<SPAN name="startofbook"></SPAN>
<h1>WATER WONDERS EVERY <br/>CHILD SHOULD KNOW</h1>
<p class="center"><span class="smaller">BY</span>
<br/><span class="large">JEAN M. THOMPSON</span></p>
<h2><span class="h2line1">WHEN THE DEW FALLS</span></h2>
<div class="fig"><ANTIMG src="images/p04.jpg" alt="" width-obs="500" height-obs="724" /> <p class="caption">3. Grass blade with dew deposit—three drops held in suspension on top of blade</p> </div>
<div class="fig"><ANTIMG src="images/p04a.jpg" alt="" width-obs="500" height-obs="714" /> <p class="caption">4. Showing how sharp pointed grasses collect and retain the dew drops, while blunt or broken blades collect none</p> </div>
<div class="fig"><ANTIMG src="images/p04c.jpg" alt="" width-obs="500" height-obs="758" /> <p class="caption">5. Grass-blade holding two drops—dew drop preparing to fall</p> </div>
<div class="fig"><ANTIMG src="images/p04d.jpg" alt="" width-obs="500" height-obs="712" /> <p class="caption">6. Dew drops on grass blade; showing inverted landscape held in drop</p> </div>
<h2 id="c1"><span class="h2line1">CHAPTER I</span> <br/><span class="h2line2">WHEN THE DEW FALLS</span></h2>
<div class="verse">
<p class="t0">“Everything shone with the dew drops that sparkling and trembling lay</p>
<p class="t0">Scattered to left and to right, and the webs of the spiders were hung</p>
<p class="t0">Thickly with pearls and diamonds; light in the wind they swung.”</p>
</div>
<p>One of the most interesting and
instructive phenomena in the lessons
of nature is the falling of the dew—a
seeming miracle which begins with the
setting of the sun, and goes on mysteriously,
collecting and distributing its countless
exquisite water jewels, all through the long
stillness of the night, only to be dispelled
again by the heat of the rising sun.</p>
<p>We are more or less familiar, through
casual observation, with the varied beauties
of the dew. A walk in the country or
park, in the early midsummer morning,
just after the sun has risen, if possible,
will enable you fully to appreciate its
charms; especially if the dewfall during
the preceding night has been a copious
one. Every bit of plant-life and vegetation
will sparkle and twinkle in the early
sunshine, hung and embellished with millions
of glittering jewels. The very smallest
grass blade, you will discover, has not
been neglected by the Dew Fairy. And
even the delicate, gossamer-like spider’s
web swung from twig to twig or caught
among the grasses, is dew laden, and an
object of beauty well worthy of consideration.</p>
<div class="fig"><ANTIMG src="images/p05.jpg" alt="" width-obs="600" height-obs="497" /> <p class="caption">7. Spider’s web entire: showing manner of collecting dew</p> </div>
<div class="fig"><ANTIMG src="images/p05a.jpg" alt="" width-obs="600" height-obs="478" /> <p class="caption">8. Detail of spider’s web dew-laden. Observe the pearl-like strands.</p> </div>
<p>Happy indeed are you, if you have
enjoyed a stroll in an old-fashioned country
flower garden in the early morning.
No need to dwell upon its charms if you
have enjoyed that pleasure, for you will
long remember the refreshment and peace
which came to you with the close companionship
of the great pink, damask
roses, their petals still heavy with the
night dews; the tall, sentinel-like lilies,
cool and fragrant, their cups filled with
dewy nectar, which great blundering bees
were eagerly plundering; clean-smelling
phlox, waist-high, each velvet cluster moist
and bent with its weight of dew. Then the
beds of gray-green mignonette; and best of
all, down in an out-of-the-way corner, a
tangle of unobtrusive old-fashioned pinks,
where you knelt and buried your face for
a moment to inhale their spicy fragrance,
and found them doubly sweet and satisfying
after their drenching dew bath.
