on various Objects, 1$ 



the moment of the explosion by the electrical discharge, 

 the sudden expansions and contractions might occasion 

 some momentary communication with the external air 

 through the aperture ; and I resolved to make the experi- 

 ments in a method by which the atmosphere was entirely 

 excluded. This was easily done by plunging the whole of 

 the apparatus, except the upper parts of the communicating 

 wires, under oil, and carrying on the process as before. In 

 this experiment the residuum did not seem to increase 

 quite so fast as in the former one. It was carried on for 

 nearly two months. After 310 explosions, the permanent 

 gas equalled -£fo of a cubical inch. It was carefully exa- 

 mined : six measures of it, detonated with three measures 

 of oxygen, diminished to rather less than one measure ; — a 

 result which seems to show, that nitrogen is not formed 

 during the electrical decomposition and recomposition of 

 water, and that the residual gas is hydrogen. That the 

 hydrogen 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 oxygen, hydrogen, and nitrogen, 

 lead directly to the conclusion, that the nitrous acid some- 

 times generated in experiments on the production of water, 

 owes its origin to nitrogen, mixed with the oxygen and 

 hydrogen, and is never produced from those two gases 

 alone. In the Bakerian lecture for 1806, I have stated 

 several facts, which seem to show that the nitrous acid, 

 which appears in many processes of the Voltaic electrization 

 of water, cannot be formed, unless nitrogen 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 assertion, that both acids and alkalies may be pro- 

 duced from pure water, has again been repeated*. The 

 energy with which the large Voltaic apparatus, recently 

 constructed in the Royal Institution, acts upon water, en- 

 abled me to put this question to a more decided test than 

 was before in my power. J had formerly found in an ex- 

 periment, in which pure water was electrified in two gold 

 cones in hydrogen gas, that no nitrous acid nor alkali was 

 formed. It might be said, that in this case the presence of 

 hydrogen dissolved in the water, would prevent nitrous 

 acid from appearing; I therefore made two series of ex- 

 periments, one in a jar filled with oxygen gas, and the 



* Nicholson's Journal, Augutt 1809, p. 258. 



B 2 other 



