456 Royal Society. 



The method of performing the experiment was to conduct a stream 

 of electrolytic oxygen through a compound apparatus previously 

 weighed, which contained on one side an acid solution of iodide of 

 potassium, and on the other sulphuric acid ; the former to decompose 

 the ozone, the latter to prevent the escape of moisture. The increase 

 in weight of this apparatus gave the entire weight of the ozone ; the 

 iodine set free, when reduced to its equivalent in oxj'gen, the weight 

 of the active oxygen. The precautions to he taken in conducting 

 this experiment are fully described in the communication. 



The following are the numerical results of five experiments per- 

 formed according to the above method : — 



The agreement in these numbers proves that the active oxygen is 

 exactly equal to the entire weight of the ozone, and is therefore iden- 

 tical with it. 



In the next series of experiments the author shows that no water 

 is produced in the decomposition of electrolytic ozone by heat. 

 Large quantities of electrolytic oxygen, containing from 38 to 27 

 milligrammes of ozone, were decomposed bj' heat, but no water was 

 obtained in a weighed absorption apparatus, in which the gas was 

 exposed, not only to the action of sulphuric acid, but was also passed 

 through a tube containing anhydrous phosphoric acid. 



Ha\ang confirmed by new experiments the fact that ozone is 

 formed by the action of the electrical spark on pure and dry oxygen, 

 the author proceeds to institute a comparison between the properties 

 of ozone derived from diff'erent sources. These he finds to be in 

 every respect the same. Thus ozone, however prepared, is de- 

 stroyed, or rather converted into ordinary oxygen, by exposure to a 

 temperature of about 237° C, and catalytically, by being passed over 

 peroxide of manganese, no water being formed in either case ; it is 

 not absorbed by water, but when sufficiently diluted with other 

 gases, is destroyed by agitation with a large quantity of water ; it is 

 also, contrary to the common statements, destroyed by being agi- 

 tated with lime-water and baryta- water, provided a sufficient quan- 

 tity of those solutions be used ; it has always the same peculiar 

 odour ; it bleaches without producing previously an acid reaction ; 

 it oxidizes in all cases the same bodies, &c. 



From the whole investigation the author draws the conclusion, 

 " that ozone, from whatever source derived, is one and the same 

 substance, and is not a compound body, but oxygen in an altered or 

 allotropic condition." 



