, 1873-07-20
THE WARM FULL MOON.

THE WARM FULL MOON.
Poets have go long sung Of tho cold, chasto
moon, palid with woarinosB Of hor long watch
upon tho oarth according to tho image used
mike by Wordsworth and shel1ey), that 1t seoms
strange to learn from scionco that tho full moon
iB 80 intonBely hot TINT no crcature known to uB
could long endure contact with hor heated eur
faco. Such is the latest nows which science Inns
brought us Respecting our satellito. Tho news
ia not altogether unexpected; in fact, reasoning
had shown, long boforo tile fact had boon
demonstrated, that it muat be 30. The aatron-
omer knows that tho surface Of tho moon ia OK
poaod during tho long lunar day, lasting fort
night Of our terrestrial time, to tho rays Of
sun as powerful Us that which gives us our daily
heat Without an atmosphere to tonper the
SUMS hoat aa ours doos,-not, indeed, BY i'm
pcding tho passage Of the solar rays but by bear
ing aloft tho oloud-yel which tho sun raises from
our oceanB,-tho moon's surface must be-
come intensely hot long bofore tho middle Of
tho lunar day. Undoubtedly the want OF an at
moyphcro causos tho moons lcat to be rapidly
radiated away into space. It ia our atmosphere
which causes q steady heat to proynil on our
Garth. And At the Rulnmits Of lofty mountains,
whore the atmosphere is raro although the mid
day heat IL intonao, yet 30 rapidly docs tho hcat
pnsg away that snow CROWNS forever the noun
tain loights. Yet, although the moon's heat
must .pass nway even mora rapidly, thia doos
not prevent the heating Of the moons actual
BurIaco, any more than tho rarty Of the air pre-
vonts tho Alplno travolor from feeling tho ac-
tion Of tho SUMS direct heat even whom tho air
in shadow is Jolly cold. Accordingly, Sir John
Horschol long since pointed out TINT the moons
slrfaco must be heated at lunar midday-or
rather, at tho timo Of lunar mid-heat, corre-
spending to about o'clock in our nfternoon--to
u dcGrce probably Hurpassing the heat Of boiling
water.
Such, iu point Of fact. has now been proven to
bo tue case. 1Ae Earl Of RosBo nas shown, by
experiments Which need not hero be deHcrlhed,
that tho moon not only retects heat to the
earth (which Of course must ba the case), but
TINT sho gives ont heat by which she had been
herself warmed. Tho distinction may not per-
hapB appear olear at first sight to every rcador,
but 1t may easily be explained and illustrated.
smooth, but not too vol polished metal, aud by
moans Of 1t reflect the suns light upon the face,
senaation Of heat will DO experienced this is
REFLECTED suu-Aoat: but it We wait while 40 hold
hot under tho solar rays, we shall rocog-
nize o sensation OF beat from the more
proximity OF tho plate to the faco, oven
when the plate is 80 held ae not to
reflect sun-hent. Wo can III succession try
first, reiiocted lcat alone, before tho metal has
grown hot; no1t, the Loat which the metai gives
out OF itself when wa1ulod by the SUITS rays;
and, lastly, tho two kinda Of heat together, when
the metal il caused to reflect Bun-hent. and also
eoE hoa 9 o no fse to wyS out 9e1sne @dla
hn8 done has been to show that tho full moon
eenda earthward both kinds Of heat; she REFLECTS
solar heat just as she reflects solar light, and
sho also giyos out the heat By Which nor own
RurfAce has boen warmed.
1t may perhaps occur to tho reador to Inquire
how much heak we actually obtain from the full
moon. There is d Bimpls way Of vlowing tho mat-
tor. II the full moon woro oxaotly a. hot
aB boiling wator, wo should receive from her Just
az much neat Qeaviug the elloot Of cur atmoH-
phoro out of aecount) aH wo should receive from
ns,unll globo AZ hot aa boiling HAtH, and at such
distance as to look juat aa largo as tho moon
does. Or disk Of metal would serve equally
we. Now, tho experiment may be easily tried.
4 bronze halfpenny il exactly one inch in damo-
tor, aud as the moons average distance iB about
Ill times her own diameter, haltpenny at @
distance OF III 1nches Or throo yards and three
inches, looks just as largo as the moon. Now
while, 30 that IL becomes as hot as the water;
thou TINT coin taken quickly aud set threo
yards from tho observer will give out, for the fow
moments that its heat remains appreolably that
ho recoiveH from tlla full moon supposed to be as
hot as boiling water. Or globe OF thin metal,
ono inch iii diametor and full Of water at boiling
heat, would serve as q moro constant artificial
moon in reBpoot of heat supply. It mood not bo
thought remarkable, thon, II tho ileat given out
by tho full moon il not easily measured, or oven
recognized. lmagine how little the cold Of q
winters day would be relieved by tho. presence.
In room no otherwise warmed, of a 0ne-lnoh
globe OF boiling water, three yartls awayl And
by tho way we aro horo reminded Of Oil catt-
rato by lrof. O. +. Smytll, resulting from OBJ
seryationH made on tho moons heat during Lis
Teneriffe experiments. lIo found tho heat
equal to that emitted by tho hand at distance
OF tAreo foot.
But aftor Ill, tho most interesting results flow
ing from the rocont reacarOhoH arc thoBe which
relate to tho muun lorsolf. We cannot but
speculate OIL tho condition OF world 10 strange
ly circunBta1.ced TINT d cold moro bitter
than tl1at Of our arctic nlghta alternates with
heat exceeding that Of boiling wator. It In
strange to think that tho ca!m-loohing moon III
exposed to such extraordinary yioissltudes.
Iloro oau scarcely bo life IN any part Of tho
moon-ulloss 1t BIO underground lifo, like that
OF tho MOdoo 1nliana (wo commo1d this idoa
specially to the more artlent advocates OF Drown-
ter!an ideap respecting other worlds than olsrs).
And yot thore must 10 singuarIy aotlye meohan-
| oat lrocos. at work III yollaer orb. Tho uoon's
nniatallco must expand aud contract maryelously
aB tho alternate wayos Of }loat md cold pass over
It., Tho material 0f that crat0s-c0Yorol surface
muBt be positively crumbng away under the
oirootB Of those expansions aud contraotlonH.
Tho moUt plastic terrestrial subBtanooa could not