[ 329 3 
not feize on, nor difengage the aqua-fortis from the 
ftronger folution of mercury, though it did in a very 
fmall degree in the weak folution of hlver, fo as to 
let loofe a very little of the filver, which thereby 
caufed the faint clouds. When a drop of the folu- 
tion of mercury was dropped into the diftilled water, 
after a drop of the folution of iilver, it reforbed the 
filver cloud, and made the Vv^ater clear, by means of 
the great proportion of acid aqua-fortis that was in 
it. 
>36. Now in order to make fome eftimate of the very 
fmall quantity of fpirit of fait in thefe fever al diftilied 
waters, I dropped a drop of the folution of filver in- 
to an ounce, or 480 grains of pure rain water, which 
gave no clouds ; but on dropping in a drop of fea- 
water, which weighed a grain, the white clouds 
were hrong. And fince fea-water can dilfolve nine 
times more fait than it has in it; therefore, fuppofing 
the drop to be fo fully impregnated with fait, then 
the fait would be the 480th part of the ounce of 
water. But as there is nine times lefs fait, therefore 
the proportion of the quantity of fpirit of fait will 
be but the 4320th part. And how much lefs muft 
be the proportion of fait in thefe diftilied waters, 
which is not fufficient to make a fenftble impreflion 
on folution of mercury, and but a faint one on much 
diluted folution of filver ? Such diftilied fea-water 
will not therefore probably be unwholfome ; almoft 
all fpring-waters have fome degree of fait in them : 
But if there were more of the fpirit of fait, a very 
fmall quantity of pot-afh, or pearl-aflies, or fait of 
tartar, combined with it, will turn it into common 
fait, th^ quantity of which would be extremely lit- 
tle. 
VoL. 49. U 11 37* 
