52 Mr . Davy's Experiments on 
contain metallic matter united to oxygene : and the results of 
the distillation of the fusible substance, from potassium and 
ammonia, notwithstanding the objections I have made, can 
perhaps be explained on such a supposition. 
I have made a number of experiments upon the decompo- 
sition of considerable quantities of ammonia, both by Voltaic 
and common electricity ; and I have used an apparatus (of 
which a figure is attached to this paper, ) in which nothing was 
present but the gas, the metals for conveying the electricity, 
and glass. The ammonia was introduced by a stopcock which 
was cleared of common air, into a globe that was exhausted, 
after being filled two or three times with ammonia : the gas 
that was used was absolutely pure, the decomposition was 
performed without any possibility of change in the volume of 
the elastic matter, and the apparatus was such, that the gas 
could be exposed to a freezing mixture, and the whole weighed 
before, and after the experiment. 
The object in keeping the volume the same during the de- 
composition, was to produce the condensation of any aqueous 
vapour, which if formed in small quantity in the operation, 
(on the theory of the mechanical diffusion of vapour in 
gasses,) might in the common case of decomposition, under 
the usual pressure, be in quantity nearly twice as much in the 
hydrogene and nitrogene, as in the ammonia. 
In all instances it was found, that there was no loss of 
weight of the apparatus, nor was there any deposition of 
moisture, during or after the electrization ; but the wires were 
uniformly tarnished ; and in an experiment in which surfaces 
of brass were used, a small quantity of olive coloured matter 
formed on the metal, but though in this case nearly 8 cubical 
