18 Mr. Davy's Experiments on the 
proportions; for, according to Mr. Chenevix’s analysis, which 
is confirmed by one made in the Laboratory of the Royal 
Institution, by Mr. E. Davy, hyperoxymuriate of potash must 
consist of 40.5 potassium, 32.9 oxymuriatic gas, and 45 of 
oxygene. 
I have mentioned, that by strongly heating the peroxide of 
potassium in oxymuriatic acid, all the oxygene is expelled, 
and a mere combination of oxymuriatic gas and potassium 
formed. I thought it possible, that at a low temperature, a 
combination might be effected, and I have reason to believe 
that this is the case. I made a peroxide of potassium, by 
heating potassium with about twice the quantity of nitre, and 
admitted oxymuriatic gas which was absorbed: some oxygene 
was expelled on the fusion of the peroxide, but a salt remained, 
which gave oxymuriatic gas, as well as muriatic acid, by the 
action of sulphuric acid. 
It seems evident, that in the formation of the hyperoxy- 
muriate of potash, one quantity of potash is decomposed by 
the attraction of oxymuriatic gas to form muriate of potash ; 
but the oxygene, instead of being set free in the nascent state, 
enters into combination with another portion of potash, to form 
a peroxide, and with oxymuriatic gas. 
The proportions required for these changes may be easily 
deduced from the data which have been stated in the preced- 
ing pages. 5 proportions of potash, equal to 240 grains, must 
be decomposed to form with an equal number of proportions 
and Thomson; and above all, in the decompositions by the Voltaic apparatus. 
Where oxygene and hydrogene, oxygene and inflammable bodies, acids and alkalies, 
$c. must separate in uniform ratios. 
