852 
PEOFESSOE B. C. BEODIE ON THE OXIDATION AND 
It may be observed that, if the decomposition of permanganic acid were, "as in this 
case, preceded by an oxidation, the corresponding degree of oxidation would be formed 
thus • 
Mn4 0^4-5 H 2 02= Mn4 0^2+5 H 2 O, 
Mn4 O 12 =:2Mn2 O +502. 
The decomposition of permanganic acid is, in a somewhat strong solution, instanta- 
neous ; but it is remarkable that, if the solution of peroxide of hydrogen be very dilute, 
the addition of the first drops of permanganic acid produce no apparent change. A 
certain time is required for the commencement of the decomposition, after which it 
proceeds with regularity. It may be questioned whether this decomposition also may 
not be effected by successive stages which escape observation, and whether the period 
which intervenes before the commencement of the action may not be occupied in the 
production of those substances by the agency of which the final result is attained, and 
Avhich are successively formed and decomposed. 
On the Oxidation effected hy the Peroxide of Hydrogen. 
We have seen that the peroxides of hydrogen, potassium, and barium possess certain 
chemical properties which do not belong to the analogous compounds of lead and man- 
ganese. An elaborate attempt* has been made to account for the different reactions 
of the two classes of peroxides, by the assumption that there are two kinds or varieties of 
oxygen, a positive and a negative variety ; it is said that the peroxide of manganese acts 
as an agent of oxidation because it contains the negative variety, and that the peroxide 
of barium acts as a reducing agent, because it contains the positive variety of this 
element. This hypothesis finds its only support in an imperfect and incorrect view of 
the facts. In truth no such fundamental distinction exists between the properties of the 
different peroxides as that which it is proposed thus to characterize. The chemical pro- 
perties of the alkaline peroxides, as of other chemical substances, vary with the condi- 
tions in which they are placed, and the substances with which they are associated ; and 
it is in our power so to modify these conditions as to produce with these peroxides the 
very same effects of oxidation as are produced by the peroxides of the other group. This 
is evident from the following examples, to which it would be easy to add others : — 
1. An acid solution of peroxide of hydrogen causes the conversion of a solution of 
ferrocyanide to ferricyanide of potassium. 
2. An alkaline solution of peroxide of sodium added to a solution of a protosalt of 
manganese forms hydrated peroxide of manganese. 
3. An alkaline solution of peroxide of sodium oxidizes an alkaline solution of sesqui- 
oxide of chromium, with the formation of chromate of potassium. 
4. A strong solution of hydrochloric acid evolves chlorine with peroxide of barium f, 
* ScHoXBEix, Annalen der Cheniie, vol. cviii. p. 166. 
t Professor Sckokbeix lays the greatest stress on the different behaviour of the two classes of peroxides 
with hydrochloric acid. He says, “Dieerste Gruppe ist weiter negativ dadurch charakterisirt dass kein 
ihr augehdriges Superoxyd mit irgend einer wasserhaltigen Saure .... Wasserstoffsuperoxyd zu erzeugen 
