EXTINGUISHES COMBUSTION* 103 



But it is not on its being an absolute incombustible, that its 

 powers depend, for we find, when combined with certain pro- 

 portions of other matter, it is inflammable, and explosive in the 

 highest degree. Chloride of (azote) nitrogen, iodide of nitro- 

 gen, protoxide, and binoxide of nitrogen, are instances of this 

 description. It is to the excessive proportion of aggregation 

 in which it exists in atmospheric air, we are to attribute its 

 negative or neutralizing powers. And we find that oxygen, 

 a well-known supporter of combustion, if in excess, for in- 

 stance, in greater proportion than 2J volumes to 1 of carbu- 

 retted hydrogen gas (as before stated), totally prevents its com- 

 bustion ; w r e find also that a taper plunged into a jar of hydro- 

 gen gas, although open to the atmosphere, is at once ex- 

 tinguished, that the hydrogen only burns at the surface in 

 actual contact with atmospheric air. Let it be held in recollec- 

 tion that nitrogen is four to one of oxygen in our atmosphere, 

 and that oxygen, the most brilliant and effectual supporter of 

 combustion, at but 2J volumes to 1, acts, in the instance of 

 carburetted hydrogen, as a decided extinguisher of combustion. 

 Not from their nature or qualities of oxygen and nitrogen are 

 such phenomena derivable, but from their opposition when in 

 a state of aggregation to permit the junction of appropriate 

 poles of fixed matter, to effect transition to the state of radiancy 

 or light. It is evident also that any of the simple gases will 

 not inflame, nor burn of themselves in close vessels, but that a 

 mixture of them with each other, or in contact with common 

 atmospheric air (composed of nitrogen, four to one of oxygen), 

 will submit to immediate combustion, often brilliant, and pro- 

 ducing much heat and light for the former is but the latter 

 111 an imperfect state. 



The equality of expansion of matter in a gaseous state, has 

 been before observed, and the rays of light tare similarly affected 

 by caloric, uninfluenced by their respective densities, or spe- 

 cific gravities. 



