Prof. Clausius on flie Nature uf Ozone. 47 



oxygen atoms, which, in their relation to foreign bodies, must natu- 

 rally differ from those utoins ivhich are combined, two and two, to 

 molecules, are, in my opinion, ozone. 



Let us now consider, in the first place, the most important 

 modes of formation of ozone. 



If electricity passes out into oxygen or atmospheric air, or if 

 electric sparks are discharged through either of these gases, 

 ozone is formed; and this foroiation is independent of the 

 nature of the electricity, that is, whether it be positive or 

 negative. This action may probably be attributed simply to the 

 repulsive power of the electricity, by virtue of which the two 

 atoms of a molecule, being charged with the same kind of elec- 

 tricity, are driven apart in the same manner as is observed with 

 larger bodies. 



Oxygen, when separated from its combinations by electrolysis, 

 under favoui-able circumstances is obtained in an ozonified state. 

 This is explained thus : — at the moment of disengagement the 

 atoms of oxygen are separate. Most of them combine imme- 

 diately upon the electrode, two and two together, to molecules ; 

 and here perhaps the electrode itself, when, for instance, it is 

 formed of platinum, exerts an auxiliary action. A small portion 

 of- the atoms, however, remain in the separate condition, and 

 this constitutes the ozone with which the oxygen is mixed. 



Finally, a third mode of formation occurs when atmospheric 

 air is in contact with moist phosphorus. This process may per- 

 haps be imagined to proceed as follows : — As the phosphorus 

 combines with the surrounding oxygen, a number of oxygen 

 molecules, in contact with the phosphorus, must be decomposed 

 into their two constituent atoms ; and it may happen that the 

 phosphorus does not combine with both of such atoms, but that 

 one of them, being removed from the sphere of activity of the 

 phosphorus through the motion caused by the heat developed, 

 remains in the separate condition. We know from electrolysis 

 that in the combination of heterogeneous atoms to a molecule, 

 one part of the molecule is positively, and the other negatively 

 electrical. This may perhaps also be the case in the combination 

 of two homogeneous atoms, as for instance of two oxygen atoms, 

 one of them becoming jjositively, and the other negatively elec- 

 trical. Inasmuch, now, as, by the oxidation of the phosphorus, 

 the oxygen doubtless enters into combination as the electro- 

 negative constituent, it may come to pass that of the two oxygen 

 atoms, resulting from the splitting up of a molecule, the negative 

 one is that especially retained by the phosphorus, and the positive 

 one may be free to move away, or at least may be less hindered 

 from doing so. Kvcn after such an atom, in the course of its 

 motions, and through contact with other molecules, or the walls of 



