58 Mr. Davy’s Lecture on some new analytical Researches 
soluble in t^drogene ; but, under common circumstances, hy- 
drogene does not seem to be absorbable by potassium. 
moisture suspended in the hydrogene, and to consider it as a triple compound of potas- 
sium, oxygene, and hydrogene. 
When potassium is heated in a gas containing hydrogene, and from to of 
common air, it is formed in greater quantities, and a crust of it covers the metal, and 
in the process there is an absorption both of hydrogene and oxygene. It is likewise 
produced in experiments on the generation of potassium by exposing potash to ignited 
iron, at the time (I believe) that common air is admitted, during the cooling of the 
tube. 
It is non-conducting, inflames spontaneously in air, and produces potash and aque- 
ous vapour by its combustion. 
When potassium is heated in hydrogene in a flint glass retort, or even for a great 
length of time in a green glass retort, there is an absorption of the gas ; but this is 
independent of the presence of potassium, and is owing to the action of the metallic 
oxides in the glass upon the hydrogene. 
If a solid compound of hydrogene and potassium could be formed, we might ex- 
pect its existence in the experiment with the gun barrel, in which potassium is ex- 
posed to hydrogene at almost every temperature ; but the metal formed in this 
process, when proper precautions are taken to exclude carbonaceous matters, is uni- 
form in its properties, and generates for equal quantities, equal proportions of hydro- 
gene by the action of water. 
The general phenomena of this operation, shew indeed that the solution of potassium 
in hydrogene is intimately connected with the general principle of the decomposition, 
and confirm my first idea of the action of the two bodies. 
Hydrogene dissolves a large quantity of potassium by heat, but the greater portion 
is precipitated on cooling. The attractions which determine the chemical change, seem 
to be that of iron for oxygene, of iron for potassium, and of hydrogene for potassium ; 
and in experiments, in which a very intense heat is used for the production of potas- 
sium by iron, I have often found, that the gas which comes over, though it has passed 
through a tube cooled by ice, inflames spontaneously in the atmosphere, and burns 
with a most brilliant light which is purple at the edges, and throws off a dense 
vapour containing potash. 
Sodium appears to be almost insoluble in hydrogene, and this seems to be one 
reason why it cannot be obtained, except in very minute quantities, in the experi- 
ment with the gun barrel. 
Sodium, though scarcely capable of being dissolved in hydrogene alone, seems to be 
