434 Dr. Schocnbein on the relation of 



The bottom of a spacious bottle was covered with this mix- 

 ture, and then a large piece of carbonate of ammonia suspended 

 within the vessel. After the atmosphere, standing over the 

 acid liquid, had assumed the power of colouring rapidly blue 

 a strip of reddened litmus paper, it continued to possess the 

 following properties : — 



1. Strips of paper charged with paste of starch containing 

 some iodide of potassium were coloured blue. 



2. Strips of paper drenched with an alcoholic solution of 

 guaiacum assumed a blue colour. 



3. Strips of paper coloured blue by a solution of indigo 

 turned white. 



4. Strips of paper to which sulphuret of lead had been at- 

 tached, by means of nitrate of lead and sulphuretted hydrogen, 

 gradually turned white. 



5. Strips of paper charged with a solution of the common 

 prussiate of potash became deeply yellow. 



6. Crystals of the yellow prussiate, after having been sus- 

 pended for twenty-four hours within this atmosphere, were 

 covered with a crust of the red sesqui-ferrocyanuret of potas- 

 sium. 



From the facts just stated, it appears that the atmosphere 

 in question acts exactly in the same way as ozonized air does, 

 and from the circumstances under which those reactions took 

 place, it follows that the latter could not proceed from free 

 hyponitric or nitrous acid, these acids not being able to co- 

 exist in a state of isolation with the vapours of carbonate of 

 ammonia. We must therefore conclude from these facts, that 

 there was a principle present, in the atmosphere mentioned, 

 which acted after the manner of ozone, and conducted itself, 

 in spite of the presence of ammoniacal vapour, as a highly 

 oxidizing agent. 



But if neither free hyponitric nor nitrous acid were the 

 cause of the reactions mentioned, nor nitrite of ammonia, what 

 then is the substance to which the oxidizing powers are to be 

 ascribed ? I can answer that question only by supposing that 

 the peroxide of nitrogen and hydrogen is that agent. Before 

 passing to another subject, I take the liberty to mention a 

 circumstance which seems to bear upon the matter in ques- 

 tion, and merit some attention. On breathing strongly ozo- 

 nized air three or four times, a disagreeable and strangling 

 sensation will be experienced near the throat and in the chest. 

 This sensation is very similar to that caused by inhaling air 

 which has stood for some time over a mixture of hyponitric 

 acid and water, and this is the case even if the air happens 

 to be charged with ammoniacal vapours. We observe also 

 in such an atmosphere a peculiar and disagreeable odour, 



