On Catalysis, and the Nomenclature of Oxides* 127 



is proved by experiment, that a small quantity of cobalt per- 

 oxide can effect the decomposition of an unlimited amount of 

 hydroxyl, time being, of course, an important factor. On the 

 other hand, the amount of hydroxy 1 destroyed by the nickel 

 compound is simply that required for its own decomposition. 



The causes of the resolution of hydrogen peroxide into water 

 and oxygen by contact with these peroxides may be due, not 

 to any opposite polarity of the two oxygen atoms, contained 

 one in the metallic oxide and the other in the hydroxy!, which 

 coalesce to yield a molecule of oxygen, but simply to the pre- 

 sence of a strain in the two reacting molecules. These oxides, 

 water and cobalt or nickel oxide, are compounds in which the 

 attractions are, as it were, evenly balanced, the attraction of 

 the metal, or hydrogen, being satisfied by the counteracting 

 atom of oxygen ; and the fact that special means, such as the 

 employment of powerful oxidizers, must be taken to introduce 

 additional oxygen into the molecule, justifies the view that the 

 latter is held there by a comparatively weak affinity — and that 

 the condition of this extra oxygen is such, that w\hen in the 

 presence of a foreign body similarly constituted, for example 

 hydroxyl, there results an effective outward strain. The affi- 

 nity between the extra atoms of oxygen in the two compounds 

 being greatest, they coalesce to form oxygen, leaving the me- 

 tallic oxide and water. Cobalt, however, has a greater affinity 

 for oxygen than has nickel ; and while the cobalt oxide thus 

 formed becomes immediately reoxidized by the excess of hy- 

 droxyl, nickel once reduced is not further acted upon. This 

 difference in the deportment of the two metals confirms the 

 view that catalysis is due to a series of molecular decomposi- 

 tions and reformations of the catalyzing body. 



The mutual decomposition of hydroxyl and silver oxide 

 closely resembles that between nickel peroxide and the same 

 body. For although the silver compound is not a peroxide in 

 the ordinary sense, the ease with which it is reduced by heat 

 and by comparatively weak reducing agents shows that its 

 oxygen is held by a weak attraction; and when it is in con- 

 tact with hydroxyl, there is a tendency for the oxygen in the 

 silver oxide and the second loosely combined oxygen atom in 

 the hydroxyl to unite. The metallic silver thus produced is 

 nofc reoxidized ; and the action is therefore not continuous. 

 When hydroxyl acts upon suspended copper hydrate, the first 

 product is a yellowish-red substance, probably a peroxide, of 

 transient existence, which disappears as soon as the catalysis 

 commences, and is never afterwards visible. The action, 

 although differing from that of cobalt in that there is no final 

 production of a peroxide, resembles it in the essential fact of 



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