500 On the Analysis of the 
gas, a property discovered by Dr. Priestley, 
but first applied to the purpose of its analysis 
by Sir H. Davy, in the course of his researches 
into the compounds of nitrogen.(a) In the 
experiments of that philosopher, the results, 
approaching most nearly to precision, were 
obtained by detonating nitrous oxide with 
rather more than an equal volume of hydro- 
gen, viz. 39 measures of the former to 40 of 
the latter. Both gases were in this case de- 
composed ; water was produced; no nitrous 
acid was formed; anda volume of nitrogen 
remained, which always a little exceeded 
that of the nitrous oxide decomposed, viz. 
in the proportion of about 41 to 39. 
In the repetitions which I have frequently 
made of this experiment, a similar excess 
of the accruing nitrogen, over the volume of 
the nitrous oxide employed, has always been 
observed, and generally in about the same 
proportion. But according to the law re- 
gulating the combination of gaseous bodies 
with each other, which has been deduced by ~ 
M. Gay Lussac from a great variety of ex- — 
amples, (b) all tending to shew, that gases ’ 
unite in proportions as to volume, which are 
(a) Davy’s Researches, London 1800 p. 286. 
(b) Mémoires de la Soc. d’ Arcueil 11. 207. 
