1813.] Azote, of Hydrogen, and of Ammonia. 279 



monia. It was then washed upon a filter till every trace of 

 ammonia disappeared. When dried at a temperature a little 

 above 212°, it assumed the form of a white powder. When 

 applied to the tongue, it had a weak, but very styptic taste. It 

 dissolved readily in nitric acid without effervescence, and of 

 course contained no carbonic acid. Neither did it contain any 

 ammonia, as caustic potash decomposed it without the evolu- 

 tion of any ammoniacal odour. 



Ten parts (amounting to 154*H grains troy) of this salt 

 exposed in a small crucible, exactly weighed, and placed in a 

 sand-bath to a height considerably higher than that of boiling 

 water, gave out pure water, and assumed a yellow colour. The 

 loss of weight was 0.18. The heat being raised still higher, a 

 little water was disengaged, but it was accompanied by red 

 fumes. The loss now amounted to 0*198. As the last portions 

 of water were disengaged at the same time with the acid, I 

 cannot determine the quantity of water with rigorous exactness: 

 but this experiment shows us that the proportion of water ex- 

 ceeds a little 1*8 per cent., but docs not amount to 1*98. The 

 residue, heated in the crucible till the acid was completely ex- 

 pelled, left a quantity of yellow oxide of lead weighing 9'08. 



To ascertain whether this subnitrate could be always pro- 

 duced with the same properties and composition Avhen the ex- 

 cess of ammonia employed was great, I prepared a new quan- 

 tity of it, and obtained exactly the same results: 10 parts of it 

 left 9*064 of yellow oxide, and furnished 0*185 of water, con- 

 taining traces of acid. The subnitrate at a maximum, then 3 

 is composed as follows: — 



Oxide of lead 90*80 



Nitric acid 7*37 



Water of combination 1*83 



.* 



100 



But 90*8 parts of yellow oxide of lead contain G"492 of 

 oxygen. The 7*37 of nitric acid, if we consider it as composed 

 of oxygen and azote, contain only 5*417; but such a composi- 

 tion i* inconsistent with the laws of chemical proportions. On 

 the other hand, if we suppose azote to be an oxide, and nitric 

 icid to be composed as we have stated at the beginning of this 

 dissert Ltioto, then the T'.iT of acid will contain 6.508 of oxygen, 

 that i.^ to -ay, the same quantity with the oxide of lead. The 

 1*83 of water contains 1*615 of oxygen, which multiplied by 

 lour give-; 6*46. Hence it follows that the oxygen of the water 



• The mcau of two experiments. 



