112 
PROFESSOR H. B. DIXON ON THE RATE OF EXPLOSION IN GASES. 
experiments were made above and below the atmospheric pressure, which showed 
that the maximum rate always occurred when the same percentage of steam was 
present. Under 1100 mm. pressure the fastest rate was found when the mixture 
was saturated at 48°— i.e., contained 5'6 per cent, of steam; and under 400 mm. 
pressure the fastest rate was found when the mixture was saturated at 25°— i.e., 
contained 5'6 per cent, of steam. Increase of pressure increased, and diminution of 
pressure diminished, the rate of explosion of moist carbonic oxide and oxygen. 
Under 300 mm. pressure the explosion-wave was not propagated in the mixture of 
carbonic oxide and oxygen saturated at 10° C. In one experiment the flame reached 
the end of the tube, taking about 30 seconds to travel 100 metres. Under 400 mm. 
pressure the explosion-wave was propagated. 
Table XII. — Rate of Explosion of Carbonic Oxide and Oxygen. 
1 . Under 1100 mm. pressure. 
Condition. 
Per cent, of 
Mean rate in 
.steam present. 
metres per second. 
Saturated at 26° C. 
2-3 
1737 
„ 43° C. 
5'6 
1782 
53° C. 
9-5 
1742 
2 . Under 400 mm. pressure. 
Condition. 
Per cent, of 
Mean rate in | 
steam present. 
metres per second. 
Saturated at 10° C. 
2-3 
1576 
„ 25° C. 
5-6 
1616 
33° C. 
9-5 
1570 
These results are shown graphically by curves on fig. 2, Plate 1, in which the 
ordinates are the rates of explosion, and the abscissae the percentages of steam present 
in the mixture. 
These curves show the very marked increase of the rate of explosion on adding 
1 or 2 per cent, of steam to the dried gases. Now the addition of steam to other 
dry gaseous mixtures, such as hydrogen and oxygen, ethylene and oxygen, cyanogen 
and oxygen, has been found to loiver the rate of explosion. I think these results, 
therefore, are strong evidence that at the extreme temperatures of the explosion-u'ave, 
as well as in ordinary comhustion, carhonic oxide is oxidised by the steam, and not 
directly by the oxygen. 
