PROFESSOR H. B. DIXON OX THE RATE OF EXPLOSION IX GASES. 121 
Mixtures. Pressures. 
rC^N^ + Oj.25’ll atmospheres. 
IC 2 N 0 + 263 .20-96 
rC 3 N 3 + 2 N 20 .26-02 
IC3N3 + 4N0P.22-66 
103^3 +-2^0.23-34 
IC 3 N 3 + 4 NO.16-92 
It is difficult to reconcile these numbers with the received view as to the burning 
of carbon ; they are readily explained on the hypothesis that carbon burns in two 
stages. 
Berthelot has also made some observations of the initial rate of explosion of 
cyanogen when burnt to carbonic oxide and when burnt to carbonic acid. The time 
taken by the flame in travelling a distance of about 130 mm. from the point of 
inflammation was less for the incomplete than for the complete combustion ; a result 
which agrees with my measurements of the rate of the explosion-wave in the two 
cases. When a mixture of carbonic oxide, oxygen and nitrogen, having a composition 
corresponding to the first stage of the combustion of cyanogen, was fired in the same 
apparatus, the rate of the flame was found by BerTHelot to be far slower than in 
the complete combustion of cyanogen ;— 
Time taken by flame to travel 130 mm. 
C 3 N 3 + O 2 .1’05 thousandths of a sec. 
C 3 N 3 - 1-203 .1-55 
2 CO -h O 3 + Ng . . . 17*78 „ ,, 
M. Berthelot adds :—“ D’apres ces nombres, il ne parait pas cpte la combustion 
totale du cyanogene s’effectue en deux temps, en formant cTabord en totalite de 
I’oxyde de carbone qui brfilerait ensuite ; car la combustion totale est beaucoup plus 
rapide que la somme de ces deux effets separes.”''^ 
On first reading this passage I understood M. Berthelot to mean that in the 
complete combustion of cyanogen there ■was no intermediate formation of carbonic 
oxide. But I am led to think that this interpretation cannot be correct for two 
reasons. First, because the conditions of temperature and pressure are so entirely 
different in the two cases compared, that no argument drawur from one can be applied 
to the other. In one case, a reaction is initiated in a mixture of carbonic oxide, 
oxygen, and nitrogen at the atmospheric temperature and pressure ; in the other, the 
same gases are at an enormously high temperature and pressure when the reaction 
begins. Secondly, because M. Berthelot, in the same paper, has drawn from 
analogous facts an argument in an exactly opposite sense. Having determined the 
initial rate of explosion of hydrogen and oxygen, and of carbonic oxide and oxygen 
* ‘ Ann. Cbim. et Pliys.,’ [VI.] vol. 4, p. 4.3. 
MDCCCXCTII.—A. E 
