353 



that both hydrogen and nitrogen are oxides ; but from the action of 

 potassium on ammonia, it would rather appear that nitrogen alone 

 is in that instance decomposed. 



But there is great difficulty in reasoning upon the precise nature 

 of this amalgam, on account of the presence of water, which it is at 

 least extremely difficult to avoid, as the amalgam cannot be formed 

 in dry ammoniacal gas, nor by means of any dry compound of am- 

 monia yet tried. 



The driest amalgam is that formed by an alloy in which potassium 

 is also present. In endeavouring to distil ammonium from this com- 

 pound, there is always a partial regeneration of ammonia mixed with 

 about one third hydrogen ; and if the proportion of oxygen contained 

 in ammonia be inferred from this product, it would appear to be forty- 

 eight per cent., a result which agrees with the quantity which might 

 be presumed to exist in ammonia, from the proportion in which it 

 unites with acids. But if the proportion of hydrogen to ammonia 

 thus evolved be less than that of one to two, the results will not ac- 

 cord ; and then, says Mr. Davy, it may reasonably be supposed that 

 hydrogen and nitrogen are both oxides, either of the same metal or 

 of different metallic bases. But if, instead of endeavouring to accom- 

 modate our general antiphlogistic notions to the peculiar facts re- 

 specting ammonia, we endeavour to frame a phlogistic hypothesis to 

 account for them, we must then suppose nitrogen to be a simple 

 basis, which becomes alkaline with one dose of hydrogen ; and me- 

 tallic, by uniting with some greater proportion of the same element. 



The author next details a variety of experiments, made on several 

 of the earths, for the purpose of decomposing them. The metals of 

 silica, alumina, and glucine, were obtained in alloy with iron ; but it 

 appeared that these metals could not be made either in direct com- 

 bination with mercury, or as a triple alloy with mercury and potas- 

 sium. By passing potassium, however, through the alkaline earths, 

 lime and magnesia, and afterwards introducing mercury, solid triple 

 amalgams were obtained. The triple amalgam from magnesia was 

 easily deprived of its potassium by means of water ; and it then ap- 

 peared as a solid white metallic mass, which by long exposure to air 

 was covered with a crust of magnesia. This section concludes with 

 speculations on the probable quantity of oxygen contained in the 

 earths, founded on Mr. Dalton's law of chemical union by simple 

 particles, which appears to Mr. Davy more near the truth than that 

 modification of it lately observed by M. Gay-Lussac. 



The concluding section of the lecture contains some theoretic con- 

 siderations on the nature of hydrogen in particular, and on the whole 

 class of simple substances in general. 



The fact of hydrogen uniting with tellurium and with sulphur into 

 compounds apparently acid, it is observed, militate strongly against 

 its being simple ; and Mr. Davy inclines to consider it an oxide, of 

 which the base exists in the amalgam of ammonium. Ammonia "will 

 then be the deutoxide of the same base, and nitrogen the tritoxide. 



The class of pure inflammables will on this antiphlogistic hypo- 

 2 A 



