322 On the Properties of Ozone. 



I have tried to produce images by drawing with a solution of 

 sulphate of manganese upon paper, and exposing the latter (when 

 dry) to the action of atmospheric air which has previously been 

 strongly ozonized by the means of phosphorus ; and I may say 

 that I have obtained very pretty results. The drawing or wri- 



ting comes out within a few minutes, first exhibiting a yellow- 



ish tint and afterwards a deep brown shade. Gaseous sulphurous 

 acid, readily uniting with the hydrate of peroxyd of manganese 

 to form colorless sulphate and hypo-sulphate of manganese, these 

 manganese images or writings may be almost instantaneously 

 destroyed by introducing them into a bottle containing some 

 gaseous sulphurous acid. And it is a matter of course that the 

 images thus extinguished are restored by reexposing them to the 

 action of ozonized air. These reactions may be used for making 

 very pretty class-room experiments to show the action of ozone 

 upon manganese salts, and that of sulphurous acid upon peroxyd 

 of manganese. They will perhaps also allow of a practical ap- 

 plication. I may add that my test paper after having been 

 turned slightly brown by ozone serves as a test for sulphurous acid. 



2. Ozone enjoying so many properties in common with chlo- 

 rine and bromine, I suspected the two latter bodies would act like 

 ozone upon the solutions of manganese salts, and found my con- 

 jecture confirmed by experiment. If aqueous chlorine or bromine 

 is mixed up with a solution of sulphate, nitrate or muriate of 

 manganese, a very slight action takes place in the dark, but no 

 sooner has the mixture been exposed to the action of solar light 

 than a reaction begins and peroxyd of manganese is thrown 

 down. 



3. Sufficient quantities of ozonized air being treated with a 

 solution of basic acetate of lead (extractum Saturni), throw 

 down all the excess of oxyd of lead in the shape of the brown 

 peroxyd transforming the basic salt into a neutral one. Chlorine 

 and bromine act in a similar manner. If aqueous chlorine or 

 bromine be added to a solution of the subacetate mentioned, until 

 the whole precipitate first formed has disappeared, and the mix- 

 ture becomes limpid agam, very soon after, the liquid will become 

 turbid, peroxyd of lead being thrown down. To show these 

 reactions in the most simple manner, I drench strips of white 

 filtering paper with a solution of the subacetate and suspend 

 them in bottles, containing some ozone, chlorine or bromine. 

 After a certain time these strips will have assumed a browi 



color resulting 

 cumstances. 



under 



*. uzone nas tne power of forming permanganic a< 

 following circumstances. If the bottom of a large 

 with atmospheric air be covered with a solution of sul^ 

 ganese and a bit of phosphorus having a clean surfa 



