1814.] On the Cause of Chemical Proportions. 61 



shows that thev are not absolutely exact. If we take them for the 

 base of our calculation, we find that 100 of carbonic acid combines 

 ^ith 506-83 of oxide of lead, which oxide contains 36"24 parts of 

 oxygen : but 36-J4 X 2 = T-'^^S. This approaches very near the 

 determinations given above. 



M. Clievreul has lately found, by repeating some of my experi- 

 ments on the salts of lead, that carbonate of lead leaves for residue 

 8;i'()5 parts of oxide of lead. Hence it follows that, neglecting 

 tlie humidity, which is very trifling, it contains lG-35 parts of 

 carl)onic acid ; but as M. Clu-vreul prepared his carbonate of lead 

 by passing a current of carbonic acid gas through the solution of 

 subnitrate of lead, it is probable that it contained some subnitrate 

 of lead at a maximum ; at least 1 have found this to be the case, 

 ilven when 1 decomposed in the same manner a solution of sub- 

 acetate of lead, ihe precipitate, though well washed with boih'ng 

 water, contained a j)oitIon of subacetale of lead at a maximum 

 sufficiently great to reduce a part of ilie oxide lo the metallic state 

 when 1 decomposed tlie carbonate by heat. 



If we ado|)t as must exact the composition of carbonic acid as 

 determined by tlie specific gravity of the gases ascertained by Biol, 

 the volume of carbon will weigh "^rt-i: if we adopt Saussure's , 

 experiments, it will weigh /"^-Sll; if mine, 7^'-^> if that of 

 Chcvrcul, 7'^'^ 



7. Ntlricinn, radicle of azote t^). — I have proved in a former 

 paper that nitric acid is composed of 11-71 of nitric radicle and 

 a&'Z^ of oxygen ; and that nitric acid is N -f 6 O. Hence the 

 volume of nitriann must weigh 7^*45 1. If we calculate the 

 weigiit of nitricum from the weight of oxygen and azotic gases, 

 the last of which contains half its volume of oxygen gas, it will be 

 foimd To weigh only 75*5. It is difficult to explain the cause of 

 this diHercnce : for very little variation in the base of these calcu- 

 lations produces a great difference in the result. If, for example, 

 in calculating the specific gravity of azotic gas from the specific 

 gravity of oxygen gas and atmospherical air, we make the volume 

 of azote in air too small, the calculation will give the weight of 

 nitricum too small. On the other hand, if 100 parts of nitrate of 

 lead were to give 67 '4 parts of oxide of lead, instead of 67 '3 or 

 67*31, the volume of nitricum would be exactly "Jb'b. Perhaps 

 both methods are to a certain amount inaccurate. 



1 have endeavoured to prove that azote, or the sub-oxide of 

 nitricum, is composed of N + O ; nitrous oxide, of N -H 2 O ; 

 nitric oxide, or nitrous gas, of N + 3 O; nitrous acid, of N + 4 Oj 

 and nitric acid, of N -I- 6 O. The oxides of nitricum are the first 

 series of oxides of which we know all the degrees. The radicle of 

 ammonia, as I have shewn in a preceding dissertation, is composed 

 of N + 6 H. May it be considered as a compound metal ? 



H. liydro^enium, hydrogen (H). — We know that water is com- 

 posed of 2 volumes of hydrogen and 1 volume of oxygen. Accord- 

 ing to the specific gravity of these gases determined by Biot, the 



