EXPLOSIONS OF COAL-GAS AND AIR. :?97 



T.\ 1:1.1: XI. 15-per-cent. Mixtures of Coal-gas and Air. Fluorite Window. 



It will be seen from this table that the intrinsic radiance from a certain thickness 

 of the hot gas is about 30 per cent, greater when the gas is enclosed in the vessel 

 with reflecting walls than when it is enclosed in the vessel with black walls. 



The same experiments were repeated with the bolometer placed at the centre of 

 the end cover (position C, fig. Ib). The results were very much the same as those 

 shown above with the bolometer in position A. 



Experiments of the same kind were also made with the window of quartz. The 

 results were very much the same as those obtained with the fluorite window, but the 

 ratios of the intrinsic^ radiance from 59 cm. of the gaseous mixture to that from 

 30 cm. were rather greater than those obtained with the fluorite window. This 

 seems to show that the water vapour is more transparent to the radiation which it 

 emits than is the mixture CO a . H a O.* to its radiation. 



These experiments support those whose results are shown in fig. 13 and Table X. 

 The following table gives the ratio of the intrinsic radiance when the walls are 



TABLE XII. 15-per-cent. Mixtures of Coal-gas and Air. 



* The gaseous mixture in the above experiments (15-per-cent. mixtures of coal-gas and air) contains 

 after explosion alwiit 8 5 per cent, of COj and 20 per cent, of H^O, the remainder being mainly N. 





