270 



Sir James Dewar 



[Jan. 20, 



Examination for the Presence of Solid Particles in the 

 Gases from the Ozoniser. 



A litre bulb with a U-tube on either side was sealed between the 

 ozoniser and the charcoal condenser, and an arc lamp arranged to 

 project a beam of light through this relatively large space filled with 

 the transforming material from the ozoniser. The glow in the 

 ozoniser was screened off, and thus any solid particles in the bulb 



would be made evident by the 

 ilhimination of the beam through 

 the bulb. 



The arc lamp beam within 

 the bulb was invisible, whether 

 it Avas arranged converging to a 

 focus or parallel. Several good 

 patches of transforming material 

 were condensed on the bulb by 

 local cooling with a cotton-wool 

 plug soaked in liquid air ; 35 

 seconds after turning off the 

 discharge in the ozoniser only 

 white carbon disulphide was thus 

 condensed, all the transforming 

 material having gone. A five 

 minutes' deposit in the second 

 U-tube beyond the litre bulb gave 

 the usual detonating trans- 

 formation, and shattered the 

 tube. A similar deposit in the 

 first U-tube produced, however, 

 a distinctly more violent effect, 

 and 2 or 3 inches of the tube 

 were completely shattered. No 

 cotton-wool plug was used 

 betw^een the ozoniser and the 

 bulb in the above experiment. 

 Similar results as to the non- visibility of the beam within the bulb 

 were obtained when a cotton-wool plug was used ; but the deposits 

 now gave less violent transformations. These observations indicate 

 that the transformation of the gas into the brown solid only takes 

 place in contact with solid surfaces. 



Theoretically, the detonation of carbon disulphide with the pro- 

 duction of carbon and sulphur could produce a temperature above 

 2000° C, and if the transforming ozoniser product is comparatively 

 endothermic, then a similar rise of temperature might occur if it 

 could decompose in the same manner. 



Fig. 9. 



