8 M. Thenard’s new Experiments on [Jane 
oxygen the more real acid they contain ; or whether the water 
by its quantity has not an influence on the greater or smaller 
oxygenizement of the acid. My essays have not yet enabled 
me to answer that question. 
I have attempted likewise, without any decisive success, to 
oxygenate magnesia and alumina; but I have succeeded in 
superoxygenating several other oxides; namely, oxide of zinc, 
oxide of copper, oxide of nickel. We should not succeed, or, 
at least, we should succeed very imperfectly, if we satisfied our- 
selves with adding oxygenized acid to the saline solutions of 
these three metals and precipitating the liquid by potash, 
It is necessary to dissolve the oxides of these metals in oxyge- 
nized muriatic acid three or four times, and to decompose the 
oxygenized muriate by potash or soda, taking care to add but a 
small excess of these bodies. The preparation of superoxide of 
copper requires an additional precaution; namely, to put the 
deutoxide of copper into oxygenized muriatic acid in portions ; 
so that the acid shall always be in excess. Ifthe oxide predo- 
minates, the greater part of the oxygen is disengaged. In all 
cases the oxide is precipitated in a gelatinous mass, or in the 
state of a hydrate. That of zinc is yellowish; that of copper 
olive-green ; and that of nickel, dirty, dark apple-green. The 
first two allow a portion of their oxygen to be disengaged at the 
ordinary temperature. When they are boiled in water, the 
disengagement is still more abundant ; but they do not give out 
(especially the superoxide of zinc) all the oxygen which they have 
absorbed ; for when we dissolve them afterwards in muriatic 
acid, and heat the liquid, we obtain a new quantity of gas. The 
oxide of nickel is decomposed likewise at the boiling tempera- 
ture, and its decomposition begins even below that point. en 
treated with muriatic acid, it is dissolved like the oxides of zinc 
and copper, and is disoxygenated by heat without. the evolution 
of chlorine. We may add likewise that these different oxyge- 
nated hydrates recover the colours which characterize the ordi- 
nary oxides after they have been boiled in water. Thus the 
hydrate of zinc passes from yellow to white, that of copper from 
olive-green to dark brown. M. Rothoff, a Swedish chemist, had 
already observed that the deutoxide of nickel is decomposed by 
desiccation. 
These new hydrates resemble, as we see, those of barytes, 
strontian, and hme, and form a class analogous to that of the 
oxygenized acids. I shall probably discover more of them. 
