ON THE COMPOUNDS OP SX:LPHUR AND OXYGEN. t)5 



abforbs rather more than eight parts of it by weight. Perhaps 

 this difference was owing to the prefence of the fulphuric acid 

 in the liquid. For water, (lightly acidulated with fulphuric 

 acid, abforbs a fmaller proportion of gas, than pure water. 



5. After trying various experiments, in order to afcertain Arialyfis of ful- 

 the confiituents of fulphurous acid, I found the following P^"'^ous acid, 

 method moft to be depended on. 



Sulphite of potaOi was obtained by Bertholiet's method. Sulphite of pot- 

 It is a fine white fait, the properties of which have been verv"'^. ^°f" <°'"f 



f 11 1 •! 1 1 T-. ^ weight by a lovf 



hilly detailed by Fourcroy and Vauquelin, though they haveheat: by igni- 

 neglected to analyfe it. tionitlo(es2».3. 



When this fait is expofed for a few minutes to a heat of add with "he al- 

 300°, it lofes 3.3 per cent, of its weight; and fufTers no ad- ''^'''"^e left, 

 ditional lofs, though the heat be continued for an hour. 

 When heated to rednefs in a platinum crucible, it decrepi- 

 tates, becomes of an opake white, a blue flame iffues from 

 below the lid, and, on taking off the cover at that inftant, 

 the fait may be obferved of a glowing red heat in the middle. 

 When tliis glow difappears, tiie fait will be found to have fuf- 

 tained a lofs of 22.3. per cent, and it lofes no more, though 

 melted, and kept half an hourinfufion. On evolving, it fplits 

 into the fine thin tranfparent plates, which diflinguifli fulphate of 

 potath in the lame circumfcances. Wiien this refidue is dif- 

 folved in water, and treated with muriate of barytes, this 

 precipitate of fulpliate of barytes obtained, when dried and 

 heated to rednefs, weighs 95.5, indicating the prefence of 

 22,92 fulphuric acid. Suppofing with M. Chenevix, that 

 fulphate of barytes contains 24' per cent, of fulphuric acid ^ 

 hence it follows that fulphate of polafh is compofed of 



22,30 volatile matt.er 



22.25 fulphuric acid 



55.45 potath 



iOO.OO 

 When 100 grains of fulphate of pofafh were expofed lo (he The volatile 

 heat of a lamp in a retort willi a very long beak, fitted to a ""'""'' '^"'f'?'^' 



. ' •' ° reus gas, with. 



mercurial air holder, they decrepiLated and affumed the ap- feme fuiphur 

 pearance of an opake white powder ; 18 cubic inches of gas a"'^* little water. 

 were extricated, and fuiphur, with a little water, was volati- 

 lized into the beak of the retort ; the gas was abforbed by 

 water, and had the ufual fmell of fulphurous acid : the retort 



had 