While the beds of simples and humbler
things, the sage and wormwood, with their
silvery leaves heavy with dew, exhaled a
pungent, aromatic odour as you brushed
them in passing. For the dew had refreshed
them and enhanced their dormant spiciness
tenfold.</p>
<p>The phenomenon of the dew is simply
explained, and well worthy of a short study
as it is really a most important factor in
nature’s laws. Simply explained, the dew
is really an actual deposit of water from
the atmosphere upon the surface of the
earth, and is formed when the earth
is sufficiently cooled during the night
by radiation.</p>
<p>Upon a pleasant day during summer,
especially if the sun shines brightly, much
aqueous vapour or mist is held suspended
in the air, and if the temperature at sunset
falls below the dew point, that vapour
can no longer be retained in suspension
in the air, and falls to the earth. The
dew is the vapour of the air. Sometimes
it can readily be seen falling in a fine mist
resembling rain. It is the humidity of the
air deposited upon all surfaces of the earth
with which it comes in contact. When
the temperature falls below the dew point,
or 32°, the dew then becomes converted
into frost, and we have a deposit of hoar
frost, instead of the dew. It has been
remarked that horizontal and flat surfaces
exposed to the dew receive a greater
deposit than sheltered or oblique surfaces.</p>
<div class="fig"><ANTIMG src="images/p06.jpg" alt="" width-obs="500" height-obs="443" /> <p class="caption">9. A dew-laden strawberry leaf with dew jewels set in each serration about the edges</p> </div>
<div class="fig"><ANTIMG src="images/p06a.jpg" alt="" width-obs="500" height-obs="378" /> <p class="caption">10. Dew drop caught on vegetable hairs of mullein leaf</p> </div>
<div class="fig"><ANTIMG src="images/p06c.jpg" alt="" width-obs="431" height-obs="600" /> <p class="caption">11. The sleeping caterpillar was a good subject and received a copious collection of dew</p> </div>
<div class="fig"><ANTIMG src="images/p06d.jpg" alt="" width-obs="422" height-obs="600" /> <p class="caption">12. The surface of a leaf dew-covered</p> </div>
<p>Dew has frequently been quoted as
“A shower from heaven,” but this is
not literally correct. True, it appears
rather mysteriously from a clear sky, and
upon a still, cloudless night covers thickly
every blade of grass and plant life with
seeming raindrops, and that frequently
where rain clouds rarely appear, and the
rain seldom falls. In such climates,
where a rainfall is rare, it is certainly a
most beneficial and wise provision, for it
gathers upon all herbage and vegetation,
in sparkling, refreshing profusion; while
it avoids instinctively all barren rocky
formations and all things which could
not be benefited by its grateful cooling,
moisture. Also, in cold, damp climates,
where the air is continually saturated with
moisture, and where an additional amount
is not required, the gathering clouds and
the dampness of the chilly atmosphere
prevent a radiation of heat from the earth,
and the dew never falls in such climates.</p>
<p>There are three requisites which appear
to be essential for the formation of the
dew: First, that the air should be moist;
second, that the surface upon which it
falls shall be cold, and third, that the sky
be clear.</p>
<p>Of course the atmosphere always contains
a greater amount of moisture after
a rainfall, when the air has been greatly
cooled. Evaporation is then continually
going on among all objects lying near the
surface of the earth. Blades of grass
and all plants near the ground gradually
cool and assume a lower temperature after
sunset; they are preparing for the fall
of the dew.</p>
<p>It has been remarked that certain plants
possess greater powers of radiating heat
and of expelling moisture through evaporative
process than others; upon such plants
the dew deposit is always more profuse,
while those plants possessing less powers
of radiation and evaporation, collect little
dew.</p>
<div class="fig"><ANTIMG src="images/p07.jpg" alt="" width-obs="600" height-obs="438" /> <p class="caption">13. Dew caught and held upon down of plant stem</p> </div>
<div class="fig"><ANTIMG src="images/p07a.jpg" alt="" width-obs="600" height-obs="442" /> <p class="caption">14. Dew upon the down of a leaf</p> </div>
<p>There are very many plants whose leaves
are downy, with a thick growth of tiny
vegetable hairs; the mullein leaf is a
good example, its thick velvety leaves are
thickly covered with this growth of vegetable
down, and present a velvety surface;
these leaves always collect a fine display
of dew jewels. One has been caught by
the camera, perched upon the down of
a mullein leaf, as shown in the photographic
illustration.</p>
<p>During still nights in early spring and fall,
when there are no disturbing winds, the water
molecules or dewdrops in countless numbers
form one upon another, all night long, and
settle upon blades of grass and all growing
plants, and in the morning sunshine dance
and sparkle in strings of scintillating diamonds
from every pasture and hedge row.</p>
<p>The sharp-pointed grasses collect the
dew very copiously and in a most interesting
manner. Dewdrops formed upon
the grass blades, it will be observed, are
arranged in a truly wonderful symmetrical
fashion, and one marvels at the orderly
arrangement. Frequently one large dewdrop,
clear as a diamond, is deposited
upon the very tip of the little grass
blade, sometimes two and even three large
drops are held in suspension thus, while
upon the extreme sharp edge of one or
both sides of the blade a collection of small,
bead-like drops cling in orderly, precise
fashion, strung from tip to root of the grass
blade. A broken or blunted blade of
grass collects no dew, or very little. When
the large dewdrop perched upon the tip
of the grass blade decides to fall, it descends
rather slowly at first, following the extreme
edge of the blade in its course, and thus
meets and collects all the other dewdrops
which it encounters strung along the edge
of the blade, until forming at last one
heavy drop, it suddenly falls to earth, where
it is instantly absorbed, and goes to give
life and strength to the very roots of the
plant.</p>
<div class="fig"><ANTIMG src="images/p08.jpg" alt="" width-obs="387" height-obs="600" /> <p class="caption">17. Hoar frost deposit upon a stick. The butterflies have settled to rest</p> </div>
<div class="fig"><ANTIMG src="images/p08a.jpg" alt="" width-obs="404" height-obs="600" /> <p class="caption">18. Dainty lace-like formation of hoar frost collected upon a straw</p> </div>
<div class="fig"><ANTIMG src="images/p08d.jpg" alt="" width-obs="600" height-obs="444" /> <p class="caption">19. Winter tabular hoar frost resembling a group of butterflies</p> </div>
<p>Cobwebs attract the dew in a rather
singular manner. It is yet to be discovered
why the dew forms only upon
the horizontal threads of a spider’s web,
while the vertical threads, though smaller,
collect no dew deposit. This curious fact
is well shown in the photograph of the
entire spider’s web, also in the section of a
web, showing the dew deposit in detail.
