320 



plied, neither potash nor ammonia can be produced ; and if oxygen 

 merely be applied, potash and nitrogen are the result. 



In consequence of the supposition of Messrs. Gay-Lussac and The- 

 nard, that they had formed a compound of potassium and hydrogen, 

 Mr. Davy repeated their experiment frequently, without any success ; 

 neither has he, by any other means, been able to form a compound 

 of hydrogen with potassium. 



In the residuum obtained by heat, after the action of potassium on 

 ammonia, the nitrogen appears to be combined with an oxide of po- 

 tassium, in which the oxygen amounts to about three per cent. By 

 greater heat this compound itself sublimes, and does not yield nitro- 

 gen without the intervention of oxygen ; as if some portion of the 

 latter were essential to the constitution of nitrogen gas. 



Mr. Davy refers to an hypothesis formerly advanced, that all me- 

 tals may possibly be compounds of unknown bases with hydrogen ; 

 but replies to those arguments by which Messrs. Gay-Lussac and 

 Thenard imagined that they had proved the existence of hydrogen in 

 potassium ; for which there appears to be no foundation in fact. Un- 

 til hydrogen can be separated from some metallic substance, until a 

 metal can be deprived of its imflammability by the separation of hy- 

 drogen, that theory must be preferred, which, in explaining all the 

 facts, admits the presence of no ponderable agents of which the ex- 

 istence cannot be proved. 



Mr. Davy next proceeds to an examination of sulphur, first by 

 passing discharges through it in a fluid state from a common electric 

 machine, but afterwards with better success by the voltaic battery, 

 and obtained gas from it in sufficient quantity to ascertain that the 

 gas consists wholly of sulphuretted hydrogen. In the course of the 

 process, the sulphur had acquired the power of reddening litmus. 

 After long-continued electrization, the sulphur became extremely dif- 

 ficult of fusion and acquired a dirty brown colour. 



By the action of potassium on sulphur, sulphuretted hydrogen is 

 also evolved with intense heat and light ; and the circumstances of 

 this operation appear to be similar to what occurs when potassium is 

 heated in contact with resin, camphor, wax, and fixed oils, in close 

 vessels. For in this case also, great heat is generated, and great 

 quantities of carburetted hydrogen evolved. In addition to this 

 analogy in their chemical actions, Mr. Davy also remarks, that the 

 physical qualities of these bodies resemble those of sulphur. 



They agree in being non-conductors, whether fluid or solid ; trans- 

 parent when fluid, but semi-transparent when solid, and highly re- 

 fractive ; but resinous and oily bodies contain a small quantity of 

 hydrogen and oxygen, with a large quantity of carbonaceous matter. 

 So also in sulphur, the mixture of hydrogen is fully proved, and the 

 existence of oxygen might be inferred from the effect of the residual 

 sulphur on litmus paper, but is more distinctly evinced by the for- 

 mation of potash when potassium is heated in sulphuretted hydro- 

 gen. From such experiments as were most to be depended upon, it 



