128 On Iodine. [Aua. 
says that ** euchlorine produces the phenomena which Chenevix in 
his paper on oxymuriatic acid ascribes to hyper-oxymuriatic acid :” 
and that “ it is probably combined with the peroxide of potassium 
in the hyper-oxymuriate of potash.” But I shal! ‘emonstrate that 
this is not the case.* ; 
We must admit it as an incontestable principle, establi-hed by 
Berthollet, that an acid put into a saline solution acts on the base 
of the salt, and separates a portion of it from its acid. This prin- 
ciple holds especially with the strong acids when brought in com- 
petition with the weak acids. On the other side, we must recollect, 
that peroxide of potassium does not combine with sulphuric acid, 
and that as soon as these two bodies are brought in contact, oxygen 
is disengaged. Hence, if hyperoxymuriate of potash were pro- 
duced by the combination of euchlorine with peroxide or potash, 
there ought to be disengaged oxygen gas, when diluted sulphuric 
acid is poured into a solution of this salt. Since at Jeast the euchlo 
rine, a gaseous oxide, whose acid properties, if it has any, are 
very weak, will be partly separated by the sulphuric acid, and this 
acid is incapable of dissolving peroxide of potassium. But no 
oxygen is disengaged, and consequently the potassium is not in the 
state of peroxide in hyper-oxymuriate of potash. Besides, even 
supposing potash super-oxygenated in the hyperoxymuriate, it ought 
to contain five times its usual quantity of oxygen, a conclusion 
which it would be very difficult to admit. The fact is, that potas- 
sium is in the same degree of oxydation in the hyper-oxymuriate 
as in the sulphate, as ] shall now demonstrate, by giving an account 
of the real acid which forms the fulminating salts of chlorine. 
In consequence of the above considérations, I was led'to believe, 
that since sulphate of barytes is insoluble, and barytes is not super- 
oxydated in this salt, if sulphuric acid be put into the hyper-oxy- 
muriate of barytes, it would be easy to see if oxygen be disengaged, 
and perhaps even to obtain chloric acid. Jl accordingly prepared a 
certain quantity of this salt, employing the ingenious process of 
Mr. Chenevix, and I obtained it easily in fine rhomboijdal prisms, 
quite exempt from muriate. Into a diluted solution of this salt I 
poured weak sulphuric acid. Though 1] only added a few drops of 
acid, not nearly enough to saturate the barytes, the liquid became 
sensibly acid, and not a bubble of oxygen escaped. By continuing 
* In a preceding mémoir on oxymuriatic acid, Davy appears to doubt the 
existence of an acid in the hyper-oxymuriates. He expresses himself in this 
manner. ‘* If we consider with attention the facts concerning the hyper-oxy- 
muriate of potash, we can only consider itas a triple compound of oxymuriatic 
acid, potassium, and oxygen. We have no sufficient motive to conclude that any 
particular acid exists in that body, or that it contains a considerable quantity of 
water. IJtis perhaps more conformable to chemical analogy, to suppose the great 
quantity of oxygen io be combined with the potassium, the very great affinity of 
which for oxygen we know, rather than to consider this quantily of oxygen as in a 
state of combination with the oxymuriatic acid, which, asfar as we know, has ne 
affinity for that subsianee. And from some experiments, Lam induced to believe 
that potassium may combine directly with more oxygen than exists in potash,” 
