2 
This discovery they communicated to Davy early in June, 
1808, declaring their conviction that ammonia, like potash 
and soda, must he an oxide, and that the new substance 
was a combination of its metallic constituent with mercury. 
Davy* immediately commenced a series of elaborate experi- 
ments 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 basis 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 ammonia, 
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 Thenar d*f* investiga- 
ted 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 hydrogen gases in the 
proportion of 2 \ volumes to 1. But the electrically pre- 
pared substance gave off the gases in quite another pro- 
* Phil. Trans., 1808, p. 355. 
t Pecherches Physico- Chimi ques, I. 52, 
