415 
ARTICLE XIV. 
On the Nature of Aqua Regia, on Hyponitric Acid as an oxidi- 
zing agent, on the Constitution of that Acid, and the part which 
it acts towards Organic Substances. By Dr. Kane, Pro- 
JSessor of Chemistry in Brussels*. 
[From Poggendorff's Annalen der Physik und Chemie, 1845, No. 3.} 
1. AMONG the most powerful agents for oxidizing, acidifying 
or dissolving a large number of simple and compound bodies, 
aqua regia occupies the first place. Nevertheless this liquid, so 
important for the above purposes and so interesting on account 
of the phenomena which accompany them, is one of those whose 
nature is but very imperfectly known. 
2. Berthollet ascribes the properties of agua regia to the 
formation of chlorine and nitrous acid, 
3. This view was adopted by Sir Humphry Davy, who ob- 
tained a liquid by the addition of hydrochloric acid to nitrous 
acid, which did not possess the properties of agua regia. But 
at the time when Davy made this experiment the hyponitric acid 
was not yet known. The English chemist may therefore have 
very possibly worked with this acid, since several French chemists, 
following M. Dumas, look upon it as a compound radical, and 
as a less powerful oxidizing agent than nitric acid, and capable 
of replacing hydrogen in some organic substances which contain 
more than 1 equivalent of that metalloid. 
4. Lastly, M. Millon considers the nitrous acid to be the 
most powerful oxidizing agent of the different oxides of nitrogen, 
an hypothesis which leads to the assumption that the hydrogen 
of the hydrochloric acid is capable of destroying the nitrous acid, 
since the same metalloid deoxidizes nitric acid. 
5. The point then to be ascertained, is whether hydrochloric 
acid reduces nitric acid to hyponitric acid, to nitrous acid, or to 
nitric oxide. 
6. If it were decidedly proved that nitrous acid was the most 
powerful oxidizing agent of the three oxyacids of nitrogen, the 
last hypothesis might deserve the preference. But if we bear in 
* Tranelated by W. Francis, Ph. D., F.L.S. 
