Lost Pressure in Gaseous Explosions. 



27 



This is the shape of curve 1 (fig. 4), found experimentally 

 by Grover for coal-gas and acetylene, in weak mixtures with 



Fig. 4. 



t oba 



initial compression *, that is, with the number of combustible 

 molecules per unit volume N increased mechanically in the 

 ratio of compression. 



{}>) below P : ^ ob8 . =j9,(A-BN)&(l + &N), 



= Pl (A, + K 2 N-C 2 W). 



This agrees with the shape of curve 2 (fig. 4), obtained 

 in explosions at initial atmospheric pressure f. The point 

 P appears, however, to be passed through without a sudden 

 change in the curve. 



The agreement shows that by the use of the expression 

 taken for the explosion efficiency rj = A— BN, and the 

 conception of the unit of combustion, the two types of 

 curve expressing the experimental relation of maximum 

 explosion pressure to percentage of combustible gas may be 

 explained. 



The peculiar feature of the curves connecting the observed 

 velocities of explosion with the percentage of combustible 

 gas is that they consist, for the most part, of two straight 

 lines forming a triangle upon the axis of N with the vertex 

 at or near the percentage of complete combustion, and the 

 base coinciding with the range of inflammability. The 

 straightness of the rising and falling sides of this can be 

 explained if the velocity falls from a maximum in proportion 



* Clerk, ' The Gas, Petrol and Oil Engine/ vol. i. p. 1G4, fig. 53. 

 t Loc. cit. figs. 46, 49. 



