t 344 ] 
matter feems to have been miftaken by many ; how- 
ever, it may be eafily apprehended that the increments 
of fpecific gravity, from the addition of equal quan- 
tities of fait to a given weight of water, ought per- 
petually to decreafe ; becaufe the difference between 
the fpecific gravities of the water and of the fait 
perpetually decreafes, as the water approaches to 
perfedt faturation. In like manner, if to a given 
quantity of water we add any number of equal 
quantities of oil of vitriol, or any fluid mifcible with 
and heavier than water ; the increments of fpecific 
gravity will perpetually decreafe, though they will 
never entirely vanifh, becaufe there is a perpetual 
approximation to the fpecific gravity of the acid, 
which yet the mixture can never acquire ; and, vice 
verfa , if to water we add a lighter fluid, as fpirits of 
wine by equal portions, the fpecific gravity of the 
mixture will conflantly decreafe by unequal decre- 
ments ; but the decrements will never vanifh, becaufe 
the mixture mull; ever remain fpecifically heavier than 
fpirit of wine. 
Experiment IX. 
The quantities of various falts, which may be 
difiolved in a given quantity of water, have been 
afcertained by Boerhaave, Eller, Spielman, and 
others ; their accounts differ fomewhat from one 
another, as might be expected from the different 
temperatures of the air, the different ftate of their 
falts; the different times (a circumftance of no fmall 
confideration in this matter) which they allowed the 
water to adt upon the falts before they concluded it 
to 
I 
