398 Progress of Foreign Science. 



2 atoms oxide . . . 5.910, quantity obtained. 

 1 acid . . . 0.703 



0.613 

 6.8 parts had been employed. 



" It follows," says he, " from these analyses, that in the 

 nitrates hitherto examined, the oxygen of the acid is to that of 

 theo.xide, as 5 to 1, 2, 3, 4, 6, 7, 8." 



Of the acidulous nitrates. As we now know the composition 

 of the subnitrates of bismuth and mercury, in order to learn 

 what takes place when the neutral nitrates are decomposed by 

 water, we must examine the proportion between the quantity 

 of oxide precipitated in the state of subnitrate, and that which 

 remains in solution. 



10.142 gr. of crystallized nitrate of bismuth, dried at the 

 fire, to expel as much as possible the excess of acid, were 

 treated with a great quantity of water. There was thus ob- 

 tained — 



5,493 gr. of subnitrate, retaining still a little humidity be- 

 sides the water of combination ; 

 10.142 of neutral nitrate, contain oxide 6.014 3 atoms. 

 5.493 of subnitrate 4.471 2 



3 atoms of neutral nitrate have then let fall 2 atoms of oxide 

 and 1 atom of acid. There remained in solution 1 atom of 

 oxide and 5 atoms of acid. 



16.319 of protonitrate of mercury, well dried, gave 2.491 

 of subnitrate, containing 2.226 of oxide. 



These 16.319 contain 12.972 of oxide. Hence 12 atoms of 

 neutral nitrate afforded 1 atom of subnitrate. Tha water re- 

 tained 10 atoms of oxide and 11 atoms of acid. 



17.950 of deuto-nitrate of mercury, containing 12 of oxide, 

 yielded with cold water 4.622 of subnitrate, containing 4.112 

 of oxide. 



2 atoms of oxide 4.112 precipitated; 



4 8.224 left in the solution. 



Total 12.336 



There has been deposited, therefore, 1 atom of sub-nitrate, 

 while 4 atoms of oxide and 1 1 of acid have been dissolved. 



We perceive that the acidulous nitrate of bismuth is formed 

 of oxide 1 atom, acid 5 atoms ; that of protoxide of mercury, 

 of oxide 10 atoms, acid 11 atoms; that of the deutoxide, of 

 oxide 4 atoms, acid 1 1 atoms ; that is to say, of a quantity of 

 acid in excess over the neutral nitrate, which is by no means 

 proportional to that which constitutes the neutral salt or sub- 

 ealt ; for they would all be composed as follows : — 



