PHILOSOPHICAL TRANSACTIONS. 
I. Additional Researches on the Electrolysis of Secondary Compounds. By J. Frederic 
Daniell, Esq., D.C.L., For. Sec. R.S., Prof. Chem. in King's College, London, and 
W. A. Miller, Esq., M.D., Dem. of Chem. in King's College, London. 
Received February 15, — Read February 25, 1844. 
The authors of the following paper having agreed to work together upon the subject 
of the electrolysis of secondary compounds as opened by one of them, in two letters 
addressed to Dr. Faraday, and honoured with a place in the Philosophical Transac- 
tions for 1839 and 1840, have arrived at some results, which probably will not be 
without interest to the Royal Society, and which they have now the honour to com- 
municate. 
In the two papers just alluded to, the following points were established. First. 
When aqueous solutions of the neutral metallic salts are exposed to the action of the 
voltaic current, they are invariably decomposed. When the metal is one of that class 
which does not decompose water at ordinary temperatures, it is precipitated in the 
metallic state at the platinode : when it is of the class which does decompose water, 
its oxide, with an equivalent proportion of hydrogen, appears at the same electrode. 
The acid at the same time is set free at the zincode, accompanied by an equivalent pro- 
portion of oxygen. Second. When these results are compared with those of an inde- 
pendent voltameter in the same circuit, it is found that a certain proportion of the 
force which resolves a single equivalent of a simple* electrolyte into its anion and 
cation, produces the resolution of a full equivalent of the complex electrolyte into a 
simple metallic cation and a compound anion. Third. When aqueous solutions of 
ammoniacal salts are electrolysed, similar results are obtained ; but instead of a simple 
metal being disengaged at the platinode, an equivalent of ammonia, accompanied in 
all cases by an equivalent of hydrogen, appears at the platinode. Fourth. We are 
thus entitled to conclude that in the electrolysis of complex electrolytes, different 
* By a simple electrolyte is meant one containing only two elementary substances, being the simplest form 
of matter capable of electrolysis. 
MDCCCXLIV. B 
