Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1889-11-01
LITTLE DROPS OF DEW.
the Tsue THEORY OF THEIR oHi-
CIV AND ,orHeR FACTS

TIE Tsue THEORY OF THEIR oar
CIV AND .orHER FACTS
c~t~~s gAsssnsas Th<y Eahkhts sas Es-
r..s.s. Bssa. C~.esrakag rAso-Wss-
a~rf.I Prsasrsssa. - S.ssrs rhss Pas
ss-Ss the As<sest Philosophers
Tosne anei~at paib.spners the apf-arssee
Il dew asd frost was . eomptsts mysfery, and
nnns-saas s~re the theories sdvaneed, oy
tbs.e srieusi6cniiy Inclined, 10 account for
,hssr produefipn. and the interesting pc
nsmesaa they pre~.utsi Many, it i aid. b.
ii~v.d that In. d-s w.s nsthimg ~i's than the
tears shed by ths Almighty upon our earth,
and they rexartiei II ~ s.fred Substance
that f.s~es~esi nambss Of WONDERFUL and In
~xplrable properties. They aiso attTiboted
o. il many strange events and curious mani
feSfafiass that occurred IN the~e times, and
s,ns~ rubbed IL over their bodies in order TO
rrote4t thes,sselvs. from the evil spirit, whose
malignant influeoee was held responsible for
eli the marvellous and unAccoautable opera
siprs' Of nature Observed in thu earth and the
heavens above.
sYRANGKR THAN FICTION.
Among all the numerous truths stranger
than fiction that the study Of natural ~ct
eaee has revealed there are few more inter
e~tiux and instructive than rhose relating 70
the phenousena Of dew and frost.
The Iate Professor J. Dcrinan Steele. in his
excelisat work, Fourteen Weeks in Physics"
says: Dew Was anesently thought to possess
|, ANY wonderful properties Baths In this
,xecis,s liquni were said to conduce greatly
% beauty II was coll.--ted for thin purpose,
ami for the use Of the slchemists in their
weird experinsot.. by spreading 6eeces Of
wool upon the ground. Laurens. u philoso-
pher Of the middle ages, claimed that de~
was ethereal, 80 that il We should dill larks
egg with it and lay It out ia the sun, iniine-
tiafely on the rising Of that iuminary, the
egg would ny off into the ART This expert
u,ent is te-t performed with q gooss's egg"
There Is considerable misapprehension
among the general public concerning the ma
turs end origin Of dew and frost. IL being
comInoniy supposed by the great majority Of
people that dew actually falls from the sky,
and how frequently do we hear the ex-
preston ''the dew Is falling fast The fact
is, dew never falls but i formed on the sur
face Of the earth, and always at the identical
place where il is sen by the observer. Dew
IL simply the moisture Of the air condensed by
coming in contact with objects upon the
ground that are colder than itself. The earth,
heated during the day By the suns rays, at
night cools of and radiates considerable
portion Of its heat into space. All bodies. left
to themselves, will gradually become cool IL
previously heated. This is termed in natural
philosophy, radiation. and it may be easily
demonstrated by experiment. Take an iron
hall for instance, heat IL To incandescence or
until IL becomes red hot" and then suspend
It by wire In little while it will part
with all its heat, and feel quite cold to the
touch The hca. has been thrown of. as it
were, or radiate,i and not carried away by
the surrounding air, for precisely the same
effect will lie produced il this experiment he
perfected in u vacuum Our earth Is con-
stai.tly rndiating its heat. like the imaginary
bali iii all directions. and vt night becomes
~ cool that the invisible vapor resting
upon Its surface Is condensed into water
aud deposited us dew" The temperature at
which this takes place Ii called the dew
Isiint, AS indicated by an accurate and reli-
able thermometer Bat this point Is by no
means constant or invarable, since dew is de
Ir~it-d only when the air is saturated with
valaDr. ami the amount of moisture required
to saturate mir Of high temperature Is much
greater than for air Il low tenn ,erature.
LIKE THE SWEATING" PITCHER.
All bodies have not the same capacity for
radia;ing heat. but some cool much more rap
i,ily than Others. Hence, with the same ex-
lo-ure some bodies will he covered densely
with dew. while Others will remain perfectly
dry. Dark obj,ct- have more dew deposited
upon them than ASi, oltes. because they are
better ratiiators, aid. therefore, part with
larger amount OF heat. This fact may also
be demonstrated by placing black WOODEN
cloth and White linen or cotton one upon
the ground over night Grass, the leaves Of
trees, wood, etc, radiafe heat very freely;
but polished metals. smooth stones and cotton
cloth part with their heat more slowly, 80
that the former ii these substances will be
completely sirenched with dew, while the lat
ter, in the salne situation. will he compare
lively dry.
The amount Of dew formed on any night is
greatly influenced 10y the condition Of the at
mosphere. More dew is formed on clear even
ings shan when the sky is obscured by clouds,
because they act shield. and reflect back
the heat ra,iint,sl by the earth into space, he
sides furnishing that received by them dur
ing she day, which prevents the earth from
cooling of enough To produce large deposit
OF dew But when the sky is free from clouds
the earth rs,liates IA larger amount Of heat,
as there is nothing To intercept that thrown
off from its surface. THIS is the reason why
we always have colcr nights when no clouds
obscure the sky.
The formation OF dew is prevented by a
strong breeze, which removes the layers Of
moisture resting upon the ground before they
have time TO cool down to the dew point"
A slight hreeze, however, is favorable to the
production of dew, as it replaces the layer Of
air from which water has been deposited by
another containing more moisture. No dew
may ever be expected when the sky is OBJ
scured by clouds. or when there strong
wind.
The moisture that appears upon the outside
Of pitcher when it contains very cold water
is nothing but dew, and rs produced by the
same cause explained above This dampness
frequently observed upon a cold pitcher
even during the hottest weather in summer,
is commonly referred to by saying the
pitcher is sweating" and in this simple illus
tration we are permitted to recognize before
our eyes, OH a small scale, the same interest
ing process Of dew formation that takes place
over the surface of the great earth. Dew is
alluded to in the writings Of many ancient
philosophers, and the Bible contains quaint
passage in regard TO Gideon's fleece. (See
Judges vi 31-i0l--A. K. Bartlett in Detroit
Free Press