,,man',s ,,place ,,9 ,,! ,,univ]se      
,,man',s ,,place ,,9 ,,! ,,univ]se  ,a  
,/udy ( ! ,results ( ,sci5tific ,rese>* 
9 ,relation to ! ,unity or ,plurality ( 
,worlds   ,,by ,,alfr$ ,r4 ,,wallace    
,,ll4,d41 ,d4,c4,l41 ,f4,r4,s41 ,,etc4  
',o1 glitt]+ ho/6 ,o1 gold5 l9e6        
,i w\ld ,i _h an angel's k51     ,y\r   
deepe/ secrets to div9e1       ,& read  
y\r my/]ies to m54'   ,,?ird ,,edition  
,,london ,,*apman ,,& ,,hall ,,limit$   
#aijd      ',i said unto my inmo/ he>t1 
,%all ,i don corslet1 helm1 & %ield1    
,& %all ,i ) a ,giant /rive1       ,&   
*>ge a ,dragon on ! field8'      ,j4,h4 
,,dell4     ,,preface   ,?is "w has be5 
writt5 9 consequ5ce ( ! great int]e/    
excit$ by my article1 "u ! same title1  
:i* appe>$ simultane\sly 9 ,! ,=tnightly
 ,review & ! ,new ,york ,indep5d5t4 ,two
 fri5ds :o read ! manuscript 7 ( op9ion 
t a volume1 9 :i* ! evid5ce c\ld be giv5
 mu* m fully1 w\ld be desirable1 & !    
result ( ! publication ( ! article      
confirm$ _! view4  ,i 0 l$ to a /udy ( !

 subject :5 writ+ f\r new *apt]s on     
,a/ronomy = a new edition ( ,! ,wond]ful
 ,c5tury4 ,i !n f\nd t almo/ all writ]s 
on g5]al a/ronomy1 f ,sir ,john ,h]s*el 
to ,pr(essor ,simon ,newcomb & ,sir     
,norman ,locky]1 /at$1 z an indisputable
 fact1 t our sun is situat$ 9 ! plane ( 
! great r+ ( ! ,milky ,way1 & also v    
ne>ly 9 ! c5tre ( t r+4 ,! mo/ rec5t    
rese>*es also %[$ t !re 0 little or no  
pro( ( !re be+ any />s or nebul v f>    
beyond ! ,milky ,way1 :i* ?us seem$ to  
be ! limit1 9 t direction1 ( ! /ell>    
univ]se4  ,turn+ to ! e>? & ! o!r       
planets ( ! ,sol> ,sy/em1 ,i f\nd t !   
mo/ rec5t rese>*es l$ to ! conclusion t 
no o!r planet 0 likely to be ! seat (   
organic life1 unless p]haps ( a v l[    
type4 ,= _m ye>s ,i _h paid special     
att5tion to ! problem ( ! measurem5t (  
geological "t1 & also t ( ! mild        
climates & g5]ally uni=m conditions t _h
 prevail$ ?r\gh\t all geological epo*s2 
& on consid]+ ! numb] ( concurr5t causes
 & ! delicate balance ( conditions      

requir$ to ma9ta9 su* uni=mity1 ,i      
became /ill m conv9c$ t ! evid5ce 0     
exce$+ly /rong aga9/ ! probability or   
possibility ( any o!r planet be+        
inhabit$4  ,hav+ long be5 acqua9t$ ) mo/
 ( ! works deal+ ) ! "q ( ! suppos$     
,plurality ( ,worlds1 ,i 0 q aw>e ( ! v 
sup]ficial treatm5t ! subject _h        
receiv$1 ev5 9 ! h&s ( ! mo/ able       
writ]s1 & ?is made me ! m will+ to set  
=? ! :ole ( ! available                 
evid5ce--a/ronomical1 physical1 &       
biological--9 su* a way z to %[ bo? :at 
0 prov$ & :at sugge/$ by x4  ,! pres5t  
"w is ! result1 & ,i v5ture to ?9k t ^? 
:o w read x c>efully w admit t x is a   
book t 0 wor? writ+4 ,x is f\nd$ almo/  
entirely on ! m>vell\s body ( facts &   
conclusions ( ! ,new ,a/ronomy toge!r ) 
^? rea*$ by mod]n physici/s1 *emi/s1 &  
biologi/s4 ,its novelty consi/s 9 comb9+
 ! v>i\s results ( ^! diff]5t bran*es ( 
sci5ce into a connect$ :ole1 s z to %[  
_! be>+ ^u a s+le problem--a problem :i*
 is ( v great int]e/ to ourselves4  ,?is

 problem is1 :e!r or no ! logical       
inf]5ces to be drawn f ! v>i\s results (
 mod]n sci5ce l5d support to ! view t   
our e>? is ! only inhabit$ planet1 n    
only 9 ! ,sol> ,sy/em b 9 ! :ole /ell>  
univ]se4 ,( c\rse x is a po9t z to :i*  
absolute demon/ration1 "o way or ! o!r1 
is impossible4 ,b 9 ! abs5ce ( any      
direct pro(s1 x is cle>ly rational to   
inquire into probabilities2 & ^!        
probabilities mu/ be det]m9$ n by our   
prepossessions = any p>ticul> view1 b by
 an absolutely imp>tial & unprejudic$   
exam9ation ( ! t5d5cy ( ! evid5ce4  ,z !
 book is writt5 = ! g5]al1 educat$ body 
( read]s1 _m ( :om may n be acqua9t$ )  
any aspect ( ! subject or ) ! wond]ful  
advance ( rec5t k 9 t dep>tm5t (t5 t]m$ 
! ,new ,a/ronomy1 a popul> acc\nt has   
be5 giv5 ( all ^? bran*es ( x :i* be> ^u
 ! special subject "h discuss$4 ,?is "p 
( ! "w occupies ! fir/ six *apt]s4 ,^?  
:o are fairly acqua9t$ ) mod]n          
a/ronomical lit]ature1 z giv5 9 popul>  
works1 may beg9 at my sev5? *apt]1 :i*  

m>ks ! comm5cem5t ( ! consid]able body (
 evid5ce & ( argum5t ,i h be5 able to   
adduce4  ,to ^? ( my read]s :o may h be5
 influ5c$ by any ( ! adv]se criticisms  
on my views z set =? 9 ! article already
 ref]r$ to1 ,i mu/ aga9 urge1 t ?r\gh\t 
! :ole ( ?is "w1 nei!r ! facts nor ! m  
obvi\s conclusions f ! facts are giv5 on
 my own au?ority1 b always on t ( ! be/ 
a/ronom]s1 ma!maticians1 & o!r m5 (     
sci5ce to ^: works ,i h _h access1 & ^: 
names1 ) exact ref]5ces1 ,i g5]ally     
give4  ,:at ,i claim to h done is1 to h 
br\ght toge!r ! v>i\s facts & ph5om5a !y
 h accumulat$2 to h set =? ! hypo!ses by
 :i* !y acc\nt = !m1 or ! results to :i*
 ! evid5ce cle>ly po9ts2 to h judg$     
betwe5 conflict+ op9ions & !ories2 &    
la/ly1 to h comb9$ ! results ( ! v>i\s  
widely-sep>at$ dep>tm5ts ( sci5ce1 & to 
h %[n h[ !y be> ^u ! great problem :i*  
,i h "h endeav\r$1 9 "s slight degree1  
to elucidate4  ,z su* a l>ge body (     
facts & argum5ts f di/9ct sci5ces h be5 
"h br\ght toge!r1 ,i h giv5 a r full    

summ>y ( ! :ole argum5t1 & h /at$ my    
f9al conclusions 9 six %ort s5t5ces4 ,i 
!n briefly discuss ! two aspects ( !    
:ole problem--^? f ! mat]iali/ic & f !  
spirituali/ic po9ts ( view2 & ,i        
conclude ) a few g5]al obs]vations on ! 
almo/ un?9kable problems rais$ by ideas 
( ,inf9ity--problems :i* "s ( my critics
 ?\ght ,i _h attempt$ 9 "s degree to    
deal )1 b :i*1 ,i "h po9t out1 are      
altoge!r above & beyond ! que/ions ,i h 
discuss$1 & equally above & beyond !    
highe/ p[]s ( ! human intellect4        
,,broad/one1 ,,dorset1      ,septemb]   
#aijc4       ',! wild]'d m9d is to/ &   
lo/1       ,o sea1 9 ?y et]nal tide2    
,! reel+ bra9 essays 9 va91       ,o    
/>s1 to grasp ! va/ness wide6     ,!    
t]rible trem5d\s s*eme       ,t glimm]s 
9 ea* glanc+ light1     ,o night1 ,o    
/>s1 too rudely j>s       ,! f9ite ) !  
inf9ite6'      ,j4,h4 ,,dell4           
,,cont5ts      ,,*ap4                   
,,page       ,i4 ,,e>ly ,,ideas1        
#a      ,,ii4 ,,mod]n ,,ideas1          

#g     ,,iii4 ,,! ,,new ,,a/ronomy1     
#bd      ,,iv4 ,,! ,,di/ribution ,,( ,,!
 ,,/>s1                                 
#dg       ,v4 ,,di/ances ,,( ,,/>s3 ,,! 
,,sun',s ,,motion1                      
#gc      ,,vi4 ,,unity ,,& ,,evolution  
,,( ,,! ,,/>-,,sy/em1                   
#ii     ,,vii4 ,,are ,,! ,,/>s          
,,inf9ite8                              
#ace    ,,viii4 ,,our ,,relation ,,to   
,,! ,,milky ,,way1                      
#aef      ,,ix4 ,,! ,,uni=mity ,,(      
,,matt] ,,& ,,its ,,laws1               
#ahc       ,x4 ,,! ,,ess5tial ,,*>act]s 
,,( ,,organisms1                        
#aia      ,,xi4 ,,physical ,,conditions 
,,ess5tial ,,= ,,life1                  
#bjf     ,,xii4 ,,! ,,e>? ,,9 ,,relation
 ,,to ,,life1                           
#bah    ,,xiii4 ,,! ,,atmosph]e ,,9     
,,relation ,,to ,,life1                 
#bdc     ,,xiv4 ,,! ,,o!r ,,planets     
,,are ,,n ,,habitable1                  
#bfb      ,,xv4 ,,! ,,/>s3 ,,h ,,!y     
,,planets8 ,,are ,,!y           ,,useful

 ,,to ,,u8                              
#bhb     ,,xvi4 ,,/ability ,,( ,,!      
,,/>-,,sy/em3 ,,importance ,,(          
,,c5tral ,,position3 ,,summ>y ,,&       
,,conclusion1                 #bie      
,,index1                                
#cbf  ,,eight ,,diagrams ,,9 ,,! ,,text 
,,& ,,two ,,/> ,,*>ts ,,at ,,end4       
',:o is man1 & :at 8 place8             
,anxi\s asks ! he>t1 p]plext     ,9 ?is 
recklessness ( space1       ,worlds )   
worlds ?us int]mixt3     ,:at has he1   
?is atom creature1       ,9 ! inf9itude 
( ,nature8'      ,f4,t4 ,,palgrave4     
,,man',s ,,place ,,9 ,,! ,,univ]se      
,,*apt] ,i  ,,e>ly ,,ideas ,,z ,,to ,,! 
,,univ]se ,,& ,,its ,,relation ,,to     
,,man   ,:5 m5 atta9$ to suffici5t      
intellig5ce = speculations z to _! own  
nature & t ( ! e>? on :i* !y liv$1 !y   
mu/ h be5 pr(\ndly impress$ by ! nightly
 pageant ( ! />ry heav5s4 ,! int5se     
sp>kl+ brilliancy ( ,sirius & ,vega1 ! m
 massive & /eady lum9osity ( ,jupit] &  
,v5us1 ! /range gr\p+ ( ! bright] />s   

into con/ellations to :i* fanta/ic names
 indicat+ _! resemblance to v>i\s       
animals or t]re/rial objects seem$      
appropriate & 7 soon g5]ally adopt$1    
toge!r ) ! app>5tly innum]able />s (    
less & less brilliancy scatt]$ broadca/ 
ov] ! sky1 _m only be+ visible on !     
cle>e/ nights & to ! acute/ vision1     
con/itut$ altoge!r a sc5e ( m>vell\s &  
impressive spl5d\r ( :i* x mu/ h seem$  
almo/ impossible to atta9 any real k1 b 
:i* af=d$ an endless field = !          
imag9ation ( ! obs]v]4  ,! relation ( ! 
/>s to ! sun & moon 9 _! respective     
motions 0 "o ( ! e>lie/ problems = !    
a/ronom]1 & x 0 only solv$ by c>eful &  
cont9u\s obs]vation1 :i* %[$ t !        
invisibility ( ! =m] dur+ ! day 0 :olly 
due to ! blaze ( light1 & ?is is said to
 h be5 prov$ at an e>ly p]iod by !      
obs]v$ fact t f ! bottom ( v deep wells 
/>s c be se5 :ile ! sun is %9+4 ,dur+   
total eclipses ( ! sun also ! bright]   
/>s become visible1 &1 tak5 9 connection
 ) ! fixity ( position ( ! pole-/>1 & ! 

c\rse ( ^? circumpol> />s :i* nev] set 9
 ! latitudes ( ,greece1 ,egypt1 &       
,*aldea1 x soon became possible to frame
 a simple hypo!sis :i* suppos$ ! e>? to 
be susp5d$ 9 space1 :ile at an unkn[n   
di/ance f x a cry/al sph]e revolv$ ^u an
 axis indicat$ by ! pole-/>1 & c>ri$ ) x
 ! :ole ho/ ( heav5ly bodies4 ,?is 0 !  
!ory ( ,anaxim&] 7#edj ,b4,c471 & x s]v$
 z ! />t+-po9t = ! m complex !ory :i*   
cont9u$ to be held 9 v>i\s =ms & )      
endless modifications d[n to ! end ( !  
sixte5? c5tury4  ,x is believ$ t ! e>ly 
,greeks obta9$ "s k ( a/ronomy f !      
,*aldeans1 :o appe> to h be5 ! fir/     
sy/ematic obs]v]s ( ! heav5ly bodies by 
means ( in/rum5ts1 & :o are said to h   
discov]$ ! cycle ( eighte5 ye>s & t5    
days aft] :i* ! sun & moon return to !  
same relative positions z se5 f ! e>?4  
,! ,egyptians p]haps d]iv$ _! k f ! same
 s\rce1 b !re is no pro( t !y 7 great   
obs]v]s1 & ! accurate ori5tation1       
proportions1 & angles ( ! ,great        
,pyramid & its inn] passages may p]haps 

indicate a ,*aldean ar*itect4  ,! v     
obvi\s dep5d5ce ( ! :ole life ( ! e>? ^u
 ! sun1 z a giv] ( heat & light1        
suffici5tly expla9s ! orig9 ( ! belief t
 ! latt] 0 a m]e appanage ( ! =m]2 & z !
 moon also illum9ates ! night1 :ile !   
/>s z a :ole also give a v p]ceptible   
am\nt ( light1 especially 9 ! dry       
climate & cle> atmosph]e ( ! ,ea/1 & :5 
comp>$ ) ! pit*y d>kness ( cl\dy nights 
:5 ! moon is bel[ ! horizon1 x seem$    
cle> t ! :ole ( ^! gr& lum9>ies--sun1   
moon1 />s1 & planets--7 b p>ts ( !      
t]re/rial sy/em1 & exi/$ solely = !     
b5efit ( its inhabitants4  ,emp$ocles   
7#ddd ,b4,c47 is said to h be5 ! fir/ :o
 sep>at$ ! planets f ! fix$ />s1 by     
obs]v+ _! v peculi> motions1 :ile       
,py?agoras & 8 foll[]s det]m9$ correctly
 ! ord] ( _! succession f ,m]cury to    
,saturn4 ,no attempt 0 made to expla9 ^!
 motions till a c5tury lat]1 :5 ,eudoxus
 ( ,cnidos1 a contempor>y ( ,plato & (  
,ari/otle1 resid$ = "s "t 9 ,egypt1 :]e 
he became a skilful a/ronom]4 ,he 0 !   

fir/ :o sy/ematically work$ out &       
expla9$ ! v>i\s motions ( ! heav5ly     
bodies on ! !ory ( circul> & uni=m      
motion r\nd ! e>? z a c5tre1 by means ( 
a s]ies ( conc5tric sph]es1 ea* revolv+ 
at a diff]5t rate & on a diff]5t axis1 b
 s unit$ t all %>$ 9 ! motion r\nd !    
pol> axis4 ,! moon1 = example1 0 suppos$
 to be c>ri$ by ?ree sph]es1 ! fir/     
revolv$ p>allel to ! equator & acc\nt$ =
 ! diurnal motion--! ris+ & sett+--( !  
moon2 ano!r mov$ p>allel to ! ecliptic &
 expla9$ ! mon?ly *anges ( ! moon2 :ile 
! ?ird revolv$ at ! same rate b m       
obliquely1 & expla9$ ! incl9ation ( !   
moon's orbit to t ( ! e>?4 ,9 ! same way
 ea* ( ! five planets _h f\r sph]es1 two
 mov+ l ! fir/ two ( ! moon1 ano!r "o   
also mov+ 9 ! ecliptic 0 requir$ to     
expla9 ! retrograde motion ( ! planets1 
:ile a f\r? oblique to ! ecliptic 0 ne$$
 to expla9 ! div]g+ motions due to !    
diff]5t obliquity ( ! orbit ( ea* planet
 to t ( ! e>?4 ,?is 0 ! celebrat$       
,ptolemaic sy/em 9 ! simple/ =m ne$$ to 

acc\nt = ! m obvi\s motions ( ! heav5ly 
bodies4 ,b 9 ! c\rse ( ages ! ,greek &  
,arabian a/ronomical obs]v]s discov]$   
small div]g5ces due to ! v>i\s degrees (
 exc5tricity ( ! orbits ( ! moon &      
planets & _! consequ5t v>y+ rates (     
motion2 & to expla9 ^! o!r sph]es 7     
add$1 toge!r ) small] circles sometimes 
revolv+ exc5trically1 s t at l5g? ab\t  
sixty ( ^! sph]es1 epicycles & exc5trics
 7 requir$ to acc\nt = ! v>i\s motions  
obs]v$ ) ! rude in/rum5ts1 & ! rates (  
motion det]m9$ by ! v imp]fect          
"t-measur]s ( ^? e>ly ages4 ,& al?\gh a 
few great philosoph]s _h at diff]5t     
times reject$ ?is cumbr\s sy/em & _h    
endeav\r$ to promulgate m correct ideas1
 _! views _h no influ5ce on public      
op9ion ev5 among a/ronom]s &            
ma!maticians1 & ! ,ptolemaic sy/em held 
full sway d[n to ! "t ( ,cop]nicus1 & 0 
n f9ally giv5 up till ,kepl]'s ,laws &  
,galileo's ,dialogues compell$ !        
adoption ( simpl] & m intelligible      
!ories4  ,we are n[ s accu/om$ to look  

^u ! ma9 facts ( a/ronomy z m]e elem5t>y
 k t x is difficult = u to picture to   
ourselves ! /ate ( almo/ complete       
ignorance :i* prevail$ ev5 among ! mo/  
civilis$ nations ?r\gh\t antiquity & !  
,middle ,ages4 ,! rotundity ( ! e>? 0   
held by a few at a v e>ly p]iod1 & 0    
fairly well e/abli%$ 9 lat] classical   
times4 ,! r\gh det]m9ation ( ! size (   
our globe foll[$ soon aft]2 & :5        
in/rum5tal obs]vations became m p]fect1 
! di/ance & size ( ! moon 7 measur$ )   
suffici5t accuracy to %[ t x 0 v mu*    
small] ?an ! e>?4 ,b ?is 0 ! f>!/ limit 
( ! det]m9ation ( a/ronomical sizes &   
di/ances be=e ! discov]y ( ! telescope4 
,( ! sun's real di/ance & size no?+ 0   
kn[n except t x 0 mu* f>!r f u & mu*    
l>g] ?an ! moon2 b ev5 9 ! c5tury be=e !
 comm5cem5t ( ! ,*ri/ian era ,posidonius
 det]m9$ ! circumf]5ce ( ! e>? to be    
#bdj1jjj /adia1 equal to ab\t #bh1fjj   
miles1 a wond]fully close approximation 
consid]+ ! v imp]fect data at 8 comm&4  
,he is also said to h calculat$ ! sun's 

di/ance1 mak+ x only "o-?ird less ?an ! 
true am\nt1 b ?is mu/ h be5 a *ance     
co9cid5ce1 s9ce he _h no means ( measur+
 angles m accurately ?an to "o degree1  
:]eas 9 ! det]m9ation ( ! sun's di/ance 
in/rum5ts are requir$ :i* measure to a  
second ( arc4  ,be=e ! discov]y ( !     
telescope ! sizes ( ! planets 7 q       
unkn[n1 :ile ! mo/ t c\ld be asc]ta9$   
ab\t ! />s 01 t !y 7 at a v great       
di/ance f u4 ,?is be+ ! ext5t ( ! k ( ! 
anci5ts z to ! actual dim5sions &       
con/itution ( ! visible univ]se1 ( :i*1 
be x rememb]$1 ! e>? 0 held to be !     
c5tre1 we _c be surpris$ at ! almo/     
univ]sal belief t ?is univ]se exi/$     
solely = ! e>? & its inhabitants4 ,9    
classical times x 0 held to be at once !
 dwell+-place ( ! gods & _! gift to man1
 :ile 9 ,*ri/ian ages ?is belief 0 b    
slightly1 if at all1 *ang$2 & 9 bo? x   
w\ld h be5 consid]$ impi\s to ma9ta9 t !
 planets & />s did n exi/ = ! s]vice &  
delight ( mank9d alone b 9 all          
probability _h _! own inhabitants1 :o   

might 9 "s cases be ev5 sup]ior 9       
intellect to man himself4 ,b app>5tly1  
dur+ ! :ole p]iod ( :i* we are n[       
treat+1 no "o 0 s d>+ z ev5 to sugge/ t 
!re 7 o!r worlds ) o!r inhabitants1 & x 
0 no d\bt because ( ! idea t we occupi$ 
! _w1 ! v c5tre ( ! :ole surr\nd+       
univ]se :i* exi/$ solely = u1 t !       
discov]ies ( ,cop]nicus1 ,ty*o ,brah1   
,kepl]1 & ,galileo excit$ s mu*         
antagonism & 7 held to be impi\s &      
altoge!r incr$ible4 ,!y seem$ to upset !
 :ole accept$ ord] ( nature1 & to       
degrade man by remov+ 8 dwell+-place1 ! 
e>?1 f ! comm&+ c5tral position x _h    
always be=e occupi$4     ,,*apt] ,,ii   
,,mod]n ,,ideas ,,z ,,to ,,man',s       
,,relation ,,to ,,! ,,univ]se   ,!      
beliefs z to ! subord9ate position held 
by sun1 moon1 & />s 9 relation to ! e>?1
 :i* 7 almo/ univ]sal d[n to ! "t (     
,cop]nicus1 began to give way :5 !      
discov]ies ( ,kepl] & ! revelations ( ! 
telescope demon/rat$ t our e>? 0 n      
specially di/+ui%$ f ! o!r planets by   

any sup]iority ( size or position4 ,!   
idea at once arose t ! o!r planets might
 be inhabit$2 & :5 ! rapidly increas+   
p[] ( ! telescope1 & ( a/ronomical      
in/rum5ts g5]ally1 reveal$ ! wond]s ( ! 
sol> sy/em & ! ev]-increas+ numb]s ( !  
fix$ />s1 ! belief 9 o!r inhabit$ worlds
 became z g5]al z ! opposite belief _h  
be5 9 all prec$+ ages1 & x is /ill held 
9 modifi$ =ms to ! pres5t day4  ,b x may
 be truly said t ! lat] l ! e>li] belief
 is f\nd$ m ^u religi\s ideas ?an ^u a  
sci5tific & c>eful exam9ation ( ! :ole (
 ! facts bo? a/ronomical1 physical1 &   
biological1 & we mu/ agree ) ! late ,dr4
 ,:ewell1 t ! belief t o!r planets are  
inhabit$ has be5 g5]ally ent]ta9$1 n 9  
consequ5ce ( physical reasons b 9 spite 
( !m4 ,& he adds3--',x 0 held t ,v5us1  
or t ,saturn 0 inhabit$1 n because      
anyone c\ld devise1 ) any degree (      
probability1 any organis$ /ructure :i*  
w\ld be suitable to animal exi/5ce on ! 
surfaces ( ^? planets2 b because x 0    
conceiv$ t ! greatness or goodness ( !  

,creator1 or ,8 wisdom1 or "s o!r ( ,8  
attributes1 w\ld be manife/ly imp]fect1 
if ^! planets 7 n t5ant$ by liv+        
creatures4' ,^? p]sons :o h only he>d t 
_m em95t a/ronom]s d[n to our own day h 
upheld ! belief 9 a ',plurality (       
,worlds' w naturally suppose t !re mu/  
be "s v cog5t argum5ts 9 its fav\r1 & t 
x mu/ be support$ by a consid]able body 
( m or less conclusive facts4 ,!y w     
!re=e probably be surpris$ to he> t any 
direct evid5ce :i* may be held to       
support ! view is almo/ :olly want+1 & t
 ! great] "p ( ! argum5ts are weak &    
flimsy 9 ! extreme4  ,( late ye>s1 x is 
true1 "s few writ]s h v5tur$ to po9t out
 h[ _m difficulties !re are 9 ! way (   
accept+ ! belief1 b ev5 ^! h nev] exam9$
 ! "q f ! v>i\s po9ts ( view :i* are    
ess5tial to a prop] consid]ation ( x2   
:ile1 s f> z x is /ill upheld1 x is     
?\ght suffici5t to %[1 t 9 ! case ( "s (
 ! planets1 !re seem to be su*          
conditions z to r5d] life possible4 ,9 !
 millions ( planet>y sy/ems suppos$ to  

exi/ x is held to be incr$ible t !re are
 n great numb]s z well fitt$ to be      
inhabit$ by animals ( all grades1       
includ+ "s z high z man or ev5 high]1 & 
t we mu/1 !re=e1 believe t !y are s     
inhabit$4 ,z 9 ! pres5t "w ,i propose to
 %[1 t ! probabilities & ! weight (     
direct evid5ce t5d to an exactly        
opposite conclusion1 x w be well to pass
 briefly 9 review ! v>i\s writ]s on !   
subject1 & to give "s indication ( !    
argum5ts !y h us$ & ! facts !y h set =?4
 ,= ! e>li] uphold]s ( ! !ory ,i am     
indebt$ to ,dr4 ,:ewell1 :o1 9 8        
,dialogue on ! ,plurality ( ,worlds--a  
,supplem5t to 8 well-kn[n volume on !   
subject--ref]s to all writ]s (          
importance kn[n to him4  ,! e>lie/ are !
 great a/ronom]s ,kepl] & ,huyg5s1 & !  
le>n$ ,bi%op ,wilk9s1 :o all believ$ t !
 moon 0 or might probably be inhabit$2 &
 ( ^! ,:ewell consid]s ,wilk9s to h be5 
by f> ! mo/ ?\ghtful & e>ne/ 9 support+ 
8 views4 ,!n we h ,sir ,isaac ,newton   
himself :o1 at consid]able l5g?1 argu$ t

 ! sun 0 probably inhabit$4 ,b ! fir/   
regul> "w devot$ to ! subject appe>s to 
h be5 writt5 by ,m4 ,font5elle1         
,secret>y to ! ,academy ( ,sci5ces 9    
,p>is1 :o 9 #afhf publi%$ 8             
,conv]sations on ! ,plurality ( ,worlds4
 ,! book consi/$ ( five *apt]s1 ! fir/  
expla9+ ! ,cop]nican ,!ory2 ! second    
ma9ta9+ t ! moon is a habitable _w2 !   
?ird gives p>ticul>s z to ! moon1 &     
argues t ! o!r planets are also         
inhabit$2 ! f\r? gives details z to !   
worlds ( ! five planets2 :ile ! fif?    
decl>es t ! fix$ />s are suns1 & t ea*  
illum9ates a _w4 ,?is "w 0 s well       
writt51 & ! subject prov$ s attractive1 
t x 0 translat$ into all ! *ief         
,european languages1 :ile ! a/ronom]    
,lal&e edit$ "o ( ! ,fr5* editions4     
,?ree ,engli% translations 7 publi%$1 & 
"o ( ^! w5t ?r\gh six editions d[n to ! 
ye> #agcg4 ,! influ5ce ( ?is "w 0 v     
great & no d\bt l$ to t g5]al acceptance
 ( ! !ory by su* m5 z ,sir ,william     
,h]s*el1 ,sir ,john ,h]s*el1 ,dr4       

,*alm]s1 ,dr4 ,dick1 ,dr4 ,isaac        
,taylor1 & ,m4 ,arago1 al?\gh x 0 :olly 
f\nd$ on pure speculation1 & !re 0 no?+ 
t c\ld be call$ evid5ce on "o side or ! 
o!r4  ,?is 0 ! /ate ( public op9ion :5  
an anonym\s "w appe>$ 79 #ahec7 "u !    
some:at mislead+ title ( ,! ,plurality (
 ,worlds3 ,an ,essay4 ,?is 0 writt51 z  
already /at$1 by ,dr4 ,:ewell1 :o1 = !  
fir/ "t1 v5tur$ to d\bt ! g5]ally       
accept$ !ory1 & %[$ t all ! evid5ce at  
our comm& l$ to ! conclusion t "s ( !   
planets 7 c]ta9ly n habitable1 t o!rs 7 
probably n s1 :ile 9 none 0 !re t close 
correspond5ce ) t]re/rial conditions :i*
 seem$ ess5tial = _! habitability by !  
high] animals or by man4 ,! book 0 ably 
writt5 & %[$ consid]able k ( ! sci5ce ( 
! "t1 b x 0 v diffuse1 & ! l>g] "p ( x 0
 devot$ to %[+ t 8 views 7 n 9 any way  
oppos$ to religion4 ,"o ( 8 be/ argum5ts
 0 f\nd$ on ! proposition t '! ,e>?'s   
,orbit is ! ,temp]ate ,zone ( ! ,sol>   
,sy/em1' t !re only is x possible to h  
^? mod]ate v>iations ( heat & cold1     

dryness & moi/ure1 :i* are suitable =   
animal life4 ,he sugge/$ t ! out]       
planets ( ! sy/em consi/$ ma9ly ( wat]1 
gases1 & vap\r1 z indicat$ by _! l[     
specific gravity1 & 7 !re=e q unsuitable
 = t]re/rial life2 :ile ^? ne> ! sun 7  
equally unsuit$1 because1 ow+ to ! great
 am\nt ( sol> heat1 wat] c\ld n exi/ on 
_! surfaces4 ,he devotes a great deal ( 
space to ! evid5ce t !re is no animal   
life on ! moon1 & tak+ ?is z prov$1 he  
uses x z a c\nt] argum5t aga9/ ! o!r    
side4 ,!y always urge t1 ! e>? be+      
inhabit$1 we mu/ suppose ! o!r planets  
to be s too2 to :i* he replies3--,we "k 
t ! moon is n inhabit$ ?\gh x has all ! 
advantage ( proximity to ! sun t ! e>?  
has2 :y !n %\ld n o!r planets be equally
 un9habit$8  ,he !n comes to ,m>s &     
admits t ?is planet is v l ! e>? s f> z 
we c judge1 & t x may !re=e be inhabit$1
 or z ! au?or expresses x1 'may h be5   
judg$ wor?y ( inhabitants by its ,mak]4'
 ,b he urges ! small size ( ,m>s1 its   
coldness ow+ to di/ance f ! sun1 & t !  

annual melt+ ( its pol> ice-caps w keep 
x cold all ?r\gh ! summ]4 ,if !re are   
animals !y are probably ( a l[ type l ! 
saurians & iguanodons ( our seas dur+ ! 
,weald5 epo*2 b1 he argues1 z ev5 on our
 e>? ! long process ( prep>ation = man 0
 c>ri$ on = c\ntless millions ( ye>s1 we
 ne$ n discuss :e!r !re are intellig5t  
be+s on ,m>s till we h "s bett] evid5ce 
t !re are any liv+ creatures at all4    
,sev]al ( ! e>ly *apt]s are devot$ to an
 attempt to m9imise ! difficulties ( ^? 
religi\s p]sons :o feel oppress$ by !   
imm5sity & complexity ( ! mat]ial       
univ]se z reveal$ by mod]n a/ronomy2 &  
by ! almo/ inf9ite insignificance ( man 
& 8 dwell+-place1 ! e>?1 9 comp>ison )  
x1 an insignificance va/ly increas$ if n
 only ! planets ( ! sol> sy/em1 b also  
^? :i* circle ar\nd ! myriads ( suns1   
are also !atres ( life4 ,& ^! p]sons are
 fur!r disquiet$ because ! v same facts 
are us$ by sceptics ( v>i\s k9ds 9 _!   
attacks ^u ,*ri/ianity4 ,su* writ]s po9t
 out ! irrationality & absurdity (      

suppos+ t ! ,creator ( all ?is          
unimag9able va/ness ( suns & sy/ems1    
fill+ = all we "k endless space1 %\ld   
take any special int]e/ 9 s mean &      
pitiful a creature z man1 ! imp]fectly  
develop$ inhabitant ( "o ( ! small]     
worlds atta*$ to a second or ?ird-rate  
sun1 a be+ ^: :ole hi/ory is "o ( w> &  
blood%$1 ( tyranny1 torture1 & dea?2 ^: 
awful record is pictur$ by himself 9 su*
 books z ,josephus' ,hi/ory ( ! ,jews1 !
 ,decl9e & ,fall ( ! ,roman ,empire1 &  
ev5 m =cibly summ>is$ 9 t t]rible       
picture ( human fi5di%ness & mis]y1 ,!  
,m>tyrdom ( ,man2 :ile _! "* is indicat$
 by "o ( ! k9de/ & simple/ ( _! poets 9 
! re/ra9$ b expressive l9es3--          
',man's inhumanity to man     ,makes    
c\ntless ?\s&s m\rn4'  ,x is = su* a be+
 z ?is1 !y say1 t ,god %\ld h specially 
reveal$ ,8 w "s ?\s&s ( ye>s ago1 & f9d+
 t ,8 comm&s 7 n obey$1 ,8 w n fulfill$1
 yet orda9$ = _! b5efit ! necess>ily    
unique sacrifice ( ,8 ,son1 9 ord] to   
save a small portion ( ^! 'mis]able     

s9n]s' f ! natural & well-des]v$        
consequ5ce ( _! /up5d\s follies1 _!     
unimag9able crimes8 ,su* a belief !y    
ma9ta9 is too absurd1 too incr$ible1 to 
be held by any rational be+1 & x becomes
 ev5 less cr$ible & less rational if we 
ma9ta9 t !re are c\ntless o!r inhabit$  
worlds4  ,x is v difficult = ! religi\s 
man to make any adequate reply to su* an
 attack z ?is1 & z a result _m h felt _!
 position to be unt5able & h accord+ly  
lo/ all fai? 9 ! special dogmas (       
or?odox ,*ri/ianity4 ,!y feel !mselves  
really to be betwe5 ! horns ( a dilemma4
 ,if !re are myriads ( o!r worlds1 x    
seems incr$ible t !y %\ld ea* be !      
object ( a special revelation & a       
special sacrifice4 ,if1 on ! o!r h&1 we 
are ! only intellig5t be+s t exi/ 9 !   
mat]ial univ]se1 & are really ! highe/  
creative product ( a ,be+ ( inf9ite     
wisdom & p[]1 !y _c b wond] at ! va/    
app>5t disproportion betwe5 ! ,creator &
 ! creat$1 & are sometimes driv5 to     
,a!ism f ! hopelessness ( compreh5d+ s  

mean & petty a result z ! sole outcome (
 inf9ite p[]4  ,:ewell tells u t ! great
 prea*]1 ,dr4 ,*alm]s1 9 8 ,a/ronomical 
,disc\rses1 attempt$ a reply to ^!      
difficulties1 b1 9 8 op9ion1 n a v      
successful "o2 & a l>ge "p ( 8 own "w is
 devot$ to ! same purpose4 ,8 ma9 po9t  
seems to be t we "k too little ( !      
univ]se to arrive at any def9ite        
conclusions on ! "q at issue1 & t any   
ideas t we may h z to ! purposes ( !    
,creator 9 =m+ ! va/ sy/em we see ar\nd 
u are almo/ sure to be errone\s4 ,we mu/
 !re=e be cont5t to rema9 ignorant1 &   
mu/ re/ satisfi$ 9 ! belief t ! ,creator
 _h a purpose al?\gh we are n yet       
p]mitt$ to "k :at x 04 ,& to ^? :o urge 
t 9 o!r worlds !re may be o!r laws (    
nature :i* may r5d] !m q z habitable by 
intellig5t be+s z our _w is = u1 he     
replies1 t if we are to suppose new laws
 ( nature 9 ord] to r5d] ea* planet     
habitable1 !re is an end ( all rational 
inquiry on ! subject1 & we may ma9ta9 & 
believe t animals may live on ! moon )\t

 air or wat]1 & on ! sun expos$ to heat 
:i* vaporises e>?s & metals4  ,8        
conclud+ argum5t1 & p]haps "o ( 8       
/ronge/1 is t f\nd$ ^u ! dignity ( man1 
z conf]r+ a pre-em95ce ^u ! planet :i*  
has produc$ him4 ',if1' he says1 'man be
 n m]ely capable ( ,virtue & ,duty1 (   
univ]sal ,love & ,self-,devotion1 b be  
also immortal2 if 8 be+ be ( inf9ite    
duration1 8 s\l creat$ nev] to die2 !n1 
inde$1 we may well say t "o s\l         
outweighs ! :ole un9tellig5t creation4' 
,& !n1 address+ ! religi\s _w1 he urges 
t1 if1 z !y believe1 ,god has r$eem$ man
 by ! sacrifice ( ,8 ,son1 & has giv5 to
 him a revelation ( ,8 w1 !n inde$ no   
o!r conception is possible ?an t he is !
 sole & highe/ product ( ! univ]se4 ',! 
elevation ( millions ( intellectual1    
moral1 religi\s1 spiritual creatures1 to
 a de/9y s prep>$1 consummat$1 &        
develop$1 is no unwor?y occupation ( all
 ! capacities ( space1 "t1 & matt]4' ,!n
 ) a *apt] on ',! ,unity ( ! ,_w1' & "o 
on ',! ,future1' nei!r ( :i* conta9s    

any?+ :i* adds to ! =ce ( 8 argum5t1 !  
book ends4  ,! publication ( ?is able if
 r vague & diffuse "w1 conte/+ popul>   
op9ions1 0 foll[$ by a bur/ ( indignant 
criticism on ! "p ( a man ( consid]able 
em95ce 9 "s bran*es ( physics--,sir     
,david ,brew/]1 b :o 0 v inf]ior1 bo? 9 
g5]al k ( sci5ce & 9 lit]>y skill1 to ! 
writ] ^: views he oppos$4 ,! purport ( !
 book 9 :i* he set =? 8 objections is   
indicat$ by its title--,m ,worlds ?an   
,"o1 ! ,cre$ ( ! ,philosoph] & ! ,hope (
 ! ,*ri/ian4 ,?\gh writt5 ) mu* =ce &   
conviction x appeals ma9ly to religi\s  
prejudices1 & assumes ?r\gh\t t e planet
 & /> is a special creation1 & t !      
peculi>ities ( ea* 7 design$ = "s       
special purpose4 ',if1' he says1 '! moon
 _h be5 de/9$ to be m]ely a lamp to our 
e>?1 !re 0 no occasion to v>iegate its  
surface ) l(ty m\nta9s & ext9ct         
volcanoes1 & cov] x ) l>ge pat*es (     
matt] t reflect diff]5t quantities (    
light & give its surface ! appe>ance (  
cont95ts & seas4 ,x w\ld h be5 a bett]  

