on the Chemical Compounds of Azote and Oxygen, &c. 247 



Agreeably to my experience, nitrous gas consists of one mea- 

 sure of azote and one of oxvgen, and tiie latter affords two piu- 

 ticles to everv one of the former so as to constitute an atom. 



When nitrous gas and nitrous oxide are mixed, they only dif- 

 fuse through each other mechanically; for tlie nitrous gas retains 

 its second particle of oxvgen with as great force as the other 

 gas can attract it — therefore no change can be produced. None 

 of those gases possess an acid property. 



The third compound of those elements is called subnitrous 

 acid; it is what I distinguished in mv Coviparaiive F'leu' by the 

 name red nitrous acid, irom its red colour. Tiiis acid according 

 to Mr. Dalton consists of 100 of azove and 186 of oxygen by 

 measure, and the atom is represented by his diagram or symbol 

 as consisting of three ultimate particles of oxygen and two of 

 azote. Let us examine those proportions : — In the first place, 

 150 measures of oxvgen would supply everv particle in 100 of 

 azote with three particles of oxygen ; there remains therefore a 

 surplus of 36 measures of oxygen. As to the second particle of 

 azote, I cannot conceive whence it came or how supplied, unless 

 indeed the atoms were cloven in two. 



This acid, according to my experiments, contains one mea- 

 sure and a half of oxygen and one of azote ; and the atom, as re- 

 presented in my Cornparalive Fieu, consists of one particle of 

 azote and three of oxygen. It is difficult to obtain this a acid 

 pure ; that is, free from the pale or straw-coloured nitrous acid 

 which will be described presently. It is obtained in a tolerable 

 degree of purity when nitrous gas is mixed in excess with at- 

 niosj^heric air, or when nitrous gas is passed into nitric acid 

 until it is incapai<le of receiving auv more. This acid can exist 

 in the gaseous state w iien excluded from water. 



The next and fourth compound is distinguished by the name 

 of nitrous acid gas by some modern chemists. I called it in my 

 Comparative Fiew, pale or stravv-cq^oured nitrous acid, from its 

 colour. Mr. Dalton supposes this acid to consist of 100 of 

 azote and 248 of oxygen by measure. The 200 alone, laying 

 aside the 48 measures of oxygen, would snppiy every jiarticle of 

 the azote with four particles of oxygen ; and \et, to my very great 

 surprise, Mr, Daltou's symbol represents the atom of this acid 

 a.s consisting of one particle of azote and two of oxjgen, the 

 proportions which the atom of nitrous gas contains. 



In my Comparative View I represented the atom of this acid, 

 by means of a diagram, as consisting of one particle of azote and 

 four of oxygen. 



It is very difficult to obtain this acid pure; for in the common 



way of distillation it comes over with more or less of red nitrous 



acid, or with a mixture of nitric acid. This acid is produced by 



Q 4 mixing 



