\o Mr. Davyds Experiments on 
seem to increase quite so fast as in the former one. It was 
carried on for nearly two months. After 340 explosions, the 
permanent gas equalled T 2 ^L of a cubical inch. It was care- 
fully examined : six measures of it detonated with 3 measures 
of oxygene, diminished to rather less than 1 measure. A re- 
sult which seems to shew, that nitrogene is not formed during 
the electrical decomposition and recomposition of water, and 
that the residual gas is hydrogene. That the hydrogene is 
in excess, may be easily referred to a slight oxidation of the 
platina. 
The refined experiments of Mr. Cavendish on the defla- 
gration of mixtures of oxygene, hydrogene, and nitrogene, 
lead directly to the conclusion, that the nitrous acid sometimes 
generated in experiments on the production of water, owes 
its origin to nitrogene, mixed with the oxygene and hydro- 
gene, and is never produced from those two gasses alone. In 
the Bakerian lecture for 1806, I have stated several facts, 
which seem to shew that the nitrous acid, which appears in 
many processes of the Voltaic electrization of water, cannot 
be formed, unless nitrogene be present. 
Though in these experiments I endeavoured to guard with 
great care against all causes of mistake, and though I do not 
well see how I could fall into an error, yet I find that the as- 
sertion, that both acids and alkalies may be produced from 
pure water, has again been repeated.* The energy with 
which the large Voltaic apparatus, recently constructed in 
the Royal Institution, acts upon water, enabled me to put this 
question to a more decided test, than was before in my power. 
I had formerly found in an experiment, in which pure water 
* Nicholson’s Journal, August, 1809, p. 258. 
