OF BODIES CONTAINING NITROGEN. 279 



On the other hand we find that ammonia, which 

 is a compound of hydrogen and nitrogen, cannot 

 be exposed to the action of oxygen, without the 

 formation of an oxide of nitrogen, and in conse- 

 quence the production of nitric acid. 



It is owing to the great facility with which am- 

 monia is converted into nitric acid, that it is so 

 difficult to obtain a correct determination of the 

 quantity of nitrogen in a compound subjected to 

 analysis, in which it is either contained in the form 

 of ammonia, or from which ammonia is formed by 

 an elevation of temperature. For when ammonia is 

 passed over red-hot oxide of copper, it is converted, 

 either completely or partially, into binoxide of 

 nitrogen. 



When ammoniacal gas is conducted over per- 

 oxide of manganese or iron heated to redness, a 

 large quantity of nitrate of ammonia is obtained, 

 if the ammonia be in excess ; and the same decom- 

 position happens, when ammonia and oxygen are 

 together passed over red-hot spongy platinum. 



It appears, therefore, that the combination of 

 oxygen with nitrogen occurs rarely during the com- 

 bustion of compounds of the latter element with 

 carbon, but that nitric acid is always a product 

 when ammonia is present in the substance exposed 

 to oxidation. 



The cause wherefore the nitrogen in ammonia ex- 

 hibits such a strong disposition to become converted 

 into nitric acid is undoubtedly, that the two products, 

 which are the result of the oxidation of the consti- 



