294 CHEMICAL TRANSFORMATIONS. 



and any shock or movement is sufficient to destroy 

 the attraction of their component parts, and conse- 

 quently their existence in their definite form. 



Peroxide of hydrogen* belongs to this class of 

 bodies ; it is decomposed by all substances capable 

 of attracting oxygen from it, and even by contact 

 with many bodies, such as platinum or silver, which 

 do not enter into combination with any of its con- 

 stituents. In this respect, its decomposition depends 

 evidently upon the same causes which effect that of 

 iodide of nitrogen, or fulminating silver. Yet it is 

 singular, that the cause of the sudden separation of 

 the component parts of peroxide of hydrogen has 

 been viewed as different from those of common de- 

 composition, and has been ascribed to a new power 

 termed the catalytic force. Now, it has not been con- 

 sidered, that the presence of the platinum and silver 

 serves here only to accelerate the decomposition; 

 for without the contact of these metals, the peroxide 

 of hydrogen decomposes spontaneously, although 

 very slowly. The sudden separation of the constit- 

 uents of peroxide of hydrogen differs from the de- 

 composition of gaseous hypochlorous acid, or solid 

 iodide of nitrogen, only in so far as the decomposi- 

 tion takes place in a liquid. 



A remarkable action of peroxide of hydrogen has 

 attracted much attention, because it differs from 

 ordinary chemical phenomena. This is the reduction 

 w^hich certain oxides suffer by contact with this sub- 

 stance, on the instant at which the oxygen separates 

 from the water. The oxides thus easily reduced, 

 are those of which the whole, or part at least, of 

 their oxygen is retained merely by a feeble affinity, 

 such as the oxides of silver and of gold, and perox- 

 ide of lead. 



Now, other oxides, which are very stable in com- 

 position, effect the decomposition of peroxide of hy- 



* A remarkable compound, consisting of 1 Hydrogen, and 2 Oxygen. 

 See description and process for obtaining; in Webster's Chemistry^ 

 p. 134. 



