The Virginian. [volume] (Lynchburg [Va.]) 1822-1829, 1828-09-04

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| than countries considerably distant from any
| aceau
! Fugs, like clouds, will arrest heni which is
radialed upwards by the earth mud If they
were dense, and Of considerable perprudicu-
! lar extent, msy remit 10 II ~ mhrh rs they
receive. logs do not, IN any instance, IN
ni.h n real exception To The general rule, thai
whatever exists IN the atmosphere, capable ot
/ stopping or impeding the passage OF radiant
! heai, will prevent ~ lessen thr appearance nj
+ nsht Of cold on the surface Of the eeitt
/ greater than that If the uelghhoIing mir. The
water deposited upon the earth during n log
/ ~ night, may sometimes he derived from two
different sources cue of which Is prrcipia.
i ION III moisture from a considerable pnrl OF
! Tho atmosphere. in consequence Of lis general
cold The other real formation Of dew, from
! the condensation, by means et the superficial
/ cold of the ground, uf tho moisture Of thnt
portion OF the air, which CONES in contact
W ~ il.
When bodies become cold by radiation the
de- rce OF ethel observed must depend. uai
only ON Their rHdiatug puwer. but in part also
on the greater ~ less cRse which they eau de-
/ rive heat, by coaduction, from warmer sub
stances ia contact with them
The nriinl Effects OF cold oeg eur chiefly in
hollow places, aud ia clear and siil nights,
frosts are less severe upon hills lhau ~ neigh
boring plains Inc rrdsOus OF the former utt,
that Tie air heiag sillcr, the cold, from rndiH-
ii0n in the bodies which IL contains will he
less diminished by qte renewed application Of
warmer ar and thrxtfcm the long cpntluu-
ance ur the snlae sHf ~ contact with hhe
giound, ,ess dew viii be deposited, aud there
fore less heat exificucd durinz ds formation
tHe ressdh otthe latter, IN contradiction 10 the
commonly received orHioa, IS tnbi ~ very
clear aud III nigals, the M nfar the 'artn n
colder than thal aujcb is more distant, to
;the height. nj lrasi ut ''utett tbs being the
greatest IL which Spr. meuls relate. n then
a hill be supposed to Else from plain to the
height Of ~ fect, having upon IL summit II
small ild sa1laee covered with grBsB aud il
the atnosp ipfe during "A cal.n and serene
uighi. he admitted 20 h' 10 degrees warmer
/ than ii /. neer the surface Of IL ioW ,,ounds,
which is - difference tn what some
times oce0is in snrh circumstances, il is ma
nifesl, shonll both III" gra-s upon tlr l,li, and
| that uIon tie plaio. hrqnife cold II lu- by
| radiation, HE former wiz notwithstanding, be
! 10 degree warmer than the Mlter Heuce
also the t9p 1 trees are solarbmes found dry
when he 4f4as tn The gronad5a surface has
been found covered with dow.
! hll often, observes nr Veil, in the pride
! Of hslf knowledge, smiled al the mean, fee
! quautly employed by Eadenfr=, - protect
tender plaut- from cold, as il 0ppearra 10 me
! impossible, TINT thin mat, or any sueh nlm-
'y snl slance, could prevent tbrfa from attnin-
M the temperature oi the atmosphere. by
which aIoHe tiioueht them ia ne 10 I've inju-
. !eJ. But, wien mad learned, that bodies on
the 81, iRcr Of tue earth become. dnrin@ a still
| aud serene nieat, colder ihan the alm".phue,
bv radiatiug thrit hcat TO The henNens, per
nm
tic,. hlan art urfpre Deemed useless. Rr.
iug De ,nons however, ot acquiring some pre-
I els. information on tins subject, hIed, per.
I ptndicn.arlV. ~ the cHtih OF n grass plot tour
small sticks and overtheir nppel eAiremties-
uhiCh we're sA inches above Ia" grass. aud
formed tae corners I'll a sqnare, the SIDES OF
+ which WIRE two feri Tong. drew trinity Hyo ~
,h,n cambfic haudterchtrf In tbs Ji+pueItion
uf things, thririerr, nothing existed 20 PIE
vent the iree passagr OF a,r from the exposed
grns-, 10 thai winch was sheltered, scePt the
tDur small ,tlCa-, and there Va III suhsianCe
to radiafc IIoaf DOWN sr1.io lue lalfcr grass,
r\ccpi lhe cambrfc handkerchief. the ten.
prralure oil The grass, winch MAS thu shield
ed from the SKY, "Hs, upon many nights after
csamined ~ n.e and WIS always found Idghcl
than thai OF ndgbbrlIug Pras, VII CHI Was onco-
v,ycd. II this WI colder thdm the air. When
the difference IL temperature between the all
several feet .bosr inc ground aud ihr un,hclicr-
ed grass, did mol oNr'cd . degrees. the sheltered
grass was about ~ warm as the an. II thut dit
. terence, honcyei exceeded , degrees, the air
WAS found Ia br somewhat warmer Than the she
tcrrd grass. Thus, rpou uur night when iulls
'cA posed t,,,ss was / dr"rcrs colder than IL,
AIR, the latter vas dr-iers warmer thar Ut
sheltered efass aud the sumo distance c;.,ste,
r Oh anotbel nigh'. wheu the ait wax II drercc
Il, .,H...