[ 339 ] 
7 pennyweights. In the fame matrafs I tried a 
fimilar experiment with nitre; the water was raifed 
through io divifions, by 3 pennyweights of powdered 
nitre; and by 18 more, it flood after the iolutionat 
the 70th divifion from the firft mark, and confe- 
quently rofe through fix times the fpace, through 
which it had been raifed by 3 pennyweights. From 
thefe, and other experiments of the fame kind, I am 
difpofed to believe that equal portions of fait produce 
equal augmentations in the bulk of the water wherein 
they are dilfolved ; at leaft, this holds true when the 
fait dilfolved bears but a fmall proportion to what 
would be requifite to faturate the water. But, in 
making this experiment, great care muft be taken to 
keep the falts of the fame drynels ; I had once tried 
it with three equal quantities of fea fait, and arrived 
at a quite different conclufion ; the increafes of bulk 
occafioned by the folution of the feveral falts being 
feparately taken, as 15, 16, 17, but the fait being 
much drier than the air in the laboratory, had un- 
doubtedly attracted the humidity, and that portion 
had attra&ed the moft which had been the longeft in 
it, and which was laft dilfolved. Nor fhould the 
temperature of the water be negledted ; a fenfible 
error may proceed from a minute change in that. 
This experiment confirms the firft, for, was any part 
of fait abforbed into the pores of the water, it cer- 
tainly ought to be expedited that the elevation oc- 
cafioned by the folution of 3 pennyweights of 
nitre fhould be lefs than 4-th of that occafioned by 
18 pennyweights, and yet I found it to be accurately 
4-th upon repeating the experiment with diftilled 
water. It confirms it too in another view, 3 penny- 
X x 2 weights 
