CHEMICAL SCIENCE. 265 



account in addition; for when oxygen is evolved out of a compound in 

 which it was electro-negative, it will for two reasons easily enter into another 

 combination, in which it has also to play an electro-negative part: first, 

 because the atoms are in the separate state ; secondly, because they already 

 are in the proper electrical condition. Hence oxygen in the nascent state 

 may, in many cases, surpass ozone in activity. 



The galvanic polarization of a plate of platinum, by immersion in ozoni- 

 fied oxygen, is related to the above action. It is known that the two elec- 

 trodes, which serve for the galvanic electrolysis of water, become thereby 

 polarized in such a manner as to be capable of giving rise by themselves to 

 a current in the opposite direction. This is explained by supposing the one 

 electrode to be covered by a layer of hydrogen, and the other with a layer 

 of oxygen ; and such explanation accords with the fact that a plate of plat- 

 inum, when immersed in hydrogen, acquires thereby also a positive polariza- 

 tion. But if a platinum-plate be immersed in common oxygen, the corre- 

 sponding phenomenon, which might, perhaps, be expected, namely, the 

 acquirement of negative polarity by the plate, does not occur; and this 

 appears to contradict the above-given explanation. I imagine, however, 

 that this difference may be accounted for as follows : Inasmuch as a mole- 

 cule of water consists of two atoms of hydrogen and one atom of oxygen, 

 the atoms of hydrogen, which, like the atoms of oxygen, are also combined 

 two and two to molecules, may enter into combination with oxygen without 

 separating from one another. The atoms of oxygen, on the contrary, as 

 long as they are combined together as molecules, are not in a suitable con- 

 dition for combination with the hydrogen. Hence oxygen, in its ordinary 

 state, is incapable of causing galvanic polarization, but acquires this power 

 by ozonification. 



Besides an oxidizing action, ozone may exert an opposite or deoxidizing 

 one, as Schonbein has proved in the case of peroxide of lead, the ozone 

 itself being converted thereby into ordinary oxygen. Now, as this trans- 

 formation of ozone into oxygen occurs also when it is brought into contact 

 with other peroxides, it immediately suggests itself that the deoxidation of 

 the peroxide is also not confined exclusively to the peroxide of lead. This 

 action may be explained without difficulty. If we imagine an oxide which 

 readily gives up the whole, or a part of its oxygen, in contact Ifcth a gas in 

 which separate oxygen atoms are moving about, seeking to combine witli 

 second atoms, these moving atoms, on coming into contact with the oxide, 

 are able to withdraw the atoms of oxygen which are only feebly combined. 

 This accounts at the same time for the double effect the reduction of tho 

 oxide and the disappearance of the ozone. 



The behavior of ozone is, in many respects, similar to that of the peroxides. 

 Peroxide of hydrogen, for instance, has, as is well known, a strong oxidiz- 

 ing action, by reason of the facility with which it gives up its second atom 

 of oxygen. If, on the contrary, peroxide of hydrogen be brought into con- 

 tact with the oxides of the noble metals, or with certain metallic peroxides, 

 a reciprocal reduction takes place. We may, in such a case, presume that 

 the oxygen atoms liberated from the peroxide of hydrogen combine and 

 form molecules with those which are given off from the metallic oxides or 

 peroxides. 



In considering the above-mentioned phenomenon, the question may arise, 

 why the atoms of ozone, or the easily-separable oxygen atoms in a sin^lo 

 oxide or peroxide should not unite with on > another with as great a facility 



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