Hypochondriack, and other ill Effects of the Clayey and other gross
Particles of stagnating Well-waters, and the calculous Concretions of
others; and therefore such waters ought to be mistrusted more than any,
where they are not pure clear and soft or that don't arise from good
Chalks or stony Rocks, that are generally allowed to afford the best of
all the Well sorts.

Spring-waters are in general liable to partake of those minerals thro'
which they pass, and are salubrious or mischievous accordingly. At
_Uppingham_ in _Rutland_, their water is said to come off an
Allum-rock, and so tints their Beer with its saline Quality, that it is
easily tasted at the first Draught. And at _Dean_ in _Northamptonshire_, I
have seen the very Stones colour the rusty Iron by the constant running of
a Spring-water; but that which will Lather with Soap, or such soft water
that percolates through Chalk, or a Grey Fire-stone, is generally
accounted best, for Chalks in this respect excell all other Earths, in
that it administers nothing unwholsome to the perfluent waters, but
undoubtedly absorps by its drying spungy Quality any ill minerals that may
accompany the water that runs thro' them. For which reason they throw in,
great Quantities of Chalk into their Wells at _Ailsbury_ to soften their
water, which coming off a black Sand-stone, is so hard and sharp that it
will often turn their Beer sour in a Week's time, so that in its Original
State it's neither fit to Wash nor Brew with, but so long as the Alcalous
soft Particles of the Chalk holds good, they put it to both uses.

River-waters are less liable to be loaded with metallick, petrifying,
saline and other insanous Particles of the Earth, than the Well or Spring
sorts are, especially at some distance from the Spring-head, because the
Rain water mixes with and softens it, and are also much cured by the Sun's
heat and the Air's power, for which reason I have known several so strict,