•268 Sir James Deicar [Jan. 20, 



this explosive polymerization takes place a little above the temperature 

 of liquid air, and possibly also at a still lower temperature, though 

 more slowly. At normal temperature the real monosulphide can 

 only exist for about half a minute ; under ordinary circumstances it 

 at once polymerizes, or its temporary existence, at any rate, cannot 

 be detected. 



A number of experiments made to ascertain if the phenomena 

 were in any way dependent on the presence of impurities proved that 

 when carbon disulphide, however purified, distilHng from the liquid 

 kept at - 78° C. into a charcoal condenser cooled to - 185° C. was 

 submitted to the action of the silent electric discharge, and the 

 vapour together with any new product condensed in a U-tube 

 placed in liquid air, a brown solid resulted, the formation of which was 

 accompanied by a glow or a flash and usually by a detonation on 

 removing the liquid air surrounding the U-tube. Hence it is clear 

 that these phenomena are not caused by the presence of impurities 

 in the carbon disulphide, and that the evolution of light and heat 

 are definitely associated with the transformation of the condensed 

 gaseous product into the brown solid. It will be seen later that the 

 flash and the detonation are to some extent variable phenomena. 



The apparatus may be modified by connecting the ozoniser by 

 means of a 8-way tap with two similar U -tubes packed with finely 

 shredded cotton wool or asbestos offering an equal resistance to the 

 passage of the stream of carbon disulphide vapour, and through a 

 second 8-way tap to the charcoal condenser immersed in liquid air. 

 When it was desired to observe the action of substances such as finely 

 divided metals on the gases from the ozoniser these substances were 

 either mixed with or deposited on asbestos, so that the deposit obtained 

 when the gases were passed through it and subsequently condensed by 

 hquid air could be compared with that obtained w^hen the gases had 

 passed over pure asbestos. Alternatively, either tube could be left 

 free of any filtering material, and the character and proportion of 

 the material deposited compared. 



In order to ascertain if the rate of production of the brown solid 

 could be increased, experiments were made in which the vapour of 

 carbon disulphide evolved from the liquid at different temperatures 

 between - 78° C. and 0° C. was allowed to pass through an apparatus 

 in which an ordinary vacuum tube with flat platinum electrodes 

 replaced the ozonisei', and from this entered the wide tube condenser 

 which replaced the U-tube used in other cases. The surface of the 

 vacuum tube soon becamec oated with a whitish deposit of sulphur, 

 and later with the brown solid. The product condensed at the tem- 

 perature of licpiid air transformed into a brown solid with the evolu- 

 tion of hght and heat as usual, and this also occurred when the vapour 

 had passed through a cotton-wool filter. 



Experiments were also made in which the ozoniser was either cooled 

 to - 80° C. or heated to 220" C, the other conditions being as usual. 



