82 E. 
had not time to pursue them far enough to afford any very defi- 
nite result. ‘They may however serve to point the way to some 
one who has sufficient zeal for the science, to carry them out to 
some more useful end than I cou!d hope to attain. I must here 
make my acknowledgments to Prof. Booth, in whose laboratory, 
and with whose assistance, these examinations were made. 
The peroxide of manganese has never been investigated, as 
its existence has until lately been questioned by some of the first 
chemists in Europe, and the tendency of its salts to convert 
themselves into proto-salts, contributed to render it problematical 
whether it was not merely the protoxide disguised. It can be 
obtained in various ways, but the most convenient is to calcine 
' the proto-nitrate gently until the nitrous acid ceases to be given 
off. A less troublesome method is to heat the common black or 
deutoxide, until part of its oxygen is given off, but this method is 
uncertain, as too great a heat converts it into the manganoso- 
manganic oxide, and it is almost impossible to obtain the black ox- 
ide free from admixture with iron. When obtained by calcining, 
its color is of a deep black, and sometimes shining; but when 
precipitated from a liquid, as the permanganate of potassa, it is of 
a dark brown. It has sometimes been found native, and is then 
known to mineralogists under the name of Braunite. It unites 
with water and forms the hydrate, which may be readily produ+ 
ced by precipitating the hydrated protoxide from a proto-salt, and 
exposing it to the action of the atmosphere. Obtained in this 
manner it appears under the form of a brown powder, but when 
found native, it is black and crystallizes sometimes in acicular 
crystals, and sometimes in octahedra, resembling in this state the 
deutoxide. The peroxide is composed, according to the calcu- 
lations of Berzelius, of 43.37 of oxygen to 100 of manganese. 
With the different acids it has very various actions; with some 
it is converted into protoxide, forming proto-salts; while with 
others it immediately forms per-salts, which seem to have no reg- 
ular color, some being red, while others are nearly white, brown, 
or yellowish ; a dirty white is however the most usual appearance. 
I have found it to be the case, that most vegetable acids which 
convert the peroxide into protoxide by giving off oxygen, when 
ts upon the deutoxide, will form per-salts by the loss of oxy- 
They all contain a 6 rated acid, without the 
“- ‘incapable of 
of the Peroxide of Manganese. 
forming any 