lamp _h x be5 a smoo? piece ( lime or ( 
*alk4' ,x is1 !re=e1 he ?9ks1 prep>$ =  
inhabitants2 & !n he argues t all ! o!r 
satellites are also inhabit$4 ,aga9 he  
says t ':5 x 0 f\nd t ,v5us 0 ab\t !    
same size z ! ,e>?1 ) m\nta9s & valleys1
 days & nights1 & ye>s analog\s to our  
own1 ! absurdity ( believ+ t %e _h no   
inhabitants1 :5 no o!r rational purpose 
c\ld be assign$ = h] creation1 became an
 argum5t ( a c]ta9 am\nt t %e 01 l !    
,e>?1 ! seat ( animal & vegetable life4'
 ,!n1 :5 x 0 f\nd t ,jupit] 0 s gigantic
 'z to require f\r moons to give him    
light1 ! argum5t f analogy t he 0       
inhabit$ became /rong] also1 because x  
ext5d$ to two planets4' ,& ?us ea*      
successive planet hav+ c]ta9 po9ts (    
analogy ) ! o!rs becomes an additional  
argum5t2 s t :5 we take acc\nt ( all !  
planets1 ) atmosph]e1 & cl\ds1 & arctic 
sn[s1 & trade-w9ds1 ! argum5t f analogy 
becomes1 he urges1 v p[]ful2--'& !      
absurdity ( ! opposite op9ion1 t planets
 %\ld h moons & no inhabitants1         

atmosph]es ) no creatures to brea! 9 !m1
 & curr5ts ( air )\t life to be fann$1  
became a =midable argum5t :i* few m9ds1 
if any1 c\ld resi/4'  ,! "w is full (   
su* weak & fallaci\s rhetoric & ev51 if 
possible1 /ill weak]4 ,?us aft] describ+
 d\ble />s1 he adds--',b no p]son c     
believe t two suns c\ld be plac$ 9 !    
heav5s = no o!r purpose ?an to revolve  
r\nd _! common c5tre ( gravity'2 & he   
concludes 8 *apt] on ! />s ?us3--',:]ev]
 !re is matt] !re mu/ be ,life2 ,life   
,physical to enjoy its beauties--,life  
,moral to wor%ip its ,mak]1 & ,life     
,intellectual to proclaim ,8 wisdom & ,8
 p[]4' ,& aga9--',a h\se )\t t5ants1 a  
city )\t citiz5s1 pres5ts to our m9ds ! 
same idea z a planet )\t life1 & a      
univ]se )\t inhabitants4 ,:y ! h\se 0   
built1 :y ! city 0 f\nd$1 :y ! planet 0 
made1 & :y ! univ]se 0 creat$1 x w\ld be
 difficult ev5 to conjecture4' ,argum5ts
 ( ?is k9d1 :i* 9 almo/ e case beg ! "q 
at issue1 are repeat$ ad nauseam4 ,b he 
also appeals to ! ,old ,te/am5t to      

support 8 views1 by quot+ ! f9e passage 
9 ! ,psalms--',:5 ,i consid] ,?y heav5s 
! "w ( ,?y f+]s1 ! moon & ! />s :i* ,?\ 
ha/ orda9$2 :at is man t ,?\ art m9dful 
( him8' on :i* he rem>ks--',we _c d\bt t
 inspiration reveal$ to him ,david !    
magnitude1 ! di/ances1 & ! f9al cause1 (
 ! glori\s sph]es :i* fix$ 8            
admiration4' ,& aft] quot+ v>i\s o!r    
passages f ! prophets1 all z he ?9ks    
support+ ! same view1 he sets =? !      
extraord9>y idea z a confirmatory       
argum5t1 t ! planets or "s ( !m are to  
be ! future abode ( man4 ,=1 he         
says--',man 9 8 future /ate ( exi/5ce is
 to consi/1 z at pres5t1 ( a spiritual  
nature resid+ 9 a corporeal frame4 ,he  
mu/ live1 !re=e1 ^u a mat]ial planet1   
subject to all ! laws ( matt]4' ,& he   
concludes ?us3--',if !re is n room1 !n1 
on our globe = ! millions ( millions (  
be+s :o h liv$ & di$ on its surface1 we 
c sc>cely d\bt t _! future abode mu/ be 
on "s ( ! prim>y or second>y planets ( !
 sol> sy/em1 ^: inhabitants h ceas$ to  

exi/1 or ^u planets :i* h long be5 9 a  
/ate ( prep>ation1 z our e>? 01 = !     
adv5t ( intellectual life4'  ,x is      
pleasant to turn f su* weak & trivial   
argum5ts to ! only o!r mod]n works :i*  
deal at "s l5g? ) ?is subject1 ! late   
,ri*>d ,a4 ,proctor's ,o!r ,worlds ?an  
,ours1 & a volume publi%$ five ye>s lat]
 "u ! title--,our ,place ,among         
,inf9ities4 ,writt5 z ^! 7 by "o ( ! mo/
 accompli%$ a/ronom]s ( 8 day1 rem>kable
 alike = ! acut5ess ( 8 reason+ & !     
cle>ness ( 8 /yle1 we are always int]e/$
 & in/ruct$ ev5 :5 we _c agree ) 8      
conclusions4 ,9 ! fir/ "w m5tion$ above1
 he assumes1 l ,sir ,david ,brew/]1 !   
antec$5t probability t ! planets are    
inhabit$ & on mu* ! same !ological      
gr\nds4 ,s /rongly does he feel ?is t he
 cont9ually speaks z if ! planets mu/ be
 inhabit$ unless we c %[ v good reason t
 !y _c be s1 ?us ?r[+ ! burd5 ( prov+ a 
negative on 8 oppon5ts1 :ile he does n  
attempt to prove 8 positive cont5tion t 
!y are inhabit$1 except by purely       

hypo!tical consid]ations z to !         
,creator's purpose 9 br++ !m into       
exi/5ce4  ,b />t+ f ?is po9t he         
endeav\rs to %[ h[ ,:ewell's v>i\s      
difficulties may be ov]come1 & "h he    
always appeals to a/ronomical or        
physical facts1 & reasons well ^u !m4 ,b
 he is q hone/2 &1 com+ to ! conclusion 
t ,jupit] & ,saturn1 ,uranus & ,neptune1
 _c be habitable1 he adduces ! evid5ce &
 pla9ly /ates ! result4 ,b !n he ?9ks t 
! satellites ( ,jupit] & ,saturn may be 
habitable1 & if !y may be1 !n he        
concludes t !y mu/4 ,"o great ov]sight 9
 8 :ole argum5t is1 t he is satisfi$ )  
%[+ ! possibility t life may exi/ n[1 b 
nev] deals ) ! "q ( :e!r life c\ld h be5
 develop$ f its e>lie/ rudim5ts up to ! 
production ( ! high] v]tebrates & man2 &
 ?is1 z ,i %all %[ lat]1 is ! crux ( !  
:ole problem4  ,) reg>d to ! o!r        
planets1 aft] a c>eful exam9ation ( all 
t is kn[n ab\t !m1 he arrives at !      
conclusion t if ,m]cury is protect$ by a
 cl\d-lad5 atmosph]e ( a peculi> k9d x  

may possibly1 b n probably1 support high
 =ms ( animal life4 ,b 9 ! case ( ,v5us 
& ,m>s he f9ds s mu* resemblance to & s 
_m analogies ) our e>?1 t he concludes t
 !y almo/ c]ta9ly are s4  ,9 ! case ( ! 
fix$ />s1 n[ t we "k by spectroscopic   
obs]vations t !y are true suns1 _m ( :i*
 closely resemble our sun & give out    
light & heat z he does1 ,mr4 ,proctor   
argues1 t ',! va/ supplies ( heat ?us   
emitt$ by ! />s n only sugge/ !         
conclusion t !re mu/ be worlds ar\nd ^! 
orbs = :i* ^! heat-supplies are int5d$1 
b po9t to ! exi/5ce ( ! v>i\s =ms ( =ce 
into :i* heat may be transmut$4 ,we "k t
 ! sun's heat p\r$ ^u our e>? is /or$ up
 9 vegetable & animal =ms ( life2 is    
pres5t 9 all ! ph5om5a ( nature--9 w9ds 
& cl\ds & ra91 9 ?und] & lightn+1 /orm &
 hail2 & t ev5 ! works ( man are p]=m$  
by virtue ( ! sol> heat-supplies4 ,?us !
 fact t ! />s s5d =? heat to ! worlds   
:i* circle ar\nd !m sugge/s at once !   
?\ght t on ^? worlds !re mu/ exi/ animal
 & vegetable =ms ( life4' ,we may note t

 9 ! fir/ "p ( ?is passage ! pres5ce (  
worlds or planets is 'sugge/$1' :ile    
lat] on '! worlds :i* circle r\nd !m' is
 spok5 ( z if x 7 a prov$ fact f :i* !  
pres5ce ( vegetable & animal life may be
 inf]r$4 ,a sugge/ion dep5d+ on a prec$+
 sugge/ion is n a v firm basis = s va/ &
 wide-rea*+ a conclusion4  ,9 ! second  
"w ref]r$ to above !re is "o *apt]      
entitl$1 ',a ,new ,!ory ( ,life 9 o!r   
,worlds1' :]e ! au?or gives 8 m matur$  
views ( ! "q1 :i* are briefly /at$ 9 !  
preface z be+ 't ! weight ( evid5ce     
fav\rs my !ory ( ! 7relative7 paucity ( 
worlds4' ,8 views are l>gely f\nd$ on ! 
!ory ( probabilities1 ( :i* subject he  
_h made a special /udy4 ,tak+ fir/ our  
e>?1 he %[s t ! p]iod dur+ :i* life has 
exi/$ ^u x is v small 9 comp>ison ) t   
dur+ :i* x mu/ h be5 sl[ly =m+ & cool+1 
& its atmosph]e cond5s+ s z to =m l& &  
wat] on its surface4 ,& if we consid] ! 
"t ! e>? has be5 occupi$ by man1 t is a 
v m9ute "p1 p]haps n ! ?\s&? "p1 ( !    
p]iod dur+ :i* x has exi/$ z a planet4  

,x foll[s t ev5 if we consid] only ^?   
planets ^: physical condition seems to u
 to be su* z to be able to su/a9 life1 !
 *ances are p]haps hundr$s to "o aga9/  
_! be+ at t p>ticul> /age :5 life has   
begun to be develop$1 or if x has begun 
has rea*$ z high a developm5t z on our  
e>?4  ,) reg>d to ! />s1 ! argum5t is   
/ill /rong]1 because ! epo*s requir$ =  
_! =mation are altoge!r unkn[n1 :ile z  
to ! conditions requir$ = ! =mation (   
planet>y sy/ems ar\nd !m we are totally 
ignorant4 ,to ?is ,i w\ld add t we are  
equally ignorant z to ! probability or  
ev5 possibility ( _m ( ^! suns produc+  
planets :i*1 by _! position1 size1      
atmosph]e1 or o!r physical conditions c 
possibly become life-produc+ worlds4 ,&1
 z we %all see lat]1 ?is po9t has be5   
ov]look$ by all writ]s1 includ+ ,mr4    
,proctor himself4 ,8 conclusion is1 !n1 
t al?\gh ! worlds :i* possess life at   
all approa*+ t ( our e>? may be         
relatively few 9 numb]1 yet consid]+ !  
univ]se z practically inf9ite 9 ext5t1  

!y may be really v num]\s4  ,x has be5  
necess>y to give ?is sket* ( ! views (  
^? :o h writt5 specially on ! "q ( !    
,plurality ( ,worlds1 because ! works   
ref]r$ to h be5 v widely read & h       
influ5c$ educat$ op9ion ?r\gh\t ! _w4   
,moreov]1 ,mr4 ,proctor1 9 8 la/ "w on !
 subject1 speaks ( ! !ory z be+         
'id5tifi$ ) mod]n a/ronomy'2 & 9 fact   
popul> works /ill discuss x4 ,b all ^!  
foll[ ! same g5]al l9e ( argum5t z ^?   
already ref]r$ to1 & ! curi\s ?+ is t   
:ile ov]look+ _m ( ! mo/ ess5tial       
conditions !y (t5 introduce o!rs :i* are
 by no means ess5tial--z1 = in/ance1 t !
 atmosph]e mu/ h ! same proportion (    
oxyg5 z our own4 ,!y seem to ?9k t if   
any ( our quadrup$s or birds tak5 to    
ano!r planet c\ld n live !re1 no animals
 ( equally high organisation c\ld       
inhabit x2 entirely ov]look+ ! v obvi\s 
fact t1 suppos+1 z is almo/ c]ta91 t    
oxyg5 is necess>y = life1 !n1 :atev]    
proportion ( oxyg5 )9 c]ta9 limits 0    
pres5t1 ! =ms ( life t arose w\ld       

necess>ily be organis$ 9 adaptation to t
 proportion1 :i* might be consid]ably   
less or great] ?an on ! e>?4  ,! pres5t 
volume w %[ h[ extremely inadequate has 
be5 ! treatm5t ( ?is "q1 :i* involves a 
v>iety ( important consid]ations hi!rto 
altoge!r ov]look$4 ,^! are extremely    
num]\s & v v>i$ 9 _! "*1 & ! fact t !y  
all po9t to "o conclusion--a conclusion 
:i* s f> z ,i am aw>e no previ\s writ]  
has rea*$--r5d]s x at lea/ wor?y ( !    
c>eful consid]ation ( all unbiass$      
?9k]s4 ,! :ole subject is "o z to :i* no
 direct evid5ce is obta9able1 b ,i      
v5ture to ?9k t ! conv]g5ce ( s _m      
probabilities & indications t[>ds a s+le
 def9ite !ory1 intimately connect$ ) !  
nature & de/9y ( man himself1 raises ?is
 !ory to a v mu* high] level (          
probability ?an ! vague possibilities & 
!ological sugge/ions :i* are ! utmo/ t h
 be5 adduc$ by previ\s writ]s4  ,9 ord] 
to make e /ep ( my argum5t cle>ly       
intelligible to all educat$ read]s1 x w 
be necess>y to ref] cont9ually to !     

m>vell\s ext5sion ( our k ( ! univ]se   
obta9$ dur+ ! la/ half-c5tury1 &        
con/itut+ :at is t]m$ ! ,new ,a/ronomy4 
,! next *apt] w !re=e be devot$ to a    
popul> exposition ( ! new me?ods (      
rese>*1 s t ! results rea*$1 :i* w h to 
be ref]r$ to 9 succe$+ *apt]s1 may be n 
only accept$1 b cle>ly und]/ood4        
,,*apt] ,,iii  ,,! ,,new ,,a/ronomy     
,dur+ ! latt] half ( ! n9ete5? c5tury   
discov]ies 7 made :i* ext5d$ ! p[]s (   
a/ronomical rese>* into entirely new &  
unexpect$ regions1 comp>able to ^? :i* 7
 op5$ up by ! discov]y ( ! telescope m  
?an two c5turies be=e4 ,! old] a/ronomy 
= m ?an two ?\s& ye>s 0 purely me*anical
 & ma!matical1 be+ limit$ to obs]vation 
& measurem5t ( ! app>5t motions ( !     
heav5ly bodies1 & ! attempts to d$uce1 f
 ^! app>5t motions1 _! real motions1 &  
?us det]m9e ! actual /ructure ( ! sol>  
sy/em4 ,?is 0 fir/ done :5 ,kepl]       
e/abli%$ 8 ?ree celebrat$ laws3 & lat]1 
:5 ,newton %[$ t ^! laws 7 necess>y     
consequ5ces ( ! "o law ( gravitation1 & 

:5 succe$+ obs]v]s & ma!maticians prov$ 
t ea* fre% irregul>ity 9 ! motions ( !  
planets 0 explicable by a m ?or\gh &    
m9ute application ( ! same laws1 ?is    
bran* ( a/ronomy rea*$ its highe/ po9t (
 effici5cy & left v little m to be      
desir$4  ,!n1 z ! telescope became      
successively improv$1 ! c5tre ( int]e/ 0
 %ift$ to ! surfaces ( ! planets & _!   
satellites1 :i* 7 wat*$ & scrut9is$ ) ! 
greate/ assiduity 9 ord] if possible to 
atta9 "s am\nt ( k ( _! physical        
con/itution & pa/ hi/ory4 ,a simil>     
m9ute scrut9y 0 giv5 to ! />s & nebul1  
_! di/ribution & gr\p+1 & ! :ole heav5s 
7 mapp$ out1 & elaborate catalogues     
con/ruct$ by en?usia/ic a/ronom]s 9 e "p
 ( ! _w4 ,o!rs devot$ !mselves to !     
imm5sely difficult problem ( det]m9+ !  
di/ances ( ! />s1 & by ! middle ( !     
c5tury a few su* di/ances _h be5        
satisfactorily measur$4  ,?us1 up to !  
middle ( ! n9ete5? c5tury x appe>$      
likely t ! future ( a/ronomy w\ld re/   
almo/ entirely on ! improvem5t ( !      

telescope1 & ( ! v>i\s in/rum5ts (      
measurem5t by means ( :i* m accurate    
det]m9ations ( di/ances might be obta9$4
 ,inde$1 ! au?or ( ! ,positive          
,philosophy1 ,augu/e ,comte1 felt s sure
 ( ?is t he deprecat$ all fur!r att5tion
 to ! />s z pure wa/e ( "t t c\ld nev]  
lead to any useful or int]e/+ result4 ,9
 8 ,philosophical ,treatise on ,popul>  
,a/ronomy publi%$ 9 #ahdd1 he wrote v   
/rongly on ?is po9t4 ,he !re tells u t1 
z ! />s are only accessible to u by     
sight !y mu/ always rema9 v imp]fectly  
kn[n4 ,we c "k little m ?an _! m]e      
exi/5ce4 ,ev5 z reg>ds s simple a       
ph5om5on z _! temp]ature ?is mu/ always 
be inappreciable to a purely visual     
exam9ation4 ,our k ( ! />s is = ! mo/ "p
 purely negative1 t is1 we c det]m9e    
only t !y d n belong to our sy/em4      
,outside t sy/em !re exi/s1 9 a/ronomy1 
only obscurity & confusion1 = want (    
indisp5sable facts2 & he concludes      
?us3--',x is1 !n1 9 va9 t = half a      
c5tury x has be5 endeav\r$ to di/+ui%   

two a/ronomies1 ! "o sol> ! o!r sid]eal4
 ,9 ! eyes ( ^? = :om sci5ce consi/s (  
real laws & n ( incoh]5t facts1 ! second
 exi/s only 9 "n1 & ! fir/ alone        
con/itutes a true a/ronomy2 & ,i am n   
afraid to ass]t t x w always be s4' ,&  
he adds t--'all ef=ts direct$ to ?is    
subject = half a c5tury h only produc$  
an accumulation ( incoh]5t empirical    
facts :i* c only int]e/ an irrational   
curiosity4'  ,seldom has a confid5t     
ass]tion ( f9ality 9 sci5ce receiv$ s   
cru%+ a reply z 0 giv5 to ! above       
/atem5ts ( ,comte by ! discov]y 9 #ahfj 
7only ?ree ye>s aft] 8 dea?7 ( ! me?od (
 spectrum-analysis :i*1 9 its           
application to ! />s1 has revolutionis$ 
a/ronomy1 & has enabl$ u to obta9 t v   
k9d ( k :i* he decl>$ mu/ be = ev]      
beyond our rea*4 ,?r\gh x we h acquir$  
accurate in=mation z to ! physics &     
*emi/ry ( ! />s & nebul1 s t we n[ "k   
really m ( ! nature1 con/itution1 &     
temp]ature ( ! enorm\sly di/ant suns :i*
 we di/+ui% by ! g5]al t]m />s1 ?an we d

 ( mo/ ( ! planets ( our own sy/em4 ,x  
has also enabl$ u to asc]ta9 ! exi/5ce (
 num]\s invisible />s1 & to det]m9e _!  
orbits1 _! rate ( motion1 & ev51        
approximately1 _! mass4 ,! despis$ /ell>
 a/ronomy ( ! e>ly "p ( ! c5tury has n[ 
tak5 rank z ! mo/ pr(\ndly int]e/+      
dep>tm5t ( t gr& sci5ce1 & ! bran* :i*  
(f]s ! greate/ promise ( future         
discov]ies4 ,z ! results obta9$ by means
 ( ?is p[]ful in/rum5t w (t5 be ref]r$  
to1 a %ort acc\nt ( its nature & ( !    
pr9ciples on :i* x dep5ds mu/ "h be     
giv54  ,! sol> spectrum is ! b& ( col\r$
 light se5 9 ! ra9b[ &1 p>tially1 9 !   
dew-drop1 b m completely :5 a ray (     
sunlight passes ?r\gh a prism--a piece (
 glass hav+ a triangul> section4 ,!     
result is1 t in/ead ( a spot ( :ite     
light we h a n>r[ b& ( brilliant col\rs 
:i* succe$ ea* o!r 9 regul> ord]1 f     
violet at "o end ?r\gh blue1 gre51 &    
yell[ to r$ at ! o!r4 ,we ?us see t     
light is n a simple & uni=m radiation f 
! sun1 b is made up ( a l>ge numb] (    

sep>ate rays1 ea* ( :i* produces 9 our  
eyes ! s5sation ( a di/9ct col\r4 ,light
 is n[ expla9$ z be+ due to vibrations (
 e!r1 t my/]i\s sub/ance :i* n only     
p]meates all matt]1 b :i* fills space at
 lea/ z f> z ! remote/ ( ! visible />s &
 nebul4 ,! exce$+ly m9ute waves or      
vibrations ( ! e!r produce all ! ph5om5a
 ( heat1 light1 & col\r1 z well z ^?    
*emical actions to :i* photography owes 
its wond]ful p[]s4 ,by +5i\s exp]im5ts !
 size & rate ( vibration ( ^! waves h   
be5 measur$1 & x is f\nd t !y v>y       
consid]ably1 ^? =m+ ! r$ light1 :i* is  
lea/ refract$1 hav+ a wave-l5g? ( ab\t  
#a_/cbfjjj ( an in*1 :ile ! violet rays 
at ! o!r end ( ! spectrum are only ab\t 
half t l5g? or #a_/fcjjjj ( an in*4 ,!  
rate at :i* ! vibrations succe$ ea* o!r 
is f #cjb millions ( millions p] second 
= ! extreme r$ rays1 to #gcg millions ( 
millions = ^? at ! violet end ( !       
spectrum4 ,^! figures are giv5 to %[ !  
wond]ful m9ut5ess & rapidity ( ^! heat &
 light waves on :i* ! :ole life ( ! _w1 

& all our k ( o!r worlds & o!r suns1    
directly dep5ds4  ,b ! m]e col\rs ( !   
spectrum are n ! mo/ important "p ( x4  
,v e>ly 9 ! n9ete5? c5tury a close      
exam9ation %[$ t x 0 ev]y:]e cross$ by  
black l9es ( v>i\s ?icknesses1 sometimes
 s+le1 sometimes gr\p$ toge!r4 ,_m      
obs]v]s /udi$ !m & made accurate draw+s 
or maps %[+ _! positions & ?icknesses1 &
 by comb9+ sev]al prisms1 s t ! beam (  
sunlight _h to pass ?r\gh !m            
successively1 a spectrum c\ld be produc$
 sev]al feet long1 & m ?an #cjjj ( ^!   
d>k l9es 7 c\nt$ 9 x4 ,b :at !y 7 & h[  
!y 7 caus$ rema9$ a my/]y1 till1 9 ! ye>
 #ahfj1 ! ,g]man physici/ ,kir*h(f      
discov]$ ! secret & gave to *emi/s &    
a/ronom]s a new & q unexpect$ eng9e (   
rese>*4  ,x _h already be5 obs]v$ t !   
*emical elem5ts & v>i\s comp\nds1 :5    
heat$ to inc&esc5ce1 produc$ spectra    
consi/+ ( col\r$ l9es or b&s :i* 7      
con/ant = ea* elem5t1 s t ! elem5ts c\ld
 at once be recognis$ by _! *>act]i/ic  
spectra2 & x _h also be5 notic$ t "s (  

^! b&s1 especially ! yell[ b& produc$ by
 sodium1 correspond$ 9 position ) c]ta9 
black l9es 9 ! sol> spectrum4 ,kir*h(f's
 discov]y consi/$ 9 %[+ t1 :5 ! light f 
an inc&esc5t body passes ?r\gh ! same   
sub/ance 9 a /ate ( vap\r or gas1 s mu* 
( ! light is absorb$ t ! col\r$ l9es or 
b&s become black4 ,! my/]y ( m ?an half 
a c5tury 0 ?us solv$2 & ! ?\s&s ( black 
l9es 9 ! sol> spectrum 7 %[n to be caus$
 by ! light f ! inc&esc5t matt] ( !     
sun's surface pass+ ?r\gh ! heat$ gases 
or vap\rs imm$iately above x1 & !reby   
hav+ ! bright col\r$ l9es ( _! spectra  
*ang$1 by absorption1 to comp>ative     
blackness4  ,*emi/s & physici/s         
imm$iately set to "w exam9+ ! spectra ( 
! elem5ts1 fix+ ! position ( ! sev]al   
col\r$ l9es or b&s by accurate          
measurem5t1 & comp>+ !m ) ! d>k l9es ( !
 sol> spectrum4 ,! results 7 9 ! highe/ 
degree satisfactory4 ,9 a l>ge          
proportion ( ! elem5ts ! col\r$ b&s     
correspond$ exactly ) a gr\p ( d>k l9es 
9 ! spectrum ( ! sun1 9 :i*1 !re=e1 !   

same t]re/rial elem5ts 7 prov$ to exi/4 
,among ! elem5ts fir/ detect$ 9 ?is     
mann] 7 hydrog51 sodium1 iron1 copp]1   
magnesium1 z9c1 calcium1 & _m o!rs4     
,ne>ly =ty ( ! elem5ts h n[ be5 f\nd 9 !
 sun1 & x seems highly probable t all   
our elem5ts really exi/ !re1 b z "s are 
v r>e & are pres5t 9 v m9ute quantities 
!y _c be detect$4 ,"s ( ! d>k l9es 9 !  
sun 7 f\nd n to correspond to any kn[n  
elem5t1 & z ?is 0 ?\ght to indicate an  
elem5t peculi> to ! sun x 0 nam$        
,helium2 b q rec5tly x has be5 discov]$ 
9 a r>e m9]al4 ,_m ( ! elem5ts are      
repres5t$ by a great numb] ( l9es1 o!rs 
by v few4 ,?us iron has m ?an #bjjj1    
:ile lead & potassium h only "o ea*4  ,!
 value ( ! spectroscope bo? to ! *emi/ 9
 discov]+ new elem5ts & to ! a/ronom] 9 
det]m9+ ! con/itution ( ! heav5ly       
bodies1 is s great1 t x became ( !      
highe/ importance to h ! position ( all 
! d>k l9es 9 ! sol> spectrum1 z well z !
 bright l9es ( all ! elem5ts1 det]m9$ ) 
extreme accuracy1 s z to be able to make

 exact comp>isons betwe5 diff]5t        
spectra4 ,at fir/ ?is 0 done by means ( 
v l>ge-scale draw+s %[+ ! exact position
 ( e d>k or bright l9e4 ,b ?is 0 f\nd to
 be bo? inconv5i5t & n suffici5tly      
exact2 & x 0 !re=e agre$ to adopt !     
natural scale ( ! wave-l5g?s ( ! diff]5t
 p>ts ( ! spectrum1 :i* by means ( :at  
are t]m$ diffraction-grat+s c n[ be     
measur$ ) great accuracy4               
,diffraction-grat+s are =m$ ( a poli%$  
surface ( h>d metal rul$ ) excessively  
f9e l9es1 sometimes z _m z #bj1jjj to an
 in*4 ,:5 sunlight falls ^u "o ( ^!     
grat+s x is reflect$1 & by int]f]5ce ( !
 rays f ! spaces betwe5 ! f9e grooves1 x
 is spread out into a beautiful &       
well-def9$ spectrum1 :i*1 :5 ! l9es are 
v close1 is sev]al y>ds 9 l5g?4 ,9 ^!   
diffraction spectra _m d>k l9es are se5 
:i* c be %[n 9 no o!r way1 & !y also    
give a spectrum :i* is f> m uni=m ?an t 
produc$ by glass prisms 9 :i* m9ute     
diff]5ces 9 ! composition ( ! glass     
cause "s rays to be refract$ m & o!rs   

less ?an ! normal am\nt4  ,! spectra    
produc$ by diffraction-grat+s are d\ble2
 t is1 !y are spread out on bo? sides ( 
! c5tral l9e ( ! ray :i* rema9s :ite1 & 
! sev]al col\r$ or d>k l9es are s cle>ly
 def9$ t !y c be ?r[n on a scre5 at a   
consid]able di/ance1 giv+ a great l5g?  
to ! spectrum4 ,! data = obta9+ !       
wave-l5g?s are ! di/ance ap>t ( ! l9es1 
! di/ance ( ! scre51 & ! di/ance ap>t ( 
! fir/ pair ( d>k l9es on ea* side ( !  
c5tral bright l9e4 ,all ^! c be measur$ 
) extreme accuracy by means ( telescopes
 ) micromet]s & o!r contrivances1 & !   
result is an accuracy ( det]m9ation (   
wave-l5g?s :i* c probably n be equall$ 9
 any o!r k9d ( measurem5t4  ,z !        
wave-l5g?s are s excessively m9ute1 x   
has be5 f\nd conv5i5t to fix ^u a /ill  
small] unit ( measurem5t1 & z !         
millimetre is ! smalle/ unit ( ! metric 
sy/em1 ! t5-million? ( a millimetre     
7te*nically t]m$ 't5? met]'7 is ! unit  
adopt$ = ! measurem5t ( wave-l5g?s1 :i* 
is equal to ab\t ! #bej million? ( an   

in*4 ,?us ! wave-l5g?s ( ! r$ & blue    
l9es *>act]i/ic ( hydrog5 are #fefc4jg &
 #dhfa4ea respectively4 ,?is excessively
 m9ute scale ( wave-l5g?s1 once det]m9$ 
by ! mo/ ref9$ measurem5t1 is ( v great 
importance4 ,hav+ ! wave-l5g?s ( any two
 l9es ( a spectrum s det]m9$1 ! space   
betwe5 !m c be laid d[n on a diagram (  
any l5g?1 & all ! l9es t occur 9 any o!r
 spectrum betwe5 ^! two l9es c be m>k$ 9
 _! exact relative positions4 ,n[1 z !  
visible spectrum consi/s ( ab\t #cjj1jjj
 rays ( light1 ea* ( diff]5t wave-l5g?s 
& !re=e ( diff]5t refrangibilities1 if x
 is laid d[n on su* a scale z to be ( a 
l5g? ( #cjjj in*es 7#bej feet71 ea*     
wave-l5g? w be #a_/ajj ( an in* long1 a 
space easily visible by ! nak$ eye4  ,! 
possession ( an in/rum5t ( su* wond]ful 
delicacy1 & ) p[]s :i* enable x to      
p5etrate into ! inn] con/itution ( !    
remote/ orbs ( space1 r5d]$ x possible1 
)9 ! next qu>t] ( a c5tury1 to e/abli%  
:at is practically a new                
sci5ce--,a/rophysics--(t5 popul>ly t]m$ 

! ,new ,a/ronomy4 ,a brief outl9e ( !   
ma9 a*ievem5ts ( ?is sci5ce mu/ n[ be   
giv54  ,! fir/ great discov]y made by   
,spectrum analysis1 aft] ! int]pretation
 ( ! sun's spectrum _h be5 obta9$1 01 ! 
real nature ( ! fix$ />s4 ,x is true !y 
_h long be5 held by a/ronom]s to be     
suns1 b ?is 0 only an op9ion ( !        
accuracy ( :i* x did n seem possible to 
obta9 any pro(4 ,! op9ion 0 f\nd$ on two
 facts--_! enorm\s di/ance f u1 s great 
t ! :ole diamet] ( ! e>?'s orbit did n  
lead to any app>5t *ange ( _! relative  
positions1 & _! int5se brilliancy :i* at
 su* di/ances c\ld only be due to an    
actual size & spl5d\r comp>able ) our   
sun4 ,! spectroscope at once prov$ !    
correctness ( ?is op9ion4 ,z "o aft]    
ano!r 0 exam9$1 !y 7 f\nd to exhibit    
spectra ( ! same g5]al type z t ( !     
sun--a b& ( col\rs cross$ by d>k l9es4  
,! v fir/ />s exam9$ by ,sir ,william   
,hugg9s %[$ ! exi/5ce ( n9e or t5 ( our 
elem5ts4 ,v soon all ! *ief />s ( !     
heav5s 7 spectroscopically exam9$1 & x 0

 f\nd t !y c\ld be class$ 9 ?ree or f\r 
gr\ps4 ,! fir/ & l>ge/ gr\p conta9s m   
?an half ! visible />s1 & a /ill l>g]   
proportion ( ! mo/ brilliant1 su* z     
,sirius1 ,vega1 ,regulus1 & ,alpha      
,crucis 9 ! ,s\!rn ,hemisph]e4 ,!y are  
*>act]is$ by a :ite or blui% light1 ri* 
9 ! ultra-violet rays1 & _! spectra are 
di/+ui%$ by ! bread? & int5sity ( ! f\r 
d>k b&s due to ! absorption ( hydrog51  
:ile ! v>i\s black l9es :i* indicate    
metallic vap\rs are comp>atively few1   
?\gh hundr$s ( !m c be discov]$ by      
c>eful exam9ation4  ,! next gr\p1 to :i*
 ,capella & ,arcturus belong1 is also v 
num]\s1 & =ms ! sol> type ( />s4 ,_!    
light is ( a yell[i% col\r1 & _! spectra
 are cross$ ?r\gh\t by innum]able f9e   
d>k l9es m or less closely correspond+ )
 ^? 9 ! sol> spectrum4  ,! ?ird gr\p    
consi/s ( r$ & v>iable />s1 :i* are     
*>act]is$ by flut$ spectra4 ,su* spectra
 %[ l a range ( ,doric columns se5 9    
p]spective1 ! r$ side be+ t mo/         
illum9at$4  ,! la/ gr\p1 consi/+ ( few &

 comp>atively small />s1 has also flut$ 
spectra1 b ! light appe>s to come f !   
opposite direction4  ,^! gr\ps 7        
e/abli%$ by ,fa!r ,sec*i1 ! ,roman      
a/ronom]1 9 #ahfg1 & h be5 adopt$ ) "s  
modifications by ,vogel ( !             
,a/rophysical ,obs]vatory at ,potsdam4  
,! exact int]pretation ( ^! diff]5t     
spectra is some:at unc]ta91 b !re c be  
little d\bt t !y co9cide prim>ily )     
diff]5ces ( temp]ature & ) correspond+  
diff]5ces 9 ! composition & ext5t ( !   
absorptive atmosph]es4 ,/>s ) flut$     
spectra indicate ! pres5ce ( vap\rs ( ! 
metalloids or ( comp\nd sub/ances1 :ile 
! rev]s$ flut+s indicate ! pres5ce (    
c>bon4 ,^! conclusions h be5 rea*$ by   
c>eful laboratory exp]im5ts :i* are n[  
c>ri$ on at ! same "t z ! spectral      
exam9ation ( ! />s & o!r heav5ly bodies1
 s t ea* peculi>ity ( _! spectra1 h[ev] 
puzzl+ & app>5tly unmean+1 has be5      
usually expla9$1 by be+ %[n to indicate 
c]ta9 conditions ( *emical con/itution  
or ( temp]ature4  ,b :atev] difficulty  

!re may be 9 expla9+ details1 !re rema9s
 no d\bt :atev] ( ! fundam5tal fact t   
all ! />s are true suns1 diff]+ no d\bt 
9 size1 & _! /age ( developm5t z        
indicat$ by ! col\r or int5sity ( _!    
light or heat1 b all alike possess+ a   
photosph]e or light-emitt+ surface1 &   
absorptive atmosph]es ( v>i\s qualities 
& d5sity4  ,innum]able o!r details1 su* 
z ! (t5 contra/$ col\rs ( d\ble />s1 !  
occasional v>iability ( _! spectra1 _!  
relations to ! nebul1 ! v>i\s /ages ( _!
 developm5t & o!r problems ( equal      
int]e/1 h occupi$ ! cont9u$ att5tion (  
a/ronom]s1 spectroscopi/s1 & *emi/s2 b  
fur!r ref]5ce to ^! difficult que/ions  
w\ld be out ( place "h4 ,! pres5t sket* 
( ! nature ( spectrum-analysis appli$ to
 ! />s is = ! purpose ( mak+ its        
pr9ciple & me?od ( obs]vation           
intelligible to e educat$ read]1 & to   
illu/rate ! m>vell\s precision &        
accuracy ( ! results atta9$ by x4 ,s    
confid5t are a/ronom]s ( ?is accuracy t 
no?+ less ?an p]fect correspond5ce ( !  

v>i\s bright l9es 9 ! spectrum ( an     
elem5t 9 ! laboratory ) ! d>k l9es 9 !  
spectrum ( ! sun or ( a /> is requir$   
be=e ! pres5ce ( t elem5t is accept$ z  
prov$4 ,z ,miss ,cl]ke t]sely puts      
x--',spectroscopic co9cid5ces admit ( no
 compromise4 ,ei!r !y are absolute or !y
 are wor?less4'   ,,measurem5t ,,(      
,,motion ,,9 ,,! ,,l9e ,,( ,,sight  ,we 
mu/ n[ describe ano!r & q di/9ct        
application ( ! spectroscope1 :i* is ev5
 m m>vell\s ?an t already describ$4 ,x  
is ! me?od ( measur+ ! rate ( motion (  
any ( ! visible heav5ly bodies 9 a      
direction ei!r directly t[>ds u1 or     
directly away f u1 te*nically describ$ z
 'radial motion1' or by ! expression--'9
 ! l9e ( sight4' ,& ! extraord9>y ?+ is 
t ?is p[] ( measurem5t is altoge!r      
indep5d5t ( di/ance1 s t ! rate ( motion
 9 miles p] second ( ! remote/ ( ! fix$ 
/>s1 if suffici5tly bright to %[ a      
di/9ct spectrum1 c be measur$ ) z mu*   
c]ta9ty & accuracy z 9 ! case ( a mu*   
ne>] /> or a planet4  ,9 ord] to und]/& 

h[ ?is is possible we h aga9 to ref] to 
! wave-!ory ( light2 & ! analogy ( o!r  
wave-motions w enable u bett] to grasp !
 pr9ciple on :i* ^! calculations dep5d4 
,if on a ne>ly calm day we c\nt ! waves 
t pass ea* m9ute by an an*or$ /eamboat1 
& !n travel 9 ! direction ! waves come  
f1 we %all f9d t a l>g] numb] pass u 9 !
 same "t4 ,aga91 if we are /&+ ne> a    
railway1 & an eng9e comes t[>ds u :i/l+1
 we %all notice t x *anges its tone z x 
passes u2 & z x rec$es ! s\nd w be 9 a  
l[] key1 al?\gh ! eng9e may be at       
exactly ! same di/ance f u z :5 x 0     
approa*+4 ,yet ! s\nd does n *ange to ! 
e> ( ! eng9e driv]1 ! cause ( ! *ange   
be+ t ! s\nd-waves rea* u 9 quick]      
succession z ! s\rce ( ! waves is       
approa*+ u ?an :5 x is retreat+ f u4    
,n[1 j z ! pit* ( a note dep5ds ^u !    
rapidity ) :i* ! successive             
air-vibrations rea* our e>1 s does !    
col\r ( a p>ticul> "p ( ! spectrum dep5d
 ^u ! rapidity ) :i* ! e!real waves :i* 
produce col\r rea* our eyes2 & z ?is    

rapidity is great] :5 ! s\rce ( ! light 
is approa*+ ?an :5 x is rec$+ f u1 a    
slight %ift+ ( ! position ( ! col\r$    
b&s1 & !re=e ( ! d>k l9es1 w occur1 z   
comp>$ ) _! position 9 ! spectrum ( !   
sun or ( any /ation>y s\rce ( light1 if 
!re is any motion suffici5t 9 am\nt to  
produce a p]ceptible %ift4  ,t su* a    
*ange ( col\r w\ld occur 0 po9t$ out by 
,pr(essor ,doppl] ( ,prague 9 #ahdb1 & x
 is h5ce usually spok5 ( z ! ',doppl]   
pr9ciple'2 b z ! *anges ( col\r 7 s     
m9ute z to be impossible ( measurem5t x 
0 n at t "t ( any practical importance 9
 a/ronomy4 ,b :5 ! d>k l9es 9 ! spectrum
 7 c>efully mapp$1 & _! positions       
det]m9$ ) m9ute accuracy1 x 0 se5 t a   
means ( measur+ ! *anges produc$ by     
motion 9 ! l9e ( sight exi/$1 s9ce !    
position ( any ( ! d>k or col\r$ l9es 9 
! spectra ( ! heav5ly bodies c\ld be    
comp>$ ) ^? ( ! correspond+ l9es produc$
 artificially 9 ! laboratory4 ,?is 0    
fir/ done 9 #ahfh by ,sir ,william      
,hugg9s1 :o1 by ! use ( a v p[]ful      

spectroscope con/ruct$ = ! purpose1 f\nd
 t su* a *ange did occur 9 ! case ( _m  
/>s1 & t _! rate ( motion t[>ds u or    
away f u--! radial motion--c\ld be      
calculat$4 ,z ! actual di/ance ( "s ( ^!
 />s _h be5 measur$1 & _! *ange (       
position annually 7_! prop] motion7     
det]m9$1 ! additional factor ( ! am\nt (
 motion 9 ! direction ( our l9e ( sight 
complet$ ! data requir$ to fix _! true  
l9e ( motion among ! o!r />s4 ,!        
accuracy ( ?is me?od "u fav\rable       
conditions & ) ! be/ in/rum5ts is v     
great1 z has be5 prov$ by ^? cases 9 :i*
 we h indep5d5t means ( calculat+ ! real
 motion4 ,! motion ( ,v5us t[>ds or away
 f u c be calculat$ ) great accuracy =  
any p]iod1 be+ a resultant ( ! comb9$   
motions ( ! planet & ( our e>? 9 _!     
respective orbits4 ,! radial motions (  
,v5us 7 det]m9$ at ! ,lick ,obs]vatory 9
 ,augu/ & ,septemb] #ahij1 by           
spectroscopic obs]vations1 & also by    
calculation1 to be z foll[s3--          
,by ,obs]vation4                   ,by  

