370 Literature of Ozone, 



III. The exact nature of the relations existing between 



OZONE AND ORDINARY OXYGEN". ,j 



We have] seen that Marignac and De la Rive, as the result of 

 their experiments performed in 1845, had enunciated the view 

 that ozone was oxygen^ rendered allotropic by its passage into a 

 peculiar electric state. They proposed to abandon the name 

 " ozone," which assumed an independent chemical existence for 

 this body, and to call it merely ' ' electricized oxygen. " This view 

 of ozone was not readily susceptible of investigation by usual 

 chemical methods. But the case was different with the hypo- 

 thesis, which was shortly afterwards advanced by Dr. T. S terry 

 Hunt, in 1848. Since his intuition of a truth, not f ally demon- 

 strated until twenty years later, is of a very striking character, 

 it will be interesting to quote it as originally announced. In a 

 paper on the anomalies presented in the atomic volume of sul- 

 phur and nitrogen, Dr. Hunt says : — "In considering such com- 

 binations as S 2 and Se0 2 , which contain three equivalents 

 of the elements of the oxygen group, it was necessary to admit a 

 normal species which should be a polymere of oxygen, and be 

 represented by 3 = (OOO). The replacement of one equiva- 

 lent of oxygen by one of sulphur, would yield sulphurous acid 

 gas (OOS), and a complete metalepsis would give rise to (SSS). 

 The first compound is probably the ozone of Schonbein, which 

 the late researches of Marignac and De la Rive have shown to be 

 in reality only oxygen in a peculiarly modified form,*' etc. The 

 hypothesis herein stated, thatjDzone is triatomic oxygen, neces- 

 sarily involved the assumption of a corresponding difference in 

 density and other physical properties — differences admitting of 

 exact quantitative proof or disproof. Such were the experimental 

 difficulties in the way, however, that it was not until 1860, that 

 an investigation was made into the volumetric relations of ozone 

 to oxygen. The experiments of Profs. Andrews and Tait then 

 resulted in establishing, that where perfectly pure and dry oxy- 

 gen is converted into ozone, under the influence of the silent 

 electric discharge, it becomes more dense, the amount of con- 

 traction being proportional to the quantity of ozone produced. 

 Also, that when ozone, thus condensed, is exposed for a short 



