212 PROFESSOR DAN I ELL ON THE ELECTROLYSIS OF SECONDARY COMPOUNDS. 
Experiment 23. — From sulphate of palladium I obtained in a similar way metallic 
palladium; but it had little lustre, and did not exhibit the beautiful appearance of the 
copper and silver. 
Experiment 24. — Protonitrate of mercury, of all the saline electrolytes which I 
submitted to experiment, exhibited the most striking phenomenon. Not only were 
metallic globules formed in abundance upon the membrane, but when the exterior 
cell was of glass a shower of small globules was seen to fall from the diaphragm 
during the whole continuance of the experiment. 
Experiment 25. — I now tried sulphate of magnesia, not without hopes of finding- 
metallic magnesium amongst the products of the experiment ; but abundance of mag- 
nesia alone was precipitated upon the diaphragm. I hence conclude that the affinity 
of the metal for oxygen is too strong in this instance to allow of any portion escaping 
combination. 
Combining the proofs which I have now adduced with the totally different class of 
evidence which I brought forward in my last communication, I think it must now 
be admitted that I have established the important point that, considered as electro- 
lytes, the inorganic oxyacid salts must be regarded as compounds of metals, or of 
that extraordinary compound of nitrogen and four equivalents of hydrogen to which 
Berzelius has given the name of ammonium, and compound anions, which are ex- 
actly analogous to the simple anions, chlorine, iodine, &c. of the haloide salts ; and 
that this evidence goes far to establish experimentally the hypothesis, originally 
brought forward by Davy, of the general analogy in the constitution of all salts, 
whether derived from oxyacids or hydroacids. 
Before I proceed with the details of my experimental researches, I must beg your 
indulgence for a few remarks upon the subject of nomenclature, a change in which 
seems absolutely necessary from such a change of views ; and without which it 
seems scarcely possible to avoid circumlocutions of the most embarassing kind, of 
which you will find abundant evidence in what I have already written. In speaking 
of salts as electrolytes, we greatly need significant expressions for the compound 
anions with which their metallic cathions are combined. In referring to sulphate of 
copper as an electrolyte, I have been obliged to designate its anion as sulphuric acid 
+ oxygen, than which nothing can be more clumsy and, as far as the significancy of 
the words is concerned, erroneous. After much reflection upon the subject, it has 
occurred to me that the term ion which you have introduced to designate indifferently 
the two constituents of an electrolyte, and which you have further compounded into 
anion and cathion, to designate the elements which travel respectively to the anode 
and cathode of the voltaic battery, might be adopted as a general termination to de- 
note the compounds which in the electrolysis of a salt pass to the zincode, and that 
they might be specifically distinguished by prefixing the name of the acid slightly 
modified : thus, electrolytically considered, the sulphate of copper might be called 
the oxysulphion of copper ; nitrate of potassa, the oxynitrion of potassium. The oxy- 
sulpkion of the former, which would travel to the zincode of the battery, would con- 
