236 Intelligence and Miscellaneous Articles* 



As nothing containing sulphur had been used about the apparatus, 

 the acid was evidently derived from the ebonite itself. The first 

 thought was that the material had been heated in the process of 

 vulcanization sufficiently to oxidize the sulphur; but as the sulphu- 

 rous oxide, if thus formed, would be dissipated by the heat, this 

 could hardly be regarded as the source of the sulphuric acid, especially 

 as the latter did not appear until after the apparatus had been used. 

 It is well known that vulcanized caoutchouc is affected by ozone, 

 ^nd that the ordinary rubber tubes through which it is passed are 

 attacked and quickly perforated by it. It seemed most probable, then, 

 that the acid was the result of the action of the ozone upon the 

 insulators ; and experiments were made which entirely confirmed 

 this supposition. 



To the exit-tube of the ozonizing apparatus described in the Phil. 

 Mag. for August (p. 15 6) was attached one end of a vulcanized rubber 

 tube a few inches long, the other end being slipped upon the glass 

 tube of a small wash-bottle containing some thirty or forty cubic cen- 

 timetres of water. Air was slowly driven through the apparatus, and, 

 having been strongly ozonized by the action of the electricity, bub- 

 bled up through the water. This was continued for an hour and a half. 

 At the end of this time common air was passed through the appara- 

 tus to displace the ozone left in it, the tubes were removed, and the 

 bottle closed with a glass stopper. On opening the bottle some 

 time afterward, there was an unmistakable odour of sulphurous oxide, 

 and the water reddened blue litmus paper very quickly and strongly. 

 A strip of litmus paper, hung in the bottle so as not to touch the 

 water, was completely reddened in a short time ; and this happened 

 even after several days had elapsed from the time of the experiment. 

 The water tested with chloride of barium gave a considerable crys- 

 talline precipitate, leaving no doubt of the presence of sulphuric acid. 



A small slip was cut from a thin plate of ebonite, cleaned and 

 dried, and placed in a small bottle, into which ozone was driven as 

 before. In a short time it was bedewed with moisture having an 

 acid taste, and exhibiting the same properties as that found upon 

 the insulators of the machine. 



In order to determine whether the sulphur itself could be directly 

 oxidized by ozone, a quantity of fine flowers of sulphur was gently 

 rubbed into a loose lock of dry cotton, so as to diffuse it as much as 

 possible. The cotton was placed in a dry wash-bottle, and connected 

 by means of a glass tube with a second wash-bottle containing a 

 little water, all the connecting tubes being of glass. Ozone was 

 passed through the bottles for an hour and a half; but at the end of 

 this time not the slightest evidence of any action upon the sulphur 

 could be detected. This was what might have been expected ; for 

 as the air often contains a small percentage of ozone, sulphur exposed 

 to it would undergo slow alteration, with loss of weight; and it does 

 not appear that any thing of the kind has ever been observed. 



It is evident that while the ebonite is undergoing decomposition 

 by the ozone, the oxygen combines with the issuing sulphur to form 

 sulphurous oxide, which with the atmospheric moisture produces 