,calculation4      ,aug4 #af?4 #g4c     
miles p] second4       #h4a miles p]    
second4         #bbnd4 #h4i             
#h4b                     #cj?4 #g4c     
#h4c                 ,sep4  #crd4 #h4c  
#h4c                      #d?4 #h4b     
#h4c              %[+ t ! maximum error 
0 only "o mile p] second1 :ile ! mean   
error 0 ab\t a qu>t] ( a mile4 ,9 ! case
 ( ! />s ! accuracy ( ! me?od has be5   
te/$ by obs]vations ( ! same /> at times
 :5 ! e>?'s motion 9 its orbit is t[>ds 
or away f ! />1 ^: app>5t radial        
velocity is1 !re=e1 increas$ or dim9i%$ 
by a kn[n am\nt4 ,obs]vations ( ?is k9d 
7 made by ,dr4 ,vogel1 ,director ( !    
,a/rophysical ,obs]vatory at ,potsdam1  
%[+1 9 ! case ( ?ree />s1 ( :i* t5      
obs]vations 7 tak51 a mean error ( ab\t 
two miles p] second2 b z ! /ell> motions
 are m rapid ?an ^? ( ! planets1 !      
proportionate error is no great] ?an 9 !
 example giv5 above4  ,! great          
importance ( ?is mode ( det]m9+ ! real  
motion ( ! />s is1 t x gives u a k ( !  

scale on :i* su* motions are progress+2 
& :5 9 ! c\rse ( "t we discov] :e!r any 
( _! pa?s are rectil9e> or curv$1 we    
%all be 9 a position to le>n some?+ ( ! 
nature ( ! *anges t are go+ on & ( !    
laws on :i* !y dep5d4   ,,invisible     
,,/>s ,,& ,,imp]ceptible ,,motions  ,b  
!re is ano!r result ( ?is p[] ( det]m9+ 
radial motion :i* is ev5 m unexpect$ &  
m>vell\s1 & :i* has ext5d$ our k ( ! />s
 9 q a new direction4 ,by its means x is
 possible to det]m9e ! exi/5ce (        
invisible />s & to measure ! rate (     
o!rwise imp]ceptible motions2 t is ( />s
 :i* are invisible 9 ! mo/ p[]ful mod]n 
telescopes1 & ^: motions h su* a limit$ 
range t no telescope c detect !m4       
,d\ble or b9>y />s =m+ sy/ems :i*       
revolve ar\nd _! common c5tre ( gravity 
7 discov]$ by ,sir ,william ,h]s*el1 & v
 great numb]s are kn[n2 b 9 mo/ cases _!
 p]iods ( revolution are long1 ! %orte/ 
be+ ab\t twelve ye>s1 :ile _m ext5d to  
sev]al hundr$ ye>s4 ,^! are1 ( c\rse1   
all visible b9>ies1 b _m are n[ kn[n (  

:i* "o /> only is visible :ile ! o!r is 
ei!r non-lum9\s or is s close to its    
companion t !y appe> z a s+le /> 9 ! mo/
 p[]ful telescopes4 ,_m ( ! v>iable />s 
belong to ! =m] class1 a good example ( 
:i* is ,algol 9 ! con/ellation ,p]seus1 
:i* *anges f ! second to ! f\r?         
magnitude 9 ab\t f\r & a half h\rs1 & 9 
ab\t f\r & a half h\rs m rega9s its     
brilliancy till its next p]iod (        
obscuration :i* occurs regul>ly e two   
days & tw5ty-"o h\rs4 ,! "n ,algol is f 
! ,arabic ,al ,gh\l1 ! famili> 'gh\l' ( 
! ,arabian ,nights1 s nam$--',!         
,demon'--f its /range & weird behavi\r4 
,x _h long be5 conjectur$ t ?is         
obscuration 0 due to a d>k companion :i*
 p>tially eclips$ ! bright /> at e      
revolution1 %[+ t ! plane ( ! orbit ( ! 
pair 0 almo/ exactly direct$ t[>ds u4 ,!
 application ( ! spectroscope made ?is  
conjecture a c]ta9ty4 ,at an equal "t   
be=e & aft] ! obscuration1 motion 9 !   
l9e ( sight 0 %[n1 t[>ds & away f u1 at 
a rate ( tw5ty-six miles p] second4 ,f  

^! scanty data & ! laws ( gravitation   
:i* fix ! p]iod ( revolution ( planets  
at v>i\s di/ances f _! c5tres (         
revolution1 ,pr(essor ,pick]+ ( ! ,h>v>d
 ,obs]vatory 0 able to arrive at !      
foll[+ figures z highly probable1 & !y  
may be consid]$ to be c]ta9ly n f> f !  
tru?4      ,diamet] ( ,algol1           
#a1jfa1jjj miles4     ,diamet] ( d>k    
companion1       #hcj1jjj               
,di/ance betwe5 _! c5tres1 #c1bcj1jjj   
,orbital spe$ ( ,algol1                 
#bf4c miles p] sec4     ,orbital spe$ ( 
companion1          #ee4d               
,mass ( ,algol1                         
#d_/i mass ( our ,sun4     ,mass (      
companion1                    #b_/i     
,:5 x is consid]$ t ^! figures relate to
 a pair ( />s only "o ( :i* has ev] be5 
se51 t ! orbital motion ev5 ( ! visible 
/> _c be detect$ 9 ! mo/ p[]ful         
telescopes1 :51 fur!r1 we take into     
acc\nt ! enorm\s di/ance ( ^! objects f 
u1 ! great results ( spectroscopic      
obs]vation w be bett] appreciat$4  ,b   

besides ! m>vel ( su* a discov]y by su* 
simple means1 ! facts discov]$ are      
!mselves 9 ! highe/ degree m>vell\s4    
,all t we _h kn[n ( ! />s ?r\gh         
telescopic obs]vation indicat$ t !y 7 at
 v great di/ances f ea* o!r h[ev] ?ickly
 !y may appe> scatt]$ ov] ! sky4 ,?is is
 ! case ev5 ) close telescopic d\ble    
/>s1 ow+ to _! enorm\s remot5ess f u4 ,x
 is n[ e/imat$ t ev5 />s ( ! fir/       
magnitude are1 on a g5]al av]age1 ab\t  
eighty millions ( millions ( miles      
di/ant2 :ile ! close/ d\ble />s t c be  
di/9ctly sep>at$ by l>ge telescopes are 
ab\t half a second ap>t4 ,^!1 if at !   
above di/ance1 w be ab\t #aejj millions 
( miles f ea* o!r4 ,b 9 ! case ( ,algol 
& its companion1 we h two bodies bo?    
l>g] ?an our sun1 yet ) a di/ance ( only
 #b-a_/d millions ( miles betwe5 _!     
surfaces1 a di/ance n mu* exce$+ _!     
comb9$ diamet]s4 ,we %\ld n h anticipat$
 t su* huge bodies c\ld revolve s       
closely to ea* o!r1 & z we n[ "k t !    
neighb\rhood ( our sun--& probably ( all

 suns--is full ( meteoric & cometic     
matt]1 x w\ld seem probable t 9 ! case (
 two suns s ne> toge!r ! quantity ( su* 
matt] w\ld be v great1 & w\ld lead      
probably by cont9u$ collisions to       
increase ( _! bulk1 & p]haps to _! f9al 
coalesc5ce into a s+le giant orb4 ,x is 
said t a ,p]sian a/ronom] 9 ! t5? c5tury
 calls ,algol a r$ />1 :ile x is n[ :ite
 or some:at yell[i%4 ,?is w\ld imply an 
increase ( temp]ature caus$ by          
collisions or friction1 & increas+      
proximity ( ! pair ( />s4  ,a           
consid]able numb] ( d\ble />s ) d>k     
companions h be5 discov]$ by means ( !  
spectroscope1 al?\gh _! motion is n     
directly 9 ! l9e ( sight1 & !re=e !re is
 no obscuration4 ,9 ord] to discov] su* 
pairs ! spectra ( l>ge numb]s ( />s are 
tak5 on photographic plates e night & = 
consid]able p]iods--= a ye> or = sev]al 
ye>s4 ,^! plates are !n c>efully exam9$ 
) a high magnify+ p[] to discov] any    
p]iodical displacem5t ( ! l9es1 & x is  
a/oni%+ 9 h[ l>ge a numb] ( cases ?is   

has be5 f\nd to exi/ & ! p]iod (        
revolution ( ! pair det]m9$4  ,b besides
 discov]+ d\ble />s ( :i* "o is d>k & "o
 bright1 _m pairs ( bright />s h be5    
discov]$ by ! same means4 ,! me?od 9 ?is
 case is r diff]5t4 ,ea* compon5t />1   
be+ lum9\s1 w give a sep>ate spectrum1 &
 ! be/ spectroscopes are s p[]ful t !y w
 sep>ate ^! spectra :5 ! />s are at _!  
maximum di/ance al?\gh no telescope 9   
exi/5ce1 or ev] likely to be made1 c    
sep>ate ! compon5t />s4 ,! sep>ation ( !
 spectra is usually %[n by ! mo/ prom95t
 l9es becom+ d\ble & !n aft] a "t s+le1 
indicat+ t ! plane ( revolution is m or 
less obliquely t[>ds u1 s t ! two />s if
 visible w\ld appe> to op5 out & !n get 
ne>] toge!r e revolution4 ,!n1 z ea* /> 
alt]nately approa*es & rec$es f u !     
radial velocity ( ea* c be det]m9$1 &   
?is gives ! relative mass4 ,9 ?is way n 
only d\bles1 b triple & multiple sy/ems1
 h be5 discov]$4 ,! />s prov$ to be     
d\ble by ^! two me?ods are s num]\s t x 
has be5 e/imat$ by "o ( ! be/ obs]v]s t 

ab\t "o /> 9 e ?irte5 %[s inequality 9  
its radial motion & is !re=e really a   
d\ble />4   ,,! ,,nebul  ,"o o!r great  
result ( spectrum-analysis1 & 9 "s      
respects p]haps ! greate/1 is its       
demon/ration ( ! fact t true nebul exi/1
 & t !y are n all />-clu/]s s remote z  
to be irresolvable1 z 0 once suppos$4   
,!y are %[n to h gase\s spectra1 or     
sometimes gase\s & /ell> spectra comb9$1
 & ?is1 9 connection ) ! fact t nebul   
are frequ5tly aggregat$ ar\nd nebul\s   
/>s or gr\ps ( />s1 r5d]s x c]ta9 t !   
nebul are 9 no way sep>at$ 9 space f !  
/>s1 b t !y con/itute ess5tial p>ts ( "o
 va/ /ell> univ]se4 ,!re is1 inde$1 good
 reason to believe t !y are really !    
mat]ial out ( :i* />s are made1 & t 9 _!
 =ms1 aggregations1 & cond5sations1 we c
 trace ! v process ( evolution ( />s &  
suns4   ,,photographic ,,a/ronomy  ,b   
!re is yet ano!r p[]ful eng9e ( rese>*  
:i* ! new a/ronomy possesses1 & :i*1    
ei!r alone or 9 comb9ation ) !          
spectroscope1 _h produc$ & w yet produce

 9 ! future an am\nt ( k ( ! /ell>      
univ]se :i* c\ld nev] be atta9$ by any  
o!r means4 ,x has already be5 /at$ h[ ! 
discov]y ( new v>iable & b9>y />s has   
be5 r5d]$ possible by ! pres]vation ( ! 
photographic plates on :i* ! spectra are
 self-record$1 night aft] night1 ) e    
l9e1 :e!r d>k or col\r$1 9 true         
position1 s z to be> magnification1 &1  
by comp>ison ) o!rs ( ! s]ies1 enabl+ ! 
mo/ m9ute *anges to be detect$ & _!     
am\nt accurately measur$4 ,)\t !        
pres]vation ( su* comp>able records1 :i*
 is 9 no o!r way possible1 by f> ! l>g] 
portion ( spectroscopic discov]ies c\ld 
nev] h be5 made4  ,b !re are two o!r    
uses ( photography ( q a diff]5t nature 
:i* are equally & p]haps 9 _! f9al      
outcome may be f> m important4 ,! fir/  
is1 t by ! use ( ! photographic plate ! 
exact positions ( scores1 hundr$s1 or   
ev5 ?\s&s ( />s c be self-mapp$         
simultane\sly ) extreme accuracy1 :ile  
any numb] ( copies c be made ( ^!       
/>-maps4 ,?is entirely obviates !       

necessity = ! old me?od ( fix+ !        
position ( ea* /> by repeat$ measurem5t 
by means ( v elaborate in/rum5ts1 & _!  
regi/ration 9 labori\s & exp5sive       
catalogues4 ,s important is ?is n[ se5  
to be1 t specially con/ruct$ cam]as are 
made = /ell> photography1 & by means ( !
 be/ k9ds ( equatorial m\nt+ are made to
 revolve sl[ly s t ! image ( ea* />     
rema9s /ation>y ^u ! plate = sev]al     
h\rs4  ,arrangem5ts h be5 n[ made among 
all ! *ief obs]vatories ( ! _w to c>ry  
out a photographic survey ( ! heav5s )  
id5tical in/rum5ts1 s z to produce maps 
( ! :ole />-sy/em on ! same scale4 ,^! w
 s]ve z fix$ data = future a/ronom]s1 :o
 w ?us be able to det]m9e ! movem5ts (  
/>s ( all magnitudes ) a c]ta9ty &      
accuracy hi!rto unatta9able4  ,! o!r    
important use ( photography dep5ds ^u ! 
fact t ) a long] exposure )9 c]ta9      
limits we increase ! light-collect+ p[]4
 ,x w surprise _m p]sons to le>n t an   
ord9>y good portrait-cam]a ) a l5s ?ree 
or f\r in*es 9 diamet]1 if prop]ly m\nt$

 s t an exposure ( sev]al h\rs c be     
made1 w %[ />s s m9ute t !y are         
invisible ev5 9 ! great ,lick telescope4
 ,9 ?is way ! cam]a w (t5 reveal        
d\ble-/>s or small gr\ps :i* c be made  
visible 9 no o!r way4  ,su* photographs 
( ! />s are n[ con/antly reproduc$ 9    
works on ,a/ronomy & 9 popul> magaz9e   
articles1 & al?\gh "s ( !m are v /rik+1 
_m p]sons are disappo9t$ ) !m1 & _c     
und]/& _! great value1 because ea* /> is
 repres5t$ by a :ite circle (t5 (       
consid]able size & ) a some:at undef9$  
outl9e1 n by a m9ute po9t ( light z />s 
appe> 9 a good telescope4 ,b ! ess5tial 
matt] 9 all su* photographs is n s mu* !
 smallness1 z ! r\ndness1 ( ! />-images1
 z ?is proves ! extreme precision ) :i* 
! image ( e /> has be5 kept by !        
clockwork motion ( ! in/rum5t on ! same 
po9t ( ! plate dur+ ! :ole exposure4 ,= 
example1 9 ! f9e photograph ( ! ,great  
,nebula 9 ,&rom$a1 tak5 #bi? ,decemb]   
#ahhh1 by ,dr4 ,isaac ,rob]ts1 ) an     
exposure ( f\r h\rs1 !re are probably   

ov] a ?\s& />s l>ge & small to be se51 e
 "o repres5t$ by an almo/ exactly       
circul> :ite dot ( a size dep5d5t on !  
magnitude ( ! />4 ,^! r\nd dots c be    
bisect$ by ! cross hairs ( a micromet] )
 v great accuracy1 & ?us ! di/ance      
betwe5 ! c5tres ( any ( ! pairs1 z well 
z ! direction ( ! l9e jo9+ _! c5tres1 c 
be det]m9$ z accurately z if ea* 0      
repres5t$ by a po9t only4 ,b z a m9ute  
:ite speck w\ld be almo/ invisible on ! 
maps1 & w\ld convey no in=mation z to ! 
approximate magnitude ( ! />1 mi/akes   
w\ld be mu* m easily made1 & x w\ld     
probably be f\nd necess>y to surr\nd ea*
 /> ) a circle to indicate its          
magnitude1 & to enable x to be easily   
se54 ,x is probable1 !re=e1 t ! suppos$ 
defect is really an important advantage4
 ,! above-m5tion$ photograph is         
beautifully reproduc$ 9 ,proctor's ,old 
& ,new ,a/ronomy1 publi%$ aft] 8 greatly
 lam5t$ dea?4  ,b besides ! am\nt (     
altoge!r new k obta9$ by ! me?ods (     
rese>* "h briefly expla9$1 a great deal 

( light has be5 ?r[n on ! di/ribution ( 
! />s z a :ole1 & h5ce on ! nature &    
ext5t ( ! /ell> univ]se1 by a c>eful    
/udy ( ! mat]ials obta9$ by ! old       
me?ods1 & by ! application ( ! doctr9e (
 probabilities to ! obs]v$ facts4 ,9 ?is
 way alone "s v /rik+ results h be5     
rea*$1 & ^! h be5 support$ & /r5g!n$ by 
! new] me?ods1 & also by ! use ( new    
in/rum5ts 9 ! measurem5t ( /ell>        
di/ances4 ,"s ( ^! results be> s closely
 & directly ^u ! special subject ( !    
pres5t volume1 t our next *apt] mu/ be  
devot$ to a consid]ation ( !m4          
,,*apt] ,,iv  ,,! ,,di/ribution ,,( ,,! 
,,/>s   ,if we look at ! heav5s on a    
cle>1 moonless night 9 w9t]1 & f a      
position embrac+ ! entire horizon1 !    
sc5e is an inexpressibly gr& "o4 ,!     
int5se sp>kl+ brilliancy ( ,sirius1     
,capella1 ,vega1 & o!r />s ( ! fir/     
magnitude2 _! /rik+ arrangem5t 9        
con/ellations or gr\ps1 ( :i* ,orion1 ! 
,great ,be>1 ,cassiopei1 & ! ,pleiades1 
are famili> examples2 & ! fill+ up      

betwe5 ^! by less & less brilliant po9ts
 d[n to ! limit ( vision1 s z to cov] ! 
:ole sky ) a sc9tillat+ trac]y ( m9ute  
po9ts ( light1 convey toge!r an idea (  
su* confus$ scatt]+ & su* enorm\s       
numb]s1 t x seems impossible to c\nt !m 
or to r$uce !m to sy/ematic ord]4 ,yet  
?is 0 done = all except ! fa9te/ />s by 
,hipp>*us1 #acd ,b4,c41 :o catalogu$ &  
fix$ ! positions ( m ?an #ajjj />s1 &   
?is is ab\t ! numb]1 d[n to ! fif?      
magnitude1 visible 9 ! latitude (       
,greece4 ,a rec5t enum]ation ( all ! />s
 visible to ! nak$ eye1 "u ! mo/        
fav\rable conditions & by ! be/         
eyesight1 has be5 made by ! ,am]ican    
a/ronom]1 ,pick]+4 ,8 numb]s are--= !   
,nor!rn ,hemisph]e #beji1 & = ! ,s\!rn  
,hemisph]e #bhbd1 ?us %[+ a some:at     
great] ri*ness 9 ! s\!rn cele/ial       
hemisph]e4 ,b z ?is diff]5ce is due     
entirely to a prepond]ance ( />s betwe5 
magnitudes #e-a_/b & #f1 t is1 j on !   
limits ( vision1 :ile ^? d[n to         
magnitude #e-a_/b are m num]\s by #he 9 

! ,nor!rn ,hemisph]e1 ,pr(essor ,newcomb
 is ( op9ion t !re is no real sup]iority
 ( numb]s ( visible />s 9 "o hemisph]e  
ov] ! o!r4 ,aga91 ! total numb] ( !     
visible />s by ! above enum]ation is    
#eccc4 ,b ?is includes />s d[n to #f4b  
magnitude1 :ile x is g5]ally consid]$ t 
magnitude #f m>ks ! limit ( visibility4 
,on a re-exam9ation ( all ! mat]ials1 ! 
,italian a/ronom] ,s*iap>elli concludes 
t ! total numb] ( />s d[n to ! six?     
magnitude is #dcjc2 & !y seem to be ab\t
 equally divid$ betwe5 ! nor!rn & s\!rn 
skies4   ,,! ,,milky ,,way  ,b besides !
 />s !mselves1 a mo/ conspicu\s object  
bo? 9 ! nor!rn & s\!rn hemisph]e is t   
wond]ful irregul> belt ( fa9tly diffus$ 
light t]m$ ! ,milky ,way or ,galaxy4    
,?is =ms a magnific5t ar* across ! sky1 
be/ se5 9 ! autumn mon?s 9 our latitude4
 ,?is ar*1 :ile foll[+ ! g5]al c\rse ( a
 great circle r\nd ! heav5s1 is         
extremely irregul> 9 detail1 sometimes  
be+ s+le1 sometimes d\ble1 s5d+ (f      
occasional bran*es or (f%oots1 & also   

conta9+ 9 its v mid/ d>k rifts1 spots1  
or pat*es1 :]e ! black backgr\nd ( almo/
 />less sky c be se5 ?r\gh x4 ,:5 exam9$
 ?r\gh an op]a-glass or small telescope 
quantities ( />s are se5 on ! lum9\s    
backgr\nd1 & ) e increase 9 ! size & p[]
 ( ! telescope m & m />s become visible1
 till ) ! l>ge/ & be/ mod]n in/rum5ts ! 
:ole ( ! ,galaxy seems d5sely pack$ )   
!m1 ?\gh /ill full ( irregul>ities1 wavy
 /reams ( />s1 & d>k rifts & pat*es1 b  
always %[+ a fa9t nebul\s backgr\nd z if
 !re rema9$ o!r myriads ( />s :i* a /ill
 high] optical p[] w\ld reveal4  ,!     
relations ( ?is great belt ( telescopic 
/>s to ! re/ ( ! />-sy/em h long int]e/$
 a/ronom]s1 & _m h attempt$ its         
solution4 ,by a sy/em ( gaug+1 t is     
c\nt+ all ! />s t pass$ ov] ! field ( 8 
telescope 9 a c]ta9 "t1 ,sir ,william   
,h]s*el 0 ! fir/ :o made a sy/ematic    
ef=t to det]m9e ! %ape ( ! /ell>        
univ]se4 ,f ! fact t ! numb] ( />s      
increas$ rapidly z ! ,milky ,way 0      
approa*$ f :atev] direction1 :ile 9 !   

,galaxy itself ! numb]s visible 7 at    
once m ?an d\bl$1 he =m$ ! idea t ! %ape
 ( ! entire sy/em mu/ be t ( a highly   
compress$ v broad mass or r+ r less d5se
 t[>ds ! c5tre :]e our sun 0 situat$4   
,r\ghly speak+1 ! =m 0 lik5$ to a flat  
disc or gr9d/one1 b ( irregul> ?ickness1
 & split 9 two on "o side :]e x appe>s  
to be d\ble4 ,! imm5se quantity ( ! />s 
:i* =m$ x 0 suppos$ to be due to ! fact 
t we look$ at x edgewise ?r\gh an imm5se
 dep? ( />s2 :ile at "r angles to its   
direction :5 look+ t[>ds :at is t]m$ !  
pole ( ! ,galaxy1 & also 9 a less degree
 :5 look+ obliquely1 we see out into    
space ?r\gh a mu* ?9n] /ratum ( />s1 :i*
 ?us seem on ! av]age to be v mu* f>!r  
ap>t4  ,b1 9 ! latt] "p ( 8 life1 ,sir  
,william ,h]s*el realis$ t ?is 0 n !    
true explanation ( ! features pres5t$ by
 ! ,galaxy4 ,! brilliant spots & pat*es 
9 x1 ! d>k rifts & op5+s1 ! n>r[ /reams 
( light (t5 b\nd$ by equally n>r[ /reams
 or rifts ( d>kness1 r5d] x q impossible
 to conceive t ?is complex lum9\s r+ has

 ! =m ( a compress$ disc ext5d+ 9 !     
direction 9 :i* we see x to a di/ance _m
 times great] ?an its ?ickness4 ,9 "o v 
lum9\s clu/] ,h]s*el ?\ght t 8 telescope
 _h p5etrat$ to regions tw5ty times z f>
 (f z ! m brilliant />s =m+ ! ne>]      
portions ( ! same object4 ,n[1 9 ! case 
( ! ,magellanic cl\ds1 :i* are two      
r\ndi% nebul> pat*es ( l>ge size "s     
di/ance f ! ,milky ,way 9 ! ,s\!rn      
,hemisph]e & look+ l deta*$ portions (  
x1 ,sir ,john ,h]s*el himself has %[n t 
any su* int]pretation ( its =m is       
impossible2 because x requires u to     
suppose t 9 bo? ^! cases we see1 n r\nd$
 masses ( a r\ghly globul> %ape1 b      
imm5sely long cones or cyl9d]s1 plac$ 9 
su* a direction t we see only ! ends (  
!m4 ,he rem>ks t "o su* object s situat$
 w\ld be an extraord9>y co9cid5ce1 b t  
!re %\ld be two or _m su* is altoge!r   
out ( ! "q4 ,b 9 ! ,milky ,way !re are  
hundr$s or ev5 ?\s&s ( su* spots or     
masses ( exceptional brilliancy or      
exceptional d>kness2 &1 if ! =m ( !     

,galaxy is t ( a disc _m times broad]   
?an ?ick1 & :i* we see edgewise1 !n e "o
 ( ^! pat*es & clu/]s1 & all ! n>r[ w9d+
 /reams ( bright light or int5se        
blackness1 mu/ be really excessively    
long cyl9d]s1 or tunnels1 or deep curv+ 
lam91 or n>r[ fissures4 ,& e "o ( ^!1   
:i* are to be f\nd 9 e "p ( ?is va/     
circle ( lum9osity1 mu/ be s arrang$ z  
to be exactly turn$ t[>ds our sun4 ,!   
weight ( ?is argum5t1 :i* has be5 mo/   
=cibly & cle>ly set =? by ! late ,mr4   
,r4,a4 ,proctor1 9 8 v in/ructive volume
 ,our ,place among ,inf9ities1 is n[    
g5]ally admitt$ by a/ronom]s1 & !       
natural conclusion is t ! =m ( ! ,milky 
,way is t ( a va/ irregul> r+1 ( :i* !  
section at any "p is1 r\ghly speak+1    
circul>2 :ile ! _m n>r[ rifts or lanes  
or op5+s :]e we seem to be able to see  
completely ?r\gh x to ! d>kness ( out]  
space beyond1 r5d] x probable t 9 ^?    
directions its ?ickness is less in/ead (
 great] ?an its app>5t wid?1 t is1 t we 
see ! broad] side r ?an ! n>r[ edge ( x4

  ,be=e ent]+ on ! consid]ation ( !     
relations :i* ! bulk ( ! />s we see     
scatt]$ ov] ! entire vault ( heav5 be>  
to ?is great belt ( telescopic />s1 x w 
be advisable to give a some:at full     
description ( ! ,galaxy itself1 bo?     
because x is n (t5 del9eat$ on />-maps )
 suffici5t accuracy1 or s z to %[ its   
wond]ful intricacies ( /ructure1 & also 
because x con/itutes ! fundam5tal       
ph5om5on ^u :i* ! argum5t set =? 9 ?is  
volume prim>ily re/s4 ,= ?is purpose ,i 
%all use ! description ( x giv5 by ,sir 
,john ,h]s*el 9 8 ,outl9es ( ,a/ronomy1 
bo? because he1 ( all ! a/ronom]s ( !   
la/ c5tury1 _h /udi$ x mo/ ?or\ghly1 9 !
 nor!rn & 9 ! s\!rn hemisph]es1 by      
eye-obs]vation & ) ! aid ( telescopes ( 
great p[] & admirable quality2 & also   
because1 amid ! ?rong ( mod]n works & ! 
excit+ novelties ( ! la/ ?irty ye>s1 8  
in/ructive volume is1 comp>atively      
speak+1 v little kn[n4 ,?is precise &   
c>eful description w also be ( s]vice to
 any ( my read]s :o may wi% to =m a     

clos] p]sonal acqua9tance ) ?is         
magnific5t & int5sely int]e/+ object1 by
 exam9+ its peculi>ities ( =m & beauties
 ( /ructure ei!r ) ! nak$ eye1 or ) !   
aid ( a good op]a-glass1 or ) a small   
telescope ( good def9+ p[]4   ,a        
,,description ,,( ,,! ,,milky ,,way     
,sir ,john ,h]s*el's description is z   
foll[s3--',! c\rse ( ! ,milky ,way z    
trac$ ?r\gh ! heav5s by ! unaid$ eye1   
neglect+ occasional deviations & foll[+ 
! l9e ( its greate/ brightness z well z 
its v>y+ bread? & int5sity w p]mit1     
con=ms1 z ne>ly z ! indef9it5ess ( its  
b\nd>y w all[ x to be fix$1 to t ( a    
great circle incl9$ at an angle ( ab\t  
#fc to ! equ9octial1 & cutt+ t circle 9 
,"r ,asc5sion #f;h4 #dgm4 & #ah;h4      
#dgm41 s t its nor!rn & s\!rn poles     
respectively are situat$ 9 ,"r ,asc5sion
 #ab;h4 #dgm41 ,nor? ,pol> ,di/ance #fc1
 & ,r4,a4 #j;h4 #dgm41 ,,npd4 #aag4     
,?r\gh\t ! region :]e x is s rem>kably  
subdivid$1 ?is great circle holds an    
int]m$iate situation betwe5 ! two great 

/reams2 ) a ne>] approximation h[ev] to 
! bright] & cont9u\s /ream ?an to !     
fa9t] & int]rupt$ "o4 ,if we trace its  
c\rse 9 ord] ( "r asc5sion1 we f9d x    
trav]s+ ! con/ellation ,cassiopei1 its  
brighte/ "p pass+ ab\t two degrees to ! 
nor? ( ! /> ,delta ( t con/ellation4    
,pass+ !nce betwe5 ,gamma & ,epsilon    
,cassiopei1 x s5ds (f a bran* to !      
s\?-prec$+ side1 t[>ds ,alpha ,p]sei1 v 
conspicu\s z f> z t />1 prolong$ fa9tly 
t[>ds ,eta ( ! same con/ellation1 &     
possibly traceable t[>ds ! ,hyades &    
,pleiades z remote outli]s4 ,! ma9      
/ream1 h[ev] 7:i* is "h v fa9t71 passes 
on ?r\gh ,auriga1 ov] ! ?ree rem>kable  
/>s1 ,epsilon1 ,zeta1 ,eta1 ( t         
con/ellation call$ ! ,hdi1 prec$+       
,capella1 betwe5 ! feet ( ,gem9i & !    
horns ( ! ,bull 7:]e x int]sects !      
ecliptic ne>ly 9 ! ,sol/itial ,colure7 &
 !nce ov] ! club ( ,orion to ! neck (   
,monoc]os1 int]sect+ ! equ9octial 9     
,r4,a4 #f;h4 #edm4 ,up to ?is po9t1 f ! 
(fset 9 ,p]seus1 its light is feeble &  

indef9ite1 b !nce=w>d x receives a      
gradual accession ( brightness1 & :]e x 
passes ?r\gh ! %\ld] ( ,monoc]os & ov] !
 head ( ,canis ,major x pres5ts a broad1
 mod]ately bright1 v uni=m1 & to ! nak$ 
eye1 />less /ream up to ! po9t :]e x    
ent]s ! pr[ ( ! %ip ,argo1 ne>ly on !   
s\!rn tropic4 ,"h x aga9 subdivides     
7ab\t ! /> m ,puppis71 s5d+ (f a n>r[ & 
w9d+ bran* on ! prec$+ side z f> z      
,gamma ,args1 :]e x t]m9ates abruptly4  
,! ma9 /ream pursues its s\?w>d c\rse to
 ! #abcrd p>allel ( ,,npd41 :]e x       
diffuses itself broadly & aga9          
subdivides1 op5+ out into a wide fan-l  
expanse1 ne>ly #bj 9 bread?1 =m$ (      
int]lac+ bran*es1 :i* all t]m9ate       
abruptly1 9 a l9e drawn ne>ly ?r\gh     
,lambda & ,gamma ,args4  ',at ?is place 
! cont9uity ( ! ,milky ,way is int]rupt$
 by a wide gap1 & :]e x recomm5ces on ! 
opposite side x is by a some:at simil>  
fan-%ap$ assemblage ( bran*es :i*       
conv]ge ^u ! bright /> ,eta ,args4 ,!nce
 x crosses ! h9d feet ( ! ,c5taur1 =m+ a

 curi\s & %>ply-def9$ semicircul>       
concavity ( small radius1 & ent]s !     
,cross by a v bright neck or i/hmus ( n 
m ?an ?ree or f\r degrees 9 bread?1 be+ 
! n>r[e/ portion ( ! ,milky ,way4 ,aft] 
?is x imm$iately exp&s into a broad &   
bright mass1 enclos+ ! />s ,alpha &     
,beta ,crucis & ,beta ,c5tauri1 & ext5d+
 almo/ up to ,alpha ( ! latt]           
con/ellation4 ,9 ! mid/ ( ?is bright    
mass1 surr\nd$ by x on all sides1 &     
occupy+ ab\t half its bread?1 occurs a  
s+ul> d>k pe>-%ap$ vacancy1 s conspicu\s
 & rem>kable z to attract ! notice ( !  
mo/ sup]ficial gaz] & to h acquir$ among
 ! e>ly s\!rn navigators ! unc\? b      
expressive appellation ( ! coal-sack4 ,9
 ?is vacancy1 :i* is ab\t #h 9 l5g? & #e
 broad1 only "o v small /> visible to ! 
nak$ eye occurs1 ?\gh x is f> f devoid (
 telescopic />s1 s t its /rik+ blackness
 is simply due to ! effect ( contra/ ) !
 brilliant gr\nd ) :i* x is on all sides
 surr\nd$4 ,?is is ! place ( ne>e/      
approa* ( ! ,milky ,way to ! ,s\? ,pole4

 ,?r\gh\t all ?is region its brightness 
is v /rik+1 & :5 comp>$ ) t ( its m     
nor!rn c\rse already trac$1 conveys     
/rongly ! impression ( great] proximity1
 & w\ld almo/ lead to a belief t our    
situation z spectators is sep>at$ on all
 sides by a consid]able int]val f ! d5se
 body ( />s compos+ ! ,galaxy1 :i* 9 ?is
 view ( ! subject w\ld come to be       
consid]$ z a flat r+ or "s o!r re-ent]+ 
=m ( imm5se & irregul> bread? &         
?ickness1 )9 :i* we are exc5trically    
situat$1 ne>] to ! s\!rn ?an to ! nor!rn
 "p ( its circuit4  ',at ,alpha ,c5tauri
 ! ,milky ,way aga9 subdivides1 s5d+ (f 
a great bran* ( ne>ly half its bread?1 b
 :i* ?9s (f rapidly1 at an angle ( ab\t 
#bj ) its g5]al direction to ,eta & d   
,lupi1 beyond :i* x loses itself 9 a    
n>r[ & fa9t /reamlet4 ,! ma9 /ream      
passes on increas+ 9 bread? to ,gamma   
,norm1 :]e x makes an abrupt elb[ & aga9
 subdivides into "o pr9cipal & cont9u\s 
/ream ( v irregul> bread? & brightness1 
& a complicat$ sy/em ( int]lac$ /reaks &

 masses1 :i* cov]s ! tail ( ,scorpio1 & 
t]m9ates 9 a va/ & fa9t effusion ov] !  
:ole ext5sive region occupi$ by ! prec$+
 leg ( ,ophiu*us1 ext5d+ nor?w>d to !   
p>allel ( #ajc ,,npd41 beyond :i* x _c  
be trac$2 a wide int]val ( #ad1 free f  
all appe>ance ( nebul\s light1 sep>at+ x
 f ! great bran* on ! nor? side ( !     
equ9octial ( :i* x is usually repres5t$ 
z a cont9uation4  ',return+ to ! po9t ( 
sep>ation ( ?is great bran* f ! ma9     
/ream1 let u n[ pursue ! c\rse ( !      
latt]4 ,mak+ an abrupt b5d to ! foll[+  
side1 x passes ov] ! />s ,iota ,ar1 ,!ta
 & ,iota ,scorpii1 & ,gamma ,tubi to    
,gamma ,sagitt>ii1 :]e x sudd5ly        
collects into a vivid oval mass ab\t #f 
9 l5g? & #d 9 bread?1 s excessively ri* 
9 />s t a v mod]ate calculation makes _!
 numb] exce$ #ajj1jjj4 ,nor?w>d ( ?is   
mass1 ?is /ream crosses ! ecliptic 9    
longitude ab\t #bgf1 & proce$+ along !  
b[ ( ,sagitt>ius into ,ant9\s has its   
c\rse rippl$ by ?ree deep concavities1  
sep>at$ f ea* o!r by rem>kable          

protub]ances1 ( :i* ! l>g] & bright] =ms
 ! mo/ conspicu\s pat* 9 ! s\!rn portion
 ( ! ,milky ,way visible 9 our          
latitudes4  ',cross+ ! equ9octial at !  
#ai? h\r ( ,r4,a41 x next runs 9 an     
irregul>1 pat*y1 & w9d+ /ream ?r\gh     
,aquila1 ,sagitta1 & ,vulpecula up to   
,cygnus2 at ,epsilon ( :i* con/ellation 
its cont9uity is int]rupt$1 & a v       
confus$ & irregul> region comm5ces1 m>k$
 by a broad d>k vacuity1 n unlike !     
s\!rn coal-sack1 occupy+ ! space betwe5 
,epsilon1 ,alpha1 & ,gamma ,cygni1 :i*  
s]ves z a k9d ( c5tre = ! div]g5ce (    
?ree great /reams2 "o1 :i* we h already 
trac$2 a second1 ! cont9uation ( ! fir/ 
7across ! int]val7 f ,alpha nor?w>d1    
betwe5 ,lac]ta & ! head ( ,cepheus to ! 
po9t 9 ,cassiopei :5ce we set out1 & a  
?ird bran*+ (f f ,gamma ,cygni1 v vivid 
& conspicu\s1 runn+ (f 9 a s\!rn        
direction ?r\gh ,beta ,cygni1 & s ,aquil
 almo/ to ! equ9octial1 :]e x loses     
itself 9 a region ?9ly spr9kl$ ) />s1   
:]e 9 "s maps ! mod]n con/ellation      

