54 LETTEKS OF BEEZELIUS 



positive polarity of this air is chiefly due to phos- 

 phorus vapour, and also partly to traces of hydrogen 

 phosphide ; and it is easy to see from what I have 

 said, that these substances would exert a destructive 

 action on the ozone. This action of phosphorus 

 vapour may easily be shown by putting a test paper 

 ,first into it and then into an atmosphere of ozone. 

 As long as any traces of phosphorus vapour adhere 

 to the paper it will not be turned blue. Conversely, 

 if a test paper is turned blue by ozone and then 

 plunged into an atmosphere containing phosphorus 

 vapour, the blue colour disappears. 



Finally I must mention, that if ozone is breathed 

 in small quantities it produces on the organism effects 

 similar to those produced by chlorine: coughing, 

 oppression of the chest, in short, all the symptoms of 

 a cold. A mouse placed in a flask filled with air con- 

 taining only very small quantities of ozone died after 

 five minutes in violent convulsions. From the results 

 described above, as well as from certain other facts 

 which I have discovered, some of which still remain 

 to be mentioned, it seems to me that we may con- 

 clude with a fair degree of certainty that nitrogen is 

 the source of ozone, or, to be more explicit, that 

 nitrogen consists of ozone and hydrogen. However 

 different the circumstances under which ozone is 

 formed may appear at first sight, there is yet one 

 condition which the electric, voltaic, and chemical 

 methods of production all fulfil alike, and that is 

 the presence of nitrogen. The formation of ozone by 

 ordinary electricity, by the voltaic current, and by 



