On Oxidation and Dtidxidation by Peroxide of Nitrogen. 393 



investigation as to the remarkable disoxidation of certain metallic 

 oxides (of which the decomposition of the oxide of silver may be 

 regarded as typical) by the peroxide of hydrogen. I suggested that 

 this decomposition was of a simple and normal chemical character ; 

 that the element oxygen was formed according to a molecular law 

 identical with that according to which compound substances are 

 formed ; and that the mutual decomposition of the two oxides was 

 determined by the synthesis of the particles of oxygen in opposite 

 polar conditions, according to the equation 



Ag 2 + H 2 2 =Ag 2 + H 2 + 2 . 



After an interval of nearly ten years, this explanation, together 

 with various facts bearing upon the theory of this action, and which 

 were given for the first time in the paper alluded to, have been 

 reproduced as original discoveries by Schonbein, Professor of Che- 

 mistry at Basle*. 



The reaction does not, however, present itself under this simple 

 form. The amount of oxygen lost by the oxide of silver is a variable 

 quantity, comprised between the extreme limits of the catalytic action 

 in which the reduction is zero, and the normal chemical action as 

 expressed in the above equation. The reason for this variation is 

 to be sought in the disturbing influence of the metal formed during 

 the decomposition. 



It is my intention shortly to communicate to the Society a prose- 

 cution of the above inquiry, in which I investigate the decomposition 

 by the peroxide of hydrogen of certain oxygenated substances con- 

 tained in solution, where the perturbing causes which affect the de- 

 composition of the solid oxides and conceal the simplicity of the 

 reaction, do not exist. 



The methods by which the following results have been obtained 

 will hereafter be given in detail. I confine myself to a brief resume 

 of the conclusions. 



(l)f When an acid solution of permanganic acid is decomposed 

 by peroxide of hydrogen, the decomposition is in an invariable atomic 

 proportion, according to the equation 



Mn 4 7 + 5H 2 2 =2Mn 2 + 5H 2 + 5 2 . 



(2) An alkaline solution of ferricyanide of potassium is reduced 

 by the peroxide of barium to ferrocyauide, with the evolution of 

 two atoms of oxygen, thus 



2K 3 Fe 2 Cy c + 2KHO + Ba 2 2 = 2K 1 Fe 2 Cy u + 2BaIIO + ;; . 



(3) An alkaline solution of hypochlorite of barium is reduced by 

 the peroxide of barium, according to the equation 



BaC10 + Ba 2 2 + II 2 = BaCl + 2BaHO + (X. 



A similar change takes place, as might be anticipated, with an 



* Phil. Mag. [4] xvi. 178. 



t This reaction has, I find, been published by Aschoff (see Repertoire deChimie 

 Pure, August 18G1, page 29G). It \vas last year made the subject of a communi- 

 cation by me to the British Association, " On the Quantitative Estimation of the 

 Peroxide of Hydrogen." 



Phil. Mag. S. 4. Vol. 24. No. 162. Nov. 1862. 2 D 



