250 Prof. Schonbein ore the Connexion of 



That oxygen also belongs to the number of allotropic elements 

 may now, I think, be considered as certain, as the allotropism of 

 carbon, of sulphur, phosphorus, &c. And I have repeatedly 

 endeavoured to show, that not only free, but also chemically 

 combined oxygen may exist in two different allotropic modifica- 

 tions ; as chemically active and passive, as ozonized and common 

 oxygen, or as and O. 



With respect to the second equivalent of oxygen in peroxide 

 of hydrogen, there appears to me to be no doubt that it exists in 

 the ozonized condition ; from the simple reason, indeed, that it 

 produces oxidizing actions, which free ozonized, but not common 

 oxygen, is able to effect. 



Of fi-ee 0, my experiments have shown that it may be con- 

 verted into O not only by heating, but also by contact with 

 certain substances; as, for example, carbon, the oxides of the 

 noble metals, the peroxides of lead, manganese, iron, &c., at 

 ordinary temperatures. ^ 



If now, as I assume, peroxide of hydrogen be really HO + 0, 

 if the free O can be changed into by carbon, peroxide of man- 

 ganese, ^&c., and further, if it be the fact that carbon, &c. changes 

 HO + into HO + 0, it appears to me in the highest degree 

 probable that the ultimate cause of the catalysis of the peroxide 

 of hydrogen _^ effected by the above substances lies iu the conver- 

 sion of the of this compound into 0. 



It is well known that water and common oxygen caunot be 

 united to form the peroxide, and that the latter must exist in the 

 O condition to be capable of uniting with HO. That oxygen 

 at the moment of its electrolytic separation from hydrogen 

 is in this condition, is an admitted fact, and also that a part 

 of this oxygen ^combines at the positive electrode with water 

 to form HO + 0, whilst another part becomes free; by far the 

 greatest part, however (probably under the influence of the 

 platinum), is converted into ordinary oxygen. Peroxide of ba- 

 rium also contains the half of its oxygen asO, and every chemist 

 knows that with the aid of a strong acid this may be trans- 

 ferred to the HO ; upon this reaction, indeed, the usual pre- 

 paration of peroxide of hydrogen is founded. 



But if O, as such, can form no chemical compound with water, 

 and only O can do so, it follows that peroxide of hydrogen must 

 be decomposed or catalysed by all agents which can transform 

 the O of this compound into ; for after O has been changed 

 into O, its relations to water are altered, and must be elimi- 

 nated, o 



The change of condition of the O contained in peroxide of hy- 

 drogen may, as is well known, be effected so rapidly by heat, that 

 the altered oxygen separates from the water with an explosion, 



