HE water that we use every day is hardly ever pure.
However clear it may be, it always contains certain
foreign substances in solution, as is proved by the
slight coating of earthy matter that forms little by
little on the inside of our water-bottles, tarnishing
the glass and lessening it transparency."
"That earthy coating is very hard to wash off,"
remarked Marie. "I remember one day I tried and tried
to get it off with water alone, but it seemed to have
become a part of the glass itself."
"Yes, that coating sticks so fast just because it is of
stony matter, of veritable stone such as the mason uses
for building our houses. It is not at all surprising,
therefore, if mere washing with water fails to remove
it. To make it let go its hold it should be dissolved
in an acid, vinegar for example, or lemon-juice. Pour
a little vinegar into a carafe and shake it up until it
has wet all the clouded part of the glass; you will see
the stony coating dissolve, creating a little foam as
it does so. When the acid has done its work, wash it
off with water, and you will find that all the foreign
matter comes away with it, leaving the glass once more
as clear and transparent as ever."
 "Then even the clearest water," Jules observed, "water
in which the eye can detect nothing, absolutely
nothing, nevertheless contains dissolved stone, just as
sweetened water contains sugar invisible to the eye;
and when we drink a glass of water we drink with it a
little of this stony matter. Who would ever suspect
"It is very fortunate, my dear boy, that we do thus
drink a little of this dissolved stone. Our bodies, in
order to grow and become strong, require a certain
proportion of stony matter for the formation of our
bones, which are to us what its solid framework is to a
house. This needed matter we cannot by any possibility
create by ourselves; we must get it from our food and
drink. Water, for its part, furnishes a good share,
and if it did not contain the required mineral matter
we should remain puny and ailing, being unable to
attain our natural size."
"Is there much of this dissolved stone in the water we
drink?' asked Emile.
"To be fit for drinking, water must contain a little,
for the reason I have just explained; but when it
contains too much it is hard to digest and burdens the
stomach. The right proportion is from one to two
decigrams for a liter of water; or, in other words,
about as much as you would take up between your thumb
and forefinger. Any considerable excess makes the
water heavy, as we say, because it weighs on the
"Certain waters are so rich in dissolved stony matter
that they quickly encrust anything they touch.
 Such is the water of the celebrated spring of Saint
Allyre at Clermont-Ferrand. It is made to fall upon a
heap of tree branches which break up the water and
divide it into spray. This fine shower is allowed to
fall on objects that it is desired to coat with an
incrustation of stone—on birds' nests, baskets of
fruit, bouquets of flowers, and foliage. A layer of
stony matter is soon deposited by this mineralized dew,
and the birds' nest, the basket of fruit, the bouquet
are turned to stone, or, more exactly they are overlaid
with a coating of stone, so that one would say a
sculptor's chisel had deftly cut these objects out of
marble. Such water, needless to say, is unfit for
"I should think so!" cried Claire. "It would pave the
stomach with marble, which would not be very good for
"Never does the water such as we use," Uncle Paul
continued, "have anything like that super-abundance of
stony matter, though it often does contain enough to
cause difficulty in certain domestic operations,
especially laundry-work. You must have noticed how the
water in which clothes are washed with soap always
turns more or less white; perhaps you have even
observed that little flakes or clots of whitish matter
are formed in the water and float about in it."
"Yes, I know what you mean," Marie hastened to reply;
"and when there are too many of those white clots it is
hard to get any suds; the soap is just wasted."
"Well, now you will know that the white tinge and
 the floating particles are caused by the presence of
dissolved stony substances. Perfectly pure water,
distilled water, takes up soap without losing its
clearness, or with very little loss; it does not turn
white, it does not form flakes. To convince yourselves
of this, try a little rain-water some day for washing
out a piece of linen; for rain-water is almost as pure
as distilled water. You will see how easy it is and
how the soap does its work without waste. There will
be no white particles left in the water, though there
will be plenty of lather, and no whitish tinge to the
water under the foam such as you commonly see in
"When water turns very white under the action of soap
and shows abundant flakes, it is a sure sign of too
much stony matter in the water. Laundry-work then
becomes difficult and soap gives trouble about
dissolving, dissipating itself in tiny clots without
acting on the soiled linen. Such water is also bad for
drinking, overburdening the stomach with its excess of
mineral matter the water found in regions rich in
limestone is liable to this objection."
"I can see well enough," said Emile, "that a little
stony substance in the water must be a good thing for
us, and I also see how troublesome too much must be.
The stomach would soon get tired of digesting stone."
"Finally," his uncle continued, "hard water like that
is unfit for certain culinary purposes, particularly
cooking vegetables such as green peas, and
chick-peas—the last named especially. The mineral
matter in the water becomes incorporated with the
 vegetables and then, no matter how long you boil them,
they will not become soft."
"Yes," said Marie, "I know how chick-peas act
sometimes; after hours and hours of cooking they are
just as hard as at first and will bound like marbles if
you throw them on the floor. What prevents their
softening, you say, is the stony matter dissolved in
"That, and nothing else. Now, since all water contains
more or less of this, we are often troubled about
cooking the vegetables I have named. But there is a
simple remedy that I recommend in all such cases: drop
a little pinch of potash into the water, and the most
obstinate beans or peas will cook to perfection, even
the chick-pea itself softening to a mush."
"Without getting any bad taste?" asked Marie.
"Without getting any bad taste or anything else that
need be feared, on condition, however, that the potash
be used very sparingly—just a pinch and no more.
"But there is another way to use it that is more
readily at our command. Since potash is obtained from
wood-ashes it is plain that wood-ashes can here play
the part of potash. In a small piece of cotton cloth
folded two or three times tie up a thimbleful of clean
ashes, and drop this into the pot with your vegetables.
The potash in the ashes will dissolve and permeate the
water, while the earthy matter will be left in the
cloth, which is to be taken out when the vegetables are
done. By this means, however hard
 the water, you will get the better of the most
refractory peas and beans."
"Uncle Paul is always finding some new use for
wood-ashes," remarked Claire; "and now we see that they
will soften event he hardest of chick-peas."