,taurus ,poniat[ski is plac$4 ,?is is ! 
bran* :i*1 if cont9u$ across !          
equ9octial1 might be suppos$ to unite ) 
! great s\!rn effusion 9 ,ophiu*us      
already notic$4 ,a consid]able (fset1 or
 protub]ant app5dage1 is also ?r[n (f by
 ! nor!rn /ream f ! head ( ,cepheus     
directly t[>ds ! pole1 occupy+ ! great] 
"p ( ! qu>tile =m$ by ,alpha1 ,beta1    
,iota1 & ,delta ( t con/ellation4'  ,to 
complete ?is c>eful1 detail$ description
 ( ! ,milky ,way1 x w be well to add a  
few passages f ! same "w z to its       
telescopic appe>ance & /ructure4  ',:5  
exam9$ ) p[]ful telescopes1 !           
con/itution ( ?is wond]ful zone is f\nd 
to be no less v>i\s ?an its aspect to ! 
nak$ eye is irregul>4 ,9 "s regions !   
/>s ( :i* x is compos$ are scatt]$ )    
rem>kable uni=mity ov] imm5se tracts1   
:ile 9 o!rs ! irregul>ity ( _!          
di/ribution is q z /rik+1 exhibit+ a    
rapid succession ( closely clu/]+ ri*   
pat*es sep>at$ by comp>atively poor     
int]vals1 & inde$ 9 "s in/ances by      

spaces absolutely d>k & completely void 
( any />1 ev5 ( ! smalle/ telescopic    
magnitude4 ,9 "s places n m ?an #dj or  
#ej />s on an av]age occur 9 a          
gauge-field ( #ae'1 :ile 9 o!rs a simil>
 av]age gives a result ( #djj or #ejj4  
,nor is less v>iety obs]vable 9 ! "* (  
its diff]5t regions 9 respect ( !       
magnitudes ( ! />s !y exhibit1 & !      
proportional numb]s ( ! l>g] & small]   
magnitudes associat$ toge!r1 ?an 9      
respect ( _! aggregate numb]s4 ,9 "s1 = 
in/ance1 extremely m9ute />s occur 9    
numb]s s mod]ate z to lead u irresi/ibly
 to ! conclusion t 9 ^! regions we see  
fairly ?r\gh ! />ry /ratum1 s9ce x is   
impossible o!rwise t ! numb]s ( ! small]
 magnitudes %\ld n g on cont9ually      
increas+ ad inf9itum4 ,9 su* cases1     
moreov]1 ! gr\nd ( ! heav5s is = ! mo/  
"p p]fectly d>k1 :i* aga9 w\ld n be !   
case if innum]able multitudes ( />s1 too
 m9ute to be individually disc]nible1   
exi/$ beyond4 ,9 o!r regions we are     
pres5t$ ) ! phnom5on ( an almo/ uni=m   

degree ( brightness ( ! individual />s1 
accompani$ ) a v ev5 di/ribution ( !m   
ov] ! gr\nd ( ! heav5s1 bo? ! l>g] &    
small] magnitudes be+ /rik+ly defici5t4 
,9 su* cases x is equally impossible n  
to p]ceive t we are look+ ?r\gh a %eet (
 />s ne>ly ( a size1 & ( no great       
?ickness comp>$ ) ! di/ance :i* sep>ates
 !m f u4 ,7 x o!rwise we %\ld be driv5  
to suppose ! m di/ant />s uni=mly !     
l>g]1 s z to comp5sate by _! great]     
intr9sic brightness = _! great] di/ance1
 a supposition contr>y to all           
probability4444  ',?r\gh\t by f> ! l>g] 
portion ( ! ext5t ( ! ,milky ,way 9 bo? 
hemisph]es1 ! g5]al blackness ( ! gr\nd 
( ! heav5s on :i* its />s are project$1 
& ! abs5ce ( t innum]able multitude &   
excessive cr[d+ ( ! smalle/ visible     
magnitudes1 & ( gl>e produc$ by !       
aggregate light ( multitudes too small  
to affect ! eye s+ly1 mu/1 we ?9k1 be   
consid]$ unequivocal indications t its  
dim5sions 9 directions :]e ^! conditions
 obta9 are n only n inf9ite1 b t !      

space-p5etrat+ p[] ( our telescopes     
suffices fairly to pi]ce ?r\gh & beyond 
x4'  ,9 ! above-quot$ passage ! italics 
are ^? ( ,sir ,john ,h]s*el himself1 &  
we see t he drew ! v same conclusions f 
! facts he describes1 & = mu* ! same    
reasons1 z ,mr4 ,proctor has drawn f !  
obs]vations ( ,sir ,william ,h]s*el2 &1 
z we %all see1 ! be/ a/ronom]s to-day h 
arriv$ at a simil> result1 f !          
additional facts at _! disposal1 & 9 "s 
cases f fre% l9es ( argum5t4   ,,! ,,/>s
 ,,9 ,,relation ,,to ,,! ,,milky ,,way  
,sir ,john ,h]s*el 0 s impress$ ) ! =m1 
/ructure1 & imm5sity ( ! ,galactic      
,circle1 z he sometimes t]ms x1 t he    
says 79 a footnote p4 #ege1 #aj? ed471  
',?is circle is to sid]eal :at !        
inv>iable ecliptic is to planet>y       
a/ronomy--a plane ( ultimate ref]5ce1 ! 
gr\nd-plane ( ! sid]eal sy/em4' ,we h n[
 to consid] :at are ! relations ( ! :ole
 body ( ! />s to ?is ,galactic          
,circle--?is plane ( ultimate ref]5ce = 
! :ole /ell> univ]se4  ,if we look at ! 

heav5s on a />ry night1 ! :ole vault    
appe>s to be ?ickly /rewn ) />s ( v>i\s 
degrees ( brightness1 s t we c\ld h>dly 
say t any ext5sive region--! nor?1 ea/1 
s\?1 or we/1 or ! portion v]tically     
above u--is v conspicu\sly defici5t or  
sup]ior 9 numb]s4 ,9 e "p !re are to be 
f\nd a fair proportion ( />s ( ! fir/   
two or ?ree magnitudes1 :ile :]e ^! may 
seem defici5t a cr[d ( small] />s takes 
_! place4  ,b an accurate survey ( !    
visible />s %[s t !re is a l>ge am\nt ( 
irregul>ity 9 _! di/ribution1 & t all   
magnitudes are really m num]\s 9 or ne> 
! ,milky ,way1 ?an at a di/ance f x1    
?\gh n 9 s l>ge a degree z to be v      
conspicu\s to ! nak$ eye4 ,! area ( !   
:ole ( ! ,milky ,way _c be e/imat$ at m 
?an "o-sev5? ( ! :ole sph]e1 :ile "s    
a/ronom]s reckon x at only "o-t5?4 ,if  
/>s ( any p>ticul> size 7 uni=mly       
di/ribut$1 at mo/ "o-sev5? ( ! :ole     
numb] %\ld be f\nd )9 its limits4 ,b    
,mr4 ,gore f9ds t ( #cb />s bright] ?an 
! second magnitude #ab lie ^u ! ,milky  

,way1 or consid]ably m ?an twice z _m z 
!re %\ld be if !y 7 uni=mly di/ribut$4  
,& 9 ! case ( ! #ii />s :i* are bright] 
?an ! ?ird magnitude #cc lie ^u ! ,milky
 ,way1 or "o-?ird in/ead ( "o-sev5?4    
,mr4 ,gore also c\nt$ all ! />s 9       
,heis's ,atlas :i* lie ^u ! ,milky ,way1
 & f9ds !re are #aahf out ( a total (   
#ecef1 a proportion ( betwe5 a f\r? & a 
fif? in/ead ( a sev5?4  ,! late ,mr4    
,proctor 9 #ahga laid d[n on a *>t two  
feet diamet] all ! />s d[n to magnitude 
#i-a_/b giv5 9 ,agrel&]'s =ty l>ge *>ts 
( ! />s visible 9 ! nor!rn hemisph]e4   
,!y 7 #cbd1aih 9 numb]1 & !y di/9ctly   
%[$ by _! great] d5sity n only ! :ole   
c\rse ( ! ,milky ,way b also its m      
lum9\s portions & _m ( ! curi\s d>k     
rifts & vacuities1 :i* latt] are almo/  
:olly avoid$ by ^! />s4  ,lat] on       
,pr(essor ,seelig] ( ,muni* made an     
inve/igation ( ! relation ( m ?an       
#ace1jjj />s d[n to ! n9? magnitude to !
 ,milky ,way1 by divid+ ! :ole ( !      
heav5s into n9e regions1 "o & n9e be+   

circles ( #bj wide 7equal to #dj        
diamet]7 at ! two poles ( ! ,galaxy2 !  
middle region1 five1 is a zone #bj wide 
includ+ ! ,milky ,way itself1 & ! o!r   
six int]m$iate zones are ea* #bj wide4  
,! foll[+ table %[s ! results z giv5 by 
,pr(essor ,newcomb1 :o has made "s      
alt]ations 9 ! la/ column ( ',d5sity (  
,/>s' 9 ord] to correct diff]5ces 9 !   
e/imate ( magnitudes by ! diff]5t       
au?orities4      ,regions4     ,area 9  
,degree4     ,numb] ( ,/>s4     ,d5sity4
         ,i4            #a1cih4g        
#d1bgg              #b4gh       ,,ii4   
#c1adf4i            #aj1ahe             
#c4jc      ,,iii4            #e1abf4f   
#ai1dhh              #c4ed       ,,iv4  
#d1ehi4h            #bd1dib             
#e4cb        ,v4            #d1eai4e    
#cc1bfg              #h4ag       ,,vi4  
#c1iga4e            #bc1ehj             
#f4jg      ,,vii4            #b1ied4d   
#aa1gij              #c4ga     ,,viii4  
#a1gif4f             #f1cge             
#c4ba       ,,ix4              #dfh4b   

#a1fdd              #c4ad               
,n4,b4--,! inequality ( ! ,n4 & ,s4     
areas is because !      enum]ation ( !  
/>s only w5t z f> z #bd ,s4 ,decl41 &   
!re=e includ$ only a "p ( ,regions      
,,vii41 ,,viii41 & ,,ix4  ,illu/ration3 
,,diagram ,,( ,,/>-,,d5sity ,f ,h]s*el's
 ,gauges 7z giv5 by ,pr(essor ,newcomb1 
p4 #bea74  ,^u ?is table ( d5sities     
,pr(essor ,newcomb rem>ks z foll[s3--',!
 />-d5sity 9 ! sev]al regions increases 
cont9u\sly f ea* pole 7regions ,i4 &    
,,ix47 to ! ,galaxy itself 7region ,v474
 ,,if ,,! ,,latt] ,,7 ,a ,,simple ,,r+  
,,( ,,/>s ,,surr\nd+ ,a ,,sph]ical      
,,sy/em ,,( ,,/>s1 ,,! ,,/>-,,d5sity    
,,w\ld ,,be ,,ab\t ,,! ,,same ,,9       
,,regions ,i41 ,,ii41 & ,,iii41 & also 9
 ,,vii41 ,,viii41 & ,,ix41 b w\ld       
sudd5ly increase 9 ,,iv4 & ,,vi4 z !    
b\nd>y ( ! r+ 0 approa*$4 ,in/ead ( su* 
be+ ! case1 ! numb]s #b4gh1 #c4jc1 &    
#c4ed 9 ! nor?1 & #c4ad1 #c4ba1 & #c4ga 
9 ! s\?1 %[ a progressive increase f !  
galactic pole to ! ,galaxy itself4 ,!   

conclusion to be drawn is a fundam5tal  
"o4 ,! univ]se1 or at lea/ ! d5s]       
portion ( x1 is really flatt5$ betwe5 ! 
galactic poles1 z suppos$ by ,h]s*el &  
,/ruve4'  ,b look+ at ! s]ies ( figures 
9 ! table1 & aga9 z quot$ by ,pr(essor  
,newcomb1 !y seem to me to %[ 9 "s      
measure :at he says !y d n %[4 ,i !re=e 
drew out ! above diagram f ! figures 9 !
 table1 & x c]ta9ly %[s t ! d5sity 9    
regions ,i41 ,,ii41 & ,,iii41 & 9       
regions ,,vii41 ,,viii41 & ,,ix41 may be
 said to be 'ab\t ! same1' t is1 !y     
increase v sl[ly1 & t !y d 'sudd5ly     
increase' 9 ,,iv4 & ,,vi4 z ! b\nd>y ( !
 ,galaxy is approa*$4 ,?is may be       
expla9$ ei!r by a flatt5+ t[>ds ! poles 
( ! ,galaxy1 or by ! ?9n+ out ( />s 9 t 
direction4  ,9 ord] to %[ ! enorm\s     
diff]5ce ( />-d5sity 9 ! ,galaxy & at ! 
galactic poles1 ,pr(essor ,newcomb gives
 ! foll[+ table ( ! ,h]s*elian gauges1  
on :i* he only rem>ks t !y %[ an        
enorm\sly increas$ d5sity 9 ! galactic  
region due to ! ,h]s*els hav+ c\nt$ s _m

 m />s !re ?an any o!r obs]v]s4         
----------------------------------------
------------     ,region1   4 ,i4       
,,ii4,,iii4 ,,iv4  ,v4  ,,vi4           
,,vii4,,viii4 ,,ix4                     
,d5sity1  4#ajg #aed #bha #efj #b1jai   
#fgb  #bfa  #aed  #aaa                  
----------------------------------------
------------  ,illu/ration3 ,,diagram   
,,( ,,/>-,,d5sity ,f a table 9 ,! ,/>s  
7p4 #bdi74  ,b an important *>act]i/ic (
 ^! figures is1 t ! ,h]s*els alone      
survey$ ! :ole ( ! heav5s f ! nor? to ! 
s\? pole1 t !y did ?is ) in/rum5ts ( !  
same size & quality1 & t f almo/        
life-long exp]i5ce 9 ?is p>ticul> "w !y 
7 unrivall$ 9 _! p[] ( c\nt+ rapidly &  
accurately ! />s t pass$ ov] ea* field (
 view ( _! telescopes4 ,_! results1     
!re=e1 mu/ be held to h a comp>ative    
value f> above ^? ( any o!r obs]v] or   
comb9ation ( obs]v]s4 ,i h !re=e ?\ght x
 advisable to draw a diagram f _!       
figures1 & x w be se5 h[ /rik+ly x      
agrees ) ! =m] diagram 9 ! v sl[        

increase ( />-ri*ness 9 ! fir/ ?ree     
regions nor? & s\?1 ! sudd5 increase 9  
regions ,,iv4 & ,,vi4 z we approa* !    
,galaxy1 :ile ! only m>k$ diff]5ce is 9 
! enorm\sly great] ri*ness ( ! ,galaxy  
itself1 :i* is an und\bt$ly real        
ph5om5on1 & is br\ght out "h by !       
unrivall$ obs]v+ p[] ( ! two greate/    
a/ronom]s 9 ?is special dep>tm5t t h ev]
 liv$4  ,we %all f9d lat] on t ,pr(essor
 ,newcomb himself1 z ! result ( a q     
diff]5t inquiry arrives at a result 9   
accordance ) ^! diagrams :i* w !n be    
aga9 ref]r$ to4 ,z ?is is a v int]e/+   
subject1 x w be well to give ano!r      
diagram f two tables ( />-d5sity 9 ,sir 
,john ,h]s*el's volume already quot$4 ,!
 tables are z foll[s3--        ,zones ( 
,galactic         ,av]age numb] ( ,/>   
,nor? ,pol> ,di/ance4         p] ,field 
( #ae'4           #j to #ae             
#d4cb         #ae to #cj                
#e4db         #cj to #de                
#h4ba         #de to #fj                
#ac4fa         #fj to #ge               

#bd4ji         #ge to #ij               
#ec4dc        ,zones ( ,galactic        
,av]age numb] ( ,/>s     ,s\? ,pol>     
,di/ance4        p] ,field ( #ae'4      
#j to #ae                      #f4je    
#ae to #cj                      #f4fb   
#cj to #de                      #i4jh   
#de to #fj                     #ac4di   
#fj to #ge                     #bf4bi   
#ge to #ij                     #ei4jf   
,9 ^! tables ! ,milky ,way itself is    
tak5 z occupy+ two zones ( #ae ea*1     
in/ead ( "o ( #bj z 9 ,pr(essor         
,newcomb's tables1 s t ! excess 9 !     
numb] ( />s ov] ! o!r zones is n s l>ge4
 ,!y %[ also a slight prepond]ance 9 all
 ! zones ( ! s\!rn hemisph]e1 b ?is is n
 great1 & may probably be due to ! cle>]
 atmosph]e ( ! ,cape ( ,good ,hope z    
comp>$ ) t ( ,engl&4  ,illu/ration3     
,,diagram ,,( ,,/>-,,d5sity4 ,f ,table 9
 ,sir ,j4 ,h]s*el's ,outl9es ( ,a/ronomy
 7#aj? ed41 pp4 #egg-egh74  ,x ne$ only 
be not$ "h t ?is diagram %[s ! same     
g5]al features z ^? already giv51 ( a   

cont9u\s increase ( />-d5sity f ! poles 
( ! ,galaxy1 b m rapidly z ! ,galaxy    
itself is m ne>ly approa*$4 ,?is fact   
mu/1 !re=e1 be accept$ z indisputable4  
,,clu/]s ,,& ,,nebul ,,9 ,,relation ,,to
 ,,! ,,galaxy  ,an important factor 9 ! 
/ructure ( ! heav5s is af=d$ by !       
di/ribution ( ! two classes ( objects   
kn[n z clu/]s & nebul4 ,al?\gh we c =m  
an almo/ cont9u\s s]ies f d\ble />s :i* 
revolve r\nd _! common c5tre ( gravity1 
?r\gh triple & quadruple />s1 to gr\ps &
 aggregations ( indef9ite ext5t--( :i* !
 ,pleiades =m a good example1 s9ce ! six
 />s visible to ! nak$ eye are increas$ 
to hundr$s by high telescopic p[]s1 :ile
 photographs ) ?ree h\rs' exposure %[ m 
?an #bjjj />s--yet none ( ^! correspond 
to ! l>ge class kn[n z clu/]s1 :e!r     
globul> or irregul>1 :i* are v num]\s1  
ab\t #fjj hav+ be5 record$ by ,sir ,john
 ,h]s*el m ?an fifty ye>s ago4 ,_m ( ^! 
are among ! mo/ beautiful & /rik+       
objects 9 ! heav5s ev5 ) a v small      
telescope or good op]a-glass4 ,su* is ! 

lum9\s spot call$ ,praesepe1 or !       
,beehive 9 ! con/ellation ,canc]1 &     
ano!r 9 ! sword h&le ( ,p]seus4  ,9 !   
s\!rn hemisph]e !re is a hazy /> ( ab\t 
! f\r? magnitude1 ,omega ,c5tauri1 :i* )
 a good telescope is se5 to be really a 
magnific5t clu/] ne>ly two-?irds !      
diamet] ( ! moon1 & describ$ by ,sir    
,john ,h]s*el z v gradually increas+ 9  
brightness to ! c5tre1 & compos$ (      
innum]able />s ( ! ?irte5? & fifte5?    
magnitudes1 =m+ ! ri*e/ & l>ge/ object (
 ! k9d 9 ! heav5s4 ,he describes x z    
hav+ r+s l lace-"w =m$ ( ! l>g] />s4 ,by
 actual c\nt1 on a good photograph1 !re 
are m ?an #fjjj />s1 :ile o!r obs]v]s   
consid] t !re are at lea/ #aj1jjj4 ,9 ! 
nor!rn hemisph]e "o ( ! f9e/ is t 9 !   
con/ellation ,h]cules1 kn[n z #ac       
,messi]4 ,x is j visible to ! nak$ eye  
or ) an op]a glass z a hazy /> ( ! six? 
magnitude1 b a good telescope %[s x to  
be a globul> clu/]1 & ! great ,lick     
telescope resolves ev5 ! d5se/ c5tral   
portion into di/9ct />s1 ( :i* ,sir     

,john ,h]s*el consid]$ !re 7 _m ?\s&s4  
,^! two f9e clu/]s are figur$ 9 _m ( !  
mod]n popul> works on a/ronomy1 & !y    
af=d an excell5t idea ( ^! beautiful &  
rem>kable objects1 :i*1 :5 m ?or\ghly   
/udi$1 w probably aid 9 elucidat+ "s ( !
 obscure problems connect$ ) !          
con/itution & developm5t ( ! /ell>      
univ]se4  ,b = ! purpose ( ! pres5t "w !
 mo/ int]e/+ fact connect$ ) />-clu/]s  
is _! rem>kable di/ribution 9 ! heav5s4 
,_! special abundance 9 & ne> ! ,milky  
,way _h (t5 be5 not$1 b ! full          
importance ( ! fact c\ld n be appreciat$
 till ,mr4 ,proctor &1 lat]1 ,mr4       
,sidney ,wat]s m>k$ d[n1 on maps ( ! two
 hemisph]es1 all ! />-clu/]s & nebul 9 !
 be/ catalogues4 ,! result is mo/       
int]e/+4 ,! clu/]s are se5 to be ?ickly 
/rewn ov] ! entire c\rse ( ! ,milky     
,way1 & along its m>g9s1 :ile 9 e o!r "p
 ( ! heav5s !y are ?9ly scatt]$ at v    
di/ant int]vals1 ) ! "o exception ( !   
,magellanic cl\ds ( ! s\!rn hemisph]e   
:]e !y are aga9 d5sely gr\p$2 & if any?+

 7 ne$$ to prove ! physical connection (
 ^! clu/]s ) ! ,galaxy x w\ld be _!     
occurr5ce 9 ^! ext5sive nebul\s pat*es  
:i* seem l outly+ portions ( ! ,milky   
,way itself4 ,) ^! two exceptions       
probably n "o-tw5tie? "p ( ! :ole numb] 
( />-clu/]s are f\nd 9 any "p ( ! heav5s
 remote f ! ,milky ,way4  ,nebul 7 = a  
long "t conf\nd$ ) />-clu/]s1 because x 
0 ?\ght t ) suffici5t telescopic p[] !y 
c\ld all be resolvable into />s z 9 !   
case ( ! ,milky ,way itself4 ,b :5 !    
spectroscope %[$ t _m ( ! nebul consi/$ 
:olly or ma9ly ( gl[+ gases1 :ile nei!r 
! highe/ p[]s ( ! be/ telescopes nor !  
/ill great] p[]s ( ! photographic plate 
gave any indications ( resolvability1   
al?\gh a few />s 7 (t5 f\nd to be1 z x  
71 entangl$ 9 !m1 & evid5tly =m+ "p (   
!m1 x 0 se5 t !y con/itut$ a di/9ct     
/ell> ph5om5on1 a view :i* 0 en=c$ &    
r5d]$ c]ta9 by _! q unique mode (       
di/ribution4 ,a few ( ! l>g] & irregul> 
type1 z 9 ! case ( ! gr& ,orion nebula  
visible to ! nak$ eye1 ! great spiral   

nebula 9 ,&rom$a1 & ! wond]ful ,keyhole 
nebula r\nd ,eta ,args1 are situat$ 9 or
 ne> ! ,milky ,way2 b ) ^! & a few o!r  
exceptions ! ov]:elm+ majority ( !      
small] irresolvable nebul appe> to avoid
 x1 !re be+ a space almo/ :olly free f  
nebul along its bord]s1 bo? 9 ! nor!rn &
 s\!rn hemisph]es2 :ile ! great majority
 are spread ov] ! sky1 f> away f x 9 !  
s\!rn hemisph]e1 & 9 ! nor? clu/]+ 9 a v
 m>k$ degree ar\nd ! galactic pole4 ,!  
di/ribution ( nebul is ?us se5 to be !  
exact opposite to t ( ! />-clu/]s1 :ile 
bo? are s di/9ctly relat$ to ! position 
( ! ,milky ,way--! gr\nd-plane ( !      
sid]eal sy/em1 z ,sir ,john ,h]s*el t]m$
 x--t we are compell$ to include !m all 
z connect$ portions ( "o gr& &1 to "s   
ext5t1 symmetrical univ]se1 ^: rem>kable
 & opposite mode ( di/ribution ov] !    
heav5s may probably af=d a clue to !    
mode ( developm5t ( t univ]se & to !    
*anges t are ev5 n[ tak+ place )9 x4 ,! 
maps ref]r$ to above are ( su* great    
importance1 & are s ess5tial to a cle>  

compreh5sion ( ! nature & con/itution ( 
! va/ sid]eal sy/em :i* surr\nds u1 t ,i
 h1 ) ! p]mission ( ! ,royal            
,a/ronomical ,society1 reproduc$ !m "h4 
7,see end ( volume47  ,a c>eful         
exam9ation ( !m w give a cle>] idea ( ! 
v rem>kable facts ( di/ribution (       
/>-clu/]s & nebul ?an c be af=d$ by any 
am\nt ( description or ( num]ical       
/atem5ts4  ,! =ms ( _m ( ! nebul are v  
curi\s4 ,"s are q irregul>1 z ! ,orion  
nebula1 ! ,keyhole nebula 9 ! s\!rn     
hemisph]e1 & _m o!rs4 ,"s %[ a decid$ly 
spiral =m1 z ^? 9 ,&rom$a & ,canes      
,v5atici2 o!rs aga9 are annul> or       
r+-%ap$1 z ^? 9 ,lyra & ,cygnus1 :ile a 
consid]able numb] are t]m$ planet>y     
nebul1 f _! exhibit+ a fa9t circul> disc
 l t ( a planet4 ,_m h />s or gr\ps (   
/>s evid5tly =m+ p>ts ( !m1 & ?is is    
especially ! case ) ^? ( ! l>ge/ size4  
,b all ^! are comp>atively few 9 numb] &
 m or less exceptional 9 type1 ! great  
majority be+ m9ute cl\dy specks only    
visible ) good telescopes1 & s fa9t z to

 leave mu* d\bt z to _! exact %ape &    
nature4 ,sir ,john ,h]s*el catalogu$    
#ejjj 9 #ahfd1 & m ?an #hjjj 7 discov]$ 
up to #ahij2 :ile ! application ( !     
cam]a has s increas$ ! numb]s t x is    
?\ght !re may really be _m hundr$s (    
?\s&s ( !m4  ,! spectroscope %[s ! l>g] 
irregul> nebul to be gase\s1 z are !    
annul> & planet>y nebul z well z _m v   
brilliant :ite />s2 & all ^! objects are
 mo/ frequ5t 9 or ne> ! ,milky ,way4 ,_!
 spectra %[ a gre5 l9e n produc$ by any 
t]re/rial elem5t4 ,) ! great ,lick      
telescope sev]al ( ! planet>y nebul h   
be5 f\nd to be irregul> & sometimes to  
be =m$ ( compress$ or loop$ r+s & o!r   
curi\s =ms4  ,_m ( ! small] nebul are   
d\ble or triple1 b :e!r !y really =m    
revolv+ sy/ems is n yet kn[n4 ,! great  
mass ( ! small nebul t occupy l>ge      
tracts ( ! heav5s remote f ! ,galaxy are
 (t5 t]m$ irresolvable nebul1 because ! 
highe/ p[]s ( ! l>ge/ telescopes %[ no  
indication ( _! be+ />-clu/]s1 :ile !y  
are too fa9t to give any def9ite        

indications ( /ructure 9 ! spectroscope4
 ,b _m ( !m resemble comets 9 _! =ms1 & 
x is ?\ght n impossible t !y may be n v 
dissimil> 9 con/itution4         99     
99       99       99       99  ,we h n[ 
pass$ 9 review ! ma9 features pres5t$ to
 u 9 ! heav5s outside ! sol> sy/em1 s f>
 z reg>ds ! numb]s & di/ribution ( !    
lucid />s 7^? visible to ! nak$ eye7 z  
well z ^? br\ght to view by ! telescope2
 ! =m & *ief *>act]i/ics ( ! ,milky ,way
 or ,galaxy2 & la/ly1 ! numb]s &        
di/ribution ( ^? int]e/+                
objects--/>-clu/]s & nebul 9 _! special 
relations to ! ,milky ,way4 ,?is        
exam9ation has br\ght cle>ly be=e u !   
unity ( ! :ole visible univ]se2 t ev]y?+
 we c see1 or obta9 any k (1 ) all !    
res\rces ( mod]n gigantic telescopes1 ( 
! photographic plate1 & ( ! ev5 m       
m>vell\s spectroscope1 =ms p>ts ( "o va/
 sy/em :i* may be %ortly & appropriately
 t]m$ ! ,/ell> univ]se4  ,9 our next    
*apt] we %all c>ry ! inve/igation a /ep 
fur!r1 by sket*+ 9 outl9e :at is kn[n ( 

! motions & di/ances ( ! />s1 & ?us     
obta9 "s important in=mation be>+ ^u our
 special subject ( inquiry4     ,,*apt] 
,v  ,,di/ance ,,( ,,! ,,/>s--,,!        
,,sun',s ,,motion ,,?r\gh ,,space   ,9  
e>ly ages1 be=e any approximate idea 0  
rea*$ ( ! great di/ances ( ! />s f u1 ! 
simple conception ( a cry/al sph]e to   
:i* ^! lum9\s po9ts 7 atta*$ & c>ri$    
r\nd e day on an axis ne> :i* our       
pole-/> is situat$1 satisfi$ ! dem&s =  
an explanation ( ! ph5om5a4 ,b :5       
,cop]nicus set =? ! true arrangem5t ( ! 
heav5ly bodies1 e>? & planets alike     
revolv+ r\nd ! sun at di/ances ( _m     
millions ( miles1 & :5 ?is s*eme 0 en=c$
 by ! laws ( ,kepl] & ! telescopic      
discov]ies ( ,galileo1 a difficulty     
arose :i* a/ronom]s 7 unable            
satisfactorily to ov]come4 ,if1 said !y1
 ! e>? revolves r\nd ! sun at a di/ance 
:i* _c be less 7accord+ to ,kepl]'s     
measurem5t ( ! di/ance ( ,m>s at        
opposition7 ?an #ac-a_/b millions (     
miles1 !n h[ is x t ! ne>] />s are n se5

 to %ift _! app>5t places :5 view$ f    
opposite sides ( ?is enorm\s orbit8     
,cop]nicus1 & aft] him ,kepl] &         
,galileo1 /\tly ma9ta9$ t x 0 because ! 
/>s 7 at su* an enorm\s di/ance f u t ! 
e>?'s orbit 0 a m]e po9t 9 comp>ison4 ,b
 ?is seem$ :olly incr$ible1 ev5 to !    
great obs]v] ,ty*o ,brah1 & h5ce !      
,cop]nican !ory 0 n s g5]ally accept$ z 
x o!rwise w\ld h be54  ,galileo always  
decl>$ t ! measurem5t w\ld "s day be    
made1 & he ev5 sugge/$ ! me?od ( effect+
 x :i* is n[ f\nd to be ! mo/ tru/wor?y4
 ,b ! sun's di/ance _h to be fir/       
measur$ ) great] accuracy1 & t 0 only   
done 9 ! latt] "p ( ! eighte5? c5tury by
 means ( transits ( ,v5us2 & by lat]    
obs]vations ) m p]fect in/rum5ts x is n[
 pretty well fix$ at ab\t #ib1ghj1jjj   
miles1 ! limits ( error be+ su* t       
#ib-c_/d millions may p]haps be q z     
accurate4  ,) su* an enorm\s base-l9e z 
twice ?is di/ance1 :i* is available by  
mak+ obs]vations at int]vals ( ab\t six 
mon?s :5 ! e>? is at opposite po9ts 9   

its orbit1 x seem$ c]ta9 t "s p>allax or
 displacem5t ( ! ne>] />s c\ld be f\nd1 
& _m a/ronom]s ) ! be/ in/rum5ts devot$ 
!mselves to ! "w4 ,b ! difficulties 7   
enorm\s1 & v few really satisfactory    
results 7 obta9$ till ! latt] half ( !  
n9ete5? c5tury4 ,ab\t =ty />s h n[ be5  
measur$ ) tol]able c]ta9ty1 ?\gh ( c\rse
 ) a consid]able m>g9 ( possible or     
probable error2 & ab\t ?irty m1 :i* are 
f\nd to h a p>allax ( "o-t5? ( a second 
or less1 mu/ be consid]$ to leave a v   
l>ge m>g9 ( unc]ta9ty4  ,! two ne>e/    
fix$ />s are ,alpha ,c5tauri & #fa      
,cygni4 ,! =m] is "o ( ! brighte/ />s 9 
! s\!rn hemisph]e1 & is ab\t #bge1jjj   
times z f> f u z ! sun4 ,! light f ?is  
/> w take #d-a_/d ye>s to rea* u1 & ?is 
'light-j\rney1' z x is t]m$1 is g5]ally 
us$ by a/ronom]s z an easily rememb]$   
mode ( record+ ! di/ances ( ! fix$ />s1 
! di/ance 9 miles--9 ?is case ab\t #be  
millions ( millions--be+ v cumbr\s4 ,!  
o!r />1 #fa ,cygni1 is only ( ab\t !    
fif? magnitude1 yet x is ! second ne>e/ 

to u1 ) a light-j\rney ( ab\t #g-a_/d   
ye>s4 ,if we _h no o!r det]m9ations (   
di/ance ?an ^! two1 ! facts w\ld be ( ! 
highe/ importance4 ,!y tea* u1 fir/1 t  
magnitude or brightness ( a /> is no    
pro( ( ne>ness to u1 a fact ( :i* !re is
 mu* o!r evid5ce2 & 9 ! second place1 !y
 furni% u ) a probable m9imum di/ance ( 
indep5d5t suns f "o ano!r1 :i*1 9       
proportion to _! sizes1 "s be+ kn[n to  
be _m times l>g] ?an our sun1 is n m ?an
 we might expect4 ,?is remot5ess may be 
p>tly due to ^? :i* 7 once ne>] toge!r  
hav+ coalesc$ "u ! influ5ce (           
gravitation4  ,z ?is measurem5t ( !     
di/ance ( ! ne>] />s %\ld be cle>ly     
und]/ood by e "o :o wi%es to obta9 "s   
real compreh5sion ( ! scale ( ?is va/   
univ]se ( :i* we =m a "p1 ! me?od n[    
adopt$ & f\nd to be mo/ effectual w be  
briefly expla9$4  ,ev]yone :o is        
acqua9t$ ) ! rudim5ts ( trigonometry or 
m5suration1 kn[s t an inaccessible      
di/ance c be accurately det]m9$ if we c 
measure a base-l9e f bo? ends ( :i* !   

inaccessible object c be se51 & if we h 
a good in/rum5t ) :i* to measure angles4
 ,! accuracy w ma9ly dep5d ^u our       
base-l9e be+ n excessively %ort 9       
comp>ison ) ! di/ance to be measur$4 ,if
 x is z mu* z half or ev5 a qu>t] z long
 ! measurem5t may be z accurate z if    
directly p]=m$ ov] ! gr\nd1 b if x is   
only "o-hundr$? or "o-?\s&? "p z long1 a
 v small error ei!r 9 ! l5g? ( ! base or
 9 ! am\nt ( ! angles w produce a l>ge  
error 9 ! result4  ,9 measur+ ! di/ance 
( ! moon1 ! e>?'s diamet]1 or a         
consid]able portion ( x1 has s]v$ z a   
base-l9e4 ,ei!r two obs]v]s at great    
di/ances f ea* o!r1 or ! same obs]v]    
aft] an int]val ( n9e or t5 h\rs1 may   
exam9e ! moon f positions six or sev5   
?\s& miles ap>t1 & by accurate          
measurem5ts ( its angul> di/ance f a />1
 or by ! "t ( its passage ov] ! m]idian 
( ! place z obs]v$ ) a transit in/rum5t1
 ! angul> displacem5t c be f\nd & !     
di/ance det]m9$ ) v great accuracy1     
al?\gh t di/ance is m ?an ?irty times ! 

l5g? ( ! base4 ,! di/ance ( ! planet    
,m>s :5 ne>e/ to u has be5 f\nd 9 ! same
 way4 ,8 di/ance f u ev5 :5 at 8 ne>e/  
po9t dur+ ! mo/ fav\rable oppositions is
 ab\t #cf million miles1 or m ?an f\r   
?\s& times ! e>?'s diamet]1 s t x       
requires ! mo/ delicate obs]vations _m  
times repeat$ & ) ! f9e/ in/rum5ts to   
obta9 a tol]ably approximate result4 ,:5
 ?is is done1 by ,kepl]'s law ( ! fix$  
proportion betwe5 ! di/ances ( planets f
 ! sun & _! times ( revolution1 !       
proportionate di/ance ( all ! o!r       
planets & t ( ! sun c be asc]ta9$4 ,?is 
me?od1 h[ev]1 is n suffici5tly accurate 
to satisfy a/ronom]s1 because ^u ! sun's
 di/ance t ( e o!r memb] ( ! sol> sy/em 
dep5ds4 ,=tunately !re are two o!r      
me?ods by :i* ?is important measurem5t  
has be5 made ) mu* great] approa* to    
c]ta9ty & precision4  ,illu/ration3     
,diagram illu/rat+ ! transit ( ,v5us4   
,! fir/ ( ^! me?ods is by means ( ! r>e 
occasions :5 ! planet ,v5us passes      
across ! sun's disc z se5 f ! e>?4 ,:5  

?is takes place1 obs]vations ( !        
transit1 z x is t]m$1 are made at remote
 p>ts ( ! e>?1 ! di/ance betwe5 :i*     
places c ( c\rse easily be calculat$ f  
_! latitudes & longitudes4 ,! diagram "h
 giv5 illu/rates ! simple/ mode (       
det]m9+ ! sun's di/ance by ?is          
obs]vation1 & ! foll[+ description f    
,proctor's ,old & ,new ,a/ronomy is s   
cle> t ,i copy x v]bally3--',v repres5ts
 ,v5us pass+ betwe5 ! ,e>? ,e & ! ,sun  
,s2 & we see h[ an obs]v] at ,e w see   
,v5us z at v'1 :ile an obs]v] at ,e' w  
see h] z at v4 ,! measurem5t ( ! di/ance
 v v'1 z comp>$ ) ! diamet] ( ! sun's   
disc1 det]m9es ! angle v ,v v' or ,e ,v 
,e'2 :5ce ! di/ance ,e ,v c be calculat$
 f ! kn[n l5g? ( ! base-l9e ,e ,e'4 ,=  
in/ance1 x is kn[n 7f ! kn[n proportions
 ( ! ,sol> ,sy/em z det]m9$ f ! times ( 
revolution by ,kepl]'s ?ird law7 t ,e ,v
 be>s to ,v v ! proportion #bh to #gb1  
or #g to #ah2 :5ce ,e ,e' be>s to v v' !
 same proportion4 ,suppose1 n[1 t !     
di/ance betwe5 ! two /ations is kn[n to 

be #gjjj miles1 s t v v' is #ah1jjj     
miles2 & t v v' is f\nd by accurate     
measurem5t to be #a_/dh "p ( ! sun's    
diamet]4 ,!n ! sun's diamet]1 z det]m9$ 
by ?is obs]vation1 is #dh times #ah1jjj 
miles1 or #hfd1jjj miles2 :5ce f 8 kn[n 
app>5t size1 :i* is t ( a globe         
#ajg-a_/c times f>!r away f u ?an its   
own diamet]1 8 di/ance is f\nd to be    
#ib1gcf1jjj miles4'  ,( c\rse1 !re be+  
two obs]v]s1 ! proportion ( ! di/ance v 
v' to ! diamet] ( ! sun's disc _c be    
measur$ directly1 b ea* ( !m c measure !
 app>5t angul> di/ance ( ! planet f !   
sun's upp] & l[] m>g9s z x passes across
 ! disc1 & ?us ! angul> di/ance betwe5 !
 two l9es ( transit c be obta9$4 ,!     
di/ance v v' c also be f\nd by          
accurately not+ ! times ( ! upp] & l[]  
passage ( ,v5us1 :i*1 z ! l9e ( transit 
is consid]ably %ort] 9 "o ?an ! o!r1    
gives by ! kn[n prop]ties ( ! circle !  
exact proportion ( ! di/ance betwe5 !m  
to ! sun's diamet]2 & z ?is is f\nd to  
be ! mo/ accurate me?od1 x is ! "o      

g5]ally adopt$4 ,= ?is purpose ! /ations
 ( ! obs]v]s are s *os5 t ! l5g? ( ! two
 *ords1 v & v'1 may h a consid]able     
diff]5ce1 ?us r5d]+ ! measurem5t m easy4
  ,! o!r me?od ( det]m9+ ! sun's di/ance
 is by ! direct measurem5t ( ! velocity 
( light4 ,?is 0 fir/ done by ! ,fr5*    
physici/1 ,fizeau1 9 #ahdi1 by ! use (  
rapidly revolv+ mirrors1 z describ$ 9   
mo/ works on physics4 ,?is me?od has n[ 
be5 br\ght to su* a decree ( p]fection t
 ! sun's di/ance s det]m9$ is consid]$  
to be equally tru/wor?y ) t d]iv$ f !   
transits ( ,v5us4 ,! reason t !         
det]m9ation ( ! velocity ( light leads  
to a det]m9ation ( ! sun's di/ance is1  
because ! "t tak5 by light to pass f !  
sun to ! e>? is indep5d5tly kn[n to be  
#h m94 #ac-a_/c sec4 ,?is 0 discov]$ s  
long ago z #afge by means ( ! eclipses (
 ,jupit]'s satellites4 ,^! satellites   
revolve r\nd ! planet 9 f #a-c_/d to #af
 days1 &1 ow+ to _! mov+ v ne>ly 9 !    
plane ( ! ecliptic & ! %ad[ ( ,jupit]   
be+ s l>ge1 ! ?ree :i* are ne>e/ to !   

planet are eclips$ at e revolution4 ,?is
 rapid revolution ( ! satellites &      
frequ5cy ( ! eclipses enabl$ _! p]iods (
 recurr5ce to be det]m9$ ) extreme      
accuracy1 especially aft] _m ye>s (     
c>eful obs]vation4 ,x 0 !n f\nd t :5    
,jupit] 0 at its f>!/ di/ance f ! e>? ! 
eclipses ( ! satellites took place a    
little m ?an eight m9utes lat] ?an ! "t 
calculat$ f ! mean p]iod ( revolution1 &
 :5 ! planet 0 ne>e/ to u ! eclipses    
occurr$ ! same am\nt e>li]4 ,& :5 fur!r 
obs]vation %[$ t !re 0 no diff]5ce      
betwe5 calculation & obs]vation :5 !    
planet 0 at its mean di/ance f u1 & t ! 
error arose & increas$ exactly 9        
proportion to our v>y+ di/ance f x1 !n x
 became cle> t ! only cause adequate to 
produce su* an effect 01 t light _h n an
 inf9ite velocity b travell$ at a c]ta9 
fix$ rate4 ,?is h[ev]1 ?\gh a highly    
probable explanation1 0 n absolutely    
prov$ till ne>ly two c5turies lat]1 by  
means ( two v difficult measurem5ts--t (
 ! actual di/ance ( ! sun f ! e>?1 & t (

 ! actual spe$ ( light 9 miles p]       
second2 ! latt] correspond+ almo/       
exactly ) ! spe$ d$uc$ f ! eclipses (   
,jupit]'s satellites & ! sun's di/ance z
 measur$ by ! transits ( ,v5us4         
,illu/ration3 7,a7 & ! la/ #b l9es ( !  
next p>agraph %\ld be replac$ )3 "o-t5? 
( an in* long1 & f a po9t 7,a7 #e-c_/d  
in*es f x 7accurately #e4gbieggie in*es7
 we draw /raight l9es to ,b & ,c4 ,!n ! 
angle at ,a is "o degree47  ,b ?is      
problem ( measur+ ! sun's di/ance1 &    
?r\gh x ! dim5sions ( ! orbits ( all !  
planets ( our sy/em1 s9ks into          
insignificance :5 comp>$ ) ! enorm\s    
difficulties 9 ! way ( ! det]m9ation ( !
 di/ance ( ! />s4 ,z a great _m p1      
p]haps ! majority ( ! read]s ( any      
popul> sci5tific book1 h little k (     
ma!matics & _c realise :at an angle ( a 
m9ute or a second really means1 a little
 explanation & illu/ration ( ^! t]ms w n
 be out ( place4 ,an angle ( "o degree  
7#a7 is ! #cfj? "p ( a circle 7view$ f  
its c5tre71 ! #ij? "p ( a "r angle1 !   

