a aohflm : ejeperimmts regarding (hsoHe. » ^4^P< Ao 451 



fo^ if I Understand it correctly, it broadly denies that any 

 peculiar substance at all is formed during the action of phos- 

 phorus upon moist air. That gentleman asserts, at least, in 

 distinct terms, that under the circumstances mentioned no 

 itiatter is produced which bears the slightest relation to that 

 disengaged at the positive electrode during the electrolysis of 

 water. Mr. Williamson made two experiments, on the re- 

 sults of which he founds his opinion : in one of them he 

 passed a current of air over a piece of phosphorus and con" 

 veyed it into the test- paste; in the other he followed the same 

 methodi, with the difference, however, that the phosphorus 

 employed by him had previously been brought into a state of 

 minute mechanical division by the means of asbestus. In 

 the first case the paste was coloured, but not in the second ; 

 atid from those results he drew the inference that the pro- 

 duction of colour was due to the action of phosphoric acid 

 and free oxygen upon the iodide of potassium, and that no 

 ozohe was formed by phosphorus. Though this conclusion 

 implied the most direct contradiction to my own statements, 

 and those made by Marignac, Mr. Williamson did not think 

 it worth his while to repeat the experiments which I have so 

 circumstantially described in my little work On the Chemical 

 Production of Ozone, and satisfy himself whether, by em- 

 ploying another method of experimenting, he might not ob- 

 tain results a little different from those he had come to. In 

 my opinion, common fairness required him to do so before he 

 had so broadly negatived the correctness of what I myself 

 and others had stated as well-ascertained facts. But what- 

 ever the reasons were which prevented him from repeating 

 my experiments, 1 take the liberty to tell him most distinctly, 

 that his conclusion, according to which the odoriferous prin- 

 ciple disengaged by phosphorus from moist atmospheric air 

 has nothing to do with the ozone developed at the positive , 

 pole during the electrolysis of water, is entirely unfoundeUi'}^ 

 and I continue, notwithstanding his results, to maintain that 

 the very same substance is produced in the action of phos- 

 phorus upon air which is disengaged either at the positive 

 electrode during the electrolysis of water, or at the points out 

 of which electricity happens to pass into the atmospheric air. 

 My reasons for being so positive on this point are founded on 

 the following facts: — 



I. Chemical ozone (and I mean by that the odoriferous 

 principle produced by phosphorus placed in moist atmo- 

 spheric air) destroys, with great energy, all vegetable coIouim* 

 ing matters at common temperatures. • 



3. Chemical ozone oxidizes at common temperatures most 



