on the Nature of certain Bodies. 41 
account of various experiments on the amalgam from ammo- 
nia, discovered by Messrs. Berzelius and Pontin, and in a 
note attached to this communication, I ventured to controvert 
an opinion of M. M. Gay Lussac and Thenard, with respect 
to the agency of potassium and ammonia, even on their own 
statement of facts, as detailed in the Moniteur for May 27, 
1808. 
The general obscurity belonging to these refined objects of 
research, their importance and connection with the whole of 
chemical theory, have induced me since that time to apply to 
them no inconsiderable degree of labour and attention ; and 
the results of my inquiries will, I trust, be found not only to 
confirm my former conclusions ; but likewise to offer some 
novel views. 
In the first of these series of operations on the action of 
potassium on ammonia, I used retorts of green glass ; I then 
suspecting oxygene might be derived from the metallic oxides 
in the green glass, employed retorts of plate glass, and last 
of all, I fastened the potassium upon trays of platina, or iron, 
which were introduced into the glass retorts furnished with 
stop cocks. These retorts were exhausted by an excellent air 
pump, they were filled with hydrogene, exhausted a second 
time, and then filled with ammonia from an appropriate mer- 
curial gas holder.* In this way the gas was operated upon 
in a high degree of purity, which was always ascertained ; 
and all the operations performed out of the contact of mer- 
cury, water, or any substances that could interfere with the 
results. 
I at first employed potassium procured by electricity ; but 
* A representation of the instruments and apparatus is annexed. 
MDCCCIX. G 
