'44 MEM O IR S of the 
appeared a whitifli cloud, which, tho' but flowly, defcended to 
the bottom, and Ihtled there in a white precipitate : The ufe- 
fulnels of this experiment is not to be eilimated only by the 
JEsamen, it helps us to make of dulcified water, but much more 
by the eftimate, that by its means may be made of natural frefh 
waters, whether of Iprings, rivers, clouds, lakes, wells, ^r. for 
it being generally granted, that thofe waters, c ceteris paribuSy 
are the beft, as we;ll for their wholelomenels, as for feveral oeco- 
nomical uies, as wafliing, brewing, ^c. that arc freeft of fait- 
nefs, w^hich is an adventitious, and in moft cafes, a hurtful qua- 
lity in waters; by this way of examining thcie liquors, an atten- 
tive eye may foon difcover, whether there be any latent laltnels 
in them, and one may be enabled, elpecially by a little praflice, 
to give a near guels, how much one water is frefher than another 5 
and after once oblerving, what change four or five drops of the 
precipitant will make in two or three, or any other number of 
Ipoonfuls of water, it will not be difficult to make a near efli- 
mate, whether any natural water propofed to him, have a greater, 
an equal, or a Icfler degree of frei'hnefs or faltnefs, than the water 
chofen for the flandard 5 and how much the propoled liquor is 
more or lefs free from faltnefs than the other , and that luch a 
difference in water may have confiderable efTe^s upon human 
bodies in regard of health, may be probably argued from the 
different effects, that waters more or lels impregnated with fait, 
have upon feveral other bodies 5 fince moft pump-water, for 
inftance, will not boil peafe and beef, and Ibme other things, 
near {o well as fpring or rain-water, which are ufually Ibfter, 
and freer of faltnefs 5 it is commonly known, that the fame pump- 
water will not fo well and uniformly diflblve wafli-balls and Ibap, 
as rain-water, and Ibme running- waters ufually will; and fkilful 
artifls obfervc, that fome tools, as gravers, ^c. would receive a 
different temper, if they were quenched in pump-water, from 
that, which the like extinftion in fprinq-water or river-water 
would give them : But here it may be obje£ted, that the trial was 
made upon water impregnated with grols or corporeal lea-falt, 
which hinders not, but that it may be embued with the fpirits of 
marine fait, which by rcafon of their activity, may be as un- 
healthful to the drinker, as the gr^jffer fait itfelf; but tho', to this 
furmife it muft be anfwered, that a very Irnall proportion of Ipint 
of fait, might in many cafes make the water feafoned therewith, 
•rather medicinal than unwholelome; yet as a more dire6t anlwer, 
Mr. !Boyle took above a thoufand grains of diftilled water, and 
infread of grols fait, he put to them one fingle drop of moderately 
ftrong 
