SULPHURIC ACID FOR WATER. 367 
of the same temperature. In opposition how- 
ever, to this conclusion may perhaps be urged 
the apparent probability that the air was never, 
during the whole course of the experiment, ren- 
dered really anhydrous ; that the concentrated 
acid might be incapable of depriving it of all its 
water, though it might be able to take some from 
it, and thereby give it a drying power great 
enough to cause it slowly to take water from the 
diluted acid, until the latter had acquired that 
degree of concentration which it was found to be 
of at the end of the experiment: but, bearing in 
mind that the maximum temperature to which the 
experiment was exposed, from the 23d to the 30th 
March, was such as would have been expected to 
give the space, if anhydrous, occupied by the air, 
a drying power equal to 0.46 of an inch of mer- 
cury, the experiments which I shall now mention 
will, I think, sufficiently show, that the concen- 
trated acid was capable of depriving the air, or 
the space it occupied, of all its water, and of 
giving it the extreme evaporating force its tem- 
perature would admit of. 
EXPERIMENT V. 
I diluted 100 grains of the concentrated acid, 
sp. gr. 1.8428, in a dish of 2} inches in diameter, 
