328 Dr.W. C.Henry's Experiments on Gaseous Interference. 



acid continues to be the predominant action. Hence the phse- 

 nomenon of " interference" is better explained by contem- 

 plating the gaseous mixture as one of carbonic oxide and 

 oxygen to which hydrogen has been added, than as one of 

 hydrogen and oxygen with which carbonic oxide has been 

 mingled. Such a simple mixture of carbonic oxide and oxy- 

 gen, in presence of the prepared plate or sponge, is in a state 

 of slow acidification ; and the admission of hydrogen, a gas 

 endowed with a feebler affinity for oxygen, occasions no essen- 

 tial change of the chemical actions previously in operation. 



This view of the mode in which carbonic oxide overrules 

 the combining tendencies of hydrogen and oxygen is sup- 

 ported by experiments, long ago recorded, on the influence of 

 increased temperature. For it has been shown* that the pha?- 

 nomena of interference disappear at a heat between 300° and 

 340° Fahrenheit, the union of the elements of a gaseous mix- 

 ture which is slowly acted upon at common temperatures 

 being then rapidly accomplished. Now this is precisely the 

 temperature at which carbonic oxide, when heated simply 

 with its equivalent of oxygen in presence of the platina sponge, 

 is rapidly converted into carbonic acid. Instant action, with 

 incandescence, I have found also follows the admission of the 

 black powder into mixtures of hydrogen, oxygen and carbonic 

 oxide ; and it has been already stated that simple mixtures of 

 carbonic oxide and oxygen (or carbonic oxide alone, the 

 oxygen being supplied by the powder,) are inflamed by platina 

 in the state of powder. The phenomena of interference are 

 observed then only at those temperatures, and with that form 

 of platina, which induce the sloiso union of carbonic oxide and 

 oxygen; and wholly disappear at the higher temperature, or 

 with that more active state of the metal which causes raind 

 combination. 



An obvious objection, however, presents itself to the view 

 that carbonic oxide possesses a stronger affinity for oxygen 

 than hydrogen exerts, viz. that while hydrogen and oxygen 

 are speedily detonated at common temperatures by the plate 

 or sponge, the union of carbonic ©xide and oxygen takes 

 place with great slowness. The explanation of this apparent 

 anomaly I believe to be, that the product of the combustion 

 of hydrogen (aqueous vapour) at once quits the surface of 

 the metal, and is liquefied by the cold sides of the tube ; 

 while the combustion of the carbonic oxide yields a gas which 

 remains for a while adherent to the metallic surface next to 

 which it is generated, and thereby prevents a sufficiently rapid 



* Dr. Henry, Phil. Trans. 1824, pp.278 and 280. 



