1825.] finely divided Platinum on Gaseous Mixtures. 419 



in the case of olefiant gas, which, under similar circumstances, 

 is always more largely converted into water and carbonic acid. 



3. Mixtures of Hydrogen and Carbonic Oxide with Oxygen. 



The addition of one volume of carbonic oxide to two volumes 

 of an explosive mixture produces a distinct effect in suspending 

 the action of the platinum balls, and even of the spongy metal 

 itself. The action of the gases upon each other still, however, 

 goes on slowly, even when the carbonic oxide exceeds the 

 explosive mixture in volume ; and after the lapse of a few days, 

 the oxygen is found to have disappeared, and to have partly 

 formed water, and partly carbonic acid. I made numerous 

 experiments to ascertain whether the oxygen, under these cir- 

 cumstances of slow combustion, is divided between the carbonic 

 oxide and the hydrogen, in proportions corresponding to the 

 volumes of chose two gases. The combustible gases being in 

 equal volumes, and the oxygen sufficient to saturate only one of 

 them, it was found that the oxygen, which had united with the 

 carbonic oxide, was to that which had combined with the hydro- 

 gen, as about 5 to 1 in volume. Increasing the carbonic oxide, 

 a still larger proportion of oxygen was expended in forming car- 

 bonic acid. On the contrary, when the hydrogen was increased, 

 a greater proportional quantity of oxygen went to the formation 

 of water. But it was remarkable, that when the hydrogen was 

 made to exceed the carbonic oxide four or five times, less oxygen 

 in the whole was consumed than before ; the activity of the 

 carbonic oxide appearing to have been diminished, without a 

 corresponding increase in thatof the hydrogen. 



In cases, where the proportion of the carbonic oxide to the 

 explosive mixture was intentionally so limited, that the platinum 

 ball was capable of immediately acting upon the latter, the 

 carbonic oxide was always in part changed into carbonic acid, 

 the more abundantly as its volume was exceeded by that of the 

 explosive mixture. Increasing the oxygen, so that it was 

 adequate to saturate both gases, and causing the hydrogen to 

 exceed the carbonic oxide in volume, a speedy action was 

 always exerted by the ball, and the whole of the combustible 

 gases was silently converted into water and carbonic acid. The 

 introduction of the platinum sponge into such a mixture was 

 almost always found to produce detonation. 



4. Mixtures of Hydrogen and Cyanogen %vith Oxygen. 



When one of the platinum balls, after being recently heated, 

 is introduced into cyanogen and explosive mixture in equal 

 volumes, no apparent action takes place. With half a volume 

 of cyanogen there is a slight diminution ; and as we reduce the 

 proportion of that gas, the action of the elements of the explo- 

 sive mixture on each other becomes more and more distinct. 



2e2 