Wonderfully beautiful are these dew-laden
webs. It will be observed that each drop
is similar in size, and closely resembles
several strings of well-matched pearls,
although in the sunshine they appear as
clear, flashing diamonds. Certain leaves
collect the dew drops in a novel manner,
notably the strawberry leaf, and similar
plants having serrate edges. The strawberry
leaf, besides being plentifully decorated
upon its surface with water beads, holds
in each tiny serration about its edge a
large, clear, sparkling dewdrop, which gives
the leaf a wonderful jewelled effect.</p>
<p>We are all familiar with the so-called
“sweating” of a glass or pitcher, or a
metal pipe containing cold water; this is
another phase of the dew, and may be
observed in the daytime.</p>
<p>A cool night in spring or autumn, after
a hot day, we usually receive a more
copious fall of dew, which gradually increases
as the night becomes cooler.
Should clouds gather, the precipitation
of the dew at once ceases. Wherever a
bush or bit of vegetation overhangs a spot,
it has a similar effect to that of a cloud,
and the dew does not collect at all, or
not as copiously, in that spot.</p>
<p>In the tropics, and in certain countries
where there are no rain clouds; where
they rarely have rain for many months
at a time, the dewfall is so heavy that it
quite supplies the lack of rainfall. If it
were not for this providential visitation
of the dew all vegetable life must certainly
perish, scorched and withered by the torrid
heat.</p>
<div class="fig"><ANTIMG src="images/p09.jpg" alt="" width-obs="600" height-obs="360" /> <p class="caption">20. Like a piece of bleached coral. Hoar frost discovered under a building</p> </div>
<div class="fig"><ANTIMG src="images/p09a.jpg" alt="" width-obs="600" height-obs="338" /> <p class="caption">21. Tabular hoar frost</p> </div>
<div class="fig"><ANTIMG src="images/p09c.jpg" alt="" width-obs="600" height-obs="654" /> <p class="caption">22. Tree form tabular hoar frost: grew in zero weather</p> </div>
<p>In the East, in the region of Palestine,
the dew frequently is so heavy that it
closely resembles rain. Upon the great
burning deserts alone the dew never
falls; for the moment the dew vapours or
molecules encounter the scorching breath
which arises from the face of these barren
seas of sand, they evaporate and are
redissolved, dissipated and consumed by
the heat. So it will be seen that the
fixed molecules which compose vegetation
alone have the power to attract and arrest
the water molecules of the air with which
they come in contact, and thus form, in
combination, the dew.</p>
<p>When the temperature is below 32°, the
tiny particles which go to form the dew
become hoar frost. It is often of great
value to the farmer or vegetable grower
to be able to know just the temperature
of the dew point, because, if he discovers
it in time, he is enabled to save his garden
from a sudden blighting visitation of the
frost.</p>
<p>Another interesting fact, and one which
is known to few of us, but which may
readily be seen, if we take time to study
the dewdrop minutely is; that each tiny
drop of dew is in itself a miniature mirror,
for upon its clear, crystal-like surface it
holds and faithfully portrays upon its
rounded form the image of any near-by
object. The picture is, of course, naturally
inverted. But you will find it; a bit of
blue sky holding a scrap of fleecy cloud,
or a pigmy forest of trees caught and
mirrored in the dewdrop. Often sleeping
and dormant insects when caught out in
the open during the night, receive a copious
deposit of dew. The caterpillar shown
in the photograph was a good subject,
and quite a collection of dew was deposited
upon his furry coat.</p>
<div class="fig"><ANTIMG src="images/p10.jpg" alt="" width-obs="600" height-obs="733" /> <p class="caption">23. A Winter type of hoar frost</p> </div>
<div class="fig"><ANTIMG src="images/p10b.jpg" alt="" width-obs="600" height-obs="220" /> <p class="caption">24. Columnar hoar frost upon a decaying log</p> </div>
<div class="fig"><ANTIMG src="images/p10c.jpg" alt="" width-obs="600" height-obs="370" /> <p class="caption">25. Striking arrangement of hoar-frost crystals upon broken edge of ice, water showing beneath</p> </div>
<p>Nature in all her moods, and they are
many, is always entertaining and instructive,
and perhaps one of her greatest marvels
is that which takes place in the silence of
the brooding night—the falling of the
gentle dew.</p>
<div class="fig"><ANTIMG src="images/p11.jpg" alt="" width-obs="500" height-obs="645" /> <p class="caption">26. Showing hoar-frost elaboration about the edge of a leaf</p> </div>
<div class="fig"><ANTIMG src="images/p11a.jpg" alt="" width-obs="500" height-obs="652" /> <p class="caption">27. Hoar-frost deposit upon grass blades</p> </div>
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