Literature of Ozone. 369 



ments (1853). He passed the electrolytic oxygen evolved in 

 such a manner as to exclude the presence of hydrogen, through 

 a very long sulphuric acid drying tube, and thence into an ab- 

 sorption apparatus containing potassium iodide, and provided 

 with a sulphuric acid bulb-apparatus, to condense evaporated 

 water. In case the matter of ozone and oxygen were identical, 

 the weight of oxygen equivalent to the weight of iodine set free 

 by the ozone, should have been equivalent to the total gain in 

 weight by the absorption apparatus. But, according to the ex- 

 periments, this weight was less, and the numbers apparently 

 assigned to electrolytic ozone, the formula H 2 3 . And since 

 Baumert found that ozone prepared by the electric charge, could 

 not be made to yield up the elements of water on strong heating, 

 while that prepared by electrolysis could, he regarded the two 

 as different bodies, the former as allotropic oxygen, the latter as 

 teroxide of hydrogen. 



Thus, the old hypothesis, against which Schonbein had so 

 long striven, that there were two (and possibly more) bodies of 

 the nature of ozone, was rehabilitated. It was finally over- 

 thrown by Andrews (1856), who showed that the preceding 

 experiments on electrolytic ozone had been vitiated by the pre- 

 sence of a small but appreciable quantity of carbonic acid, which, 

 unless very great precautious be taken, is always present in the 

 evolved gas. In very numerous experiments, he showed that 

 the weight of active oxygen was equivalent to the weight of the 

 iodine set free in the absorption apparatus, and therefore no 

 hydrogen as well as could have been present ; also, that the 

 properties of electrolytic ozone, and that obtained by the action 

 of the electrical spark on pure and dry oxygen, were identical. 

 More especially, it was shown that both were converted into ordi- 

 nary oxygen, at a temperature of about 237 Q C. ; and from the 

 whole investigation the author drew the conclusion, which was 

 confirmed by the still more elaborate experiments of Soret, in 

 1863, and is now universally adopted, "that ozone, from what- 

 ever cause derived, is one and the same substance, and is not 

 a compound body, but oxygen in an altered or allotropic con- 

 dition." 



