Edgefield advertiser. [volume] (Edgefield, S.C.) 1836-current, 1845-11-26

| (, III lnlS W0nuerlul process OF nature were
! TO cease. there would be no rains or dew
| to iertllize our fields and gardens, and The
consequence would be thai the earth would
be parched, and The productions which
afford US susteuance would wiiher and bt
destroyed. In such state. of things, mel
and all other tribes of animated natur[
would in a short time perish from the
earth. OF such Importance is ecaporaiaon
that David in The cxxxv Psalm aud Ut
verse, among many other reasons lol
praising the name of the Eternal. he men.
lions the fact that 81 He causelh the va,
pors TO ascend from the ends of the earth,
he maketh the beginnings for The rain
Evaporation is also cooling process-i
is 10 the evaporation Of the perspira1ion o.
man aud other animals, that they are ena'
bled 10 withstand The sullry cinale Of
tropical regions. il is by The evaporation
of the perspiratina that we can remain in
large ovens with lmpunily; heat to such
a degree that heeisleak and eggs can be
cooked by The side Of US, and oven waller
bolded.
THE radiation Of calOric.-Rudant rea,
is that form OF heat which is emitted from
hot budies, in all directions from lis sur
face. like radii, drawn frOui The centre, to
the circumference of circle. and when
these rays impinse al pom olher substances,
they are either absorbed, Transmitted, or
reflected.
The theory Of the coaduction, reflection,
and radiation Of caloric, long remained
one of the most obscure parts Of chemical
Inquiry, has been elevated by the research
e. OF Leslie. Fourier. Blot. LapIace,
Poisson, MaIloni and Forbes. TO The same
rank with physical optics. with which, in
these respec,s, II is very analogous. The
law of The radialon Of heal, which has
been demonstrated from induction. are
first, that The amount Of the radiation with
which a body parts with its heal. is in
proportion To the temperature oi the body.
Secondly, that il varies III the ralip of The
Inverse square of the distance from The
radiating poinl. Thirdly, all bodies have
IA tendency 10 an equilibrium OF tenpera-
lure, eilher by radiation, if they are atove
absorbtion, if they are 6lUr, and when
this equilibrium is established. uH radia.
tion ceases. Fillhy, the intensity of ra-
diation varies in different bodies, aud the
state of lis surface-itIs greatest for rough
md least for brig ht OF. polished surfaces.
The velocity with which bealis propa
gated through vacuo, is mol definitely
:. s.F4s =
1sy beTween7llle inpondorables, lis veloci-
lty probably not inferiory1o electricity, or
light.
Ea4 dasion. bodies expand, from
the accumulation of Ecatinro them But
the expansion Of solids hy increase Of heir
Temperature, is very small. It's the con
version OF solid oxygen or hydrogen into
oxygen. or hydrogen gas. that expansion
is most obvious. Among the sulds, the
metals are most eXpausiblr, aud conlrac-
tile; they vary however, much among
themselves. in this respect. But among
them mcrcury observes nore regularity in
its dllaaIl0ns than any other melal-nt nee
il is used lnr The construction Of thermom-
etcrs. Throughout all nature, there seems
10 he but one anomalous contraction ami
this takes place in water. II wafer, like
other fluids, continued To Increase Ia den
siIy till il frozed, The consequence would
he. that rivers, lakes, and other large rui
cctions of wlrer, instead Of only being
coated on heir surface with Il light stratum
of ice. they would be thoroughly CONCEAL
Ell from lhe surface TO the bottom. For
it is very evident if wafer continued 10
contract like other liquids. ils specific 2rav
ity when frozen, would be greater Than
that Of The wafer underneath, aud would
consequently " siuk 10 The bottom, aud
fresh portions Of the water being present.
ed 10 the AIR, it would also freeze aud
sink, until the Whole mass Of water, tlake
or river as the case nigh! be} would be
Thoroughly cungealed from lol. to bolIom.
But the reverse of this is lrue-lhe cold
continues 10 operaie upou the surface Of
the wator, by the culd breezcs that blow
over il, but instead. of diminishing its
bulk aud thereby yreuhering 1t heavier than
The wafer benealh, itexpands aud becomes
much lighter; so thai under these circum-
stances stratum of ice will be formed
floating Oh he warmer water benealh,-
Aud as this stratum Is very bad con
ducior of heat, The water underneath will
be KEPT al temperature even in the cold
est regions, perfectly consenal TO fish and
other aquatic animals.