1817.) during the Year 1816. 15 
Azote. Oxygen. 
1, Air, or protoxide of azote, composed of 1 atom + 1 atom 
2. Nitrous oxide, or deutoxide of azote.. 1 + 2 
ee AIEOUS Pas... Lm We abies ee ase 1 + 4 
a--Nitrie acid ...0c she. pep tial ate ag + 8 
I noticed some months ago Gay-Lussac’s new experiments on 
the compounds of azote and oxygen, His results are— 
Azote. Oxygen. 
1, Nitrous oxide, composed of .... 1 atom + 1 atom 
BPTONS LAS. 6-155 ,5/ 0'0\0' ss grrnbia tl + 2 
SPC EMNILCOUS GOI, jcicre sien suaiaierard + 3 
Se TNIUS DOU OE AL. be are aia al + 4 
Sie AMSREIES ENCE av atath eS cites we beniadcd + 5 
What he calls pernitrous acid is the substance formerly distin- 
guished by the name of nitrous acid. His nitrous acid is the nitrous 
vapour of former chemists. When I gave a sketch of Gay-Lussae’s 
paper in the Annals, (viii. 71), 1 stated that the novelty consisted 
merely in the method of procuring nitrous acid (pernitrous acid of 
Gay-Lussac) in a separate state, and that the opinions considered by 
Gay-Lussac as new had been previously entertained by chemists in 
general. In proof of this 1 quoted what I had myself stated on the 
subject in papers formerly written. M. Gay-Lussac has thought 
proper to quote what I said (Ann. de Chim. et Phys. ii. 182), and 
to draw as an inference that I claimed his discoveries, as having 
Leen previously made by myself. Nothing was further from my 
thoughts than laying any such claim. My object was merely to 
show that the opinions of Gay-Lussac had been already adopted by 
chemists before his paper appeared. 1 might have quoted other 
books on the subject if it had been requisite, some of them of 
rather an old date. Let him consult Davy’s Researches, p. 30; or 
Dobereiner’s paper in Schweigger’s Journal, xiv. 219 ; and he will 
see that my opinion respecting nitrous vapour i§ neither new nor 
singular. 
M. Dulong has lately shown, by direct experiment, that what Gay- 
Lussac considered as pernitrous acid is the same as the nitrous acid 
vapour of former chemists, and that his pernitrous acid may be 
formed directly by uniting together oxygen and nitrous gas. (See 
Ann. de Chim. et Phys. ii. 317.) 
3. Specific Gravity of Gases.—In the Annals, vii. 343, I have 
given a table of the specific gravity of gaseous bodies. Since that 
time M. Gay-Lussac has published a still fuller table (Ann. de 
Chim. et Phys. i. 218). His numbers differ very little from those 
which I had previously given ; and the chief cause of the difference 
is perhaps owing to my having reduced all the densities by caleula- 
tion to the temperature of 60°, which Gay-Lussac seems to have 
neglected. I shall insert his table here for the gratification of my 
readers. 
