246 ASTRONOMYANDTHEBIBLE
Insteadofthecontinuous bandofcolors, crossedby
darklines,whichischaracteristicofthespectrumof
astar,thevisiblenebularspectrum consistsof seven
brightlines. Threeofthese linescorrespondto the
spectrumofhydrogen;afourthwasformerlythought
tobe duetonitrogen. Thisisnowshowntobeer-
roneous,thenatureofthislineandoftheremaining
linesbeingnotknown."
—"TheStoryoftheHeavens,"
pages461,462.
Ifyouwereprivilegednightlytoscantheheavens
withevenasmalltelescope,youwouldsoonerorlater
meetoneoftheremarkablecelestialobjectswhichare
knownasnebulae. Theyare faintly cloudyspots,or
stains of light, appearing very vivid when outlined
againsttheblackbackgroundofthenightsky. There
are veryfew of thesevisible tothenaked eye, and
thenonlytothosewhounderstandwhattheyareob-
serving;theylooksomuchlikeanordinarystar.
Thenebulaearemuchinappearancelikebrightwhite
clouds, but they should not for a moment be con-
foundedwiththem. Cloudsaretobe foundonlyin
theatmosphere;butnebulaeareimmersedinthedepths
ofspace. Cloudsshinebythelightofthesunwhich
theyreflecttotheeye;butnebulaeshinebytheirown
light. Clouds are ever changing and disappearing;
but the nebulaeremain unchanged. Clouds are far
smallerthantheearth;butthesmallestnebulaeknown
tousarenotonlylargerthantheearth,butincompar-
ablylarger than thesun itself. Clouds are near,at
mostbutafewmiles away;butthenebulaearemany
millionsofmilesawayfromus.