Radiation emitted in Gaseous Explosions. 73 



for the various mixtures (which it should be noticed vary in 

 density as well as in strength). These ratios are all pretty 

 much the same — indeed, having regard to the large varia- 

 tions in li ma x., ^max.j Q» and £) it is somewhat surprising to 

 find them agree with one another so closely. 



8. It would therefore appear that certainly within the limits 

 of mixture strength 9*2 per cent, to 15 per cent.* and of density 

 7T atmosphere to a little over 1J atmospheres (as shown in 

 Table I.) li ma x. in the explosion vessel used in the experi- 

 ments is proportional to the . square root of the product 

 Q x ^ m ax.- Expressed in the form of an equation 



Kmax. = Kv / Qxtf' ma x., (1) 



where K is a constant equal to 1*0 x 10" 2 or 0*01, i. e. the 

 mean value of the figures in column 10. 



. 7) 



It may be noticed that as 6 is proportional to j^ (the ratio 

 ■ — : — being equal to 19*6) this equation may be written 



v? — T\ a / ^ X Pmax . x 9 x 



-ti max. — IVi A^ jj , . . . . . {£) 



where K x = 001 X v / i9 : 6= 0*0445. 



9. Some confirmation is lent to the proportionality between 

 Il max . and \/Q x ^max. from the writer's measurements of the 

 intrinsic radiance of coal-gas and air mixtures at various 

 densities from -J atmosphere to 1^ atmospheres f . These are 

 set out in Table II. (which contains similar information to 

 that given iu Table I.). It will be noticed that the ratios in 

 column 10 are again very much the same, though of course 

 they differ from those in column 10 in Table I. because the 

 values of R ima x. » re different from those of K max .. The 

 •equations for the maximum intrinsic radiance are therefore 



H*max.=O-O117\/Qx0 max . .... (3) 



and % max = 0-052 y^^-5-'. . . . (4) 



* A 15 per cent, mixture is the strongest that will burn completely — 

 *. e. it uses up the whole of the oxygen of the air. The weakest mixture 

 that will explode is probably between 7 per cent, and 8 per cent. The 

 limits of mixture strength in these experiments are therefore very wide. 



t Phil Trans. A. vol. ccxi. p. .395. 



