3 
portion, the ratio in four different experiments being nearly 
as 28 volumes of ammonia to 23 of hydrogen. These results 
were obtained by first drying the amalgam with bibulous 
paper, then introducing it into a tube containing a little 
mercury, closing the tube with the finger, agitating it for 
some minutes with the enclosed air, opening the tube after 
inversion in mercury, measuring the ammonia by absorbing 
with water, and determining eudiometrically the hydrogen 
mixed with the residual air. The amalgam was afterwards 
described by Thenard, in his Trait-4 cle Cliimie * under the 
name of “ ammoniacal hydride of mercury.” 
It is interesting to observe that in 1816 Ampere; f in the 
passage where the now universally received views on the 
constitution of ammoniacal compounds are first propounded, 
refers to the amalgam. Speaking of the difficulty of 
assimilating the constitution of ammoniacal to metallic 
salts, he remarks — “ This difficulty would disappear if we 
admit that, just as cyanogen, although a compound body, 
exhihits all the properties of the simple bodies which are 
capable of acidifying hydrogen, so the combination of one 
volume of nitrogen and four volumes of hydrogen which is 
united to mercury in the amalgam discovered by M. See- 
beck, and to chlorine in the liydroclilorate of ammonia, 
behaves in all the compounds which it forms like the simple 
metallic substances.” This theory was more fully developed 
by Berzelius and was soon generally received, except as re- 
gards the amalgam, concerning which various conflicting 
opinions were entertained. Daniell, j for example, speaks of 
it as a mere mixture of mercury and gases resulting from the 
cohesion of the mercury and the adhesion to it of the gases, 
and he cites the absorption of oxygen by melted silver as a 
similar case. 
* Yol. II. p. 162, 3me ed. 
f Annciles cle Cliimie et de Physique, IT. 16, Note, 
% Chemical Philosophy , p. 420. 
