£56 ACTION OF POTASSIUM ON AMMONIA. 



ammonia when exposed to air, and is considerably lighter 

 than potassium. 



Potassium does j at first thought, that a solid compound of hiuWen and 

 not a^suib hi- ... . . 



drogen, bir is potassium might be generated in the first part of this opera* 

 soluble in it tj on . Du t experiments on the immediate action of potassium 

 and hidrogen did not favour this opinion. Potassium, as 

 1 ventured to conclude in the Bakerian Lecture for 1807*, 



is 



Hidrogen said * ^- ^- ^ a y Litssac and Thenard seem to be of a different opinion, 

 to be absorbed In the Moniteur, to which I have so often referred, it is related, thaf 

 by potassium, these distinguished chemists, by exposing hidrogen to potassium at 

 a high temperature, found that the hidrogen was absorbed, and that it 

 formed a compound with the potassium of a light gray colour, from 

 which hidrogen was capable of being obtained by the action of water 

 or mercury. 

 Not in Mr. After a number of trials, I have not been able to witness this result. 



Davy's expeti- In an experiment which I made in the presence of Mr. Pepys, and 

 ments. which I have often repeated, and twice before a numerous assembly^ 



in retorts of plate glass, four grains of potassium were heated in four- 

 teen cubical inches of pure hidrogen. At first, white fumes arose and 

 precipitated themselves in the neck of the retort. When a consider- 

 able film of the precipitate had collected, its colour appeared a bright 

 gray, and after the first two or three minutes, it ceased to be formed. 



The bottom of the retort was heated to redness, when the potassium 

 began to sublime and condense on the sides. 



The process was stopped, and the retort suffered to cool. The ab- 

 sorption was not equal to a quarter of a cubical inch.' YVken the re- 

 tort was broken, the gas, in passing into the atmosphere, produced an 

 explosion with most vivid light, arid white fumes. The petassium re- 

 maining in the retort, and that which had sublimed, seemed unaltered 

 in their properties. 



The grayish substance inflamed by the action of water, but did not 



seem to be combined with mercury. I am inclined to attribute its 



, formation to the agency of moisture suspended in the hidrogen, and to 



consider it as a triple compound of potassium, oxigen, and hidrogen. 



Potassium When potassium is heated in a gas containing hidrogen, and from 



heated in hi- ^ to \ f coramon a i r> it is formed in greater quantities, and a crust 



rogen. of J it covers t | ie nieta ] > and in the process there is an absorption both of 



hidrogen and oxigen. 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 nonconducting, inflames spontaneously in air, and produces pot- 

 ash and aqueous vapour by its combustion. 



When 