#fj? "p ( ei!r ( ! angles ( an          
equilat]al triangle4 ,to see exactly h[ 
mu* is an angle ( "o degree we draw a   
%ort l9e 7,b ,c7 "o-t5? ( an in* long1 &
 f a po9t we draw /raight l9es to ,b &  
,c4 ,!n ! angle at ,a is "o degree4     
,n[1 9 all a/ronomical "w1 "o degree is 
consid]$ to be q a l>ge angle4 ,ev5 be=e
 ! inv5tion ( ! telescope ! old obs]v]s 
fix$ ! position ( ! />s & planets to    
half or a qu>t] ( a degree1 :ile ,mr4   
,proctor ?9ks t ,ty*o ,brah's positions 
( ! />s & planets 7 correct to ab\t "o  
or two m9utes ( arc4 ,b a m9ute ( arc is
 obta9$ by divid+ ! l9e ,b ,c into sixty
 equal p>ts & see+ ! di/ance betwe5 two 
( ^! ) ! nak$ eye f ! po9t ,a4 ,b z v   
long-sight$ p c see v m9ute objects at  
#aj or #ab in*es di/ance1 we may d\ble !
 di/ance ,a ,b1 & !n mak+ ! l9e ,b ,c "o
 ?ree-hundr$? "p ( an in* long1 we %all 
h ! angle ( "o m9ute :i* ,ty*o ,brah 0  
p]haps able to measure4 ,h[ v l>ge an   
am\nt a m9ute is to ! mod]n a/ronom] is1
 h[ev]1 well %[n by ! fact t ! maximum  

diff]5ce betwe5 ! calculat$ & obs]v$    
positions ( ,uranus1 :i* l$ ,adams &    
,lev]ri] to se>* = & discov] ,neptune1 0
 only #a-a_/b m9utes1 a space s small z 
to be almo/ invisible to ! av]age eye1 s
 t if !re _h be5 two planets1 "o 9 !    
calculat$1 ! o!r 9 ! obs]v$ place1 !y   
w\ld h appe>$ z "o to unassi/$ vision4  
,9 ord] n[ to realise :at "o second (   
arc really means1 let u look at ! circle
 "h %[n1 :i* is z ne>ly z possible      
"o-t5? ( an in* 9 diamet]--7"o-,o-t5? ( 
an in*74 ,if we remove ?is circle to a  
di/ance ( #bh feet #h in*es x w subt5d  
an angle ( "o m9ute1 & we %all h to     
place x at a di/ance ( ne>ly #agcj      
feet--almo/ "o-?ird ( a mile--to r$uce !
 angle to "o second4 ,b ! v ne>e/ to u (
 ! fix$ />s1 ,alpha ,c5tauri1 has a     
p>allax ( only ?ree-f\r?s ( a second2 t 
is1 ! di/ance ( ! e>? f ! sun--ab\t     
#ib-c_/d millions ( miles--w\ld appe> no
 wid]1 se5 f ! ne>e/ />1 ?an does       
?ree-f\r?s ( ! above small circle at    
"o-?ird ( a mile di/ance4 ,to see ?is   

circle at all at t di/ance w\ld require 
a v good telescope ) a p[] ( at lea/    
#ajj1 :ile to see any small "p ( x & to 
measure ! proportion ( t "p to ! :ole   
w\ld ne$ v brilliant illum9ation & a    
l>ge & p[]ful a/ronomical telescope4    
,,:at ,,is ,a ,,million8  ,b :5 we h to 
deal ) millions1 & ev5 ) hundr$s & ?\s&s
 ( millions1 !re is ano!r difficulty--t 
few p c =m any cle> conception ( :at a  
million is4 ,x has be5 sugge/$ t 9 e    
l>ge s*ool ! walls ( "o room or hall    
%\ld be devot$ to %[+ a million at "o   
view4 ,= ?is purpose x w\ld be necess>y 
to h a hundr$ l>ge %eets ( pap] ea* ab\t
 #d feet #f in*es squ>e1 rul$ 9 qu>t]   
in* squ>es4 ,9 ea* alt]nate squ>e a r\nd
 black waf] or circle %\ld be plac$ a   
little ov]-lapp+ ! squ>e1 ?us leav+ an  
equal am\nt ( :ite space betwe5 ! black 
spots4 ,at ea* t5? spot a d\ble wid?    
%\ld be left s z to sep>ate ea* hundr$  
spots 7#aj  #aj74 ,ea* %eet w\ld !n hold
 t5 ?\s& spots1 :i* w\ld all be di/9ctly
 visible f ! middle ( a room #bj feet   

wide1 ea* horizontal or v]tical r[      
conta9+ a ?\s&4 ,"o hundr$ su* %eets    
w\ld conta9 a million spots1 & !y w\ld  
occupy a space #dej feet long 9 "o r[1  
or #ij feet long 9 five r[s1 s t !y w\ld
 entirely cov] ! walls ( a room1 ab\t   
#cj feet squ>e & #be feet high1 f floor 
to ceil+1 all[+ space = doors b n =     
w9d[s1 ! hall or gall]y be+ light$ f    
above4 ,su* a hall w\ld be 9 ! highe/   
degree educational 9 a c\ntry :]e       
millions are spok5 ( s glibly & wa/$ s  
recklessly2 :ile no "o c really         
appreciate mod]n sci5ce1 deal+ z x does 
) ! unimag9ably great & little1 unless  
he is enabl$ to realise by actual       
vision1 & summ+ up1 :at a va/ numb] is  
compris$ 9 "o ( ^? millions1 :i*1 9     
mod]n a/ronomy & physics1 he has to deal
 ) n s+ly only1 b by hundr$s & ?\s&s or 
ev5 by millions4 ,9 e consid]able t[n1  
at all ev5ts1 a hall or gall]y %\ld h a 
million ?us %[n ^u its walls4 ,x w\ld 9 
no way int]f]e ) ! walls be+ cov]$ :5   
requir$ ) maps1 or ornam5tal hang+s1 or 

pictures2 b :5 ^! 7 remov$1 ! visible & 
c\ntable million w\ld rema9 z a p]man5t 
lesson to all visitors2 & ,i believe t x
 w\ld h widespread b5eficial effects 9  
almo/ e dep>tm5t ( human ?\ght & action4
 ,on a small scale any "o c d ?is =     
himself by gett+ a hundr$ %eets (       
eng9e]'s pap] rul$ 9 small squ>es1 &    
mak+ ! spots v small2 & ev5 ?is w\ld be 
impressive1 b n s mu* s z on ! l>g]     
scale4  ,9 ord] to enable e read] ( ?is 
volume at once to =m "s conception ( !  
numb] ( units 9 a million1 ,i h made an 
e/imate ( ! numb] ( lett]s conta9$ 9 x1 
& ,i f9d !m to am\nt to ab\t            
#dbj1jjj--;consid]ably less ?an half a  
million4 ,try & realise1 :5 read+ x1 t  
if e lett] 7 a p\nd /]l+1 we wa/e z _m  
p\nds z !re are lett]s 9 two su* volumes
 :5ev] we build a battle%ip4  ,hav+ ?us 
obta9$ "s real conception ( ! imm5sity (
 a million1 we c bett] realise :at x mu/
 be to h e "o ( ! dots above describ$1  
or e "o ( ! lett]s 9 two su* volumes z  
?is l5g!n$ out s z to be ea* a mile     

long1 & ev5 !n we %\ld h rea*$ little m 
?an a hundr$? "p ( ! di/ance f our e>?  
to ! sun4 ,:51 by c>eful consid]ation ( 
^! figures1 we h ev5 p>tially realis$   
?is enorm\s di/ance1 we may take ! next 
/ep1 :i* is1 to comp>e ?is di/ance ) t (
 ! ne>e/ fix$ />4 ,we h se5 t ! p>allax 
( t /> is ?ree-f\r?s ( a second1 an     
am\nt :i* implies t ! /> is #bga1djj    
times z f> f u z our sun is4 ,if aft]   
see+ :at a million is1 & kn[+ t ! sun is
 #ib-c_/d times ?is di/ance f u 9       
miles--a di/ance :i* itself is almo/    
inconceivable to u--we f9d t we h to    
multiply ?is almo/ inconceivable di/ance
 #bga1djj times--m ?an a qu>t] ( a      
million times--to rea* ! ne>e/ ( ! fix$ 
/>s1 we %all beg9 to realise1 h[ev]     
imp]fectly1 h[ va/ is ! sy/em ( suns    
ar\nd u1 & on :at a scale ( imm5sity !  
mat]ial univ]se1 :i* we see s glori\sly 
display$ 9 ! />ry heav5s & ! my/]i\s    
galaxy1 is con/ruct$4  ,?is some:at     
l5g?y prelim9>y discussion is ?\ght     
necess>y 9 ord] t my read]s may =m "s   

idea ( ! enorm\s difficulty ( obta9+ any
 measurem5t :atev] ( su* di/ances4 ,i n[
 propose to po9t out :at ! special      
difficulties are1 & h[ !y h be5 ov]come2
 & ?us ,i hope to be able to satisfy !m 
t ! figures a/ronom]s give u ( !        
di/ances ( ! />s are 9 no way m]e       
guesses or probabilities1 b are real    
measurem5ts :i*1 )9 c]ta9 n v wide      
limits ( error1 may be tru/$ z giv+ u   
correct ideas ( ! magnitude ( ! visible 
univ]se4   ,,measurem5t ,,( ,,/ell>     
,,di/ances  ,! fundam5tal difficulty (  
?is measurem5t is1 ( c\rse1 t ! di/ances
 are s va/ t ! longe/ available         
base-l9e1 ! diamet] ( ! e>?'s orbit1    
only subt5ds an angle ( little m ?an a  
second f ! ne>e/ />1 :ile = all ! re/ x 
is less ?an "o second & (t5 only a small
 fraction ( x4 ,b ?is difficulty1 great 
z x is1 is r5d]$ f> great] by ! fact t  
!re is no fix$ po9t 9 ! heav5s f :i* to 
measure1 s9ce _m ( ! />s are kn[n to be 
9 motion1 & all are believ$ to be s 9   
v>y+ degrees1 :ile ! sun itself is n[   

kn[n to be mov+ among ! />s at a rate   
:i* is n yet accurately det]m9$1 b 9 a  
direction :i* is fairly well kn[n4 ,z ! 
v>i\s motions ( ! e>? :ile pass+ r\nd ! 
sun1 ?\gh extremely complex1 are v      
accurately kn[n1 x 0 fir/ attempt$ to   
det]m9e ! *ang$ position ( />s by       
obs]vations1 _m times repeat$ at six    
mon?s' int]vals1 ( ! mom5t ( _! passage 
ov] ! m]idian & _! di/ance f ! z5i?2 &  
!n by all[+ = all ! kn[n motions ( !    
e>?1 su* z precession ( ! equ9oxes &    
nutation ( ! e>?'s axis1 z well z =     
refraction & = ! ab]ration ( light1 to  
det]m9e :at residual effect 0 due to !  
diff]5ce ( position f :i* ! /> 0 view$2 
& a result 0 ?us obta9$ 9 sev]al cases1 
?\gh almo/ always a l>g] "o ?an has be5 
f\nd by lat] obs]vations & by bett]     
me?ods4 ,^! e>li] obs]vations1 h[ev]    
p]fect ! in/rum5ts & h[ev] skilful !    
obs]v]1 are liable to errors :i* x seems
 impossible to avoid4 ,! in/rum5ts      
!mselves are subject 9 all _! p>ts to   
expansion & contraction by *anges (     

temp]ature2 & :5 ^! *anges are sudd51 "o
 "p ( ! in/rum5t may be affect$ m ?an   
ano!r1 & ?is w (t5 lead to m9ute errors 
:i* may s]i\sly affect ! am\nt to be    
measur$ :5 t is s small4 ,ano!r s\rce ( 
error is due to atmosph]ic refraction1  
:i* is subject to *anges bo? f h\r to   
h\r & at diff]5t seasons4 ,b p]haps mo/ 
important ( all are m9ute *anges 9 level
 ( ! f\ndations ( ! in/rum5ts ev5 :5 !y 
are c>ri$ d[n to solid rock4 ,bo? *anges
 ( temp]ature & *anges ( moi/ure ( !    
soil produce m9ute alt]ations ( level2  
:ile e>?-tremors & sl[ movem5ts (       
elevation or depression are n[ kn[n to  
be v frequ5t4 ,ow+ to all ^! causes1    
actual measurem5ts ( diff]5ces (        
position at diff]5t times ( ! ye>1      
am\nt+ to small fractions ( a second1   
are f\nd to be too unc]ta9 = !          
det]m9ation ( su* m9ute angles ) !      
requir$ accuracy4  ,b !re is ano!r me?od
 :i* avoids almo/ all ^! s\rces ( error1
 & ?is is n[ g5]ally pref]r$ & adopt$ = 
^! measurem5ts4 ,x is1 t ( measur+ !    

di/ance betwe5 two />s situat$ app>5tly 
v ne> ea* o!r1 "o ( :i* has l>ge prop]  
motion1 :ile ! o!r has none :i* is      
measurable4 ,! prop] motions ( ! />s 0  
fir/ suspect$ by ,halley 9 #agag1 f f9d+
 t sev]al />s1 ^: places _h be5 giv5 by 
,hipp>*us1 #acj ,b4,c41 7 n 9 !         
positions :]e !y n[ ought to be2 & o!r  
obs]vations by ! old a/ronom]s1         
especially ^? ( occultations ( />s by ! 
moon1 l$ to ! same result4 ,s9ce ! "t ( 
,halley v accurate obs]vations ( ! />s h
 be5 made1 & 9 _m cases x is f\nd t !y  
move p]ceptibly f ye> to ye>1 :ile o!rs 
move s sl[ly t x is only aft] =ty or    
fifty ye>s t ! motion c be detect$4 ,!  
greate/ prop] motions yet det]m9$ am\nt 
to betwe5 #g & #h 9 a ye>1 :ile o!r />s 
require tw5ty1 or ev5 fifty or a hundr$ 
ye>s to %[ an equal am\nt ( displacem5t4
 ,at fir/ x 0 ?\ght t ! brighte/ />s    
w\ld h ! l>ge/ prop] motion1 because x 0
 suppos$ !y 7 ne>e/ to u1 b x 0 soon    
f\nd t _m small & q inconspicu\s />s    
mov$ z rapidly z ! mo/ brilliant1 :ile 9

 _m v bright />s no prop] motion at all 
c be detect$4 ,t :i* moves mo/ rapidly  
is a small /> ( less ?an ! six?         
magnitude4  ,x is a matt] ( common      
obs]vation t ! motion ( ?+s at a di/ance
 _c be p]ceiv$ s well z :5 ne>1 ev5 ?\gh
 ! spe$ may be ! same4 ,if a man is se5 
on ! top ( a hill sev]al miles (f1 we h 
to obs]ve him closely = "s "t be=e we c 
be sure :e!r he is walk+ or /&+ /ill4 ,b
 objects s enorm\sly di/ant z we n[ "k t
 ! />s are1 may be mov+ at ! rate ( _m  
miles 9 a second & yet require ye>s (   
obs]vation to detect any movem5t at all4
  ,! prop] motions ( ne>ly a hundr$ />s 
h n[ be5 asc]ta9$ to be m ?an "o second 
( arc annually1 :ile a l>ge numb] h less
 ?an ?is1 & ! majority h no p]ceptible  
motion1 presumably due to _! enorm\s    
di/ance f u4 ,x is !re=e n difficult 9  
mo/ cases to f9d "o or two motionless   
/>s suffici5tly close to a /> hav+ a    
l>ge prop] motion 7any?+ m ?an "o-t5? ( 
a second is s call$7 to s]ve z fix$     
po9ts ( measurem5t4 ,all t is !n requir$

 is1 to measure ) extreme accuracy !    
angul> di/ance ( ! mov+ f ! fix$ />s at 
int]vals ( six mon?s4 ,! measurem5ts c  
be made1 h[ev]1 on e f9e night1 ea* "o  
be+ comp>$ ) "o at ne>ly an int]val (   
six mon?s f x4 ,9 ?is way a hundr$ or m 
measurem5ts ( ! same /> may be made 9 a 
ye>1 & ! mean ( ! :ole1 all[ance be+    
made = prop] motion 9 ! int]val1 w give 
a mu* m accurate result ?an any s+le    
measurem5t4 ,?is k9d ( measurem5t c be  
made ) extreme accuracy :5 ! two />s c  
be se5 toge!r 9 ! field ( ! telescope2  
ei!r by ! use ( a micromet]1 or by means
 ( an in/rum5t call$ a heliomet]1 n[ (t5
 con/ruct$ = ! purpose4 ,?is is an      
a/ronomical telescope ( r l>ge size1 !  
object glass ( :i* is cut 9 two /raight 
across ! c5tre1 & ! two halves made to  
slide ^u ea* o!r by means ( an exce$+ly 
f9e & accurate screw-motion1 s adju/$ & 
te/$ z to measure ! angul> di/ance ( two
 objects ) extreme accuracy4 ,?is is    
done by ! numb] ( turns ( ! screw       
requir$ to br+ ! two />s into contact ) 

ea* o!r1 ! image ( ea* "o be+ =m$ by "o 
( ! halves ( ! object glass4  ,b !      
greate/ advantage ( ?is me?od ( det]m9+ 
p>allax is1 z ,sir ,john ,h]s*ell po9ts 
out1 t x gets rid ( all ! s\rces ( error
 :i* r5d] ! old] me?ods s unc]ta9 &     
inaccurate4 ,no corrections are requir$ 
= precession1 nutation1 or ab]ration1   
s9ce ^! affect bo? />s alike1 z is !    
case also ) refraction2 :ile alt]ations 
( level ( ! in/rum5t h no prejudicial   
effect1 s9ce ! measures ( angul> di/ance
 tak5 by ?is me?od are q indep5d5t ( su*
 movem5ts4 ,a te/ ( ! accuracy ( !      
det]m9ation ( p>allax by ?is in/rum5t is
 ! v close agreem5t ( diff]5t obs]v]s1 &
 also _! agreem5t ) ! new & p]haps ev5  
sup]ior me?od by photography4 ,?is me?od
 0 fir/ adopt$ by ,pr(essor ,prit*>d ( !
 ,ox=d ,obs]vatory1 ) a f9e reflector ( 
?irte5 in*es ap]ture4 ,its great        
advantage is1 t all ! small />s 9 !     
vic9ity ( ! /> ^: p>allax is s\ght are  
%[n 9 _! exact positions ^u ! plate1 & !
 di/ances ( all ( !m f x c be v         

accurately measur$1 & by comp>+ plates  
tak5 at six mon?s' int]vals1 ea* ( ^!   
/>s gives a det]m9ation ( p>allax1 s t !
 mean ( ! :ole w lead to a v accurate   
result4 ,%\ld1 h[ev]1 ! result f any "o 
( ^! />s diff] consid]ably f t d]iv$ f !
 re/1 x w be due 9 all probability to t 
/> hav+ a prop] motion ( its own1 & x   
may !re=e be reject$4 ,to illu/rate !   
am\nt ( lab\r be/[$ by a/ronom]s on ?is 
difficult problem1 x may be m5tion$ t = 
! photographic measurem5t ( ! /> #fa    
,cygni1 #ccj sep>ate plates 7 tak5 9    
#ahhf-g1 & on ^! #cj1jjj measurem5ts (  
di/ances ( ! pairs ( />-images 7 made4  
,! result agre$ closely ) ! be/ previ\s 
det]m9ation by ,sir ,rob]t ,ball1 us+ ! 
micromet]1 & ! me?od 0 at once admitt$  
by a/ronom]s z be+ ( ! greate/ value4   
,al?\gh1 z a rule1 />s hav+ l>ge prop]  
motions are f\nd to be comp>atively ne> 
u1 !re is no regul> proportion betwe5 ^!
 quantities1 indicat+ t ! rapidity ( !  
motion ( ! />s v>ies greatly4 ,among    
fifty />s ^: di/ances h be5 fairly well 

det]m9$1 ! rate ( actual motion v>ies f 
"o or two up to m ?an a hundr$ miles p] 
second4 ,among six />s ) less ?an a t5? 
( a second ( annual prop] motion !re is 
"o ) a p>allax ( ne>ly half a second1 & 
ano!r ( "o-n9? ( a second1 s t !y are   
ne>] to u ?an _m />s :i* move sev]al    
seconds a ye>4 ,?is may be due to actual
 sl[ness ( motion1 b is almo/ c]ta9ly   
caus$ 9 "p by _! motion be+ ei!r t[>ds u
 or away f u1 & !re=e only measurable by
 ! spectroscope2 & ?is _h n be5 done :5 
! li/s ( p>allaxes & prop] motions f :i*
 ^! facts are tak5 7 publi%$4 ,x is     
evid5t t ! actual direction & rate (    
motion ( a /> _c be kn[n till ?is radial
 movem5t1 z x is t]m$--t is1 t[>ds or   
away f u--has be5 measur$2 b z ?is      
elem5t always t5ds to increase !        
visually obs]v$ rate ( motion1 we _c1   
?r\gh its abs5ce1 exagg]ate ! actual    
motions ( ! />s4   ,,! ,,sun',s         
,,movem5t ,,?r\gh ,,space  ,b !re is yet
 ano!r important factor :i* affects !   
app>5t motions ( all ! />s--! movem5t ( 

our sun1 :i*1 be+ a /> itself1 has a    
prop] motion ( its own4 ,?is motion 0   
suspect$ & s\ght = by ,sir ,william     
,h]s*el a c5tury ago1 & he actually     
det]m9$ ! direction ( its motion t[>ds a
 po9t 9 ! con/ellation ,h]cules1 n v f> 
remov$ f t fix$ ^u z ! av]age ( ! be/   
obs]vations s9ce made4 ,! me?od (       
det]m9+ ?is motion is v simple1 b at !  
same "t v difficult4 ,:5 we are travell+
 9 a railway c>riage ne> objects pass   
rapidly out ( sight beh9d u1 :ile ^?    
f>!r f u rema9 long] 9 view1 & v di/ant 
objects appe> almo/ /ation>y = a        
consid]able "t4 ,= ! same reason1 if our
 sun is mov+ 9 any direction ?r\gh      
space1 ! ne>] />s w appe> to travel 9 an
 opposite direction to our movem5t1 :ile
 ! m di/ant w rema9 q /ation>y4 ,?is    
movem5t ( ! ne>e/ />s is detect$ by an  
exam9ation & comp>ison ( _! prop]       
motions1 by :i* x is f\nd t 9 "o "p ( ! 
heav5s !re is a prepond]ance ( ! prop]  
motions 9 "o direction & a defici5cy 9 !
 opposite direction1 :ile 9 ! directions

 at "r angles to ^! ! prop] motions are 
n on ! av]age great] 9 "o direction ?an 
9 ! opposite4 ,b ! prop] motions ( ! />s
 be+ !mselves s m9ute1 & also s         
irregul>1 x is only by a mo/ elaborate  
ma!matical inve/igation ( ! motions (   
hundr$s or ev5 ( ?\s&s ( />s1 t !       
direction ( ! sol> motion c be det]m9$4 
,till q rec5tly a/ronom]s 7 agre$ t !   
motion 0 t[>ds a po9t 9 ,h]cules ne> !  
out/ret*$ arm 9 ! figure ( t            
con/ellation4 ,b ! late/ inquiries into 
?is problem1 involv+ ! comp>ison ( !    
motions ( sev]al ?\s& />s 9 all p>ts ( !
 heav5s1 h l$ to ! conclusion t ! mo/   
probable direction ( ! 'sol> apex' 7z ! 
po9t t[>ds :i* ! sun is mov+ is t]m$71  
is 9 ! adjac5t con/ellation ,lyra1 & n  
f> f ! brilliant /> ,vega4 ,?is is !    
position :i* ,pr(essor ,newcomb (       
,wa%+ton ?9ks mo/ probable1 ?\gh !re is 
/ill room = fur!r inve/igation4 ,to     
det]m9e ! rate ( ! motion is v mu* m    
difficult ?an to fix its direction1     
because ! di/ances ( s few />s h be5    

det]m9$1 & v few inde$ ( ^! lie 9 !     
directions be/ adapt$ to give accurate  
results4 ,! be/ measurem5ts d[n to #ahij
 l$ to a motion ( ab\t #ae miles a      
second4 ,b m rec5tly ! ,am]ican         
a/ronom]1 ,campbell1 has det]m9$ by !   
spectroscope ! motion 9 ! l9e ( sight ( 
a consid]able numb] ( />s t[>ds & away f
 ! sol> apex1 & by comp>+ ! av]age ( ^! 
motions1 he d]ives a motion = ! sun (   
ab\t #ab-a_/b miles a second1 & ?is is  
probably z ne> z we c yet rea* t[>ds !  
true am\nt4   ,,"s ,,num]ical ,,results 
,,( ,,! ,,above ,,measurem5ts  ,!       
measurem5ts ( di/ances & prop] motions (
 a consid]able numb] ( ! />s1 ( ! motion
 ( our sun 9 space 7its prop] motion71  
toge!r ) accurate det]m9ations ( !      
comp>ative brilliancy ( ! brighte/ />s z
 comp>$ ) our sun & ) ea* o!r1 h l$ to  
"s v rem>kable num]ical results :i* s]ve
 z indications ( ! scale ( magnitude ( !
 /ell> univ]se4  ,! p>allaxes ( ab\t    
fifty />s h n[ be5 repeat$ly measur$ )  
su* consi/5t results t ,pr(essor        

,newcomb consid]s !m to be fairly       
tru/wor?y1 & ^! v>y f "o-hundr$? to     
?ree-qu>t]s ( a second4 ,?ree m1 all />s
 ( ! fir/ magnitude--,rigel1 ,canopus1 &
 ,alpha ,cygni--h no measurable p>allax1
 not)/&+ ! long-cont9u$ ef=ts ( _m      
a/ronom]s1 af=d+ a /rik+ example ( !    
fact t brilliancy alone is no te/ (     
proximity4 ,six m />s h a p>allax ( only
 "o-fiftie? ( a second1 & five ( ^! are 
ei!r ( ! fir/ or second magnitudes4 ,(  
^! n9e />s hav+ v small p>allax or none1
 six are situat$ 9 or ne> to ! ,milky   
,way1 ano!r indication ( exce$+         
remot5ess1 :i* is fur!r %[n by ! fact t 
!y all h a v small prop] motion or none 
at all4 ,^! facts support ! conclusion1 
:i* _h be5 already rea*$ by a/ronom]s f 
a c>eful /udy ( ! di/ribution ( ! />s1 t
 ! l>g] portion ( ! />s ( all magnitudes
 scatt]$ ?r\gh\t ! ,milky ,way or along 
its bord]s really belong to ! same great
 sy/em1 & may be said to =m a "p ( x4   
,?is is a conclusion ( extreme          
importance because x tea*es u t ! gr&e/ 

( ! suns1 su* z ,rigel & ,betelgeuse 9 !
 con/ellation ,orion1 ,ant>es 9 !       
,scorpion1 ,d5eb 9 ! ,swan 7,alpha      
,cygni71 & ,canopus 7,alpha ,argus71 are
 9 all probability z f> remov$ f u z are
 ! innum]able m9ute />s :i* give !      
nebul\s or milky appe>ance to ! ,galaxy4
  ,x is well to consid] = a mom5t :at ^!
 facts mean4 ,pr(essor ,s4 ,newcomb1 "o 
( ! highe/ au?orities on ^! problems1   
tells u t ! long s]ies ( measurem5ts to 
discov] ! p>allax ( ,canopus1 ! brighte/
 /> 9 ! s\!rn hemisph]e1 w\ld h %[n a   
p>allax ( "o-hundr$? ( a second1 _h su* 
exi/$4 ,yet ! results always seem$ to   
conv]ge to a mean ( #j4jjj6 ,suppose1   
!n1 we assume ! p>allax ( ?is /> to be  
some:at less ?an ! hundr$? ( a          
second--let u say #a_/abe ( a second4   
,at ! di/ance ?is gives1 light w\ld take
 almo/ exactly #djj ye>s to rea* u1 s t 
if we suppose ?is v brilliant /> to be  
situat$ a little on ?is side ( !        
,galaxy1 we mu/ give to t great lum9\s  
circle ( />s a di/ance ( ab\t #ejj light

 ye>s4 ,we %all n[ p]ceive ! advantage (
 be+ able to realise :at a million      
really is4 ,a p]son :o _h once se5 a    
wall-space m ?an #ajj feet long & #bj   
feet high completely cov]$ ) qu>t]-in*  
spots a qu>t] ( an in* ap>t2 & !n tri$  
to imag9e e spot to be a mile long & to 
be plac$ end to end 9 "o r[1 w\ld =m a v
 diff]5t conception ( a million miles   
?an ^? :o almo/ daily read ( millions1 b
 are q unable to visualise ev5 "o ( !m4 
,hav+ really se5 "o million1 we c       
p>tially realise ! velocity ( light1 :i*
 travels ov] ?is million miles 9 a      
little less ?an #e-a_/b seconds2 & yet  
light takes m ?an #d-a_/c ye>s at ?is   
inconceivable spe$ to come to u f ! v   
ne>e/ ( ! />s4 ,to realise ?is /ill m   
impressively1 let u take ! di/ance ( ?is
 ne>e/ />1 :i* is #bf millions (        
millions ( miles4 ,let u look 9         
imag9ation at ?is l>ge & l(ty hall cov]$
 f floor to ceil+ ) qu>t]-in*           
spots--only "o million4 ,let all ^! be  
imag9$ z miles4 ,!n repeat ?is numb] (  

miles 9 a /raight l9e1 "o aft] ! o!r1 z 
_m times z !re are spots 9 ?is hall2 &  
ev5 !n y h rea*$ only "o tw5ty-six? "p (
 ! di/ance to ! ne>e/ fix$ />6 ,?is     
million times a million miles has to be 
repeat$ tw5ty-six times to rea* ! ne>e/ 
fix$ />2 & x seems probable t ?is gives 
u a good indication ( ! di/ance f ea*   
o!r ( at lea/ all ! />s d[n to ! six?   
magnitude1 p]haps ev5 ( a l>ge numb] ( !
 telescopic />s4 ,b z we h f\nd t !     
bright />s ( ! ,milky ,way mu/ be at    
lea/ "o hundr$ times f>!r f u ?an ^!    
ne>e/ />s1 we h f\nd :at may be t]m$ a  
m9imum di/ance = t va/ />-r+4 ,x may be 
imm5sely f>!r1 b x is h>dly possible t x
 %\ld be any?+ less4   ,,! ,,probable   
,,size ,,( ,,! ,,/>s  ,hav+ ?us obta9$  
an inf]ior limit = ! di/ance ( sev]al   
/>s ( ! fir/ magnitude1 & _! actual     
brilliancy or light-emission z comp>$ ) 
our sun hav+ be5 c>efully measur$1 we h 
af=d$ u "s indication ( size ?\gh p]haps
 an unc]ta9 "o4 ,by ^! means x has be5  
f\nd t ,rigel gives out ab\t t5 ?\s&    

times z mu* light z our sun1 s t if its 
surface is ( ! same brightness1 x mu/ be
 a hundr$ times ! diamet] ( ! sun4 ,b z 
x is "o ( ! :ite or ,sirian type ( />s x
 is probably v mu* m lum9\s1 b ev5 if x 
7 tw5ty times bright] x w\ld /ill h to  
be tw5ty-two & a half times ! diamet] ( 
! sun2 & z ! />s ( ?is type are probably
 :olly gase\s & mu* less d5se ?an our   
sun1 ?is enorm\s size may n be f> f !   
tru?4 ,x is believ$ t ! ,sirian />s     
g5]ally h a great] surface brilliancy   
?an our sun4 ,beta ,aurig1 a /> ( !     
second magnitude b ( ! ,sirian type1 is 
"o ( ! d\ble />s ^: di/ance has be5     
measur$1 & ?is has enabl$ ,mr4 ,gore to 
f9d ! mass ( ! b9>y sy/em to be five    
times t ( ! sun1 & _! light "o hundr$ & 
sev5te5 times great]4 ,ev5 if ! d5sity  
is mu* less ?an ! sun's1 ! intr9sic     
brilliancy ( ! surface w be consid]ably 
great]4 ,ano!r d\ble />1 ,gamma ,leonis1
 has be5 f\nd to be ?ree hundr$ times m 
brilliant ?an ! sun if ( ! same d5sity1 
b x w\ld require to be sev5 times r>]   

?an air to h ! ext5t ( surface ne$$ to  
give ! same am\nt ( light if its surface
 emitt$ no m light ?an our sun f equal  
areas4  ,x is cle>1 !re=e1 t _m ( ! />s 
are mu* l>g] ?an our sun z well z m     
lum9\s2 b !re are also l>ge numb]s (    
small />s ^: l>ge prop] motions1 z well 
z ! actual measurem5t ( "s1 prove !m to 
be comp>atively ne> to u :i* yet are    
only ab\t "o-fiftie? "p z bright z !    
sun4 ,^! mu/1 !re=e1 be ei!r            
comp>atively small1 or if l>ge mu/ be b 
slightly lum9\s4 ,9 ! case ( "s d\ble   
/>s x has be5 prov$ t ! latt] is ! case2
 b x seems probable t o!rs are v mu*    
small] ?an ! av]age4 ,up to ! pres5t "t 
no means ( det]m9+ ! size ( a /> by     
actual measurem5t has be5 discov]$1 s9ce
 _! di/ances are s enorm\s t ! mo/      
p[]ful telescopes %[ only a po9t (      
light4 ,b n[ t we h really measur$ !    
di/ance ( a good _m />s we are able to  
det]m9e an upp] limit = _! actual       
dim5sions4 ,z ! ne>e/ fix$ />1 ,alpha   
,c5tauri1 has a p>allax ( #j4ge1 ?is    

means t if ?is /> has a diamet] z great 
z our di/ance f ! sun 7:i* is n mu* m   
?an a hundr$ times ! sun's diamet]7 x   
w\ld be se5 to h a di/9ct disc ab\t z   
l>ge z t ( ,jupit]'s fir/ satellite4 ,if
 x 7 ev5 "o-t5? ( ! size suppos$ x w\ld 
probably be se5 z a disc 9 our be/ mod]n
 telescopes4 ,! late ,mr4 ,rany>d rem>ks
 t if ! ,nebul> ,hypo!sis is true1 & our
 sun once ext5d$ z f> z ! orbit (       
,neptune1 !n1 among ! millions ( visible
 suns !re ought to be "s n[ to be f\nd 9
 e /age ( developm5t4 ,b any sun hav+ a 
diamet] at all approa*+ ?is size1 &     
situat$ z f> (f z a hundr$ times !      
di/ance ( ,alpha ,c5tauri1 w\ld be se5  
by ! ,lick telescope to h a disc half a 
second 9 diamet]4 ,h5ce ! fact t !re are
 no />s ) visible discs proves t !re are
 no suns ( ! requir$ size1 & adds ano!r 
argum5t1 ?\gh n p]haps a /rong "o1 aga9/
 ! acceptance ( ! ,nebul> ,hypo!sis4    
,,*apt] ,,vi  ,,! ,,unity ,,&           
,,evolution ,,( ,,! ,,/> ,,sy/em   ,! v 
cond5s$ sket* n[ giv5 ( su* ( !         

