SULPHURIC ACID FOR WATER. 357 
200 grains of the acid, sp. gr. 1.8428, diluted in 
the manner described before, with 23.3 grains of 
water (23 grains being the quantity with which 
the 200 grains of acid were in a state of dilution 
at the conclusion of the experiment in the other 
instance, ) and into another dish 200 grains of the 
acid without being diluted. Both dishes were 
kept under the exhausted receiver as before. On 
the 29th September the diluted acid was found to 
have lost 1.3 grain; on the 6th October, 1.7 
grain ; and on the 13th, 2.4 grains: on the 20th 
and 27th, the weight was exactly the same as on 
the 13th ; the concentration being evidently car- 
ried to as high a degree as the evaporating agency 
of anhydrous space, under the circumstances of 
the case, would admit of. 
Now, by deducting 2.4 from 23.3, we find that 
the quantity of water which the 200 grains of 
concentrated acid retained is 20.9 grains, or that 
100 grains of the acid retained 10.45 grains of 
the water added. Admitting that the concen- 
trated acid contained 79 per cent. real, it must 
also have contained 21 per cent. of water :—we 
then have 21+10.45=31.45 the total quantity of 
water diluting 79 real acid at the conclusion of 
the experiment; and 79 + 31.45 = 110.45 the 
