328 



EXPERIMENTS ON THE METALS FROM THE FIXED ALKALIS. 



In iron tubes, 

 nitrogen lost, 

 and hidrogcn 

 produced^ 



5n copper, less 

 hidrogenj 



in platina, 

 hidrogen lost. 



On what do 

 these results 

 depend ? 



Action of so- 

 dium on am- 

 monia. 



In the processes on the action of potassium and ammonia, 

 in which iron tubes were used, as appears from the experi- 

 ments detailed in the last Bakerian lecture and the appen- 

 dix, there is always a loss of nitrogen, a conversion of a 

 portion of potassium into potash, and a production of 

 hidrogen. When copper tubes are employed, the hidrogcn 

 bears a smaller proportion to the nitrogen ; and more potas- 

 sium is revived. 



In those experiments, in which platina has been used, 

 there is little or no loss of potassium or nitrogen : but a 

 loss, greater or smaller, of hidrogen. 



It will be asked, on what do these circumstances depend ? 

 Do the affinity of certain metals .for potassium prevent it 

 from gaining oxigen from ammonia, and do platina and 

 copper combine with a small quantity of hidrogen, or its 

 basis ? Or are there some sources of inaccuracy in those 

 processes, in which nitrogen has appeared to be decom- 

 posed? The discussion of these difficult problems will be 

 considered in that part of this lecture, in which the nature 

 of ammonia will be illustrated by some new experiments. 

 The object of the present part of the inquiry is the demon- 

 stration of a part of chemical doctrine, no less important 

 and fundamental to a great mass of reasoning, namely, 

 that by the operation of potassium upon ammonia it is not a 

 metallic body that is decomposed, but the volatile alkali ; 

 and that the hidrogen produced does not arise from the 

 potassium, as is asserted by the French chemists, but from the 

 ammonia, as I have always supposed ; the potassium in the 

 most refined experiments is recovered, but neither the 

 ammonia nor its elements can be reproduced, except by- 

 introducing a new body, which contains oxigen and hidrogen. 

 I have made an experiment upon the action of sodium on 

 ammonia, with the same precautions as in the experiments just 

 detailed, a tray, and the same tube of platina being employed. 

 3*3 grains of sodium I found absorbed 9*1 of am- 

 monia, and produced about 4'5 of hidrogen ; and the 

 fusible substance, which was very similar to that from 

 potassium, distilled, did not give off ^ of the ammonia 

 that had disappeared ; and this small quantity I am 

 inclined to attribute to the presence of moisture. The 

 permanent gas produced equalled twelve cubical inches ; 



and, 



