AND SCHONBEIN 77 



silver into water and oxygen : whereas ozone is dis- 

 tinguished by a highly characteristic smell, scarcely 

 dissolves in water even in traces, charges platinum 

 negatively, and oxidizes silver. Since ozone is pro- 

 duced by the influence of electricity in atmospheric 

 air, and since restorations of electrical equilibrium 

 are] continually occurring, it follows that the air must 

 contain ozone. Now in the open air starch paste 

 containing potassium iodide turns blue, and potassium 

 iodide forms the iodate with the liberation of iodine 

 (though only to a small extent) ; and since in a closed 

 vessel none of these phenomena occur, and since they 

 are produced by the action of ozone on potassium 

 iodide, it would seem that we ought to ascribe them 

 to the atmospheric ozone. But if so, many slow oxi- 

 dations which take place in the air, such as bleaching 

 and various other similar phenomena, must also be due 

 to the atmospheric ozone, and not to the free oxygen 

 of the air. From the powerful physiological effects 

 of ozone, its presence in the air may have a medical 

 interest. The luminescence of phosphorus in atmos- 

 pheric air, which has so long been known and is so 

 little understood, can now be explained fairly satis- 

 factorily. The catalytic influence of the phosphorus 

 determines the combination of the oxygen and the 

 water to form ozone, which in its turn oxidizes the 

 phosphorus to phosphoric acid. The simultaneous 

 production of phosphorous acid is no doubt due to 

 the direct combination of the atmospheric oxygen 

 with the phosphorus. In absolutely dry air the 

 luminescence of phosphorus is excessively feeble, and 



