On new Combinations of Oxygen and Acids. 21 
powdered charcoal for clarifying animal and vegetable substances, 
at the same time that it takes away their smell. In 1791 he 
clarified gum-arabic, gelatine, beer, milk, red wine, vinegar, tinc- 
ture of cochineal, &c.; but the greater part of these substances 
had been decomposed. He attenuated the smell of bitumen, 
flowers of benzoin, bugs, empyreumatic oils, the infusion of vale- 
tian, &c. by the sole use of wood coal. 
In 1810, M. Figuier, professor of chemistry in Montpellier, 
after repeating M. Lowitz’s experiments, tried animal charcoal, 
and found it possessed a stronger power of clarification than ve- 
getable coal. Since this period, both are employed to keep wa- 
ter fresh at sea, and to purify oil and water, meat and fish, in the 
first stage of putrefaction. They moreover make use of it to ren- 
der the most corrupt water potable, to clarify honey, syrups, &c. 
M. Guilbert, a confectioner in Paris, remarked that wood- 
chareoal, which had been long moist, and during this state ex- 
posed to the rays of the sun, clarifies much better than what is 
pulverized dry, and employed immediately. He advises to leave 
the charcoa! intended for purifying some time in pure water, to 
grind it in the water, and then expose it to the light, covered an 
inch deep with this liquid; and to employ it after being drained, 
but still in a moist state. No one has as yet examined the ef- 
fect of light on animal charcoal, according to M. Guilbert’s pro- _ 
cess: this experiment, however, is worthy the attention of che- 
mists and manufacturers. 
VI. On new Combinations of Oxygen and Acids. By 
M.UL. J. THExarp*. 
/ 
Turse combinations were obtained by treating the peroxide of 
barium with acids. They are mostly very remarkable, and de- 
serving of the attention of chemists. 
The first I observed was the combination of nitric acid with 
oxygen. Peroxide of barium (barytes saturated with oxygen) 
when moistened, falls to powder with but little increase of tem- 
perature. When mixed, in this state, with seven or eight times 
its weight of water, if dilute nitric acid be poured gradually on 
it, by agitation it will dissolve without giving off any gas. The 
solution is neutral, producing no change on turusole or on tur- 
meric. If the requisite quantity of sulphuric acid be added to 
this solution, a copious precipitate of Sulphate of barytes is thrown 
down, and the liquid when filtered is merely water holding oxy- 
genized nitric acid in solution. 
This acid, which in almost all its properties resembles nitric 
* From Annales de Chimie et Phys, tom, viii 
B3 acid, 