discov]ies ( rec5t ,a/ronomy z relate to
 ! subject we are discuss+ w1 x is hop$1
 give "s idea bo? ( ! "w already done & 
( ! numb] ( int]e/+ problems yet rema9+ 
to be solv$4 ,! mo/ em95t a/ronom]s 9 e 
"p ( ! _w look =w>d to ! solution ( ^!  
problems n1 p]haps1 z ( any great value 
9 !mselves1 b z /eps t[>ds a m complete 
k ( our univ]se z a :ole4 ,_! aim is to 
d = ! />-sy/em :at ,d>w9 did = ! organic
 _w1 to discov] ! processes ( *ange t   
are at "w 9 ! heav5s1 & to le>n h[ !    
my/]i\s nebul1 ! v>i\s types ( />s1 & ! 
clu/]s & sy/ems ( />s are relat$ to ea* 
o!r4 ,z ,d>w9 solv$ ! problem ( ! orig9 
( organic species f o!r species1 & ?us  
enabl$ u to und]/& h[ ! :ole ( ! exi/+  
=ms ( life h be5 develop$ out (         
pre-exi/+ =ms1 s a/ronom]s hope to be   
able to solve ! problem ( ! evolution ( 
suns f "s e>li] /ell> types1 s z to be  
able1 ultimately1 to =m "s intelligible 
conception ( h[ ! :ole /ell> univ]se has
 come to be :at x is4 ,volumes h already
 be5 writt5 on ?is subject1 & _m +5i\s  

sugge/ions & hypo!ses h be5 advanc$4 ,b 
! difficulties are v great2 ! facts to  
be co-ord9at$ are excessively num]\s1 & 
!y are necess>ily only a fragm5t ( an   
unkn[n :ole4 ,yet c]ta9 def9ite         
conclusions h be5 rea*$2 & ! agreem5t ( 
_m indep5d5t obs]v]s & ?9k]s on !       
fundam5tal pr9ciples ( /ell> evolution  
seems to assure u t we are progress+1 if
 sl[ly yet ) "s e/abli%$ basis ( tru?1  
t[>ds ! solution ( ?is1 ! mo/ /up5d\s   
sci5tific problem ) :i* ! human         
intellect has ev] attempt$ to grapple4  
,,! ,,unity ,,( ,,! ,,/ell> ,,univ]se   
,dur+ ! latt] half ( ! n9ete5? c5tury ! 
op9ion ( a/ronom]s has be5 t5d+ m & m to
 ! conception t ! :ole ( ! visible      
univ]se ( />s & nebul con/itutes "o     
complete & closely-relat$ sy/em2 & dur+ 
! la/ ?irty ye>s especially ! va/ body (
 facts accumulat$ by /ell> rese>* has s 
firmly e/abli%$ ?is view t x is n[ h>dly
 que/ion$ by any compet5t au?ority4  ,! 
idea t ! nebul 7 f> m remote f u ?an !  
/>s long held sway1 ev5 aft] x _h be5   

giv5 up by its *ief support]4 ,:5 ,sir  
,william ,h]s*el1 by means ( 8 !n       
unapproa*$ telescopic p[]1 resolv$ !    
,milky ,way m or less completely into   
/>s1 & %[$ t num]\s objects :i* _h be5  
class$ z nebul 7 really clu/]s ( />s1 x 
0 natural to suppose t ^? :i* /ill      
reta9$ _! cl\dy appe>ance "u ! highe/   
telescopic p[]s 7 also clu/]s or sy/ems 
( />s1 :i* only ne$$ /ill high] p[]s to 
%[ _! true nature4 ,?is idea 0 support$ 
by ! fact t sev]al nebul 7 f\nd to be m 
or less r+-%ap$1 ?us correspond+ on a   
small] scale to ! =m ( ! ,milky ,way2 s 
t :5 ,h]s*el discov]$ ?\s&s ( telescopic
 nebul1 he 0 accu/om$ to speak ( !m z s 
_m di/9ct univ]ses scatt]$ ?r\gh !      
immeasurable dep?s ( space4  ,n[1 al?\gh
 any real conception ( ! imm5sity ( ! "o
 /ell> univ]se1 ( :i* ! ,milky ,way )   
its associat$ />s is ! fundam5tal       
feature1 is1 z ,i h %[n1 almo/          
unatta9able1 ! idea ( an unlimit$ numb] 
( o!r univ]ses1 almo/ inf9itely remote f
 our own & yet di/9ctly visible 9 !     

heav5s1 s seiz$ ^u ! imag9ation t x     
became almo/ a commonplace ( popul>     
a/ronomy & 0 n easily giv5 up ev5 by    
a/ronom]s !mselves4 ,& ?is 0 9 a l>ge "p
 due to ! fact t ,sir ,william ,h]s*el's
 volum9\s writ+s1 be+ almo/ all 9 !     
,philosophical ,transactions ( ! ,royal 
,society1 7 v little read1 & t he only  
indicat$ 8 *ange ( view by a few brief  
s5t5ces :i* might easily be ov]look$4 ,!
 late ,mr4 ,proctor appe>s to h be5 !   
fir/ a/ronom] to make a ?or\gh /udy ( ! 
:ole ( ,h]s*el's pap]s1 & he tells u t  
he read !m all ov] five times be=e he 0 
able ?or\ghly to grasp ! writ]'s views  
at diff]5t p]iods4  ,b ! fir/ p]son to  
po9t out ! real tea*+ ( ! facts z to !  
di/ribution ( ! nebul 0 n an a/ronom]1 b
 our greate/ philosophical /ud5t (      
sci5ce 9 g5]al1 ,h]b]t ,sp5c]4 ,9 a     
rem>kable essay on ',! ,nebul>          
,hypo!sis' 9 ! ,we/m9/] ,review ( ,july1
 #aheh1 he ma9ta9$ t ! nebul really =m$ 
a "p ( our own ,galaxy & ( our own /ell>
 univ]se4 ,a s+le passage f 8 pap] w    

indicate 8 l9e ( argum5t1 :i*1 x may be 
add$1 _h already be5 p>tially set =? by 
,sir ,john ,h]s*el 9 8 ,outl9es (       
,a/ronomy4  ',if !re 7 b "o nebula1 x   
w\ld be a curi\s co9cid5ce 7 ?is "o     
nebula s plac$ 9 ! di/ant regions (     
space z to agree 9 direction ) a />less 
spot 9 our own sid]eal sy/em4 ,if !re 7 
b two nebul1 & bo? 7 s plac$1 !         
co9cid5ce w\ld be excessively /range4   
,:at1 !n1 %all we say on f9d+ t !re are 
?\s&s ( nebul s plac$8 ,%all we believe 
t 9 ?\s&s ( cases ^! f>-remov$ galaxies 
happ5 to agree 9 _! visible positions ) 
! ?9 places 9 our own galaxy8 ,su* a    
belief is impossible4'  ,he !n applies !
 same argum5t to ! di/ribution ( ! nebul
 z a :ole3--',9 t zone ( cele/ial space 
:]e />s are excessively abundant1 nebul 
are r>e1 :ile 9 ! two opposite cele/ial 
spaces t are f>!/ remov$ f ?is zone1    
nebul are abundant4 ,sc>cely any nebul  
lie ne> ! galactic circle 7or plane ( ! 
,milky ,way72 & ! great mass ( !m lie   
r\nd ! galactic poles4 ,c ?is also be   

m]e co9cid5ce8' ,& he concludes1 f !    
:ole mass ( ! evid5ce1 t '! pro(s ( a   
physical connection become ov]:elm+4'   
,no?+ c\ld be m cle> or m =cible2 b     
,sp5c] n be+ an a/ronom]1 & writ+ 9 a   
comp>atively little read p]iodical1 !   
a/ronomical _w h>dly notic$ him2 & x 0 f
 t5 to fifte5 ye>s lat]1 :5 ,mr4 ,r4,a4 
,proctor1 by 8 labori\s *>ts & 8 v>i\s  
pap]s read be=e ! ,royal & ,royal       
,a/ronomical ,societies f #ahfi to      
#ahge1 compell$ ! att5tion ( ! sci5tific
 _w1 & ?us did m p]haps ?an any o!r man 
to e/abli% firmly ! gr& & f>-rea*+      
pr9ciple ( ! ess5tial unity ( ! /ell>   
univ]se1 :i* is n[ accept$ by almo/ e   
a/ronomical writ] ( em95ce 9 ! civilis$ 
_w4   ,,! ,,evolution ,,( ,,! ,,/ell>   
,,univ]se  ,amid ! enorm\s mass (       
obs]vations & ( sugge/ive speculation ^u
 ?is great & mo/ int]e/+ problem1 x is  
difficult to select :at is mo/ important
 & mo/ tru/wor?y4 ,b ! attempt mu/ be   
made1 because1 unless my read]s h "s k (
 ! mo/ important facts be>+ ^u x        

7besides ^? already set =?71 & also le>n
 some?+ ( ! difficulties t meet !       
inquir] into causes at e /ep ( 8 way1 & 
( ! v>i\s ideas & sugge/ions :i* h be5  
put =? to acc\nt = ! facts & to ov]come 
! difficulties1 !y w n be 9 a position  
to e/imate1 h[ev] imp]fectly1 ! gr&eur1 
! m>vel1 & ! my/]y ( ! va/ & highly     
complex univ]se 9 :i* we live & ( :i* we
 are an important1 p]haps ! mo/         
important1 if n ! only p]man5t outcome4 
,,! ,,sun ,a ,,typical ,,/>  ,x be+ n[ a
 recognis$ fact t ! />s are suns1 "s k (
 our own sun is an ess5tial prelim9>y to
 an inquiry into _! nature1 & into !    
probable *anges !y h und]gone4  ,! fact 
t ! sun's d5sity is only "o-f\r? t ( !  
e>?1 or less ?an "o & a half times t (  
wat]1 demon/rates t x _c be solid1 s9ce 
! =ce ( gravity at its surface be+      
tw5ty-six & a half times t at ! e>?'s   
surface1 ! mat]ials ( a solid globe w\ld
 be s compress$ t ! result+ d5sity w\ld 
be at lea/ tw5ty times great] in/ead (  
f\r times less ?an t ( ! e>?4 ,all !    

evid5ce goes to %[ t ! body ( ! sun is  
really gase\s1 b s compress$ by its     
gravitative =ce z to behave m l a       
liquid4 ,a few figures z to ! va/       
dim5sions ( ! sun & ! am\nt ( light &   
heat emitt$ by x w enable u bett] to    
und]/& ! ph5om5a x pres5ts1 & !         
int]pretation ( ^? ph5om5a4  ,proctor   
e/imat$ t ea* squ>e in* ( ! sun's       
surface emitt$ z mu* light z tw5ty-five 
electric arcs2 & ,pr(essor ,langley has 
%[n by exp]im5t t ! sun is #ecjj times  
bright]1 & eighty-sev5 times hott] ?an !
 :ite-hot metal 9 a ,bessem] conv]t]4 ,!
 actual am\nt ( sol> heat receiv$ by !  
e>? is suffici5t1 if :olly utilis$1 to  
keep a ?ree-horse-p[] eng9e cont9ually  
at "w on e squ>e y>d ( ! surface ( our  
globe4 ,! size ( ! sun is su*1 t if !   
e>? 7 at its c5tre1 n only w\ld !re be  
ample space = ! moon's orbit1 b         
suffici5t = ano!r satellite #aij1jjj    
miles beyond ! moon1 all revolv+ inside 
! sun4 ,! mass ( matt] 9 ! sun is #gde  
times great] ?an t ( all ! planets      

comb9$2 h5ce ! p[]ful gravitative =ce by
 :i* !y are reta9$ 9 _! di/ant orbits4  
,:at we see z ! sun's surface is !      
photosph]e or out] lay] ( gase\s or     
p>tially liquid matt] kept at a def9ite 
level by ! p[] ( gravitation4 ,!        
photosph]e has a granul> texture imply+ 
"s div]sity ( surface or ( lum9osity2   
al?\gh ! ev5 cont\r ( ! sun's m>g9 %[s t
 ^! irregul>ities are n on a v l>ge     
scale4 ,?is surface is app>5tly r5t     
asund] by :at are t]m$ sun-spots1 :i* 7 
long suppos$ to be cavities1 %[+ a d>k  
int]ior2 b are n[ ?\ght to be due to    
d[np\rs ( cool$ mat]ials driv5 out f !  
sun1 & =m+ ! prom95ces se5 dur+ sol>    
eclipses4 ,!y appe> to be black1 b ar\nd
 _! m>g9 is a %ad$ bord] or p5umbra =m$ 
( elongat$ %9+ pat*es cross+ &          
ov]-lapp+1 some?+ l heaps ( /raw4       
,sometimes brilliant portions ov]hang ! 
d>k spots1 & (t5 completely bridge !m   
ov]2 & simil> pat*es1 call$ facul1      
accompany spots1 & 9 "s cases almo/     
surr\nd !m4  ,sun-spots are sometimes   

num]\s on ! sun's disc1 sometimes v few1
 & !y are ( su* enorm\s size t :5 pres5t
 !y c easily be se5 ) ! nak$ eye1       
protect$ by a piece ( smok$ glass2 or1  
bett] /ill1 ) an ord9>y op]a-glass      
simil>ly protect$4 ,!y are f\nd to      
increase 9 numb] = sev]al ye>s1 & !n to 
decrease2 ! maxima recurr+ aft] an      
av]age p]iod ( elev5 ye>s1 b ) no       
exactness1 s9ce ! int]val betwe5 two    
maxima or m9ima is sometimes only n9e & 
sometimes z mu* z ?irte5 ye>s2 :ile !   
m9ima d n occur midway betwe5 two       
maxima1 b mu* ne>] to ! succe$+ ?an to !
 prec$+ "o4 ,:at is m int]e/+ is1 t     
v>iations 9 t]re/rial magnetism foll[ !m
 ) great accuracy2 :ile viol5t          
commotions 9 ! sun1 indicat$ by ! sudd5 
appe>ance ( facul1 sun-spots1 or        
prom95ces on ! sun's limb1 are always   
accompani$ by magnetic di/urbances on ! 
e>?4   ,,:at ,,surr\nds ,,! ,,sun  ,x   
has be5 well said t :at we commonly t]m 
! sun is really ! bright sph]ical       
nucleus ( a nebul\s body4 ,?is nucleus  

consi/s ( matt] 9 ! gase\s /ate1 b s    
compress$ z to resemble a liquid or ev5 
a visc\s fluid4 ,ab\t =ty ( ! elem5ts h 
be5 detect$ 9 ! sun by means ( ! d>k    
l9es 9 its spectrum1 b x is almo/ c]ta9 
t all ! elem5ts1 9 "s =m or o!r1 exi/   
!re4 ,?is semi-liquid gl[+ surface is   
t]m$ ! photosph]e1 s9ce f x are giv5 out
 ! light & heat :i* rea* our e>?4       
,imm$iately above ?is lum9\s surface is 
:at is t]m$ ! 'rev]s+ lay]' or absorb+  
lay]1 consi/+ ( d5se metallic vap\rs    
only a few hundr$ miles ?ick1 &1 ?\gh   
gl[+1 some:at cool] ?an ! surface ( !   
photosph]e4 ,its spectrum1 tak51 at !   
mom5t :5 ! sun is totally d>k5$1 ?r\gh a
 slit :i* is direct$ tang5tially to !   
sun's limb1 %[s a mass ( bright l9es    
correspond+ 9 a l>ge degree to ! d>k    
l9es 9 ! ord9>y sol> spectrum4 ,x is ?us
 %[n to be a vapor\s /ratum :i* absorbs 
! special rays emitt$ by ea* elem5t &   
=m+ its *>act]i/ic col\r$ l9es1 *ang+ !m
 into black l9es4 ,b z col\r$ l9es are n
 f\nd 9 ?is lay] correspond+ to all !   

black l9es 9 ! sol> spectrum1 x is n[   
held t special absorption mu/ also occur
 9 ! *romosph]e & p]haps 9 ! corona     
itself4 ,sir ,norman ,locky]1 9 8 volume
 on ,inorganic ,evolution1 ev5 goes s f>
 z to say1 t ! true 'rev]s+ lay]' ( !   
sun--t :i* by its absorption produc$ !  
d>k l9es 9 ! sol> spectrum--is n[ %[n to
 be n ! *romosph]e itself b a lay] above
 x1 ( l[] temp]ature4  ,above ! rev]s+  
lay] comes ! *romosph]e1 a va/ mass (   
rosy or sc>let emanations surr\nd+ ! sun
 to a dep? ( ab\t #djjj miles4 ,:5 se5  
dur+ eclipses x %[s a s]rat$ wav+       
outl9e1 b subject to great *anges ( =m1 
produc+ ! prom95ces already m5tion$4 ,^!
 are ( two k9ds3 ! 'quiesc5t1' :i* are  
some?+ l cl\ds ( enorm\s ext5t1 & :i*   
keep _! =ms = a consid]able "t2 & !     
'eruptive1' :i* %oot out 9 t[]+ tree-l  
flames or geys]-l eruptions1 & :ile do+ 
s h be5 prov$ to rea* velocities ( ov]  
#cjj miles a second1 & subside aga9 )   
almo/ equal rapidity4 ,! *romosph]e &   
its quiesc5t prom95ces appe> to be truly

 gase\s1 consi/+ ( hydrog51 helium1 &   
coronium1 :ile ! eruptive prom95ces     
always %[ ! pres5ce ( metallic vap\rs1  
especially ( calcium4 ,prom95ces        
increase 9 size & numb] 9 close         
accordance ) ! increase ( sun-spots4    
,beyond ! r$ *romosph]e & prom95ces is !
 m>vell\s :ite glory ( ! corona1 :i*    
ext5ds to an enorm\s di/ance r\nd ! sun4
 ,l ! prom95ces ( ! *romosph]e1 x is    
subject to p]iodical *anges 9 =m & size1
 correspond+ to ! sun-spot p]iod1 b 9   
inv]se ord]1 a m9imum ( sun-spots go+ ) 
a maximum ext5sion ( ! corona4 ,at !    
total eclipse ( ,july #ahgh1 :5 ! sun's 
surface 0 almo/ :olly cle>1 a pair (    
enorm\s equatorial /ream]s /ret*$ ea/ & 
we/ ( ! sun to a di/ance ( t5 millions (
 miles1 & less ext5sions ( ! corona     
occurr$ at ! poles4 ,at ! eclipses (    
#ahhb & #ahhc1 on ! o!r h&1 :5 sun-spots
 7 at a maximum1 ! corona 0 regul>ly    
/ellate ) no great ext5sions1 b ( high  
brilliancy4 ,?is correspond5ce has be5  
not$ at e eclipse1 & !re is !re=e an    

und\bt$ connection betwe5 ! two ph5om5a4
  ,! light ( ! corona is believ$ to be  
d]iv$ f ?ree s\rces--f inc&esc5t solid  
or liquid p>ticles ?r[n out f ! sun1 f  
sunlight reflect$ f ^! p>ticles1 & f    
gase\s emissions4 ,its spectrum         
possesses a gre5 ray1 :i* is peculi> to 
x1 & is suppos$ to indicate a gas nam$  
'coronium'2 9 o!r respects ! spectrum is
 m l t ( reflect$ sunlight4 ,! enorm\s  
ext5sions ( ! corona into great angul>  
/ream]s seem to indicate electrical     
repulsive =ces analog\s to ^? :i*       
produce ! tails ( comets4  ,connect$ ) !
 sun's corona is t /range ph5om5on1 !   
zodiacal light4 ,?is is a delicate      
nebulosity1 :i* is (t5 se5 aft] sunset 9
 spr+ & be=e sunrise 9 autumn1 tap]+    
upw>ds f ! sun's direction along ! plane
 ( ! ecliptic4 ,"u v fav\rable          
conditions x has be5 trac$ 9 ! ea/]n sky
 9 spr+ to #ahj f ! sun's position1     
indicat+ t x ext5ds beyond ! e>?'s      
orbit4 ,long-cont9u$ obs]vations f !    
summit ( ! ,pic du ,midi %[ t ?is is    

really ! case1 & t x lies almo/ exactly 
9 ! plane ( ! sun's equator4 ,x is !re=e
 held to be produc$ by ! m9ute p>ticles 
?r[n (f ! sun1 ?r\gh ^? coronal w+s &   
/ream]s :i* are visible only dur+ sol>  
eclipses4  ,! c>eful /udy ( ! sol>      
ph5om5a has v cle>ly e/abli%$ ! fact t  
none ( ! sun's envelopes1 f ! rev]s+    
lay] to ! corona itself1 is 9 any s5se  
an atmosph]e4 ,! comb9ation ( enorm\s   
gravitative =ce ) an am\nt ( heat :i*   
turns all ! elem5ts into ! liquid or    
gase\s /ate1 leads to consequ5ces :i* x 
is difficult = u to foll[ or compreh5d4 
,!re is evid5tly con/ant int]nal movem5t
 or circulation 9 ! int]ior ( ! sun1    
result+ 9 ! facul1 ! sun-spots1 !       
int5sely lum9\s photosph]e1 & !         
*romosph]e ) its va/ flam+ coruscations 
& eruptive protub]ances4 ,b x seems     
impossible t ?is incessant & viol5t     
movem5t c be kept up )\t "s great &     
p]iodical or cont9u\s inru% ( fre%      
mat]ials to r5ew ! heat1 keep up !      
int]nal circulation1 & supply ! wa/e4   

,p]haps ! movem5t ( ! sun ?r\gh space   
may br+ him into contact ) suffici5tly  
l>ge masses ( matt] to cont9ually excite
 t int]nal movem5t )\t :i* ! ext]ior    
surface w\ld rapidly become cool & all  
planet>y life cease4 ,! v>i\s sol>      
envelopes are ! result ( ?is int]nal    
agitation1 upru%es1 & explosions1 :ile !
 va/ :ite corona is probably ( little m 
d5sity ?an comets' tails1 probably ev5 (
 less d5sity1 s9ce comets n unfrequ5tly 
ru% ?r\gh its mid/ )\t suff]+ any loss (
 velocity4 ,! fact t none ( ! sol>      
envelopes are visible to u until ! light
 ( ! photosph]e is completely %ut (f1 & 
t !y all vani% ! v in/ant ! fir/ gleam (
 direct sunlight rea*es u1 is ano!r pro(
 ( _! extreme t5uity1 z is also ! %>ply 
def9$ edge ( ! sun's disc4 ,! envelopes 
!re=e consi/ p>tly ( liquid or vapor\s  
matt]1 9 a v f9ely divid$ /ate1 driv5 (f
 by explosions or by electrical =ces1 & 
?is matt]1 rapidly cool+1 becomes       
solidifi$ into m9ute/ p>ticles1 or ev5  
physical molecules4 ,mu* ( ?is matt]    

cont9ually falls back on ! sun's        
surface1 b a c]ta9 quantity ( ! v f9e/  
du/ is cont9ually driv5 away by         
electrical repulsion1 s z to =m ! corona
 & ! zodiacal light4 ,! va/ coronal     
/ream]s & ! /ill m ext5sive r+ ( !      
zodiacal light are !re=e 9 all          
probability due to ! same causes1 & h a 
simil> physical con/itution ) ! tails ( 
comets4  ,z ! :ole ( our sunlight mu/   
pass ?r\gh bo? ! rev]s+ lay] & ! r$     
*romosph]e1 its col\r mu/ be some:at    
modifi$ by !m4 ,h5ce x is believ$ t1 if 
!y 7 abs5t1 n only w\ld ! light & heat (
 ! sun be consid]ably great]1 b its     
col\r w\ld be a pur] :ite1 t5d+ t[>ds   
blui% r ?an t[>ds ! yell[i% t+e x       
actually possesses4   ,,! ,,nebul> ,,&  
,,meteoritic ,,hypo!ses  ,z !           
con/itution ( ! sun1 & its ag5cy 9      
produc+ magnetism & electricity 9 !     
matt] & orbs ar\nd x1 af=d u our be/    
guide to ! con/itution ( ! />s & nebul1 
& to _! possible action on ea* o!r1 &   
ev5 ^u our e>?1 s ! mode ( evolution ( !

 sun & sol> sy/em1 f "s pre-exi/+       
condition1 is likely to help u t[>ds    
ga9+ "s k ( ! con/itution ( ! /ell>     
univ]se & ! processes ( *ange go+ on    
!re4  ,at ! v comm5cem5t ( ! n9ete5?    
c5tury ! great ma!matician ,laplace     
publi%$ 8 ,nebul> ,!ory ( ! ,orig9 ( !  
,sol> ,sy/em2 & al?\gh he put x =? m]ely
 z a sugge/ion1 & did n support x ) any 
num]ical or physical data1 or by any    
ma!matical processes1 8 great           
reputation1 & its app>5t probability &  
simplicity1 caus$ x to be almo/         
univ]sally accept$1 & to be ext5d$ s z  
to apply to ! evolution ( ! /ell>       
univ]se4 ,?is !ory1 v briefly /at$1 is1 
t ! :ole ( ! matt] ( ! sol> sy/em once  
=m$ a globul> or sph]oidal mass (       
int5sely heat$ gases1 ext5d+ beyond !   
orbit ( ! out]mo/ planet1 & hav+ a sl[  
motion ( revolution ab\t an axis4 ,z x  
cool$ & contract$1 its rate ( revolution
 increas$1 & ?is became s great t at    
successive epo*s x ?rew (f r+s1 :i*1 ow+
 to slight irregul>ities1 broke up1 &1  

gravitat+ toge!r1 =m$ ! planets4 ,!     
contraction cont9u+1 ! sun1 z we n[ see 
x1 0 ! result4  ,= ab\t half a c5tury   
?is nebul> hypo!sis 0 g5]ally accept$1 b
 dur+ ! la/ ?irty ye>s s _m objections &
 difficulties h be5 sugge/$1 t x has be5
 felt impossible to reta9 x ev5 z a     
work+ hypo!sis4 ,at ! same "t ano!r     
hypo!sis has be5 put =? :i* seems m 9   
accordance ) ! facts ( nature z we f9d  
!m 9 our own sol> sy/em1 & :i* is n op5 
to any ( ! objections aga9/ ! nebul>    
!ory1 ev5 if x introduces a few new     
ones4  ,a fundam5tal objection to       
,laplace's !ory is1 t 9 a gas ( su*     
extreme t5uity z ! sol> nebula mu/ h    
be51 ev5 :5 x ext5d$ only to ,saturn or 
,uranus1 x c\ld n possibly h _h any     
cohesion1 & !re=e c\ld n h giv5 (f :ole 
r+s at di/ant int]vals1 b only small    
fragm5ts cont9u\sly z cond5sation w5t   
on1 & ^!1 rapidly cool+1 w\ld =m solid  
p>ticles1 a k9d ( meteoric du/1 :i*     
might aggregate into num]\s small       
planets1 or might p]si/ = indef9ite     

p]iods1 l ! r+s ( ,saturn or ! great r+ 
( ! ,a/]oids4  ,ano!r equally vital     
objection is1 t1 z ! nebula :5 ext5d+   
beyond ! orbit ( ,neptune c\ld h _h a   
mean d5sity ( only ab\t ! two-hundr$    
million? ( our air at sea level1 x mu/ h
 be5 _m hundr$ times less d5se ?an ?is  
at & ne> its out] surface1 & w\ld !re be
 expos$ to ! cold ( /ell> space--a cold 
t w\ld solidify hydrog54 ,x is ?us      
evid5t t ! gases ( all ! metallic & o!r 
solid elem5ts c\ld n possibly exi/ z    
su*1 b w\ld rapidly1 p]haps almo/       
in/antane\sly1 become fir/ liquid & !n  
solid1 =m+ meteoric du/ ev5 be=e        
contraction _h gone f> en\gh to produce 
su* increas$ rotation z w\ld ?r[ (f any 
portion ( ! gase\s matt]4  ,"h we h !   
f\ndations ( ! meteoritic hypo!sis :i*  
is n[ /eadily mak+ its way4 ,x is       
support$ by ! fact t we ev]y:]e f9d     
pro(s ( su* solid matt] 9 ! planet>y    
spaces ar\nd u4 ,x falls cont9ually ^u !
 e>?4 ,x c be collect$ on ! ,arctic &   
,alp9e sn[s4 ,x occurs ev]y:]e 9 !      

deepe/ abysses ( ! ocean :]e !re are n  
suffici5t organic deposits to mask x4 ,x
 con/itutes1 z has n[ be5 demon/rat$1 ! 
r+s ( ,saturn4 ,?\s&s ( va/ r+s ( solid 
p>ticles circulate ar\nd ! sun1 & :5 our
 e>? crosses any ( ^! r+s1 & _! p>ticles
 ent] our atmosph]e ) planet>y velocity1
 ! friction ignites !m & we see fall+   
/>s4 ,comets' tails1 ! sun's corona1 & !
 zodiacal light are ?ree /range ph5om5a1
 :i*1 ?\gh :olly insoluble on any !ory (
 gase\s =mation1 receive _! intelligible
 explanation by means ( excessively     
m9ute solid p>ticles--microscopic cosmic
 du/--driv5 outw>d by ! trem5d\s        
electrical repulsions t emanate f ! sun4
  ,hav+ ^! & o!r pro(s t solid matt]1   
rang+ 9 size1 p]haps1 f ! maje/ic orbs (
 ,jupit] & ,saturn d[n to !             
inconceivably m9ute p>ticles driv5      
millions ( miles into space to =m a     
comet's tail1 does actually exi/ ev]y:]e
 ar\nd u1 & by collisions betwe5 !      
p>ticles or ) planet>y atmosph]es c     
produce heat & light & gase\s           

emanations1 we f9d a basis ( fact &     
obs]vation = ! meteoritic hypo!sis :i*  
,laplace's nebul>1 & ess5tially gase\s1 
!ory does n possess4  ,dur+ ! latt] half
 ( ! n9ete5? c5tury sev]al writ]s       
sugge/$ ?is idea ( ! possible =mation ( 
! ,sol> ,sy/em1 b s f> z ,i am aw>e1 !  
late ,r4,a4 ,proctor 0 ! fir/ to discuss
 x 9 any detail1 & to %[ t x expla9$ _m 
( ! peculi>ities 9 ! size & arrangem5t (
 ! planets & _! satellites :i* ! nebul> 
hypo!sis did n expla94 ,?is he does at  
"s l5g? 9 ! *apt] on meteors & comets 9 
8 ,o!r ,worlds ?an ,ours1 publi%$ 9     
#ahgj4 ,he assum$1 in/ead ( ! fire-mi/ (
 ,laplace1 t ! space n[ occupi$ by !    
sol> sy/em1 & = an unkn[n di/ance ar\nd 
x1 0 occupi$ by va/ quantities ( solid  
p>ticles ( all ! k9ds ( matt] :i* we n[ 
f9d 9 ! e>?1 sun1 & />s4 ,?is matt] 0   
disp]s$ some:at irregul>ly1 z we see t  
all ! matt] ( ! univ]se is n[ di/ribut$2
 & he fur!r assum$ t x 0 all 9 motion1 z
 we n[ "k t all ! />s & o!r cosmical    
masses are1 & mu/ be1 9 motion t[>ds or 

ar\nd "s c5tre4  ,"u ^! conditions1     
:]ev] ! matt] 0 mo/ aggregat$1 !re w\ld 
be a c5tre ( attraction ?r\gh           
gravitation1 :i* w\ld necess>ily lead to
 fur!r aggregation1 & ! cont9ual impacts
 ( su* aggregat+ matt] w\ld produce     
heat4 ,9 c\rse ( "t1 if ! supply (      
cosmic matt] 0 ample 7z ! result %[s t x
 mu/ h be51 :atev] !ory we adopt71 our  
sun1 ?us =m$1 w\ld approximate to its   
pres5t mass & acquire suffici5t heat by 
collision & gravitation to conv]t its   
:ole body into ! liquid or gase\s       
condition4 ,:ile ?is 0 go+ on1          
subord9ate c5tres ( aggregation might   
=m1 :i* w\ld capture a c]ta9 proportion 
( ! matt] fl[+ 9 "u ! attraction ( !    
c5tral mass1 :ile1 ow+ to ! ne>ly uni=m 
direction & velocity ) :i* ! :ole sy/em 
0 revolv+1 ea* subord9ate c5tre w\ld    
revolve ar\nd ! c5tral mass1 9 some:at  
diff]5t planes1 b all 9 ! same          
direction4  ,mr4 ,proctor %[s !         
probability t ! l>ge/ outside           
aggregation w\ld be at a great di/ance f

 ! c5tral mass1 & ?is hav+ once be5 =m$1
 any c5tres f>!r away f ! sun w\ld be   
bo? small] & v remote1 :ile ^? inside ! 
fir/ w\ld1 z a rule1 become small] z !y 
7 ne>] ! c5tre4 ,! heat$ condition ( !  
e>?'s int]ior w\ld ?us be due1 n to !   
primitive heat ( matt] 9 a gase\s /ate  
out ( :i* x 0 =m$--a condition          
physically impossible--b w\ld be acquir$
 9 ! process ( aggregation by !         
collisions ( meteoric masses fall+ on x1
 & by its own gravitative =ce produc+   
cont9u\s cond5sation & heat4  ,on ?is   
view ,jupit] w\ld probably be =m$ fir/1 
& aft] him at v great di/ances1 ,saturn1
 ,uranus1 & ,neptune2 :ile ! inn]       
aggregations w\ld be small]1 z ! mu*    
great] attractive p[] ( ! sun w\ld give 
!m comp>atively little opportunity (    
captur+ ! meteoric matt] t 0 cont9u\sly 
fl[+ t[>ds him4   ,,! ,,meteoritic      
,,nature ,,( ,,! ,,nebul  ,hav+ ?us     
rea*$ ! conclusion t :]ev] app>5tly     
nebul\s matt] exi/s )9 ! limits ( ! sol>
 sy/em x is n gase\s b consi/s ( solid  

p>ticles1 or1 if heat$ gases are        
associat$ ) ! solid matt] !y c be       
acc\nt$ = by ! heat due to collisions   
ei!r ) o!r solid p>ticles or )          
accumulations ( gases at a l[           
temp]ature1 z :5 meteorites ent] our    
atmosph]e1 x 0 an easy /ep to consid]   
:e!r ! cosmic nebul & />s may n h _h a  
simil> orig94  ,f ?is po9t ( view !     
nebul are suppos$ to be va/ aggregations
 ( meteorites or cosmic du/1 or ( ! m   
p]si/5t gases1 revolv+ ) circul> or     
spiral motions1 or 9 irregul> /reams1 & 
s sp>sely scatt]$ t ! sep>ate p>ticles (
 du/ may be miles--p]haps hundr$s (     
miles--ap>t2 yet ev5 ^? nebul1 only     
visible by ! telescope1 may conta9 z mu*
 matt] z ! :ole sol> sy/em4 ,f ?is      
simple orig91 by /eps :i* c be obs]v$ 9 
! skies1 almo/ all ! =ms ( suns & sy/ems
 c be trac$ by means ( ! kn[n laws (    
motion1 ( heat-production1 & ( *emical  
action4 ,! *ief ,engli% advocate ( ?is  
view at ! pres5t "t is ,sir ,norman     
,locky]1 :o1 9 num]\s pap]s1 & 9 8 works

 on ,! ,meteoritic ,hypo!sis &          
,inorganic ,evolution1 has develop$ x 9 
detail1 z ! result ( _m ye>s' cont9u\s  
rese>*1 aid$ by ! contributory "w (     
cont95tal & ,am]ican a/ronom]s4 ,^!     
views are gradually spread+ among       
a/ronom]s & ma!maticians1 z w be se5 by 
! v brief outl9e :i* w n[ be giv5 ( !   
explanations !y af=d ( ! ma9 gr\ps (    
ph5om5a pres5t$ by ! /ell> univ]se4     
,,dr4 ,,rob]ts ,,on ,,spiral ,,nebul    
,dr4 ,isaac ,rob]ts1 :o possesses "o ( !
 f9e/ telescopes con/ruct$ = photograph+
 />s & nebul1 has giv5 8 views on /ell> 
evolution1 9 ,k ( ,febru>y #ahig1       
illu/rat$ by f\r beautiful photographs (
 spiral nebul4 ,^! curi\s =ms 7 at fir/ 
?\ght to be r>e1 b are n[ f\nd to be    
really v num]\s :5 details are br\ght   
out by ! cam]a4 ,_m ( ! v l>ge &        
app>5tly q irregul> nebul1 l !          
,magellanic ,cl\ds1 are f\nd to h fa9t  
indications ( spiral /ructure4 ,z m ?an 
t5 ?\s& nebul are n[ kn[n1 & new ones   
are cont9ually be+ discov]$1 x w be a   

long "t be=e ^! c all be c>efully /udi$ 
& photograph$1 b pres5t indications seem
 to %[ t a consid]able proportion ( !m w
 exhibit spiral =ms4  ,dr4 ,rob]ts tells
 u t all ! spiral nebul he has          
photograph$ are *>act]is$ by hav+ a     
nucleus surr\nd$ by d5se nebulosity1 mo/
 ( !m be+ also /udd$ ) />s4 ,^! />s are 
always arrang$ m or less symmetrically1 
foll[+ ! curves ( ! spiral1 :ile outside
 ! visible nebula are o!r />s arrang$ 9 
curves /rongly sugge/+ a =m] great]     
ext5sion ( ! nebul\s matt]4 ,?is is s   
m>k$ a feature t x at once leads to a   
possible explanation ( ! num]\s slightly
 curv$ l9es ( />s f\nd 9 e "p ( !       
heav5s1 z be+ ! result ( _! orig9 f     
spiral nebul ^: mat]ial sub/ance has be5
 absorb$ by !m4  ,dr4 ,rob]ts proposes  
sev]al problems 9 relation to ^! bodies3
 ,( :at mat]ials are spiral nebul       
compos$8 ,:5ce comes ! vortical motion  
:i* has produc$ _! =ms8 ,! mat]ial he   
f9ds 9 ^? fa9t cl\ds ( nebul\s matt]1   
(t5 ( va/ ext5t1 t exi/ 9 _m p>ts ( !   

