250 ASTRONOMYANDTHEBIBLE
amazingdeepsofinterstellarspace,andtoaidinthe
exploration of a huge cave, depth, orrecess in the
nebulaintheconstellationOrion.
"Recentphotographictransparenciesmadeonglass
platesattheMountWilsonObservatoryrevealtheop-
ticalpropertyofperspective. Whathasallalongap-
peared to be a flat surface of nebulous matter, the
beautiful shimmerand sheen in thegreat nebulain
theswordofOrion,is shown, inthecentralregions
ofthesenegatives,tobethemouthofacavern,adeep
opening receding into the mighty distance beyond.
These large negatives, takenby means of thegreat
concavemirror,,fivefeetindiameter,—thelargestin
the world,—actually show depths below the shining
surface ofthe nebula, theeffect being thatthe eye
looksintothe openingand alongthe apparentsides
totherear."
"The wintry months are here. Orion rises early
intheevening,displayingsplendidandregalrobesof
night, garments ofcloth ofpearl and glitteringdia-
monds. Thenebulacanbefaintlyseenbytheunaided
eye,andbetterinanoperaglass. Golookinthesilent
hours,andsummonallyourmentalpowers,imagining
thatthecentral regionofthenebula isreally thegi-
ganticopeningofacavernleadingintoinconceivable
depths.
"The outlyingportionsofthenebulaare resolved,
inthesetransparencies, when furthermagnified, into
areasofstreamers,wisps,sprays,filaments,andstarry
lace;andthesearewellseeninthegreattelescopeup
hereonEchoMountain. Butallthesearelessinglory