mineral salts in the earth through which it soaks, it
will absorb them also. Rain-water soaks through
porous earths and sands, until it finds a layer, as
of clay or rock, through which it cannot filter;
over that, it collects and runs underground until
it finds an outlet on some lower level of the
surface ground, and there it will be poured out
as a spring. The water of the springs trickles
down hill in runlets determined by the fall of
the ground, and, as these descend, the runlets
join, to form, in the lowest groove of the land
over which they flow, a river-bed. From the
soil through which the rain-water has soaked,
and from the land over which rivulets and rivers
flow, the thirsty water has absorbed all that it
could take up. According to the nature of the
soils, therefore, will be the nature of the stream.
For domestic uses, water is said to be soft or
hard, in proportion to the quantity of lime it has
been able to absorb. Absolutely pure water is
to be obtained only by distillation in closed
vessels; but rain-water is pure water obtained by
a sort of open distillation which does not guard
against absorption of strange matters from the
slight contamination usually present in the air.
Much account, however, need not be taken of
this: rain-water, before it has soaked into the
ground, may be considered pure. If it fall
upon granite, clay-slate, and the like formations,
upon which it can lie dissolving nothing, it
remains pure. A chemist or engineer fairly versed
in analysis, could tell from examination of the
water of a district what was its geology: or, if
he knew the geology of any region, could
describe its water. Regions of granite and clay
slate usually are covered with moss, peat, or
heath; and the soft rain-water, that is so ready
to dissolve anything soluble, will give a dark
tinge to streams flowing from rocks clothed with
this kind of vegetation. Rain falling upon, and
rivers flowing over, chalk, the oolites, the new
red sandstone, and the like formations, will yield
water containing lime, magnesia, iron, sulphur,
and thereby made heavier, harder, and less
competent to take into solution other things.
The dissolving power of water is, of course,
much lessened when it has already taken to
itself, and has to keep a hold upon, its load of
earth. The earths in the water also put a
chemical charm on not a few things that come
within their touch, and take away some of their
readiness to be dissolved.

To a skilled traveller, the simple aspect of a
river, dark and vegetable tinged, sparkling or
bluish grey, should indicate much of the
character of an unexplored region through which its
waters may have come. A few simple tests
would enable him to decide accurately upon the
geology of mountain districts which he wanted
time or means to traverse with his feet. Had
Doctor Barth and Doctor Livingstone possessed
this knowledge and a little pocket-case of
chemicals, how much richer in information
would have been their accounts of the streams
they saw descending from the unknown lands
of Africa? A practical geologist can tell of
a country from a glance at the surface, nearly
as much as the skilful comparative anatomist
can tell of an animal from a glance at a piece of
its bone. The outward form of bird, beast, fish,
or land, bears always a due relation to the nature
of its skeleton. Abrupt steep mountains belong
to the old crystalline strata; these are bold sea
cliffs of oolite and chalk, but the inland surfaces
of these layers are undulated in hill, valley, and
plain, and the cliffs have their own smooth,
curving upper outline to be recognised even at
telescopic distances.

Roughly speaking, the deeper the water sinks,
the more it is impregnated with earthy matter in
solution; deep well water is, therefore, usually
very hard. There is a limit to the depth through
which water can soak; in many water-bearing
strata this is found at about nine hundred or a
thousand feet. Hot springs are exceptional, for
they may rise through inverted syphon veins
and fissures, from a depth twice or three times
as great.

It is wonderful to consider how much rock
the rivers carry to the sea; nay, how much
rock goes into the stomachs of the Londoners.
In Thames water, and most of the waters
furnishing the London supply, lime is found in
the proportion of about sixteen grains to the
gallon. In a million gallons exist a Ton of
Lime. The daily supply is about eighty
milion gallons, so that thirty thousand tons of
lime is about the quantity pumped into London
with its year's supply of water. A mountain of
lime that would make mortar enough to build a
suburb!

Lime injures the coats of the stomach when
we drink the water that contains it; when we
wash with such water, it curdles soap, and takes
away the beauty of the skin. Grooms and
trainers take good care to give soft water to
their horses and dogs. There are training-stables
on the chalk downs, for the sake of the turf and
the quiet; but large tanks are formed in which
to store rain-water for the use of the horses.
However far away the animals may go to their
races, their soft water is sent with them and
supplied to them daily. Even a change of water
is avoided. One drink of hard water would put
the favourite horse out of condition, make his
coat " stare," and destroy his chance of being
winner of the Derby.

Yet, knowing all this, we ourselves, with a
curious obstinacy, stick by the hard water, drink
it, and wash in it; and, to defeat our great lime
enemy, let us engage the strong upon our side:
ladies should know that pure soft water is the
truest beauty wash, and that there is no
cosmetic that will counteract the bad effect of hard
water on the complexion. Her Majesty's adviser,
Sir James Clarke, ordained, some years ago,
the use of distilled water at the royal toilet.
The hard spring water at many of our summer
bathing-places on the coast between
Scarborough and Torquay, is a serious drawback
to the advantages of a sea holiday, where
either no water must be drunk, or we must
be content to drink what would almost
poison a horse. But a time must come when