EXPERIMENTS ON THE METALS FROM THE FIXED ALKALIS. 325 



chemists, when the operations are conducted in a refined from cautious 

 and accurate manner. proce. ing. 



In proportion as more precautions are taken to prevent Little ammonia 

 moisture from being communicated to it, so, in proportion, regenerated, 

 is less ammonia regenerated ; and I have seldom obtained 

 as much as T ~ of the quantity absorbed. And I have 

 never procured hidrogcn and nitrogen, in the proportions 

 in which they exist in ammonia; but there has been always and an excess of 

 an excess of nitrogen. $£$" pro " 



The processes which I have detailed in the last Bakerian potassium al- 

 lecture, and iu the appendix to it, show this; and they wa Y s revived. 

 likwise show, that a considerable quantity of potassium is 

 always revived. 



I have lately performed the experiments, in a manner 

 which I proposed page 458 of the last volume of the 

 Transactions*, and the results have been very satisfactory; 

 as far as they relate to the question of the nature of 1 

 potassium. 



I employed a tube of platina bored from a single piece, potassium heat- 

 which, having a stop-cock and adaptor of brass, connected ed in ammonia 

 with the mercurial apparatus, could be used as a retort: 

 the potassium was employed in quantities of from 3 to 4 

 grains, and the absorption of the ammonia conducted as 

 usual, in a retort of glass free from metallic oxides : and 

 in a tray of platina. 



In some of the processes, in which the heat was rapidly rapidly, 

 applied, some of the gray matter, which I have formerly 

 described as a pyrophorus, passed over in distillation ; and 

 in these cases, there Mas a considerable deficiency of hydro* 

 gen, as well as nitrogen, in the results of the experiment. 

 But when the heat was very slowly raised, the loss was and vety slowly, 

 much less considerable, and in several cases, I obtained 

 more than four fifths of the potassium, which had been em- 

 ployed; and very nearly the whole of the nitrogen, ex- 

 isting in the ammonia that had been acted upon. 



I shall give an account of one process, conducted with Experiment 

 scrupulous attention. The barometer was at 30*2 in. ; 

 thermometer at 54* Fahrenheit. Three grains and a 



* Journal, vol. xxv, p. 143» 



half 



