91 HEPOBT— 1841. 



The results of the author's investigations fully proved — 1st, that the disengagement 

 of the peculiar odour was not confined to the less easily oxidable metals ; 2nd, that 

 by certain arrangements all metals, when acting as positive electrodes, may be made 

 to develope the odoriferous principle ; 3rd. that certain positive metals, when not 

 acting as electrodes, will evolve this principle ; 4th, that charcoal forms no excep- 

 tion to this rule ; 5th, that all substances, whether crystalline in structure or other- 

 wise, possessing the property of appearing luminous by friction, or of yielding sparks 

 when struck, likewise possess the property of discharging, under such circumstances, 

 the "peculiar odour;" 6th, that iron and nickel develope this principle much more 

 strongly than any other metal. 



The author conceived that Schonbein's error, in stating that gold and platina alone 

 developed the odour, arose from the fact of his applying but one mode of evolving 

 the principle, namely, by using the substances on which he experimented as positive 

 electrodes in electrolytic fluids ; it was therefore clear that if, as he stated, gold and 

 platina only produced the odour when clean, it must have been next to an impossibi- 

 lity for the Professor to have evolved it from metals with surfaces more easily oxi- 

 dable, and therefore in a condition to conceal rather than develope so subtile an element. 

 There was no doubt of its evolution from all the metals employed by the Professor t 

 but it was clear that, immediately on its disengagement, combination ensued with 

 the particles of the film which enveloped the ill-cleaned surfaces of the inferior metals, 

 and thus that all evidence of its existence vanished. 



The author, considering the possibility of such an obstruction to the disengage- 

 ment of the odour, contrived an apparatus, by means of which he applied friction to 

 the surfaces of the positive electrodes, and in every case found that the odour was 

 evolved more or less strongly. Schonbein's opinion, that ozone was the electro- 

 negative element of an electrolytic compound, existing not only in aqueous fluids, but 

 also in the atmosphere, made it a point of much importance to ascertain whether it 

 could be produced in dry air or in vacuo. The author stated that he devised various 

 expedients for the purpose of determining that interesting question. Having ob- 

 served the odour to be produced with great intensity at the points where contact 

 was made and broken in an electro-magnetic engine, when connected with the 

 battery, the author constructed an apparatus by which magnets were made to revolve 

 within a glass cylinder, in such a manner that the points of contact, and the pivots 

 whereon the axis turned, were all within it. The cylinder could be exhausted at 

 pleasure, or filled with dry air or gases ; and efl'ectual means were adopted for pre- 

 venting leakage. He thus obtained a vacuum, and operated also in dry air, collect- 

 ing the matters evolved over distilled water ; and by such modes he clearly proved 

 that ozone could not only he produced in a dry atmosphere, but also in a vacuum, mer- 

 curial, and common. In several instances, where distilled water had been admitted 

 into an exhausted tube connected with the glass cylinder containing the odour, there 

 was a much larger proportion of the tube unoccupied by the water, than calculation 

 gave as the maximum space for the residual air after exhaustion, thus proving that 

 ozone had been concentrated, or reduced to a substantial condition. On opening the 

 tubes the odour was extremely strong, and quickly diffused, causing the same sul- 

 phurous smell as that prevailing in a place struck by lightning. 



These experiments, varied and frequently repeated with similar results, led the 

 author to the conclusion that the ozone of Schonbein, which he proposed, for 

 reasons which formed the subject of a future paper, to name Electrogen, must be 

 admitted into the list of supposed elements ; that it was not, as developed by Schon- 

 bein and himself, an anion of an electrolytic compound, whose cation was unknown ; 

 and that probably it existed in combination in various forms of matter, which at 

 present are considered, but which in reality are not, elementary. 



The author added that he was still prosecuting those experiments, and hoped 

 shortly to be able to add considerably to the proofs already adduced as to the elemen- 

 tary condition of ozone, and its chemical properties. 



Mr. Tweedy mentioned, that about six months ago, a specimen was shown to 

 him by a respectable mineral dealer at Truro, of what he called molybdic silver. 

 As, however, it was of a very fusible character— melting before the blow-pipe readily, 

 even in the flame of a candle — Mr. Tweedy conceived that bismuth must enter largely 

 into its composition, and sent a small specimen to Mr. Prideaux for examination. 



