20 Mr. Davy’s Experiments on 
The processes which I have detailed in the last Bakerian 
lecture, and in the appendix to it, shew this ; and they like- 
wise shew 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 
potassium. 
I employed a tube of platina bored from a single piece, 
which having a stop-cock and adaptor of brass, connected 
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 
applied, some of the gray matter, which I have formerly 
described as a pyrophorus, passed over in distillation, and in 
these cases, there was a considerable deficiency of hydrogene, 
as well as nitrogene, in the results of the experiment ; but 
when the heat was very slowly raised, the loss was much 
less considerable, and in several cases, I obtained more than 
four fifths of the potassium which had been employed ; and 
very nearly the whole of the nitrogene, existing in the am- 
monia that had been acted upon. 
I shall give an account of one process, conducted with scru- 
pulous attention. The barometer was at 30.2 in *, thermometer 
at 54 0 Fahrenheit. Three grains and a half of potassium 
were heated in 12 cubical inches of ammonia, 7.5 were ab- 
