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III. Bakeeiax Lectuee.^— The Rate of Explosion in Gases. 
By Haeold B. Dixon, M.A., F.R.S., late Felloiv of Balliol College, Oxford; 
Professor of Chemistry in Owens College, Manchester. 
Received July 8, 1892,—Read January 19, 1893. 
[Plate 1.] 
Cap. I.— Inteoduction. 
The experiments described in this memoir were undertaken with two objects : in the 
first place, to obtain information conceiiiing the course of chemical change pursued I>y 
reacting gases; and, secondly, to examine the nature of the “ explosion-wave ” in 
gaseous mixtures discovered by M. Beethelot. 
The idea of using the rate of explosion as a means of determining the course of a 
chemical reaction occurred to me in 1877, when investigating the influence of steam 
on the union of carbonic oxide and oxygen. If steam acts as a carrier of oxygen to 
the carbonic oxide by a series of alternate reductions and oxidations, an increase in 
the amount of steam present, beyond that required to initiate the reaction, should lie 
accompanied by an increase in the rate of combination up to a certain limit. 
Attempts were therefore made to detect such an increase by measuring the velocity 
of the flame in a tube.* But while the difference in the rate of explosion between 
the nearly dry and the moist gases was well marked, the attempts to directly 
measure the rate of the explosion of the moist gases failed, owing to the great 
rapidity of the flame. In the spring of 1881 I attempted to measure the rate of 
explosion of cai'bonic oxide and oxygen with varying quantities of steam by photo¬ 
graphing on a moving plate the flashes at the beginning and end of a closed tube 
20 feet long. The two flashes appeared to be simultaneous to the eye, but no record 
of the rate was obtained, for the apparatus was broken to pieces by the violence of 
the explosion. Shortly after this attempt was made the first of the brilliant series of 
papers by MM. Beethelot and Yieille, and by MM. Mallard and Le Chateliee, 
was read before the French Academy of Sciences. The work of these French chemists 
has opened a new era in the theory of explosions. 
* ‘ Phil. Trans.,’ 1884, Pt. II., p. 63.5. 
MDCCCXCIII.—A. 
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