PROFESSOR H. B. DIXON ON THE RATE OF EXPLOSION IN GASES. 161 
irregular period of vibration, and that everything depends on the quickness with 
which the explosion-wave is developed. Again, Berthelot compares the rate of 
explosion of hydrocarbons with that of hydrogen in the same apparatus :— 
Gas. Time. 
Acetylene.1'94 
Ethylene. 2’8 6 
Ethane.‘83 
Marsh Gas.1’24 
Hydrogen.1’04 
“ The rate of combustion of gases rich in hydrogen is very close to that of hydrogen. 
This seems to indicate that the hydrogen burns before the carbon, even in total 
combustions.” 
I do not think this conclusion is justified by the figures ; nor do I see how the 
second argument can be reconciled with the first. 
I have made experiments on the rate of the explosion-wave in ethylene and in 
acetylene mixed with their own volume of oxygen. In both cases the main reaction 
is the formation of carbonic oxide and hydrogen ; but the rates found are not so near 
the calculated velocities as I have found in other cases. The explosions being made 
in a gas-tight tube surrounded with water, the increase in pressure gave the expan¬ 
sion due to the chemical changes. With ethylene and oxygen the volume was almost 
doubled ; with acetylene and oxygen the volume was increased by one-half In the 
following table I have given the observed rates of explosion for ethylene and acetylene, 
with an equal volume of oxygen, compared with the rate calculated by Berthelot’s 
formula and with the sound-wave 2 :— 
Table XLII.—Bates of Explosion of Ethylene and Acetylene with an equal 
volume of Oxygen. 
1 . C^H^, -k 0^ = 2C0 -h 2 H 2 (Q = 67,000 cals.) 
2 . CoH^ + 03 = 2 CO -f II 2 (Q = 112,700 cals.) 
jMixture. 
' 
CHL-fOo 
Beethelot’s 0 . . . 
21.34 
2733 
Rate of explo.sion . 
2507 
2961 
2. 
23.30 
3084 
The rate of explosion of ethylene and an equal volume of oxygen was found to be 
MPCCCXCIII.—A. Y 
