Antozone and Peroxide of Hydrogen. 413 



most important future is before it, and that alike in the chemist's 

 laboratory and in the arts, as a most powerful oxidizing and re- 

 ducing agent, — for it can act as both, — for bleaching purposes, 

 etc., it is destined to play a great part. With its cheapening, 

 many new uses will be found for it, and it is probable before 

 very long, it will take its place, as Mr. G. C. Davis has strongly 

 urged (Ohem. News, XXXIX, p. 220), as an indispensable arti- 

 cle upon the working-table of every chemist. 



But it is not these considerations, which mainly interest us in 

 connection with its scientific history. It is rather the acces- 

 sions to our knowledge, which more especially of late have 

 elucidated many obscure points connected with its sources and 

 properties. 



That the method of preparation from peroxide of barium and 

 hydrochloric acid (Thenard, 18J8), or from the same oxide and 

 carbonic acid (Duprey, 1862 : Balard, 1862), is not used to obtain 

 it on a commercial scale, is familiar to many, — the method of 

 Pelouze, in which hydrofluoric or fiuosilicic acid is used to 

 effect the decomposition, being that employed in the arts. 



That peroxide of hydrogen was formed in the electrolysis of 

 water strongly acidulated with sulphuric acid, was stated by 

 Meidinger (1853), and was apparently so well confirmed by the 

 experiments of Bunsen (1854), 0. Hoffmann (1867), and others, 

 that until the researches of Berthelot (1878) were published, 

 the production of peroxide of hydrogen in electrolysis was 

 looked upon as a fully established fact. But the great French 

 chemist showed that the body dissolved in the acid electrolyte, 

 did not exhibit the reactions characteristic of peroxide of hydro- 

 gen : i. e., it did not decompose potassium permanganate (Bro- 

 die's test), nor oxidize chromic to perchromic acid (Barreswil's 

 test), nor convert calcium hydrate into an insoluble peroxide in 

 alkaline solution (Berthelot's test ?). He demonstrated that it 

 contained in solution the same oxide of sulphur, which he had 

 previously formed as a beautifully crystalline body by the long- 

 continued exposure of dry ozone and dry sulphurous acid to the 

 action of the silent electric discharge — Berthelot's persulphuric 

 anhydride, S 2 O 7 . 



Finally, during the course of the year just passed, Schone has 

 demonstrated in his elaborate research upon the behavior of 



