, 1874-03-10

IlllNtI
and ta s,lrfaco 10 fivo timca tho nun's. all tlis
HuppoBing TINT tho st1rfnco uf tho htar la OF tho
Hnme intrinsic brightness rs tho sr1n-tl,nt Ia.
that n squaro milo Of lilo Htnr gives ns n,ucA
light na Square milo Of tho at,n.
CONSTITUTION OF TIE srAns.
pass from that stnr to tho king Of stars, tho
Btar Sirius. It Is four tin1oH ns bright rs tho
stnr III the Contnnr, and iH five tmos as fur
i Should nhno with tic 25th part Of tho light of
tl,nt star iu tho Contaur. Hut, bolng four times
nj bright, 1t IL really 100 tinlos ~ bright. THAT
star III tho Contn.lr IL three times as bright
as tho hun, anl sirias is, therefore, 'oo
volume ozceoda lilo Bun 2,ooo times.
There is MI orb differing from our aun oven In
creator dooEfco tlan tte relation Of tho sun to
Jupiter. Tllore iB StrlnB giving ont MI onor"
nous amount of light. but how do wo know 1t IL
q siln ]iko ours-thnt tllobo Btars nro not vnpor.
ous bodios? If 30, while They hayo enormous
tnnBaou, thoy may not havo tl,e amount of power
by which they aro ablo 10 attract, md therefore
rule nystems OF bodies circ!ing aroutd. Until
ta!ning whether that notion was truo or not:
But by the method Of tic speotroacopo wo flnd
they aro worlds like ours. You know TINT We
haye learned that ollr Bnn shines like burning
mass through ovorlying yapors Of known cle-
rainbow tinted Btroak, crossed BY darh lines, wo
can know tliat they nre sul.s like orrB. Fathcr
scccbi Of Italy, who haR examined grcnt many.
Tas t anticipated by your own coun,rymnn, Dr.;
the spectra Of about coo, part Of
them Of characteristic nature, differont
from our sun, but NIL having tho rainbow
tinted HIreals. Tho star Sirius gives this
characteristic spectrum, showing it to belong to
IN that way, and by much creator magnitude.
1t BllowH very strongly tho four lines Of hydro
got. Another class Of Bpoctra aro those which
rcsomblo our Bnl. III instance being tho bright
stnr Capella. Those Of third claBs, wllilo tloy
rcfetn1lo the preceding allow several dar. bolts,
which Father secclli Bays rcso,nbIo tho spectrum
Of tho SUMS spots, md TINT tho stars which
prosont tloEo banda, are really covered with
spots.
oxY-1IYDHonEN ILLUSTRATIONS.
Alr. Proctor hero Ind tllc hall dnrlcnc1.. and
mado uso of the oxy-hydrogon light to throw
upon the screen tho various pictures REPRESENT
ing different portions Of tho heavens. tho forms
and constitution Of 1nnny Htar-clouts, ec.
Tho following portion Of tl,e report gyes only
those parts of the 1cctula which did not rotor
directly to tho illustratious:
It is noteworthy fnot that among tho stara
giving thnt spectrum thoro nre spno of tlle most
remarkable variable stars in the hoaycns, aB tho
star Mira (CotD, which sometimes shines III q
altogether invisible. Other Htara nro noted for
their ruddy color, md altogether tho idca Blg-
gestoa is that Sccchi is right, and wo hayo to
doal with stara which. for some roaBon or olllor,
aro covered with 2 great number of spotB. Or.
uuggina and Dr. N1illor carried OH kind OF work
Much moro exac: than SecchiB, ind, not content
cd with hs treatment Of tho lities, thoy compared
tho different limos with those belonging to certain
particular ololnohts, sodium, magnesium, iron.
be1nt1th, antimony, sltc. 1t III a strango thought
that iron exists i'll tho atmosphere OF q star
millions Of mlos away, and that the astronomer
eau toll tlat nB certainly rs though llo could
bliuE portion Of tho iron into Ills study, aud
examine 1t Mt hiB lelBure.
Sccchis analysis in 4 means Of determining not
norcly that thoro exists certain clements n tho
star, but tllat t!loy exist i'll certain conditions.
When wo ox;mino tho spectrum OF the stnr
Detegeux, NO find that tho lines Of hydrogen ate
wanting then wo lind ttat there arc other stars
that tho hydrogen exists in Bomowhat
moro heated slato. There WINS q star
appeared ia 1aG6-a tclcncopic star-
which iiashct into yiew, and roso to the second
magnitude; mud when tant was examined, during
Its grlatcst brl lliiancy 1t was found TINT OIL tho
raiubow-t tinted streak forming its spectrum there
wore lines VI briglttncss, Of glowing hydrogen.
THE LIGHT OF coLonED srAl!s.
another interesting foa.,lro Of stoilar astronomy
tho Gaze, mcal, OF tho coiorcd double Btar6
Among tho stars il tho llcaYoes there are some
that whom oxallined By. good telescopes are
jDlitlu to DO uOlIllD. AtH nuDw very Wcil-llnTEGH
colUru. some rcd. sono orange. mid uoulo blue,
ind 10 on; and tic question suggests itself Ii
TINT color iuloront III tue ytarligllt, or pro-
duccl by tue cutting or OF a portion
Of the stars light By yapor ? Take
tic familiar case Of light used at lie theatre.
,Ihoro yu,l hnyo 1iro Ike particular color, MI
ahaplutoly Inherent color: l1t then Won 1aay also
haye n colored light produced in another way.
You may layo III ordinary wllto light, and put
before it n colored glass. There ave two waya
i'll which light may Eppoar colorol md it IL Il
matter Of exceeding lutoroEt to determine by
what way colored stars haYo teir color glyen
them. Take the Bpoctra OF the component stars
OF the splendid double star Bota Cygni. 1t Inns
two compouents, ono purple and tho other
orange, mud those two stars hayo spcctra co,ro-
spending to tho Two shown. Tho purple star
LAS spectrum in which thero arc d num-
ber Of bands opposite tho orange yellow
parts Of tho spectrum, md these bands cut
or q part Ut Lilo orange light. They
lonvo superabundanco of tho violet a,,d purple
portion, aud therefore tho star looks lso Il bfue
star. Tho yellow star shows some strong limo .
aorosa tho bluo; but tI,oro ls q Buperabulldanco
OF orange aud yoow light, 10 tint thc star shops
as MI orange star. Titus wo loarn TINT tho col
,,a Il 1a,,t =, hat ,,,,to,,. ..,1 ,,..L