The Production of Peroxide of Hydrogen. 23 



The purpose of the present article, is to demonstrate by a 

 method entirely different from that which I have previously 

 employed : — 



I. That both hydrogen peroxide and ozone are generated by 

 the action of air upon moist phosphorus. 



II. That in this highly dilute condition, they are not com- 

 pletely destroyed, even after prolonged intermixture. 



III. When the current of ozonized air, containing hydrogen 

 ])eroxide, is passed through a tube heated to various tempera- 

 tures, the amount of water, obtained by the decomposition of the 

 hydrogen pei'oxide, increases with the increment of temperature. 



IV. That, under these circumstances, the amount of ozone 

 regularly diminishes. At 200°, no ozone reaction whatsoever is 

 obtained. 



V. That after this point has been attained, if a solution of 

 potassium iodide (entirely free from iodate), which has jDrevi- 

 ously been acidified with sulphuric acid, be substituted for the 

 neutral solution employed to titrate the ozone, it will undergo 

 slow decomi)osition. This result is due not to ozone, which is 

 completely destroyed by continued exposure to a temperature of 

 200,° but to the spontaneous decomposition of an acidified solu- 

 tion of potassium iodide in presence of oxygen. 



The objects kept jDrominently in view, in devising the method 

 of the experiment, were : — 



1st. To bring filtered and purified air in contact with a large 

 surface of pho3j)horus, the phosphorus being partly immersed in 

 distilled water quite free from ammoniacal and nitrous com- 

 pounds, and maintained during the course of the experiment at 

 the temperature of maximum evolution of ozone (24° — 25° C). 



'2d. To wash out of the ozonized air as large an amount of 

 hydrogen peroxide as possible, by means of an extended series 

 of wash-bottles. 



'dd. To free the ozonized air, after its escape from the Avash- 

 bottles, from every trace of moisture. 



4/A. To decompose the hydrogen peroxide and ozone at gradu- 

 ally increasing temperatures. 



bill. To weigh any water, and to titrate any ozone, remaining 

 after the ozonized air had been subjected to the action of heat. 



These views were embodied in the apparatus shown in Plate I. 

 The air was filtered through a train of purifiers, of which A 



