Mr Herschel on the Hyposulplmrous Acid, 
40 grains, in a less stale of purity, were ignited in a glass 
tube blown into a bulb and coated, the extremity being plunged 
under mercury. A copious evolution of sulphuretted hydrogen 
in great purity took place on the first impression of the heat, 
which, reduced to the temperature and pressure SO inches 
at perfect dryness, equalled 2643 grain measures, or 4.09 grains 
(10.21 per cent.) taking 1.1912 for the specific gravity of this 
gas, and for that of dry atmospheric air. This quantity 
contains 9.57 sulphur, and 0.64 hydrogen. The tube weighed, 
well washed out with muriatic acid and dried, lost 23.7 grains 
(59.25 per cent.), which is the weight of the residue ; while, in 
another experiment, 15 grains of the crysttils left 8.99, or 60.00 
per cent. This residue was of a pinkish white colour, and retained 
exactly the shape of the crystals. Abundance of water distilled 
over. These results give, for the ultimate component parts, 
Lime, 42.9 
Sulphur, 26.0 viz. 9.57 in the sulphuretted hyd. -f 16.39 in 
Hydrogen, 0.6 residue after ignition. 
69.5 
30.5 water and loss. 
100.0 
Now, if we calculate on the atomic composition of the sub« 
stance, as being 2L-}-(2S-f-H) neglecting its water of crystalli-* 
zation, we shall find these 69.5 parts to consist of 
Lime, 43.92 
bisulphuretted hydrogen. 
69.50 
With regard to the water, as it was not actually collected, 
the estimation 30.5 per cent, may be somewhat erroneous. W ere 
it 28.75 per cent, it would exactly agree with 4 atoms water 
(4 W.) ; and the difficulty of procuring the crystals in any de« 
finite state as to dryness or integrity of composition, admits an 
error to even a larger extent. Calculating the composition^ 
then, from the formula 2 L -r ^ -f H) -f- W, we have 
