the compounds of chromium. 169 
and sulphurous add is driven off, at least if heat be applied 
to the liquid. A careful analysis of this salt gave its consti- 
tuents as follows : 
1 atom hyposulphurous acid - - 5 
1 atom soda - - 4 
4 atoms water - - - - 4 5 
i3'5 
It is obvious, that the hyposulphurous acid in this salt is a 
compound of 2 atoms sulphur and one atom oxygen, and 
that its atomic weight is 5. It is equally obvious, that the 
hydrosulphuret employed in its fabrication contains not sul- 
phuretted hydrogen, but bisulphuretted hydrogen. 
For, let us suppose a mixture to be made of 14- 875 of the 
hydrosulphuret of soda and 4 sulphurous acid, 2 of sulphur will 
precipitate, and a neutral hyposulphite of soda will be formed. 
14-875 hydrosulphuret contain 2 atoms sulphur and only 
1 atom hydrogen. There remain in solution (as half the 
sulphur falls) 1 atom sulphur -j- 1 atom hydrogen. 
The 4 sulphurous acid are composed of 1 atom sulphur 
2 atoms oxygen. 
One of these atoms of oxygen in the sulphurous acid will 
combine with the atom of hydrogen in the hydrosulphuret, 
and form water ; so that there remain for the constituents of 
the hyposulphurous acid, 
2 atoms sulphur = 4 
1 atom oxygen = 1 
5 
There cannot have been more than 1 atom of hydrogen in 
the hydrosulphuret. For had there been two atoms, consti- 
mdcccxxvii. Z 
