COMPOSITION OF AMMONIUM AMALGAM. 171 



This discovery they communicated to Davy early in June 

 1808, declaring their conviction that ammonia, like potash 

 and soda, must be an oxide, and that the new substance 

 was a combination of its metallic constituent with mercury. 

 Davy immediately commenced a series of elaborate expe- 

 riments on the production and properties of the amalgam ; 

 and in an account of these experiments laid before the 

 Royal Society in the same month* he first uses the name 

 ammonium to indicate the supposed metallic base of am- 

 monia. So convinced was Davy that the substance united 

 with mercury in the amalgam was of a metallic nature, 

 and that by combining with oxygen it constituted am- 

 monia, that he was inclined to view nitrogen and hydrogen, 

 if not as oxides of metals, at least as metallic gases. 



Davy discovered that the ammonium amalgam was 

 readily produced when an amalgam of potassium was made 

 to act on moistened sal-ammoniac. He found that the 

 electrically prepared amalgam, when introduced into a 

 tube, rapidly evolved gas, which he describes as consisting 

 of " about two thirds to three fourths of ammonia, and the 

 remainder hydrogen." In another experiment, amalgam 

 obtained by potassium was moistened with strong liquid 

 ammonia, and when heated in a tube generated gas which 

 was proved to consist of two thirds ammonia and one 

 third hydrogen. 



In the following year Gay-Lussac and Thenardf investi- 

 gated the ammonium amalgam, and were led to regard it 

 as a triple compound of mercury, ammonia, and hydrogen. 

 They found, on putting some of the amalgam prepared by 

 potassium into a tube which was filled up with mercury 

 and then inverted in a vessel of that liquid, that the 

 amalgam gave off, in decomposing, ammonia and hydro- 

 gen gases in the proportion of i\ volumes to i. But the 



* Phil. Trans. 1808, p. 355. 



t Recherches Physico-Chimiques, i. p. 52. 