sky1 & ^! are s num]\s t ,sir ,william  
,h]s*el alone record$ ! positions (     
fifty-two su* regions1 _m ( :i* h be5   
confirm$ by rec5t photographs4 ,dr4     
,rob]ts consid]s ^! to be ei!r gase\s or
 ) discrete solid p>ticles int]mix$4 ,he
 also enum]ates small] nebul\s masses   
und]go+ cond5sation & segregation into m
 regul> =ms2 spiral nebul 9 v>i\s /ages 
( cond5sation & ( aggregation2 elliptic 
nebul2 & globul> nebul4 ,9 ! la/ ?ree   
classes !re is cle> evid5ce1 on e       
photograph t has be5 tak51 t cond5sation
 into />s or /> l =ms is n[ go+ on4  ,he
 adopts ,sir ,norman ,locky]'s view t   
collisions ( meteorites )9 ea* sw>m or  
cl\d w\ld produce lum9\s nebulosity2 s  
also w\ld collisions betwe5 sep>ate     
sw>ms ( meteorites produce ! conditions 
requir$ to acc\nt = ! vortical motions &
 ! peculi> di/ribution ( ! nebulosity 9 
! spiral nebul4 ,almo/ any collision    
betwe5 unequal masses ( diffus$ matt]   
w\ld1 9 ! abs5ce ( any massive c5tral   
body r\nd :i* !y w\ld be =c$ to revolve1

 lead to spiral motions4 ,x is to be    
not$ t1 al?\gh ! />s =m$ 9 ! spiral     
convolutions ( ! nebul foll[ ^? curves1 
& reta9 !m aft] ! nebul\s matt] has be5 
all absorb$ by !m1 yet1 :5ev] su* a     
nebula is se5 by u edgewise1 !          
convolutions ) _! enclos$ />s w appe> z 
/raight l9es2 & ?us n only numb]s ( />  
gr\ps arrang$ 9 curves1 b also ^? :i* =m
 almo/ p]fect /raight l9es1 may possibly
 be trac$ back to an orig9 f spiral     
nebul4  ,motion be+ a necess>y result ( 
gravitation1 we "k t e />1 planet1      
comet1 or nebula mu/ be 9 motion ?r\gh  
space1 & ^! motions--except 9 sy/ems    
physically connect$ or :i* h _h a common
 orig9--are1 app>5tly1 9 all directions4
 ,h[ ^! motions orig9at$ & are n[       
regulat$ we d n "k2 b !re !y are1 & !y  
furni% ! motive p[] ( ! collisions1 :i*1
 :5 affect+ l>ge bodies or masses (     
diffus$ matt]1 lead to ! =mation ( !    
v>i\s k9ds ( p]man5t />s2 :ile :5 small]
 masses ( matt] are conc]n$ ^? tempor>y 
/>s are =m$ :i* h int]e/$ a/ronom]s 9   

all ages4 ,x mu/ be not$ t al?\gh !     
motions ( ! s+le />s appe> to be 9      
/raight l9es1 yet ! spaces ?r\gh :i* !y 
h be5 obs]v$ to move are s small t !y   
may really be mov+ 9 curv$ orbits ar\nd 
"s c5tral body1 or ! c5tre ( gravity (  
"s aggregation ( />s bright & d>k1 :i*  
may itself be comp>atively at re/4 ,!re 
may be ?\s&s ( su* c5tres ar\nd u1 & ?is
 may suffici5tly expla9 ! app>5t motions
 ( />s 9 all directions4   ,a           
,,sugge/ion ,,z ,,to ,,! ,,=mation ,,(  
,,spiral ,,nebul  ,9 a rem>kable pap] 9 
! ,a/rophysical ,j\rnal 7,july #aija71  
,mr4 ,t4,c4 ,*amb]l9 sugge/s an orig9 = 
! spiral nebul1 z well z ( sw>ms (      
meteorites & comets1 :i* seems likely to
 be a true1 al?\gh p]haps n ! only "o4  
,!re is a well-kn[n pr9ciple :i* %[s t  
:5 two bodies 9 space1 ( /ell> size1    
pass )9 a c]ta9 di/ance ( ea* o!r1 !    
small] "o w be liable to be torn into   
fragm5ts by ! diff]5tial attraction ( ! 
l>g] & d5s] body4 ,?is 0 orig9ally prov$
 9 ! case ( gase\s & liquid bodies1 & ! 

di/ance )9 :i* ! small] "o w be disrupt$
 7t]m$ ! ,ro*e limit7 is calculat$ on ! 
supposition t ! disrupt$ body is a      
liquid mass4 ,mr4 ,*amb]l9 %[s1 h[ev]1 t
 a solid body w also be disrupt$ at a   
less] di/ance dep5d5t on its size &     
cohesive /r5g?2 b1 z ! size ( ! two     
bodies increases1 ! di/ance at :i*      
disruption w occur increases also1 till 
) v l>ge bodies1 su* z suns1 x becomes  
almo/ z l>ge z 9 ! case ( liquids or    
gases4  ,! disruption occurs f !        
well-kn[n law ( diff]5tial gravitation  
on ! two sides ( a body lead+ to tidal  
de=mation 9 a liquid1 & to unequal /ra9 
9 a solid4 ,:5 ! *anges ( gravitative   
=ce take place sl[ly1 & are also small 9
 am\nt1 ! tides 9 liquids or /ra9s 9    
solids are v small1 z 9 ! case ( our e>?
 :5 act$ on by ! sun & moon1 ! result is
 a small tide 9 ! ocean & atmosph]e1 &  
no d\bt also 9 ! molt5 int]ior1 to :i* !
 comp>atively ?9 cru/ may p>tially adju/
 itself4 ,b if we suppose two d>k or    
lum9\s suns ^: prop] motions are 9 su* a

 direction z to br+ !m ne> ea* o!r1 !n1 
z !y approa*1 ea* w be deflect$ t[>ds ! 
o!r1 & w pass r\nd _! common c5tre (    
gravity ) imm5se velocity1 p]haps       
hundr$s ( miles 9 a second4 ,at a       
consid]able di/ance !y w beg9 to produce
 tidal elongation t[>ds & away f ea*    
o!r1 b :5 ! disruptive limit is ne>ly   
rea*$1 ! gravitative =ces w be increas+ 
s rapidly t ev5 a liquid mass c\ld n    
adju/ its %ape ) suffici5t quickness & !
 trem5d\s int]nal /ra9s w\ld produce !  
effects ( an explosion1 te>+ ! :ole mass
 7( ! small] ( ! two7 into fragm5ts &   
du/4  ,b x is also %[n t1 dur+ ! entire 
process1 ! two elongat$ portions ( !    
orig9ally sph]ical mass w\ld be s act$  
^u by gravity z to produce increas+     
rotation1 :i* z ! crisis approa*$ w\ld  
ext5d ! elongation1 & aid 9 ! explosive 
result4 ,?is rapid rotation ( ! elongat$
 mass w\ld1 :5 ! disruption occurr$1    
necess>ily give to ! fragm5ts a :irl+ or
 spiral motion1 & ?us initiate a spiral 
nebula ( a size & "* dep5d5t on ! size &

 con/itution ( ! two masses1 & on !     
am\nt ( ! explosive =ces set up by _!   
approa*4  ,!re is "o v sugge/ive        
ph5om5on :i* seems to prove t ?is is "o 
( ! modes ( =mation ( spiral nebul4 ,:5 
! explosive disruption occurs ! two     
protub]ances or elongations ( ! body w  
fly ap>t1 & hav+ also a rapid rotatory  
movem5t1 ! result+ spiral w necess>ily  
be a d\ble "o4 ,n[1 x is ! fact t almo/ 
all ! well-develop$ spiral nebul h two  
su* arms opposite to ea* o!r1 z         
beautifully %[n 9 ,m4 #ajj ,com1 ,m4 #ea
 ,canum1 & o!rs photograph$ by ,dr4 ,i4 
,rob]ts4 ,x does n seem likely t any o!r
 orig9 ( ^! nebul %\ld give rise to a   
d\ble r ?an to a s+le spiral4   ,,!     
,,evolution ,,( ,,d\ble ,,/>s  ,!       
advance 9 k ( d\ble & multiple />s has  
be5 wond]fully rapid1 num]\s obs]v]s    
hav+ devot$ !mselves to ?is special     
bran*4 ,_m ?\s&s 7 discov]$ dur+ ! fir/ 
half ( ! n9ete5? c5tury1 & z telescopic 
p[] increas$ new ones cont9u$ to fl[ 9  
by hundr$s & ?\s&s1 & !re has be5       

rec5tly publi%$ by ! ,y]kes ,obs]vatory 
a catalogue ( #abij su* />s1 discov]$   
betwe5 #ahga & #ahii by "o obs]v]1 ,mr4 
,s4,w4 ,burnham4 ,all ^! h be5 f\nd by !
 use ( ! telescope1 b dur+ ! la/ qu>t] (
 a c5tury ! spectroscope has op5$ up a  
new _w ( d\ble />s ( enorm\s ext5t & !  
highe/ int]e/4  ,! telescopic b9>ies :i*
 h be5 obs]v$ = a suffici5t "t to       
det]m9e _! orbits1 range f p]iods ( ab\t
 elev5 ye>s z a m9imum up to hundr$s &  
ev5 m ?an a ?\s& ye>s4 ,b ! spectroscope
 reveals ! fact t ! _m ?\s&s (          
telescopic b9>ies =m only a v small "p (
 ! b9>y sy/ems 9 exi/5ce4 ,! ov]:elm+   
importance ( ?is discov]y is1 t x c>ries
 ! times ( revolution f ! m9imum ( !    
telescopic d\bles d[nw>d 9 unbrok5 s]ies
 ?r\gh p]iods ( a few ye>s1 to ^?       
reckon$ by mon?s1 by days1 & ev5 by     
h\rs4 ,& ) ?is r$uction ( p]iod !re     
necess>ily foll[s a correspond+ r$uction
 ( di/ance1 s t sometimes ! two />s mu/ 
be 9 contact1 & ?us ! actual bir? or    
orig9 ( a d\ble /> has be5 obs]v$ to    

occur1 ev5 ?\gh n actually se54 ,?is    
mode ( orig9 0 inde$ anticipat$ by ,dr4 
,lee ( ,*icago 9 #ahib1 & x has be5     
confirm$ by obs]vation 9 ! %ort space ( 
t5 ye>s4  ,9 a rem>kable communication  
to ,nature 7,septemb] #ab?1 #aija7 ,mr4 
,alex&] ,w4 ,rob]ts ( ,lov$ale1 ,s\?    
,africa1 gives "s ( ! ma9 results ( ?is 
bran* ( inquiry4 ,( c\rse all ! v>iable 
/>s are to be f\nd among ! spectroscopic
 b9>ies4 ,!y consi/ ( t portion ( !     
class 9 :i* ! plane ( ! orbit is direct$
 t[>ds u1 s t dur+ _! revolution "o ( ! 
pair ei!r :olly or p>tially eclipses !  
o!r4 ,9 "s ( ^! cases !re are           
irregul>ities1 su* z d\ble maxima &     
m9ima ( unequal l5g?s1 :i* may be due to
 triple sy/ems or to o!r causes n yet   
expla9$1 b z !y all h %ort p]iods &     
always appe> z "o /> 9 ! mo/ p[]ful     
telescopes1 !y =m a special division ( !
 spectroscopic b9>y sy/ems4  ,!re are   
kn[n at pres5t tw5ty-two v>iables ( !   
,algol type1 t is1 />s hav+ ea* a d>k   
companion v close to x :i* obscures x   

ei!r :olly or p>tially dur+ e           
revolution4 ,9 ^! cases ! d5sity ( !    
sy/ems c be approximately det]m9$1 & !y 
are f\nd to be1 on ! av]age1 only       
"o-fif? t ( wat]1 or "o-eigh? t ( our   
sun4 ,b z _m ( !m are z l>ge z our sun1 
or ev5 consid]ably l>g]1 x is evid5t t  
!y mu/ be :olly gase\s1 &1 ev5 if v hot1
 ( a less complex con/itution ?an our   
lum9>y4 ,mr4 ,a4,w4 ,rob]ts tells u t   
five out ( ^! tw5ty-two v>iables revolve
 9 absolute contact =m+ sy/ems ( ! %ape 
( a dumb-bell4 ,! p]iods v>y f twelve   
days to less ?an n9e h\rs2 &1 />t+ f ^!1
 we n[ h a cont9u\s s]ies ( l5g!n+      
p]iods up to ! tw9 />s ( ,ca/or :i*     
require m ?an a ?\s& ye>s to complete _!
 revolution4  ,dur+ 8 obs]vations ( !   
above five />s1 ,mr4 ,rob]ts /ates t "o1
 ,x ,c>91 0 f\nd to h p>t$ company1 s t 
in/ead ( be+ actually unit$ to its      
companion ! two are n[ at a di/ance ap>t
 equal to "o-t5? ( _! diamet]s1 & he may
 ?us be said to h be5 almo/ a witness ( 
! bir? ( a /ell> sy/em4  ,a ye> lat] we 

f9d ! record 79 ,k1 ,octob] #aijb7 (    
,pr(essor ,campbell's rese>*es at !     
,lick ,obs]vatory4 ,he /ates t1 out (   
#cej />s obs]v$ spectroscopically1 "o 9 
eight is a spectroscopic b9>y2 & s      
impress$ is he ) _! abundance t1 z      
accuracy ( measurem5t increases1 he     
believes t ! /> t is n a spectroscopic  
b9>y w prove to be ! r>e exception6     
,pr(essor ,g4 ,d>w9 _h already %[n t !  
'dumb-bell' 0 a figure ( equilibrium 9 a
 rotat+ mass ( fluid2 & we n[ f9d pro(s 
t su* figures exi/1 & t !y =m !         
/>t+-po9t = ! enorm\s & ev]-increas+    
quantities ( spectroscopic b9>y         
/>-sy/ems t are n[ kn[n4 ,! orig9 ( ^!  
b9>y />s is also ( especial int]e/ z    
giv+ support to ,pr(essor ,d>w9's       
well-kn[n explanation ( ! orig9 ( ! moon
 by disruption f ! e>?1 ow+ to ! v rapid
 rotation ( ! p>5t planet4 ,x n[ appe>s 
t suns (t5 subdivide 9 ! same mann]1 b1 
ow+ p]haps to _! int5sely heat$ gase\s  
/ate !y seem usually to =m ne>ly equal  
globes4 ,! evolution ( ?is special =m ( 

/>-sy/em is !re=e n[ an obs]v$ fact2    
?\gh x by no means foll[s t all d\ble   
/>s h _h ! same mode ( orig94   ,,clu/]s
 ,,( ,,/>s ,,& ,,v>iables  ,! clu/]s (  
/>s1 :i* are tol]ably abundant 9 !      
heav5s & (f] s _m /range & beautiful =ms
 to ! telescopi/1 are yet among ! mo/   
puzzl+ ph5om5a ! philosophic a/ronom]   
has to deal )4  ,_m ( ^! clu/]s :i* are 
n v cr[d$ & ( irregul> =ms1 /rongly     
sugge/ an orig9 f ! equally irregul> &  
fanta/ic =ms ( nebul by a process (     
aggregation l t :i* ,dr4 ,rob]ts        
describes z develop+ )9 ! spiral nebul4 
,b ! d5se globul> clu/]s :i* =m su*     
beautiful telescopic objects1 & 9 "s (  
:i* m ?an six ?\s& />s h be5 c\nt$      
besides consid]able numb]s s cr[d$ 9 !  
c5tre z to be unc\ntable1 are m         
difficult to expla94 ,"o ( ! problems   
sugge/$ by ^! clu/]s is z to _!         
/ability4 ,pr(essor ,simon ,newcomb     
rem>ks on ?is po9t z foll[s3 ',:]e ?\s&s
 ( />s are cond5s$ into a space s small1
 :at prev5ts !m f all fall+ toge!r into 

"o confus$ mass8 ,are !y really do+ s1 &
 w !y ultimately =m a s+le body8 ,^! are
 que/ions :i* c be satisfactorily answ]$
 only by c5turies ( obs]vation2 !y mu/  
!re=e be left to ! a/ronom]s ( !        
future4'  ,!re are1 h[ev]1 "s rem>kable 
features 9 ^! clu/]s :i* af=d possible  
indications ( _! orig9 & ess5tial       
con/itution4 ,:5 closely exam9$ mo/ ( !m
 are se5 to be less regul> ?an !y at    
fir/ appe>4 ,vacant spaces c be not$ 9  
!m2 ev5 rifts ( def9ite =ms4 ,9 "s !re  
is a radiat$ /ructure2 9 o!rs !re are   
curv$ app5dages2 :ile "s h fa9t] c5tres4
 ,^! features are s exactly l :at are   
f\nd1 9 a m pron\nc$ =m1 9 ! l>g] nebul1
 t we c h>dly help ?9k+ t 9 ^! clu/]s we
 h ! result ( ! cond5sation ( v l>ge    
nebul1 :i* h fir/ aggregat$ t[>ds num]\s
 c5tres1 :ile ^! agglom]ations h be5    
sl[ly drawn t[>ds ! common c5tre (      
gravity ( ! :ole mass4 ,x is sugge/ive (
 ?is orig9 t :ile ! small] telescopic   
nebul are f> remov$ f ! ,milky ,way1 !  
l>g] ones are mo/ abundant ne> its      

bord]s2 :ile ! />-clu/]s are excessively
 abundant on & ne> ! ,milky ,way1 b v   
sc>ce else:]e1 except 9 or ne> va/ nebul
 l ! ,magellanic ,cl\ds4 ,we ?us see t !
 two ph5om5a may be complem5t>y to ea*  
o!r1 ! cond5sation ( nebul hav+ gone on 
mo/ rapidly :]e mat]ial 0 mo/ abundant1 
result+ 9 num]\s />-clu/]s :]e !re are  
n[ few nebul4  ,!re is "o /rik+ feature 
( ! globul> clu/]s :i* calls = notice2 !
 pres5ce 9 "s ( !m ( enorm\s quantities 
( v>iable />s1 :ile 9 o!rs few or none c
 be f\nd4 ,! ,h>v>d ,obs]vatory has =   
sev]al ye>s devot$ mu* "t to ?is class (
 obs]vations1 & ! results are giv5 9    
,pr(essor ,newcomb's rec5t volume on ',!
 ,/>s4' ,x appe>s t tw5ty-?ree clu/]s h 
be5 obs]v$ spectroscopically1 ! numb] ( 
/>s exam9$ 9 ea* clu/] v>y+ f #ade up to
 #cjjj1 ! total numb] ( />s ?us m9utely 
te/$ be+ #ai1jej4 ,out ( ?is total numb]
 #eji 7 f\nd to be v>iable2 b ! curi\s  
fact is1 ! extreme div]g5ce 9 !         
proportion ( v>iables to ! :ole numb]   
exam9$ 9 ! sev]al clu/]s4 ,9 two clu/]s1

 ?\gh #abgi />s 7 exam9$1 n a s+le      
v>iable 0 f\nd4 ,9 ?ree o!rs !          
proportion 0 f "o 9 #ajej to "o 9 #ejj4 
,five m rang$ up to "o 9 #ajj1 & !      
rema9d] %[$ f t proportion up to "o 9   
sev51 #ijj />s be+ exam9$ 9 ! la/       
m5tion$ clu/] ( :i* #acb 7 v>iable6  ,:5
 we consid] t v>iable />s =m only a     
portion1 & necess>ily a v small         
proportion1 ( b9>y sy/ems ( />s1 x      
foll[s t 9 all ! clu/]s :i* %[ a l>ge   
proportion ( v>iables1 a v mu* l>g]     
proportion--9 "s cases p]haps all1 mu/  
be d\ble or multiple />s revolv+ r\nd   
ea* o!r4 ,) ?is rem>kable evid5ce1 9    
addition to t adduc$ = ! preval5ce (    
d\ble />s & v>iables among ! />s 9      
g5]al1 we c und]/& ,pr(essor ,newcomb   
add+ 8 te/imony to t ( ,pr(essor        
,campbell already quot$1 t 'x is        
probable t among ! />s 9 g5]al1 s+le />s
 are ! exception r ?an ! rule4 ,if su*  
be ! case1 ! rule %\ld hold yet m       
/rongly among ! />s ( a cond5s$ clu/]4' 
,,! ,,evolution ,,( ,,! ,,/>s  ,s long z

 a/ronom]s 7 limit$ to ! use ( !        
telescope only1 or ev5 ! /ill great]    
p[]s ( ! photographic plate1 no?+ c\ld  
be le>nt ( ! actual con/itution ( ! />s 
or ( ! process ( _! evolution4 ,_!      
app>5t magnitudes1 _! movem5ts1 & ev5 ! 
di/ances ( a few c\ld be det]m9$2 :ile !
 div]sity ( _! col\rs (f]$ ! only clue  
7a v imp]fect "o7 ev5 to _! temp]ature4 
,b ! discov]y ( spectrum analysis has   
furni%$ ! means ( obta9+ "s def9ite k ( 
! physics & *emi/ry ( ! />s1 & has ?us  
e/abli%$ a new bran*                    
(sci5ce--,a/rophysics--:i* has already  
atta9$ l>ge proportions1 & :i* furni%es 
! mat]ials = a p]iodical & "s important 
volumes4 ,?is bran* ( ! subject is v    
complex1 & z x is n directly connect$ ) 
our pres5t inquiry1 x is only ref]r$ to 
aga9 9 ord] to introduce su* ( its      
results z be> ^u ! "q ( ! classification
 & evolution ( ! />s4  ,by a long s]ies 
( laboratory exp]im5ts x has be5 %[n t  
num]\s *anges occur 9 ! spectra ( !     
elem5ts :5 subject$ to diff]5t          

temp]atures1 rang+ upw>ds to ! highe/   
atta9able by means ( a batt]y produc+ an
 electric sp>k sev]al feet long4 ,^!    
*anges are n 9 ! relative position ( !  
b&s or d>k l9es1 b 9 _! numb]1 bread?1 &
 int5sity4 ,o!r *anges are due to !     
d5sity ( ! m$ium 9 :i* ! elem5ts are    
heat$1 & to _! *emical condition z to   
purity2 & f ^! v>i\s modifications & _! 
comp>ison ) ! sol> spectrum & ^? ( its  
app5dages1 x has become possible to     
det]m9e1 f ! spectrum ( a />1 n only its
 temp]ature z comp>$ ) t ( ! electric   
sp>k & ( ! sun1 b also its place 9 a    
developm5tal s]ies4  ,! fir/ g5]al      
result obta9$ by ?is rese>* is1 t !     
blui% :ite or pure :ite />s1 hav+ a     
spectrum ext5d+ f> t[>ds ! violet end1 &
 :i* exhibits ! col\r$ b&s ( gases only1
 usually hydrog5 & helium1 are ! hotte/4
 ,next come ^? ) a %ort] spectrum n     
ext5d+ s f> t[>ds ! violet end1 & ^:    
light is !re=e m yell[ 9 t9t4 ,to ?is   
gr\p our sun belongs2 & !y are all      
*>act]is$ l x by d>k l9es due to        

absorption1 & by ! pres5ce ( metals1    
especially iron1 9 a gase\s /ate4 ,!    
?ird gr\p h ! %orte/ spectra & are ( a  
r$ col\r1 :ile _! spectra conta9 l9es   
d5ot+ ! pres5ce ( c>bon4 ,^! ?ree gr\ps 
are (t5 spok5 ( z 'gase\s />s1'         
'metallic />s1' & 'c>bon />s4' ,o!r     
a/ronom]s call ! fir/ gr\p ',sirian     
/>s1' because ,sirius1 ?\gh n ! hotte/1 
is a *>act]i/ic type2 ! second be+ t]m$ 
'sol> />s'2 o!rs aga9 speak ( !m z />s (
 ,class ,i41 ,class ,,ii41 etc41 accord+
 to ! sy/em ( classification !y h       
adopt$4 ,x 0 soon p]ceiv$1 h[ev]1 t     
nei!r ! col\r nor ! temp]ature ( />s    
gave mu* in=mation z to _! nature & /ate
 ( developm5t1 because1 unless we       
suppos$ ! />s to beg9 _! lives already  
int5sely hot 7& all ! evid5ce is aga9/  
?is71 !re mu/ be a p]iod dur+ :i* heat  
increases1 !n "o ( maximum heat1 foll[$ 
by "o ( cool+ & f9al loss ( light       
altoge!r4 ,! meteoritic !ory ( ! orig9 (
 all lum9\s bodies 9 ! heav5s1 n[ v     
widely adopt$1 has be5 us$1 z we h se51 

to expla9 ! developm5t ( />s f nebul1 & 
its *ief expon5t 9 ?is c\ntry1 ,sir     
,norman ,locky]1 has prop\nd$ a complete
 s*eme ( /ell> evolution & decay :i* may
 be "h briefly outl9$3  ,beg9n+ ) nebul1
 we pass on to />s hav+ b&$ or flut$    
spectra1 indicat+ comp>atively l[       
temp]atures & %[+ b&s or l9es ( iron1   
manganese1 calcium1 & o!r metals4 ,!y   
are m or less r$ 9 col\r1 ,ant>es 9 !   
,scorpion be+ "o ( ! mo/ brilliant r$   
/>s kn[n4 ,^! />s are suppos$ to be 9 ! 
process ( aggregation1 to be cont9ually 
increas+ 9 size & heat1 & ?us to be     
subject to great di/urbances4 ,alpha    
,cygni has a simil> spectrum b ) m      
hydrog51 & is mu* hott]4 ,! increase (  
heat goes on ?r\gh ,rigel & ,beta       
,crucis1 9 :i* we f9d ma9ly hydrog51    
helium1 oxyg51 nitrog51 & also c>bon1 b 
only fa9t traces ( metals4 ,rea*+ !     
hotte/ ( all--,epsilon ,orionis & two   
/>s 9 ,argo--hydrog5 is pr$om9ant1 )    
traces ( a few metals & c>bon4 ,! cool+ 
s]ies is indicat$ by ?ick] l9es (       

hydrog5 & ?9n] l9es ( ! metallic        
elem5ts1 ?r\gh ,sirius1 to ,arcturus &  
our sun1 !nce to #ai ,piscium1 :i* %[s  
*iefly flut+s ( c>bon1 ) a few fa9t     
metallic l9es4 ,! process ( fur!r cool+ 
br+s u to ! d>k />s4  ,we h "h a        
complete s*eme ( evolution1 c>ry+ u f ^?
 ill-def9$ b enorm\sly diffus$ masses ( 
gas & cosmic du/ we "k z nebul1 ?r\gh   
planet>y nebul1 nebul\s />s1 v>iable &  
d\ble-/>s1 to r$ & :ite />s & on to ^?  
exhibit+ ! mo/ int5se blue-:ite lu/re4  
,we mu/ rememb]1 h[ev]1 t ! mo/         
brilliant ( ^! />s1 %[+ a gase\s        
spectrum & =m+ ! culm9at+ po9t ( !      
asc5d+ s]ies1 are n necess>ily hott]    
?an1 or ev5 s hot z1 "s ( ^? f> d[n on !
 desc5d+ scale2 s9ce x is "o ( ! app>5t 
p>adoxes ( physics t a body may become  
hott] dur+ ! v process ( contraction    
?r\gh loss ( heat4 ,! reason is t by    
cool+ x contracts & ?us becomes d5s]1 t 
a portion ( its mass falls t[>ds its    
c5tre1 & 9 do+ s produces an am\nt (    
heat :i*1 ?\gh absolutely less ?an !    

heat lo/ 9 cool+1 w "u c]ta9 conditions 
cause ! r$uc$ surface to become hott]4  
,! ess5tial po9t is1 t ! body 9 "q mu/  
be :olly gase\s1 all[+ ( free           
circulation f surface to c5tre4 ,! law1 
z giv5 by ,pr(essor ,s4 ,newcomb1 is z  
foll[s3--  ',:5 a sph]ical mass (       
inc&esc5t gas contracts ?r\gh ! loss (  
its heat by radiation into space1 its   
temp]ature cont9ually becomes high] z   
long z ! gase\s condition is reta9$4'   
,to put x 9 ano!r way3 if ! compression 
0 caus$ by ext]nal =ce & no heat 0 lo/1 
! globe w\ld get hott] by a calculable  
am\nt = ea* unit ( contraction4 ,b !    
heat lo/ 9 caus+ a simil> am\nt (       
contraction is s little m ?an ! increase
 ( heat produc$ by contraction1 t !     
slightly dim9i%$ total heat 9 a small]  
bulk causes ! temp]ature ( ! mass to    
increase4  ,b if1 z !re is reason to    
believe1 ! v>i\s types ( />s diff] also 
9 *emical con/itution1 "s consi/+ ma9ly 
( ! m p]man5t gases1 :ile 9 o!rs ! v>i\s
 metallic & non-metallic elem5ts are    

pres5t 9 v diff]5t proportions1 !re %\ld
 really be a classification by          
con/itution z well z by temp]ature1 & ! 
c\rse ( evolution ( ! diff]5tly         
con/itut$ gr\ps may be to "s ext5t      
dissimil>4  ,) ?is limitation ! process 
( evolution & decay ( sun ?r\gh a cycle 
( increas+ & decreas+ temp]ature1 z     
sugge/$ by ,sir ,norman ,locky]1 is cle>
 & sugge/ive4 ,dur+ ! asc5d+ s]ies ! /> 
is gr[+ bo? 9 mass & heat1 by ! cont9ual
 accretion ( meteoritic matt] ei!r drawn
 to x by gravitation or fall+ t[>ds x   
?r\gh ! prop] motions ( indep5d5t       
masses4 ,?is goes on till all ! matt] = 
"s di/ance ar\nd ! /> has be5 utilis$1 &
 a maximum ( size1 heat1 & brilliancy   
atta9$4 ,!n ! loss ( heat by radiation  
is no long] comp5sat$ by ! influx ( fre%
 matt]1 & a sl[ contraction occurs      
accompani$ by a slightly increas$       
temp]ature4 ,b ow+ to ! m /able         
conditions cont9u\s envelopes ( metals 9
 ! gase\s /ate are =m$1 :i* *eck ! loss 
( heat & r$uce ! brilliancy ( col\r2    

:5ce x foll[s t bodies l our sun may be 
really hott] ?an ! mo/ brilliant :ite   
/>s1 ?\gh n giv+ out q s mu* heat4 ,!   
loss ( heat is !re=e r$uc$2 & ?is may   
s]ve to acc\nt = ! und\bt$ fact t dur+ !
 enorm\s epo*s ( geological "t !re has  
be5 v little dim9ution 9 ! am\nt ( heat 
we h receiv$ f ! sun4  ,on ! g5]al "q ( 
! meteoritic hypo!sis "o ( our fir/     
ma!maticians1 ,pr(essor ,george ,d>w91  
has ?us express$ 8 views3 ',! conception
 ( ! gr[? ( ! planet>y bodies by !      
aggregation ( meteorites is a good "o1 &
 p]haps seems m probable ?an ! hypo!sis 
t ! :ole sol> sy/em 0 gase\s4' ,i may   
add1 t "o ( ! *ief objections made to x1
 t meteorites are too complex to be     
suppos$ to be ! primitive matt] out (   
:i* suns & worlds h be5 made1 does n    
seem to me valid4 ,! primitive matt]1   
:atev] x 01 may h be5 us$ up aga9 &     
aga91 & if collisions ( l>ge solid      
globes ev] occur--& x is assum$ by mo/  
a/ronom]s t !y mu/ sometimes occur--!n  
meteoric p>ticles ( all sizes w\ld be   

produc$ :i* might exhibit any complexity
 ( m9]al con/itution4 ,! mat]ial univ]se
 has probably be5 9 exi/5ce long en\gh =
 all ! primitive elem5ts to h be5 aga9 &
 aga9 comb9$ into ! m9]als f\nd ^u ! e>?
 & _m o!rs4 ,x _c be too (t5 repeat$ t  
no explanation--no !ory--c ev] take u to
 ! beg9n+ ( ?+s1 b only "o or two /eps  
at a "t into ! dim pa/1 :i* may enable u
 to compreh5d1 h[ev] imp]fectly1 !      
processes by :i* ! _w1 or ! univ]se1 z x
 is1 has be5 develop$ out ( "s e>li] &  
simpl] condition4     ,,*apt] ,,vii     
,,are ,,! ,,/>s ,,inf9ite ,,9 ,,numb]8  
,mo/ ( ! critics ( my fir/ %ort         
discussion ( ?is subject laid great     
/ress ^u ! impossibility ( prov+ t !    
univ]se1 a "p ( :i* we see1 is n        
inf9ite2 & a well-kn[n a/ronom] decl>$ t
 unless x c be demon/rat$ t our univ]se 
is f9ite ! entire argum5t f\nd$ ^u our  
position )9 x fall to ! gr\nd4 ,i _h    
laid myself op5 to ?is objection by r   
incauti\sly admitt+ t if ! prepond]ance 
( evid5ce po9t$ 9 ?is direction any     

inquiry z to our place 9 ! univ]se w\ld 
be useless1 because z reg>ds inf9ity !re
 c be no diff]5ce ( position4 ,b ?is    
/atem5t is by no means exact1 & ev5 9 an
 inf9ite univ]se ( matt] conta9+ an     
inf9ite numb] ( />s1 su* z ^? we see1   
!re might well be su* inf9ite div]sities
 ( di/ribution & arrangem5t z w\ld give 
to c]ta9 positions all ! advantages :i* 
,i submit we actually possess4 ,suppos+1
 = example1 t beyond ! va/ r+ ( ! ,milky
 ,way ! />s rapidly decrease 9 numb] 9  
all directions = a di/ance ( a hundr$ or
 a ?\s& times ! diamet] ( t r+1 & t !n =
 an equal di/ance !y sl[ly increase aga9
 & become aggregat$ into sy/ems or      
univ]ses totally di/9ct f ours 9 =m &   
/ructure1 & s remote t !y c influ5ce u 9
 no way :atev]4 ,!n1 ,i ma9ta91 our     
position )9 our own /ell> univ]se might 
h exactly ! same importance1 & be       
equally sugge/ive1 z if ours 7 ! only   
mat]ial univ]se 9 exi/5ce--z if ! app>5t
 dim9ution 9 ! numb] ( />s 7:i* is an   
obs]v$ fact7 indicat$ a cont9u\s        

dim9ution1 lead+ at "s unkn[n di/ance to
 entire abs5ce ( lum9\s--t is1 ( active1
 en]gy-emitt+ aggregations ( matt]4#a ,z
 to :e!r !re are su* o!r mat]ial        
univ]ses or n ,i (f] no op9ion1 & h no  
belief "o way or ! o!r4 ,i consid] all  
speculations z to :at may or may n exi/ 
9 inf9ite space to be utt]ly valueless4 
,i h limit$ my inquiries /rictly to !   
evid5ce accumulat$ by mod]n a/ronom]s1 &
 to direct inf]5ces & logical d$uctions 
f t evid5ce4 ,yet1 to my great surprise1
 my *ief critic decl>es t ',dr4         
,wallace's und]ly+ error is1 inde$1 t he
 has reason$ f ! area :i* we c embrace )
 our limit$ p]ceptions to ! inf9ite     
beyond our m5tal or intellectual grasp4'
 ,i h di/9ctly n done ?is1 b _m         
a/ronom]s h done s4 ,! late ,ri*>d      
,proctor n only cont9ually discuss$ ! "q
 ( inf9ite matt] z well z inf9ite space1
 b also argu$1 f ! suppos$ attributes ( 
! ,deity1 = ! necessity ( hold+ ?is     
mat]ial univ]se to be inf9ite1 & ! la/  
*apt] ( 8 ,o!r ,worlds ?an ,ours is     

ma9ly devot$ to su* speculations4 ,9 a  
lat] "w1 ,our ,place among ,inf9ities1  
he says t '! tea*+s ( sci5ce br+ u into 
! pres5ce ( ! unque/ionable inf9ities ( 
"t & ( space1 & ! presumable inf9ities (
 matt] & ( op]ation--h5ce !re=e into !  
pres5ce ( inf9ity ( en]gy4 ,b sci5ce    
tea*es u no?+ ab\t ^! inf9ities z su*4  
,!y rema9 none ! less inconceivable1    
h[ev] cle>ly we may be taught to        
recognise _! reality4' ,all ?is is v    
reasonable1 & ! la/ s5t5ce is p>ticul>ly
 important4 ,nev]!less1 _m writ]s all[  
_! reason+s f facts to be influ5c$ by ^!
 ideas ( inf9ity4 ,9 ,proctor's po/hum\s
 "w1 ,old & ,new ,a/ronomy1 ! late ,mr4 
,rany>d1 :o edit$ x1 writes3 ',if we    
reject z abhorr5t to our m9ds !         
supposition t ! univ]se is n inf9ite1 we
 are ?r[n back on "o ( two              
alt]natives--ei!r ! e!r :i* transmits ! 
light ( ! />s to u is n p]fectly ela/ic1
 or a l>ge proportion ( ! light ( ! />s 
is oblit]at$ by d>k bodies4' ,"h we h a 
well-in=m$ a/ronom] all[+ 8 abhorr5ce ( 

! idea ( a f9ite univ]se to affect 8    
reason+ on ! actual ph5om5a we c        
obs]ve--do+ 9 fact exactly :at my critic
 errone\sly accuses me ( do+4 ,b sett+  
aside all ideas & prepossessions ( ! k9d
 "h indicat$1 let u see :at are ! actual
 facts reveal$ by ! be/ in/rum5ts (     
mod]n a/ronomy1 & :at are ! natural &   
logical inf]5ces f ^? facts4   ,,are ,,!
 ,,/>s ,,inf9ite ,,9 ,,numb]8  ,! views 
( ^? a/ronom]s :o h paid att5tion to ?is
 subject are1 on ! :ole1 9 fav\r ( !    
view t ! /ell> univ]se is limit$ 9 ext5t
 & ! />s !re=e limit$ 9 numb]4 ,a few   
quotations w be/ exhibit _! op9ions on  
?is "q1 ) "s ( ! facts & obs]vations on 
:i* !y are f\nd$4  ,miss ,a4,m4 ,cl]ke1 
9 h] admirable volume1 ,! ,sy/em ( !    
,/>s1 says3 ',! sid]eal _w pres5ts u1 to
 all appe>ance1 ) a f9ite sy/em4444 ,!  
probability am\nts almo/ to c]ta9ty t   
/>-/rewn space is ( measurable          
dim5sions4 ,= f innum]able />s a        
limitless sum-total ( radiations %\ld be
 d]iv$1 by :i* d>kness w\ld be bani%$ f 

our skies2 & ! int5se inane1 gl[+ ) !   
m+l$ beams ( suns individually          
indi/+ui%able1 w\ld bewild] our feeble  
s5ses ) its monoton\s spl5d\r4444       
,unless1 t is to say1 light suff] "s    
degree ( enfeeblem5t 9 space4444 ,b !re 
is n a p>ticle ( evid5ce t any su* toll 
is exact$2 contr>y indications are      
/rong2 & ! ass]tion t its paym5t is     
inevitable dep5ds ^u analogies :i* may  
be :olly vision>y4 ,we are !n1 = !      
pres5t1 entitl$ to disreg>d !           
problematical effect ( a m ?an dubi\s   
cause4'  ,pr(essor ,simon ,newcomb1 "o (
 ! fir/ ( ,am]ican ma!maticians &       
a/ronom]s1 arrives at a simil>          
conclusion 9 8 mo/ rec5t volume1 ,! ,/>s
 7#aijb74 ,he says1 9 8 conclusions at !
 end ( ! "w3 ',t collection ( />s :i* we
 call ! univ]se is limit$ 9 ext5t4 ,!   
smalle/ />s t we see ) ! mo/ p[]ful     
telescopes are n1 = ! mo/ "p1 m di/ant  
?an ^? a grade bright]1 b are mo/ly />s 
( less lum9osity situate 9 ! same       
regions' 7p4 #cai74 ,& on page #bbi ( ! 

same "w he gives reasons = ?is          
conclusion1 z foll[s3 ',!re is a law (  
optics :i* ?r[s "s light on ! "q4       
,suppose ! />s to be scatt]$ ?r\gh      
inf9ite space s t e great portion (     
space is1 9 ! g5]al av]age1 equally ri* 
9 />s4 ,!n at "s great di/ance we       
describe a sph]e hav+ its c5tre 9 our   
sun4 ,outside ?is sph]e describe ano!r  
"o ( a great] radius1 & beyond ?is o!r  
sph]es at equal di/ances ap>t           
indef9itely4 ,?us we %all h an endless  
succession ( sph]ical %ells1 ea* ( !    
same ?ickness4 ,! volume ( ea* ( ^!     
%ells w be ne>ly proportional to !      
squ>es ( ! diamet]s ( ! sph]es :i* b\nd 
x4 ,h5ce ea* ( ! regions w conta9 a     
numb] ( />s increas+ z ! squ>e ( !      
radius ( ! region4 ,s9ce ! am\nt ( light
 we receive f ea* /> is z ! inv]se squ>e
 ( its di/ance1 x foll[s t ! sum total (
 ! light receiv$ f ea* ( ^! sph]ical    
%ells w be equal4 ,?us z we add sph]e   
aft] sph]e we add equal am\nts ( light  
)\t limit4 ,! result w\ld be t if !     

