . 



" In the case of the salts of such metals as do not decompose 

 water, the phenomena are much more simple. Thus a solution 

 of sulphate of copper, when decomposed by the battery, yields 

 metallic copper at the negative, and sulphuric acid and oxygen 

 at the positive electrode, and the quantity of copper separated re- 

 presents exactly the energy of the current which has passed, for 



