122 
PROFESSOR H. B. DIXOR ON THE RATE OF EXPLOSION ]N GASES. 
in a boml), he found the rate of explosion of the mixture of the two to be less than 
the mean of the two separately :— 
T inie. 
H 3 + 0.1-04 
CO + O. 12-86 
Hg + CO + O 3 .3-88 
“ La vitesse de combustion n’est, dans aucun cas, la moyenne de celle des compo- 
sants melanges. Mais les deux gaz paraissent tendre a bruler separementj chacun 
avec sa vitesse propre.” 
The meaning of the passage quoted, concerning the combustion of cyanogen, would 
therefore appear to be ; “ In the complete combustion of cyanogen there are not two 
flames propagated from the point of inflammation with different velocities—the 
quicker due to the burning of cyanogen to carbonic oxide, the slower to the burning 
of carbonic oxide to carbonic acid.” With this literal interpretation of the passage 
I entirely agree : there are not two flames or two explosions, but the burning of each 
molecule takes places in two stages, the second stage prolonging the duration of the 
flame clue to the first. 
§ 5. Other Experiments on the burning of Carbon. 
It is usually assumed that carbon, in all its states, burns to carbonic acid, and then 
the excess of carbon, if it is present, reduces the carbonic acid, first formed, to carbonic 
oxide. This view, no doubt, originated from the observation that solid carbon burns 
in oxygen, without apparent flame, to form carbonic acid; and that carbonic acid is 
readily reduced to carbonic oxide when passed over heated carbon. The experiments, 
however, of Mr. Brereton Baker (‘Phil. Trans.,’ 1888) show tliat purified charcoal 
may be heated to redness in a current of dry oxygen without visible combustion 
taking place, but with the formation of carbonic oxide—although the oxygen is in 
large excess. It would appear, from Mr. Baker’s observations, that carbonic oxide 
is the first jiroduct of the action of oxygen on solid carbon at a high temperature; the 
formation of carbonic acid being a secondary change clue to the interaction of carbonic 
oxide, steam and oxygen. Both solid and gaseous carbon, therefore, appear to 
undergo oxidation in two stages ; the second stage being facilitated by the presence 
of steam. 
The evidence, above described, led me, two years ago, to hazard an exjilanation of 
the appearance of a cyanogen flame burning in air. The crimson inner zone might be 
due to the jnimary reaction—the burning of the cyanogen to carbonic oxide and 
nitrogen, with the limited air supply that reaches it; the blue outer zone might be 
due to the burning of the carbonic oxide (formed in the crimson zone), as it meets 
with a plentiful supply of air outside. A few experiments I made showed the presence 
