S58 Experiments on the Nature of [Nov. 



verted into nitrous gas. According to the results of that cele- 

 brated chemist, the degrees of the oxidation of azote are 1, 2, 

 2-J, 4; but that series dots not correspond with what we have 

 found respecting other oxidable bodies. This consideration 

 renders Gay-Lussac's determination of the composition of nitrous 

 acid doubtful. 



Mr. Dalton {New System of Chemical Philosophy, ii. 231,) 

 dele-mines the constituents of this acid to be 32'7 azote and 

 6"7*3 oxygen. This is a greater proportion of oxygen than Gay- 

 Lussac obtained. According to the ingenious manner of Mr. 

 Dalton of expressing chemical compounds, nitrous acid is com- 

 posed of 2 atoms of azote and 3 of oxygen ; but there is a 

 strong objection against this hypothetical estimation. If we 

 suppose a combination of 2 atoms of one body with 3 of 

 another, we have equal reason to suppose the possibility of a 

 combination of 3 atoms with 4, 5 with 6, &c. By thus in- 

 creasing the number of atoms of each body united as much as 

 the possibility of mutual contact will permit, we extend the 

 bounds of chemical proportions indeed, but almost entirely 

 destroy the doctrine of determinate proportions. 



Among the experiments to determine the composition of 

 nitrous acid, Mr. Dalton states, that the greatest quantity of 

 nitrous gas, which one volume of oxygen gas is able to condense, 

 amounts to 3*6 volumes. This determination deserves the more 

 attention, because we shall find that it exhibits the real consti- 

 tution of nitrous acid. 



Sir Humphry Davy in his Elements of Chemical Philosophy, 

 (vol i. p. 265,) informs us, that, from experiments made on 

 purpose, he considers nitrous acid as composed of 4 volumes of 

 oxygen gas and 1 volume of azotic gas. According to this 

 observation, the degrees of oxidation of azote will be 1, 2, 4, 

 5 ; but in this series we do not find the number 3, a combina- 

 tion which would certainly have appeared had the series been 

 exact. 



I published myself a set of experiments on the composition 

 of nitrous acid ; and as I set out from another point, I had 

 different results from those which I have stated. 1 examined 

 different combinations of nitrous acid with saline bases, and 

 especially with the oxide of lead [Ann. de Chun. July, 1812,) a 

 class of salts before that time almost wholly unknown. These 

 experiments prove, 1. That the nitrous acid forms with the oxide 

 of lead three different compounds, namely, a neutral nitrite and 

 two subsalts, in one of which the acid is combined with twice as 

 much base as in the neutral nitrite. This circumstance proves 

 that the acid must contain a quantity of oxygen, which is a 

 multiple of the oxygen in the base by an even number ; and as 

 that number can neither be 2 nor 6, it must necessarily be 4. 



