1868.] SMALLWOOD — ON ozone. 377 



It is not my purpose to enter into a very long and argumentative 

 chemical reasoning on the composition of Ozone. Some difference 

 of opinion still exists as io its present character. Schonbien 

 looked upon it as a regular constituent of our atmosphere, forming 

 a part of, and always present in the air we breathe. I mi^ht 

 casually mention that Cavendish, more than half a century a^o, 

 found, what he stated was nitrous-acid, present in atmospheric air, 

 and he attributed the beautiful green colour of plants, after a thun- 

 derstorm, to a chemical combination of ammonia and nitrous- 

 acid, making a nitrate of ammonia. This effect upon plants, 

 after thunderstorms, is now referred to the effects of Ozone in 

 increased quantity. 



The absolute and uniform composition of Ozone has been the 

 subject of much controversy. Schonbien claimed it as a binoxide 

 or peroxide of hydrogen. Faraday denied this, and considered 

 Ozone as oxygen in an isomeric state, or as a simple modification 

 of oxygen in an allotropic condition of that body. Williamson 

 says that, according as Ozone is produced by a galvanic battery, 

 developed by the electric spark, or brought forth by the action of 

 phosphorus on atmospheric air, it is a peroxide of hydrogen and 

 azotic-acid, or a mixture of both. Berzelius opposed this idea 

 and went to show that Faraday was correct. De la Rive and 

 others stated that it was only oxygen in a peculiar condition oiven 

 to it by electricity. Freney and others instituted experiments to 

 confirm their ideas, and went on to state that the presence of Ozone 

 would not be developed unless the oxygen was electrified, — for it 

 was shown that in the presence of oxygen alone, or electricity 

 singly, no development of Ozone took place, but as soon as the 

 oxygen became electrified, Ozone became manifest ; they placed a 

 strip of test paper in a glass filled with oxygen and hermetically 

 sealed, and by means of metallic bulbs at each end, electric sparks 

 were made to flash across, or through the volume of oxygen ; the 

 result was, the test paper immediately became blue, indicating the 

 presence of Ozone. 



Test papers have been suspended in oxygen for ten days 

 without any apparent change, but when electrified at the 

 end of that time, they became blue, thereby indicating the 

 presence of Ozone. Test papers of the same quality have been 

 placed in a vacuum, and when the electric spark has been passed 

 through it, no change of colour in the test papers took place, but 

 the moment oxygen gas was introduced, and the otherwise same 



