38 Mr. Davy’s Lecture on the Decomposition and Composition 
was surprised to find that the weight of the hydrogene and 
nitrogene produced, rather exceeded than fell short of that of 
the ammonia considered as decomposed, which was evidently 
contradictory to the idea of its containing oxygene. This cir- 
cumstance, as well as the want of coincidence between the 
results and those of Priestley and Van Marum on the same 
subject, induced me to repeat the process of the electrization 
of ammonia, and I soon found that the quantities of the pro- 
ducts in their relations to the apparent quantity of gas de- 
stroyed were influenced by many different causes. 
Ammonia procured over dry mercury from a mixture of 
dry lime and muriate of ammonia, I found deposited moisture 
upon the sides of the vessel in which it was collected, and in 
passing the gas into the tube for electrization, it was not easy 
to avoid introducing some of this moisture, which must have 
been a saturated solution of ammonia, at the same time. 
In my first trials made upon gas, passed immediately from 
the vessel in which it had been collected into the apparatus, 
I found the expansion of 1 of ammonia vary in different in- 
stances from 2.8 to 2.2 measures, but the proportions of the 
nitrogene and hydrogene appeared uniform, as determined by 
detonation of the mixed gas with oxygene, and nearly as 1 to 
3 in volume. 
To exclude free moisture entirely, I carefully prepared 
ammonia in a mercurial airholder, and after it had been some 
hours at rest, passed a quantity of it into the tube for decom- 
position, which had been filled with dry mercury. In this case 
50 parts became 103 parts by electrization, and there was 
still reason to suspect sources of error. 
I had used iron wires not perfectly free from rust, for 
