476 



Prof. H. B. Dixon. On the Movements [June 5, 



In a similar manner the temperatures corresponding to the velocity 

 of the reflection-waves have been calculated for the other mixtures, 

 (1) assuming the ratio of the specific heats for a diatomic gas to be 141, 

 and for a triatomic gas 1'28, and (2) assuming the ratio of the specific 

 heats for a diatomic gas to be 1*29, and for a triatomic gas I'll: — 



Table II. — Temperatures of Exploded Gases calculated from the 

 Velocities of the Beflection-waves. 



Mixture. 



I. 



y for diatomic gas = 1*41. 

 y for triatomic gas = 1 "28. 



II. 



7 for diatomic gas = l - 29. 

 7 for triatomic gas = 1*11. 



2H 9 + 2 



3720° C. 



4830° C. 





3660 



4130 



2CO + Oo 



4530 



5250 



CoN 2 + Oo 



3330 



3670 



CoN 2 + 20* 



4200 



4780 



2C 2 H 2 + 50 2 



3980 



4630 



A glance at this table reveals the fact that, whether the specific- 

 heats vary or not, but on the assumption that combustion is complete 

 in each case, the explosion of cyanogen to carbonic oxide, which, ac- 

 cording to all observers, gives the brightest flash, and the highest 

 pressure, also gives (apparently) the coolest combustion products a 

 short time after the explosion-wave has gone by. The natural infer- 

 ence to be drawn from these figures is that in those mixtures where 

 steam or carbonic acid, or both, are produced, the combustion is not 

 complete at the moment the reflection-wave is measured. 



Part III. — On the Velocity of a Sound-wave in the Flame of Exploded Gases. 

 [In conjunction with E. H. Jones, B.Sc, and J. Bower, B.Sc] 



The interest attaching to the determination (even approximately) 

 of the temperatures produced in the explosion of gases led us to 

 attempt the measurement of the rate of a true sound-wave (of small 

 displacement) in the gases produced by the detonation- wave. 



In our first experiments the glass explosion-tube was fitted to a steel 

 piece containing a tap of large bore, and a small bye-tap, and connected 

 by a pipe to a steel bomb, in which a small charge of fulminate could 

 be fired. The bomb and connecting pipe were filled with air, while 

 the tube was filled with a mixture of cyanogen with two volumes of 

 oxygen. 



The lengths of the tubes were so adjusted that the sound-wave, 

 started in the bomb by the detonation of the fulminate, should be 



