i8 Mr. Davy's Experiments on 
written, I had seen no other account of the experiments of 
the French chemists, than one given in a number of the 
Moniteur, and as this was merely a sketch, which I conceived 
might be imperfect, I did not enter into a minute examination 
of it. I have since seen a detail of their enquiry in the second 
volume of the Mem. d' Arcueil, a copy of which M. Ber- 
thollet has had the goodness to send me, and the publication 
of which is dated June 7, 1809 : and from this detail, it seems 
that they still retain their opinion ; but upon precisely the 
same grounds as those to which I have before referred. 
That no step of the discussion may be lost to the Society, I 
shall venture to state fully their method of operation, and of 
reasoning. 
They say that they heated potassium* in ammonia, and they 
found that a considerable quantity of ammonia was absorbed ; 
and hydrogene produced ; and that the potassium became 
converted into an olive coloured fusible substance ; by heating 
this substance strongly, they obtained three fifths of the am- 
monia again, two fifths as ammonia, one fifth as hydrogene 
and nitrogene ; by adding a little water to the residuum, they 
procured the remaining two fifths, and found in the vessel in 
which the operation was carried on, nothing but potash. — 
Again, it is stated, that by treating a new quantity of metal with 
the ammonia disengaged from the fusible substance, they again 
obtained hydrogene, and an absorption of the ammonia ; and 
by carrying on the operation, they affirm, that they can pro- 
cure from a given quantity of ammonia, more than its volume 
of hydrogene. 
Whence, they ask, can the hydrogene proceed ? — shall it be 
* Mem. d’ Arcueil, Tom. II. page 309. 
