melt best ; if, when it is dissolved, you measure it
again you will find it much diminished. This shows
that freezing dries up and causes to disappear the
lightest and finest part, not the heaviest and coarsest,
to do which it has no power. In this way, therefore,
I am of opinion that such waters, derived from snow
or ice, and waters similar to these, are the worst for
IX. Such are the properties of rain waters, and of
those from snow and ice. Stone, kidney disease,
strangury and sciatica are very apt to attack people,
and ruptures occur, when they drink water of very
many different kinds, or from large rivers, into which
other rivers flow, or from a lake fed by many streams
of various sorts, and whenever they use foreign waters
coming from a great, not a short, distance. For one
water cannot be like another ; some are sweet,
others are impregnated with salt and alum, others
flow from hot springs. These when mixed up
together disagree, and the strongest always prevails.
But the strongest is not always the same ; sometimes
it is one, sometimes another, according to the winds.
One has its strength from a north wind, another
from the south wind, and similarly with the others.
Such waters then must leave a sediment of mud and
sand in the vessels, and drinking them causes the
diseases mentioned before. That there are exceptions
I will proceed to set forth.
Those whose bowels are loose and healthy, whose
bladder is not feverish, and the mouth of whose
bladder is not over narrow, pass water easily, and no