24 llie Production of Peroxide of Hydrogen. 



contained absorbent cotton, i? and C glass beads dren died with 

 soda solution, D and E sulphuric acid beads. The air, after 

 ozonation in the " Phosphorus Ozonator," was aspirated through 

 Kerite tubing into the first wash-bottle, and thence into the 

 four Geissler bulbs F, G, i7and /, the entire five containing 

 water. From /, the gas passed through the empty wash-bottle 

 J, thence into the sulphuric acid wash-bottle it, and finally 

 through three drying-tubes, filled to a length of 2| meters with 

 glass beads drenched with sulphuric acid. 



From the dryers, the ozonized air passed into a curved glass 

 tube, N, dipping down into an oil-bath M. The middle portion 

 of this tube, for a length of 0.25 meter, was filled with amian- 

 thus which had previously been ignited. The object of this 

 amianthus filling, was to cause the ozonized air to pass through 

 a great extent of heated air passages. After this, followed a 

 weighed sulphuric acid drying-tube P, a sulphuric acid guard- 

 tube T, and a Geissler bulb containing a neutral solution of 

 potassium iodide W. Between P and S, an empty tube closed 

 with corks at both ends was interposed, for convenience in slip- . 

 ping out the drying-tube P. 



The following experiments were performed under as nearly as 

 possible identical conditions. Twelve liters of ozonized air were 

 drawn through the apparatus in each trial, at the rate of six 

 liters per hour. The ozonator was maintained at the tempera- 

 ture of 24° C. The increase in weight of the drying-tube P, 

 corresponded to the water formed by decom2:)osition of the hydro- 

 gen peroxide when heated to the various temj)eratures indicated 

 in the table. The amounts of iodine set free in the potassium 

 iodide solution, are calculated into the corresponding amounts 

 of ozone, according to the equations : — 



2 KI + O3 +"2 HCl = 2 KCl + I, + 11,0 + 0, and 

 2 KIO3 + 2 HCl = 2 KCl + I^ + 0, + H,0, 

 each molecule of ozone corresponding to two atoms of iodine. 

 A large number of trials were made in blank, the ozonator not 

 being thrown into action, and when at last the adjustment was 

 made so perfect that the drying-tube P did not alter in weight 

 either at 20° or 200°, when 12 liters of air were aspirated through 

 the apparatus, and the potassium iodide solution in W under- 

 went no alteration under like circumstances, the experiments 

 given below were performed. 



