Analysis of Radiation emitted in Gaseous Explosions. 85 



longer wave-length than 2'8 /jl is emitted by these mixtures, 

 which becomes of importance in comparison with the 

 2'8 jjl radiation after the temperatures of the mixtures 

 have fallen to about 1400° C. abs.* 



Radiation from Coal-gas and Air Mixtures. 



5. The results of experiments on a 13 per cent, mixture of 

 coal-gas and air are shown in fig. 1. Curve A T is the mean 

 gas temperature curve for the mixture after explosion as 



Eur. 1. 























07 

 0-6 

 0-5 



0-4 













A \ 

































^\^T \y^ 















i \ 



> 







Aq. 













0-3 



. / 













V 1 









~t ^ 







/\ L^^" A* 





0-1 



n 



hz-xZh^r 







1 





" 5 pr* 



/VX A 1 ^~~~~^ — ~— ■ 





TPi V m mt mm 







— _ 



0-1 



0-3 0-4 0-5 0-6 



Time after Ignition— seconds. 



07 



08 



0-3 



deduced from the pressure curve, and curves A-p t, Aq, 

 and A& show the radiation measured by a bolometer per 

 sq. cm. of its surface when protected by plates of fluorite, 

 quartz, and plate glass respectively. Curves A/, Aq', 



* The absorption spectrum of water vapour shows a strong band 

 extending from about 4ju to about 8/*. There is also a series of small 

 bands between 8 /t and 20/z, after which it appears to become quite 

 opaque. (See Coblentz, ' Supplementary Investigations of Infra-red 

 Spectra,' Appendix, pp. 148-9.) 



| In the case of the fluorite curves an allowance of 5 per cent, has 

 been made for the absorption of the fluorite. No allowance has been 

 made in the case of the quartz and glass curves for the absorption 

 of these substances. No allowance either has been made in the case of 

 any of these curves for a 5 per cent, reflexion which takes place at the 

 blackened surface of the bolometer. 



