1911] on Chemical Change at Low Temperatures. 271 



The high temperature produced during the transformation has 

 been proved by taking a photograph of the U-tube by its own 

 detonating flasli (Fig. 9). The cracks in the fractured tube are 

 plainly visible, a flame is seen bursting through one such crack, and 

 the light extends for a considerable distance through the tube. 



Before allowing the deposit to flash by the removal of the liquid 

 air, in some experiments the U-tube was filled with dry nitrogen at 

 atmospheric pressure, through a 3-way tap on the charcoal bulb. The 

 right-hand limb of the U-tube contained copper wire gauze to cool 

 the entering nitrogen and thereby prevent any undue heating of 

 the deposit. 



Two seven-minute deposits were successfully flashed after filling 

 with nitrogen. In both cases a violent detonation resulted, and the 

 tube was shattered. The photographic plates showed good pictures 

 of each flash, w^hich was seen to be localized and not so intense, due 

 no doubt to the relatively large pressure of nitrogen in the U-tube 

 compared with previous experiments in which no inert gas was present. 



Photographs of the Spectrum of the Flash. 



The arrangement used to secure a photograph of the spectrum of 

 the flashes consisted of a German silver U-tube with a quartz wdndow 

 at the top of one limb. The flash occurring in the tube was pro- 

 jected through this window by means of a quartz prism, and reflected 

 on to the slit of a Hilger quartz spectrograph. 



About seven flashes from deposits of 15 minutes' periods were 

 necessary to get a good image of the spectrum. 



The sulphur bands, wave-lengths between 384 and 392, and the 

 cyanogen line 3885 were present. The principal hydrocarbon bands 

 were plainly visible, of which that at 436-443 was the strongest in 

 the whole spectrum. A strong band at 635-655 and scattered bands 

 from 248 to 362 were present also, and fainter bands from 540 to 605. 



The solid product obtained after the flashes taken in the metal tube 

 was found to be a mixture of carbon and sulphur due to the high tem- 

 perature of the flash, as the character of the spectrum tends to show. 



A number of tests for electric effect in the transformation of the 

 condensed ozoniser product had negative results. 



Attempts to Concentrate the New Gas. 



It was found that the gas was completely condensed in a U-tube 

 at - 185° C, but that a similar U-tube, with a cotton-wool plug in the 

 limb remote from the ozoniser, cooled to - 120° C. by immersion in 

 solid carbon dioxide under reduced pressure, allowed some of the gas 

 to pass through it and to be condensed in a second U-tube at - 185° C. 



