[ 315 ] 
Vrir. On the Movements of the Flame in the Explosion of Gases. 
By Harold B. Dixox, M.A., F.R.S., Professor of Chemistry in the Owens College, 
Manchester. 
Received 5 June,—Read 5 June, 1902. 
[Plates 10-20.] 
Contexts. Page 
Part 1. — Historicat . 315 
,, II. — Photogm])Jiic Anati/sis of Befonation-jrares (Did their Idfexions . 323 
,, III. — Velociti/ of a Sound-JBave in the Flame of Expoded Gases . 330 
,, IV. — On the Collision of Two Betomtion-JFaves and the Effect of Junrtions in the Tidies . . . 333 
,, V. — On the Initiatim of the Betonation-lFave and on the IFave of “ Itetonation ”. 339 
,, VI. — On the Initud Phases of the Explosion . 312 
,, VII. — Further Experiments on the Initial Phases . 346 
PABT T. 
H]STORICAL InTRODUCTION. 
(I.) On the Rate of Movement of the Flames, and the Pressui cs produced rn the 
Explosion of Gases. 
Humphry Davy""^^ was the first to observe tlie rate at which an explosion of gases 
Avas propagated in a tube, and he also made the first i-ough experiment on tlie tem¬ 
perature i-eaclied in an explosion. When gas from tlie distillation of coal (Avhich he 
found more infiammable than fire-danpi) was mixed Avith eight times its volume of 
air, and AA’as fired in a glass tube 1 foot long and inch in diameter, the flame took 
more than a second to traverse the tube. When cvanonen mixed AAuth twice its 
volume of oxygen Avas fired in a bent tube over Avater, the quantity of Avater 
displaced showed that the gases had exjianded fifteen times their original hulk.f 
Bunsen, I in 1867, made the first careful measurement of the rate at AAhiich an 
explosion is propagated in gases, and he also made the first systematic researches on 
the pressure and temperature produced by the explosion of gases in closed vessels. 
His results led him to the remarkable conclusion that there Avas a discontinuous 
combustion in explosions. When electrolytic gas, or AAdien carbonic oxide Avith halt 
its vnlume of oxygen, is fired, only one-third of the mixture is burnt, according to 
Bunsen, raising the temperature of the Avhole to about 3000° C. No further chemical 
.action then occurs until the gaseous mixture falls, by cooling, below 2500° C. Then 
* ‘ Phil. Trans.,’ 1816 ; ‘ Collected Works,’ a'oI. 6, jJ. 26. 
t ‘ Phil. Trans.,’ 1817; ‘ Collected Works,’ vol. 6, p. 73. 
; ‘Ann. Phys. Chem.,’ a-o1. 131, p. 161; ‘Phil. Mag.,’ vol. 34, p. 489 (1867). 
2 S 2 
(328.) 
4.2.03 
