17 
Mr Herschel on the HyposulpJiurons Acid. 
insoluble, not being absolutely so, and 2.61 grains sulphate of 
silver were thus collected. Now, the hyposulphurous acid con- 
tained in 2.66 grains of the crystallized salt, would, by the last 
experiment, have afforded this quantity, which amount must 
therefore be deducted from the 114.27 grains present in 500 
grains of the standard solution, leaving 111.61, to which the 
precipitate obtained is equivalent, Hence, 100 parts crystal- 
lized hyposulphite of lime, are equivalent to 121.77 parts hyposul- 
phite of lead. But these have been shown to contain 21.75 lime, 
taking a mean of the three foregoing estimations ; and from these 
data, without knowing the composition of the precipitate (from 
the fact that the liquid, neutral before precipitation, continues 
so after), we may deduce at once the composition and weight of 
the acid ; for, the number representing lime being L=35.5, 
while that of litharge is /==139.5, we have, supposing x the 
number of the acid, 
whence, 
Z-f^’_121.77 
L 21.75 
for the 
21.75 
35.5 
121 77 
number representing hyposulphurous acid, and 
=36.32 for the quantity of it united with the lime of 
the hyposulphite. Thus our result will be, from experiment alone. 
Lime, - - 21.75 
Hyposulphurous acid, (36.32 
Water, - 42.01 
100.08 
But, as the acid is evidently a definite compound of sulphur 
and oxygen, and it is impossible the above experiments can err so 
widely as 1 per cent., we are authorised to take 60 for the value 
of X, (which an infinitely less error in the analysis would give it,) and 
the only atomic compounds we can form to produce this number, 
being 2 8+20=40 4- 20 =60, and S + 40r=20+40=60, the lat- 
ter of which is excluded by all the characters of the compounds in 
question; we have 28 + 20 or 2(8+0) for the composition of 
the acid in this state of union with bases, that is, two atoms of acid 
VOL. I. NO. I. JUNE 1819- 
B 