sy/em ( />s ext5d$ out indef9itely !    
:ole heav5s w\ld be fill$ ) a blaze (   
light z bright z ! sun4'  ,b ! :ole     
light giv5 u by ! />s is v>i\sly e/imat$
 at f "o-=tie? to "o-tw5tie? or1 z an   
extreme limit1 to "o-t5? ( moonlight1   
:ile ! sun gives z mu* light z #cjj1jjj 
full moons1 s t />light is only         
equival5t at a fair e/imate to !        
six-million? "p ( sunlight4 ,keep+ ?is 9
 m9d1 ! possible causes ( ! ext9ction ( 
almo/ ! :ole ( ! light ( ! />s 7if !y   
are inf9ite 9 numb] & di/ribut$1 on !   
av]age1 z ?ickly beyond ! ,milky ,way z 
!y are up to its out] b\nd>y7 are       
absurdly inadequate4 ,^! causes are 7#a7
 ! loss ( light 9 pass+ ?r\gh ! e!r1 &  
7#b7 ! /oppage ( light by d>k />s or    
diffus$ meteoritic du/4 ,z to ! fir/1 x 
is g5]ally admitt$ t !re is n a p>ticle 
( evid5ce ( its exi/5ce4 ,!re is1 h[ev]1
 "s di/9ct evid5ce t1 if x exi/s1 x is s
 v small 9 am\nt t x w\ld n produce a   
p]ceptible effect = any di/ances less   
remote ?an hundr$s or p]haps ?\s&s (    

times z f> z ! f>!/ limits ( ! ,milky   
,way are f u4 ,?is is indicat$ by ! fact
 t ! brighte/ />s are n always1 or ev5  
g5]ally1 ! ne>e/ to u1 z is %[n bo? by  
_! small prop] motions & ! abs5ce (     
measurable p>allax4 ,mr4 ,gore /ates t  
out ( tw5ty-five />s1 ) prop] motions ( 
m ?an two seconds annually1 only two are
 above ! ?ird magnitude4 ,_m fir/       
magnitude />s1 includ+ ,canopus1 !      
second brighte/ /> 9 ! heav5s1 are s    
remote t no p>allax c be f\nd1 not)/&+  
repeat$ ef=ts4 ,!y mu/ !re=e be mu* f>!r
 (f ?an _m small & telescopic />s1 &    
p]haps z f> z ! ,milky ,way1 9 :i* s _m 
brilliant />s are f\nd2 :]eas if any    
consid]able am\nt ( light 7 lo/ 9 pass+ 
t di/ance we %\ld f9d b few />s ( ! fir/
 two or ?ree magnitudes t 7 v remote f  
u4 ,( ! tw5ty-?ree />s ( ! fir/         
magnitude1 only t5 h be5 f\nd to h      
p>allaxes ( m ?an "o-tw5tie? ( a second1
 :ile five range f t small am\nt d[n to 
"o or two hundr$?s ( a second1 & !re are
 two ) no asc]ta9able p>allax4 ,aga91   

!re are #cji />s bright] ?an magnitude  
#c4e1 yet only ?irty-"o ( ^! h prop]    
motions ( m ?an #ajj a c5tury1 & ( ^!   
only eighte5 h p>allaxes ( m ?an        
"o-tw5tie? ( a second4 ,^! figures are f
 tables giv5 9 ,pr(essor ,newcomb's     
book1 & !y h v great significance1 s9ce 
!y indicate t ! brighte/ />s are n !    
ne>e/ to u4 ,m ?an ?is1 !y %[ t out ( ! 
sev5ty-two />s ^: di/ance has be5       
measur$ ) "s approa* to c]ta9ty1 only   
tw5ty-?ree 7hav+ a p>allax ( m ?an      
"o-fiftie? ( a second7 are ( great]     
magnitudes ?an #c4e1 :ile no less ?an   
=ty-n9e are small] />s d[n to ! eigh? or
 n9? magnitude1 & ^! are on ! av]age mu*
 ne>] to u ?an ! bright] />s6  ,tak+ !  
:ole ( ! />s ^: p>allaxes are giv5 by   
,pr(essor ,newcomb1 we f9d t ! av]age   
p>allax ( ! ?irty-"o bright />s 7f #c4e 
magnitude up to ,sirius7 is #j4aa       
seconds2 :ile t ( ! =ty-"o />s bel[ #c4e
 magnitude d[n to ab\t #i4e1 is #j4ba   
seconds1 %[+ t !y are1 on ! av]age1 only
 half z f> f u z ! bright] />s4 ,! same 

conclusion 0 rea*$ by ,mr4 ,?omas ,lewis
 ( ! ,gre5wi* ,obs]vatory 9 #ahie1      
namely1 t ! />s f #b4gj magnitude d[n to
 ab\t #h4dj magnitude h1 on ! av]age1   
d\ble ! p>allaxes ( ! bright] />s4 ,?is 
v curi\s & unexpect$ fact1 h[ev] x may  
be acc\nt$ =1 is directly oppos$ to !   
idea ( !re be+ any loss ( light by ! m  
di/ant z comp>$ ) ! ne>] />s2 = if !re  
%\ld be su* a loss x w\ld r5d] ! above  
ph5om5on /ill m difficult ( explanation1
 because x w\ld t5d to exagg]ate x4 ,!  
bright />s be+ on ! :ole f>!r away f u  
?an ! less bright d[n to ! eigh? & n9?  
magnitudes1 x foll[s1 if !re is any loss
 ( light1 t ! bright />s are really     
bright] ?an !y appe> to u1 because1 ow+ 
to _! enorm\s di/ance "s ( _! light has 
be5 lo/ be=e x rea*$ u4 ,( c\rse x may  
be said t ?is does n demon/rate t no    
light is lo/ 9 pass+ ?r\gh space2 b1 on 
! o!r h&1 x is exactly ! opposite ( :at 
we %\ld expect if ! m di/ant />s 7      
p]ceptibly dimm$ by ?is cause1 & x may  
be consid]$ to prove t if !re is any    

loss x is exce$+ly small1 & w n affect !
 "q ( ! limits ( our /ell> sy/em1 :i* is
 all t we are deal+ )4  ,?is rem>kable  
fact ( ! enorm\s remot5ess ( ! majority 
( ! bright] />s is equally effective z  
an argum5t aga9/ ! loss ( light by d>k  
/>s or cosmic du/1 because1 if ! light  
is n appreciably dim9i%$ = />s :i* h    
less ?an ! fiftie? ( a second ( p>allax1
 x _c greatly int]f]e ) our e/imates ( !
 limits ( our univ]se4  ,bo? ,mr4 ,e4,w4
 ,maund] ( ! ,gre5wi* ,obs]vatory &     
,pr(essor ,w4,w4 ,turn] ( ,ox=d lay     
great /ress on ^! d>k bodies1 & ! =m]   
quotes ,sir ,rob]t ,ball z say+1 '! d>k 
/>s are incomp>ably m num]\s ?an ^? t we
 c see 444 & to attempt to numb] ! />s (
 our univ]se by ^? ^: transitory        
brightness we c p]ceive w\ld be l       
e/imat+ ! numb] ( horse%oes 9 ,engl& by 
^? :i* are r$-hot4' ,b ! proportion (   
d>k />s 7or nebul7 to bright ones _c be 
det]m9$ a priori1 s9ce x mu/ dep5d ^u ! 
causes t heat ! />s1 & h[ frequ5tly ^?  
causes come into action z comp>$ ) !    

life ( a bright />4 ,we d "k1 bo? f !   
/ability ( ! light ( ! />s dur+ !       
hi/oric p]iod & mu* m precisely by !    
enorm\s epo*s dur+ :i* our sun has      
support$ life ^u ?is e>?--yet :i* mu/ h 
be5 'incomp>ably' less ?an its :ole     
exi/5ce z a light-giv]--t ! life ( mo/  
/>s mu/ be c\nt$ by hundr$s or p]haps by
 ?\s&s ( millions ( ye>s4 ,b we h no k  
:atev] ( ! rate at :i* true />s are     
born4 ,! s-call$ 'new />s' :i*          
occasionally appe> evid5tly belong to a 
diff]5t category4 ,!y blaze out sudd5ly 
& almo/ z sudd5ly fade away into        
obscurity or total invisibility4 ,b !   
true />s probably g ?r\gh _! /ages (    
orig91 gr[?1 maturity1 & decay1 )       
extreme sl[ness1 s t x is n z yet       
possible = u to det]m9e by obs]vation :5
 !y are born or :5 !y die4 ,9 ?is       
respect !y correspond to species 9 !    
organic _w4 ,!y w\ld probably fir/ be   
kn[n to u z />s or m9ute nebul3 at !    
extreme limit ( telescopic vision or (  
photographic s5sitiv5ess1 & ! gr[? ( _! 

lum9osity might be s gradual z to       
require hundr$s1 p]haps ?\s&s ( ye>s to 
be di/9ctly recognisable4 ,h5ce !       
argum5t d]iv$ f ! fact t we h nev]      
witness$ ! bir? ( a true p]man5t />1 &  
t1 !re=e1 su* occurr5ces are v r>e1 is  
valueless4 ,new />s may arise e ye> or e
 day )\t our recognis+ !m2 & if ?is is !
 case1 ! res]voir ( d>k bodies1 :e!r 9 !
 =m ( l>ge masses or ( cl\ds ( cosmic   
du/1 s f> f be+ incomp>ably great] ?an !
 :ole ( ! visible />s & nebul1 may q    
possibly be only equal to x1 or at mo/ a
 few times great]2 & 9 t case1 consid]+ 
! enorm\s di/ances t sep>ate ! />s 7or  
/>-sy/ems7 f ea* o!r1 !y w\ld h no      
appreciable effect 9 %utt+ out f our    
view any consid]able proportion ( !     
lum9\s bodies con/itut+ our /ell>       
univ]se4 ,x foll[s1 t ,pr(essor         
,newcomb's argum5t z to ! v small total 
light giv5 by ! />s has n be5 ev5 weak5$
 by any ( ! facts or argum5ts adduc$    
aga9/ x4  ,mr4 ,w4,h4,s4 ,monck1 9 a    
lett] to ,k 7,may #aijc71 puts ! case v 

/rongly s z to support my view4 ,he     
says3--',! highe/ e/imate t ,i h se5 ( !
 total light ( ! full moon is #a_/cjjjjj
 ( t ( ! sun4 ,suppose t ! d>k bodies 7 
a hundr$ & fifty ?\s& times z num]\s z !
 bright ones4 ,!n ! :ole sky ought to be
 z bright z ! illum9at$ portion ( !     
moon4 ,e "o kn[s t ?is is n s4 ,b x is  
said t ! />s1 ?\gh inf9ite1 may only    
ext5d to inf9ity 9 p>ticul> directions1 
e4g4 9 t ( ! ,galaxy4 ,be x s4 ,:]e1 9 !
 v brighte/ portion ( ! ,galaxy1 w we   
f9d a "p equal 9 angul> magnitude to !  
moon :i* af=ds u ! same quantity (      
light8 ,9 ! v brighte/ spot1 ! light    
probably does n am\nt to "o hundr$? "p t
 ( ! full moon4' ,x foll[s t1 ev5 if d>k
 />s 7 fifte5 million times z num]\s z !
 bright ones1 ,pr(essor ,newcomb's      
argum5t w\ld /ill apply aga9/ an inf9ite
 univ]se ( />s ( ! same av]age d5sity z 
! portion we see4   ,,telescopic        
,,evid5ce ,,z ,,to ,,! ,,limits ,,( ,,! 
,,/> ,,sy/em  ,?r\gh\t ! e>li] portion (
 ! n9ete5? c5tury e increase ( p[] & (  

light-giv+ qualities ( telescopes add$ s
 greatly to ! numb] ( ! />s :i* became  
visible1 t x 0 g5]ally assum$ t ?is     
increase w\ld g on indef9itely1 & t !   
/>s 7 really inf9ite 9 numb] & c\ld n be
 exhau/$4 ,b ( late ye>s x has be5 f\nd 
t ! increase 9 ! numb] ( />s visible 9 !
 l>g] telescopes 0 n s great z might be 
expect$1 :ile 9 _m p>ts ( ! heav5s a    
long] exposure ( ! photographic plate   
adds comp>atively little to ! numb] (   
/>s obta9$ by a %ort] exposure ) ! same 
in/rum5t4  ,mr4 ,j4,e4 ,gore's te/imony 
on ?is po9t is v cle>4 ,he says3--',^?  
:o d n give ! subject suffici5t         
consid]ation1 seem to ?9k t ! numb] ( ! 
/>s is practically inf9ite1 or at lea/1 
t ! numb] is s great t x _c be e/imat$4 
,b ?is idea is totally incorrect1 & due 
to complete ignorance ( telescopic      
revelations4 ,x is c]ta9ly true t1 to a 
c]ta9 ext5t1 ! l>g] ! telescope us$ 9 ! 
exam9ation ( ! heav5s1 ! m ! numb] ( !  
/>s seems to increase2 b we n[ "k t !re 
is a limit to ?is increase ( telescopic 

vision4 ,& ! evid5ce cle>ly %[s t we are
 rapidly approa*+ ?is limit4 ,al?\gh !  
numb] ( />s visible 9 ! ,pleiades       
rapidly increases at fir/ ) increase 9 !
 size ( ! telescope us$1 & al?\gh       
photography has /ill fur!r increas$ !   
numb] ( />s 9 ?is rem>kable clu/]1 x has
 rec5tly be5 f\nd t an increas$ l5g? (  
exposure--beyond ?ree h\rs--adds v few  
/>s to ! numb] visible on ! photograph  
tak5 at ! ,p>is ,obs]vatory 9 #ahhe1 on 
:i* ov] two ?\s& />s c be c\nt$4 ,ev5 ) 
?is great numb] on s small an area ( !  
heav5s1 comp>atively l>ge vacant places 
are visible betwe5 ! />s1 & a glance at 
! orig9al photograph is suffici5t to %[ 
t !re w\ld be ample room = _m times !   
numb] actually visible4 ,i f9d t if !   
:ole heav5s 7 z ri* 9 />s z ! ,pleiades1
 !re w\ld be only ?irty-?ree millions 9 
bo? hemisph]es4'  ,aga91 ref]r+ to !    
fact t ,celoria1 ) a telescope %[+ />s  
d[n to ! elev5? magnitude1 c\ld see     
almo/ exactly ! same numb] ( />s ne> !  
nor? pole ( ! ,galaxy z ,sir ,william   

,h]s*el f\nd ) 8 mu* l>g] & m p[]ful    
telescope1 he rem>ks3 ',_! abs5ce1      
!re=e1 seems c]ta9 pro( t v fa9t />s d n
 exi/ 9 t direction1 & t "h1 at lea/1 ! 
sid]eal univ]se is limit$ 9 ext5t4'     
,sir ,john ,h]s*el notes ! same ph5om5a1
 /at+ t ev5 9 ! ,milky ,way !re are f\nd
 'spaces absolutely d>k & completely    
void ( any />1 ev5 ( ! smalle/          
telescopic magnitude'2 :ile 9 o!r p>ts  
'extremely m9ute />s1 ?\gh nev] altoge!r
 want+1 occur 9 numb]s s mod]ate z to   
lead u irresi/ibly to ! conclusion t 9  
^! regions we see fairly ?r\gh ! />ry   
/ratum1 s9ce x is impossible o!rwise    
7suppos+ _! light n int]cept$7 t !      
numb]s ( ! small] magnitudes %\ld n g on
 cont9ually increas+ ad inf9itum4 ,9 su*
 cases1 moreov]1 ! gr\nd ( ! heav5s1 z  
se5 betwe5 ! />s1 is = ! mo/ "p p]fectly
 d>k1 :i* aga9 w\ld n be ! case if      
innum]able multitudes ( />s1 too m9ute  
to be individually disc]nible1 exi/$    
beyond4' ,& aga9 he sums up z           
foll[s3--',?r\gh\t by f> ! l>g] portion 

( ! ext5t ( ! ,milky ,way 9 bo?         
hemisph]es1 ! g5]al blackness ( ! gr\nd 
( ! heav5s on :i* its />s are project$1 
& ! abs5ce ( t innum]able multitude &   
excessive cr[d+ ( ! smalle/ visible     
magnitudes1 & ( gl>e produc$ by !       
aggregate light ( multitudes too small  
to affect ! eye s+ly1 :i* ! contr>y     
supposition w\ld appe> to necessitate1  
mu/1 we ?9k1 be consid]$ unequivocal    
indications t its dim5sions 9 directions
 :]e ^! conditions obta91 are n only n  
inf9ite1 b t ! space-p5etrat+ p[] ( our 
telescopes suffices fairly to pi]ce     
?r\gh & beyond x4'#b  ,?is expression ( 
op9ion by ! a/ronom] :o1 probably beyond
 any n[ liv+1 0 ! mo/ compet5t au?ority 
on ?is "q1 to :i* he devot$ a long life 
( obs]vation & /udy ext5d+ ov] ! :ole   
heav5s1 _c be lightly set aside by !    
op9ions or conjectures ( ^? :o seem to  
assume t we mu/ believe 9 an inf9ity (  
/>s if ! contr>y _c be absolutely prov$4
 ,b z n a p>ticle ( evid5ce c be adduc$ 
to prove inf9ity1 & z all ! facts &     

indications po9t1 z "h %[n1 9 a directly
 opposite direction1 we mu/1 if we are  
to tru/ to evid5ce at all 9 ?is matt]1  
arrive at ! conclusion t ! univ]se ( />s
 is limit$ 9 ext5t4  ,dr4 ,isaac ,rob]ts
 gives simil> evid5ce z reg>ds ! use (  
photographic plates4 ,he                
writes3--',elev5 ye>s ago photographs ( 
! ,great ,nebula 9 ,&rom$a 7 tak5 ) !   
#bj-;in* reflector1 & exposures ( !     
plates dur+ int]vals up to f\r h\rs2 &  
^u "s ( !m 7 depict$ />s to ! fa9tness (
 #ag? to #ah? magnitude1 & nebulosity to
 an equal degree ( fa9tness4 ,! films ( 
! plates obta9able 9 ^? days 7 less     
s5sitive ?an ^? :i* h be5 available dur+
 ! pa/ five ye>s1 & dur+ ?is p]iod      
photographs ( ! nebula ) exposures up to
 f\r h\rs h be5 tak5 ) ! #bj-;in*       
reflector4 ,no ext5sions ( ! nebulosity1
 h[ev]1 nor increase 9 ! numb] ( ! />s c
 be se5 on ! lat] rapid plates ?an 7    
depict$ ^u ! e>li] sl[] ones1 ?\gh !    
/>-images & ! nebulosity h great] d5sity
 on ! lat] plates4'  ,exactly simil>    

facts are record$ 9 ! cases ( ! ,great  
,nebula 9 ,orion1 & ! gr\p ( !          
,pleiades4 ,9 ! case ( ! ,milky ,way 9  
,cygnus photographs h be5 tak5 ) ! same 
in/rum5t1 b ) exposures v>y+ f "o h\r to
 two h\rs & a half1 b no fa9t] />s c\ld 
be f\nd on "o ?an on ! o!r2 & ?is fact  
has be5 confirm$ by simil> photographs (
 o!r areas 9 ! sky4   ,,! ,,law ,,(     
,,dim9i%+ ,,numb]s ,,( ,,/>s  ,we w n[  
consid] ano!r k9d ( evid5ce equally     
weighty ) ! two already adduc$4 ,?is is 
:at may be t]m$ ! law ( dim9i%+ numb]s  
beyond a c]ta9 magnitude1 z obs]v$ by   
l>g] & l>g] telescopes4  ,= "s ye>s pa/ 
/>-magnitudes h be5 det]m9$ v accurately
 by means ( c>eful photometric          
comp>isons4 ,d[n to ! six? magnitude />s
 are visible to ! nak$ eye1 & are h5ce  
t]m$ lucid />s4 ,all fa9t] />s are      
telescopic1 & cont9u+ ! magnitudes 9 a  
s]ies 9 :i* ! diff]5ce 9 lum9osity      
betwe5 ea* successive magnitude is      
equal1 ! sev5te5? magnitude is rea*$ &  
indicates ! range ( visibility 9 ! l>ge/

 telescopes n[ 9 exi/5ce4 ,by ! scale n[
 us$ a /> ( any magnitude gives ne>ly   
two & a half times z mu* light z "o ( ! 
next l[] magnitude1 & = accurate        
comp>ison ! app>5t brightness ( ea* />  
is giv5 to ! t5? ( a magnitude :i* c    
easily be obs]v$4 ,( c\rse1 ow+ to      
diff]5ces 9 ! col\r ( />s1 ^!           
det]m9ations _c be made ) p]fect        
accuracy1 b no important error is due to
 ?is cause4 ,accord+ to ?is scale a six?
 magnitude /> gives ab\t "o-hundr$? "p (
 ! light ( an av]age fir/ magnitude />4 
,sirius is s exceptionally bright t x   
gives n9e times z mu* light z a /&>d or 
av]age fir/ magnitude />4  ,n[ x is f\nd
 t f ! fir/ to ! six? magnitude ! />s   
increase 9 numb] at ! rate ( ab\t ?ree &
 a half times ^? ( ! prec$+ magnitudes4 
,! total numb] ( />s d[n to ! six?      
magnitude is giv5 by ,pr(essor ,newcomb 
z #gfdg4 ,= high] magnitudes ! numb]s   
are s great t precision & uni=mity are m
 difficult ( atta9m5t2 yet !re is a     
wond]ful cont9uance ( ! same law (      

increase d[n to ! t5? magnitude1 :i* is 
e/imat$ to include #b1caa1jjj />s1 ?us  
con=m+ v ne>ly ) ! ratio ( #c4e z       
det]m9$ by ! lucid />s4  ,b :5 we pass  
beyond ! t5? magnitude to ^? va/ numb]s 
( fa9t />s only to be se5 9 ! be/ or !  
l>ge/ telescopes1 !re appe>s to be a    
sudd5 *ange 9 ! ratio ( increas$ numb]s 
p] magnitude4 ,! numb]s ( ^! />s are s  
great t x is impossible to c\nt ! :ole z
 ) ! high] magnitude />s1 b num]\s c\nts
 h be5 made by _m a/ronom]s 9 small     
measur$ areas 9 diff]5t p>ts ( ! heav5s1
 s t a fair av]age has be5 obta9$1 & x  
is possible to make a ne> approximation 
to ! total numb] visible d[n to !       
sev5te5? magnitude4 ,! e/imate ( ^! by  
a/ronom]s :o h made a special /udy ( ?is
 subject is1 t ! total numb] ( visible  
/>s does n exce$ "o hundr$ millions4#c  
,b if we take ! numb] ( />s d[n to ! n9?
 magnitude1 :i* are kn[n ) consid]able  
accuracy1 & f9d ! numb]s 9 ea* succe$+  
magnitude d[n to ! sev5te5?1 accord+ to 
! same ratio ( increase :i* has be5 f\nd

 to correspond v ne>ly 9 ! case ( !     
high] magnitudes1 ,mr4 ,j4,e4 ,gore f9ds
 t ! total numb] %\ld be ab\t #adjj     
millions4 ,( c\rse nei!r ( ^! e/imates  
makes any pret5ce to exact accuracy1 b  
!y are f\nd$ on all ! facts at pres5t   
available1 & are g5]ally accept$ by     
a/ronom]s z be+ ! ne>e/ approa* t c be  
made to ! true numb]s4 ,! discrepancy   
is1 h[ev]1 s enorm\s t probably no      
c>eful obs]v] ( ! heav5s ) v l>ge       
telescopes d\bts t !re is a v real & v  
rapid dim9ution 9 ! numb]s ( ! fa9t] z  
comp>$ ) ! bright] />s4  ,!re is1 h[ev]1
 yet "o m indication ( ! decreas+ numb]s
 ( ! fa9t telescopic />s1 :i* is almo/  
conclusive on ?is "q1 &1 s f> z ,i am   
aw>e1 has n yet be5 us$ 9 ?is relation4 
,i w !re=e briefly /ate x4   ,,! ,,light
 ,,ratio ,,z ,,indicat+ ,,! ,,numb] ,,( 
,,fa9t ,,/>s  ,pr(essor ,newcomb po9ts  
out a rem>kable result dep5d+ on ! fact 
t1 :ile ! av]age light ( successively   
l[] magnitudes dim9i%es 9 a ratio (     
#b4e1 _! numb]s increase at ne>ly a     

ratio ( #c4e4 ,f ?is x foll[s t1 s long 
z ?is law ( increase cont9ues1 ! total (
 />light goes on increas+ by ab\t =ty p]
 c5t4 = ea* successive magnitude1 & he  
gives ! foll[+ table to illu/rate x3--  
,mag4 #a    ,total ,light    #a         
#b                  #a4d         #c     
#b4j         #d                  #b4h   
#e                  #d4j         #f     
#e4g         #g                  #h4j   
#h                 #aa4c         #i     
#af4j        #aj                 #bb4f  
--------     ,total light to ,mag4 #aj  
#gd4h                          -------- 
,?us ! total am\nt ( ! light giv5 by all
 />s d[n to ! t5? magnitude is          
sev5ty-f\r times z great z t f ! few    
fir/ magnitude />s4 ,we also see t !    
light giv5 by ! />s ( any magnitude is  
twice z mu* z t ( ! />s two magnitudes  
high] 9 ! scale1 s t we c easily        
calculate :at additional light we ought 
to receive f ea* additional magnitude if
 !y cont9ue to increase 9 numb]s bel[ ! 
t5? z !y d above t magnitude4 ,n[ x has 

be5 calculat$ z ! result ( c>eful       
obs]vations1 t ! total light giv5 by />s
 d[n to n9e & a half magnitude is       
"o-eightie? ( full moonlight1 ?\gh "s   
make x mu* m4 ,b if we cont9ue ! table (
 light-ratios f ?is l[ />t+-po9t d[n to 
magnitude sev5te5 & a half1 we %all f9d1
 if ! numb]s ( ! />s g on increas+ at ! 
same rate z be=e1 t ! light ( all comb9$
 %\ld be at lea/ sev5 times z great z   
moonlight2 :]eas ! photometric          
measurem5ts make x actually ab\t        
"o-tw5tie?4 ,& z ! calculation f        
light-ratios only includes />s j visible
 9 ! l>ge/ telescopes1 & does n include 
all ^? prov$ to exi/ by photography1 we 
h 9 ?is case a demon/ration t ! numb]s (
 ! />s bel[ ! t5? & d[n to ! sev5te5?   
magnitude dim9i% rapidly4  ,we mu/      
rememb] t ! m9ut] telescopic />s        
prepond]ate enorm\sly 9 & ne> ! ,milky  
,way4 ,at a di/ance f x !y dim9i%       
rapidly1 till ne> its poles !y are almo/
 entirely abs5t4 ,?is is %[n by ! fact  
7already ref]r$ to at p4 #adf7 t        

,pr(essor ,celoria ( ,milan1 ) a        
telescope ( less ?an ?ree in*es ap]ture1
 c\nt$ almo/ z _m />s 9 t region z did  
,h]s*el ) 8 eighte5-in* reflector4 ,b if
 ! /ell> univ]se ext5ds )\t limit we c  
h>dly suppose x to d s 9 "o plane only2 
h5ce ! abs5ce ( ! m9ut] />s & ( diffus$ 
milky light ov] ! l>g] "p ( ! heav5s is 
n[ held to prove t ! myriads ( v m9ute  
/>s 9 ! ,milky ,way really belong to x1 
& n to ! dep?s ( space f> beyond4  ,x   
seems to me t "h we h a fairly direct   
pro( t ! />s ( our univ]se are really   
limit$ 9 numb]4  ,!re are ?us f\r di/9ct
 l9es ( argum5t all po9t+ ) m or less   
=ce to ! conclusion t ! /ell> univ]se we
 see ar\nd u1 s f> f be+ inf9ite1 is    
/rictly limit$ 9 ext5t & ( a def9ite =m 
& con/itution4 ,!y may be briefly       
summ>is$ z foll[s3--  7#a7 ,pr(essor    
,newcomb %[s t1 if ! />s 7 inf9ite 9    
numb]1 & if ^? we see 7 approximately a 
fair sample ( ! :ole1 & fur!r1 if !re 7 
n suffici5t d>k bodies to %ut out almo/ 
! :ole ( _! light1 !n we %\ld receive f 

!m an am\nt ( light !oretically great]  
?an t ( sunlight4 ,i h %[n1 at "s l5g?1 
t nei!r ( ^! causes ( loss ( light w    
acc\nt = ! enorm\s disproportion betwe5 
! !oretical & ! actual light receiv$ f !
 />s2 & !re=e ,pr(essor ,newcomb's      
argum5t mu/ be held to be a valid "o    
aga9/ ! inf9ite ext5t ( our univ]se4 ,( 
c\rse1 ?is does n imply t !re may n be  
any numb] ( o!r univ]ses 9 space1 b z we
 "k absolutely no?+ ( !m--ev5 :e!r !y   
are mat]ial or non-mat]ial--all         
speculation z to _! exi/5ce is worse ?an
 useless4  7#b7 ,! next argum5t dep5ds  
on ! fact t all ov] ! heav5s1 ev5 9 !   
,milky ,way itself1 !re are areas (     
consid]able ext5t1 besides rifts1 lanes1
 & circul> pat*es1 :]e />s are ei!r q   
abs5t or v fa9t & few 9 numb]4 ,9 _m (  
^! areas ! l>ge/ telescopes %[ no m />s 
?an ^? ( mod]ate size1 :ile ! few />s   
se5 are project$ on an int5sely d>k     
backgr\nd4 ,sir ,william ,h]s*el1       
,humboldt1 ,sir ,john ,h]s*el1 ,r4,a4   
,proctor1 & _m liv+ a/ronom]s hold t1 9 

^! d>k areas1 rifts1 & pat*es1 we see   
completely ?r\gh our /ell> univ]se into 
! />less dep?s ( space beyond4  7#c7 ,!n
 we h ! rem>kable fact t ! /eady        
increase 9 ! numb] ( />s1 d[n to ! n9?  
or t5? magnitudes1 foll[+ "o con/ant    
ratio ei!r gradually or sudd5ly *anges1 
s t ! total numb] f ! t5? d[n to !      
sev5te5? magnitudes is only ab\t "o-t5? 
( :at x w\ld h be5 _h ! same ratio (    
increase cont9u$4 ,! conclusion to be   
drawn f ?is fact cle>ly is1 t ^! fa9t   
/>s are becom+ m & m ?9ly scatt]$ 9     
space1 :ile ! d>k backgr\nd on :i* !y   
are usually se5 %[s t1 except 9 ! region
 ( ! ,milky ,way1 !re are n multitudes (
 /ill small] invisible />s beyond !m4   
7#d7 ,! la/ indication ( a limit$ /ell> 
univ]se--! e/imate ( numb]s by !        
light-ratio ( ea* successive            
magnitude--p[]fully supports ! ?ree     
prec$+ argum5ts4  ,! f\r di/9ct classes 
( evid5ce n[ adduc$ mu/ be held to      
con/itute1 z ne>ly z ! circum/ances     
p]mit1 a satisfactory pro( t ! /ell>    

univ]se1 ( :i* our sol> sy/em =ms a "p1 
has def9ite limits2 & t a full k ( its  
=m1 /ructure1 & ext5t1 is n beyond !    
possibility ( atta9m5t by ! a/ronom]s ( 
! future4  ,,footnotes3  #a ,9 a lett]  
to ,k1 ,june #aijc1 ,mr4 ,w4,h4,t4      
,monck puts ! same po9t 9 a ma!matical  
=m4  #b ,outl9es ( ,a/ronomy1 pp4       
#egh-i4 ,9 ! passages quot$ ! italics   
are ,sor ,john ,h]s*el's4  #c ,mr4      
,j4,e4 ,gore 9 ,concise ,k ,a/ronomy1   
pp4 #eda-b4     ,,*apt] ,,viii  ,,our   
,,relation ,,to ,,! ,,milky ,,way   ,we 
n[ approa* :at may be t]m$ ! v he>t ( ! 
subject ( our inquiry1 ! det]m9ation (  
h[ we are actually situat$ )9 ?is va/ b 
f9ite univ]se1 & h[ t position is likely
 to affect our globe z be+ ! !atre ( !  
developm5t ( life up to its highe/ =ms4 
,we beg9 ) our relation to ! ,milky ,way
 7:i* we h fully describ$ 9 our f\r?    
*apt]71 because x is by f> ! mo/        
important feature 9 ! :ole heav5s4 ,sir 
,john ,h]s*el t]m$ x '! gr\nd-plane ( ! 
sid]eal sy/em'2 & ! m x is /udi$ ! m we 

become conv9c$ t ! :ole ( ! /ell>       
univ]se--/>s1 clu/]s ( />s1 & nebul--are
 9 "s way connect$ ) x1 & are probably  
dep5d5t on x or controll$ by x4 ,n only 
does x conta9 a great] numb] ( />s ( !  
high] magnitudes ?an any o!r "p ( !     
heav5s ( equal ext5t1 b x also comprises
 a great prepond]ance ( />-clu/]s1 & a  
great ext5t ( diffus$ nebul\s matt]1    
besides ! innum]able myriads ( m9ute />s
 :i* produce its *>act]i/ic cl\d-l      
appe>ance4 ,x is also ! region ( ^?     
/range outbur/s =m+ new />s2 :ile gase\s
 />s ( enorm\s bulk--"s probably a ?\s& 
or ev5 t5 ?\s& times t ( our sun1 & (   
int5se heat & brilliancy--are m abundant
 !re ?an 9 any o!r "p ( ! heav5s4 ,x is 
n[ almo/ c]ta9 t ^! enorm\s />s & !     
myriads ( m9ute />s j visible ) ! l>ge/ 
telescopes1 are actually int]m+l$1 &    
toge!r con/itute its ess5tial features2 
9 :i* case ! fa9t] />s are really small 
& _c be f> ap>t1 =m+1 z x 71 ! fir/     
aggregations ( ! nebul\s sub/ratum1 &   
p]haps supply+ ! fuel :i* keeps up !    

int5se brilliancy ( ! giant suns4 ,if   
?is is s1 !n ! ,galaxy mu/ be ! !atre ( 
op]ation ( va/ =ces1 & ( cont9u\s       
comb9ations ( matt]1 :i* escape our     
notice ow+ to its enorm\s di/ance f u4  
,among its millions ( m9ute telescopic  
/>s1 hundr$s or ?\s&s may appe> or      
disappe> ye>ly )\t be+ p]ceiv$ by u1    
till ! photographic *>ts are complet$ & 
c be m9utely scrut9is$ at %ort int]vals4
 ,z und\bt$ *anges h occurr$ 9 _m ( !   
l>g] nebul dur+ ! la/ fifty ye>s1 we may
 anticipate t analog\s *anges w soon be 
not$ 9 ! />s & ! nebul\s masses ( !     
,milky ,way4 ,dr4 ,isaac ,rob]ts has ev5
 obs]v$ *anges 9 nebul aft] su* a %ort  
int]val z eight ye>s4   ,,! ,,milky     
,,way ,a ,,great ,,circle  ,not)/&+ all 
its irregul>ities1 its divisions1 & its 
div]g+ bran*es1 a/ronom]s are g5]ally   
agre$ t ! ,milky ,way =ms a great circle
 9 ! heav5s4 ,sir ,john ,h]s*el1 ^: k ( 
x 0 unrivall$1 /at$ t its c\rse 'con=ms1
 z ne>ly z ! indef9it5ess ( its b\nd>y w
 all[ x to be fix$1 to t ( a great      

circle'2 & he gives ! ,"r ,asc5sion &   
,decl9ation ( ! po9ts :]e x crosses !   
equ9octial1 9 figures :i* def9e ^? po9ts
 z be+ exactly opposite ea* o!r4 ,he    
also def9es its nor!rn & s\!rn poles by 
o!r figures1 s z to %[ t !y are ! poles 
( a great circle4 ,& aft] ref]r+ to     
,/ruve's view t x 0 n a great circle1 he
 says1 ',i reta9 my own op9ion4'        
,pr(essor ,newcomb says t its position  
'is ne>ly always ne> a great circle ( ! 
sph]e'2 & aga9 he says3 't we are 9 !   
galactic plane itself seems to be %[n 9 
two ways3 7#a7 ! equality 9 ! c\nts (   
/>s on ! two sides ( ?is plane all ! way
 to its poles2 & 7#b7 ! fact t ! c5tral 
l9e ( ! ,galaxy is a great circle1 :i* x
 w\ld n be if we view$ x f "o side ( its
 c5tral plane' 7,! ,/>s1 p4 #cag74 ,miss
 ,cl]ke1 9 h] ,hi/ory ( ,a/ronomy1      
speaks ( 'our situation 9 ! galactic    
plane' z "o ( ! undisput$ facts (       
a/ronomy2 :ile ,sir ,norman ,locky]1 9 a
 lecture deliv]$ 9 #ahii1 said1 '!      
middle l9e ( ! ,milky ,way is really n  

di/+ui%able f a great circle1' & aga9 9 
! same lecture--'b ! rec5t "w1 *iefly ( 
,g\ld 9 ,arg5t9a1 has %[n t x           
practically is a great circle4'#d  ,ab\t
 ?is fact1 !n1 !re c be no dispute4 ,a  
great circle is a circle divid+ !       
cele/ial sph]e into two equal portions1 
z se5 f ! e>?1 & !re=e ! plane ( ?is    
circle mu/ pass ?r\gh ! e>?4 ,( c\rse ! 
:ole ?+ is on su* a va/ scale1 ! ,milky 
,way v>y+ f t5 to ?irty degrees wide1 t 
! plane ( its circul> c\rse _c be       
det]m9$ ) m9ute accuracy4 ,b ?is is (   
little importance4 ,:5 c>efully laid d[n
 on a *>t1 z 9 t ( ,mr4 ,sidney ,wat]s  
7see end ( volume71 we c see t its      
c5tral l9e does foll[ a v ev5 circul>   
c\rse1 con=m+ 'z ne>ly z may be' to a   
great circle4 ,we are !re=e c]ta9ly well
 )9 ! space t w\ld be enclos$ if its    
nor!rn & s\!rn m>g9s 7 connect$ toge!r  
across ! va/ int]v5+ abyss1 & 9 all     
probability n f> f ! c5tral plane ( t   
enclos$ space4   ,,! ,,=m ,,( ,,!       
,,milky ,,way ,,& ,,our ,,position ,,on 

,,its ,,plane  ,al?\gh ! ,galaxy =ms a  
great circle 9 ! heav5s f our po9t (    
view1 x by no means foll[s t x is       
circul> 9 plan4 ,be+ unequal 9 wid? &   
irregul> 9 outl9e1 x might be elliptic  
or ev5 angul> 9 %ape )\t be+ at all     
obvi\sly s to u4 ,if we 7 /&+ 9 an op5  
pla9 or field two or ?ree miles 9       
diamet]1 & b\nd$ 9 e direction by woods 
( v irregul> height & d5sity & great    
div]sity ( t9t1 we %\ld f9d x difficult 
to judge ( ! %ape ( ! field1 :i* might  
be ei!r a true circle1 an oval1 a       
hexagon1 or q irregul> 9 outl9e1 )\t our
 be+ able to detect ! exact %ape unless 
"s p>ts 7 v mu* ne>] to u ?an o!rs4     
,aga91 j z ! woods b\nd+ ! field might  
be ei!r a n>r[ belt ( ne>ly uni=m wid?1 
or might 9 "s places be only a few y>ds 
wide & 9 o!rs /ret* out = miles1 s !re h
 be5 _m op9ions z to ! wid? ( ! ,milky  
,way 9 ! direction ( its plane1 t is1 9 
! direction 9 :i* we look t[>ds x4      
,lately1 h[ev]1 z ! result (            
long-cont9u$ obs]vation & /udy1         

a/ronom]s are fairly well agre$ z to its
 g5]al =m & ext5t1 z w be se5 by !      
foll[+ /atem5ts ( fact & reason+4  ,miss
 ,cl]ke1 aft] giv+ ! v>i\s views ( _m   
a/ronom]s--& z ! hi/orian ( mod]n       
a/ronomy h] op9ion has mu*              
weight--consid]s t ! mo/ probable view (
 x is1 t x is really v mu* :at x seems  
to u--an imm5se r+ ) /ream+ app5dages   
ext5d+ f ! ma9 body 9 all directions1   
produc+ ! v complex effect we see4 ,!   
belief seems to be n[ spread+ t ! :ole  
univ]se ( />s is sph]ical or sph]oidal1 
! ,milky ,way be+ its equator1 & !re=e 9
 all probability circul> or ne>ly s 9   
plan2 & x is also held t x mu/ be       
rotat+--p]haps v sl[ly--z no?+ else c be
 suppos$ to h l$ to ! =mation ( su* a   
va/ r+1 or c pres]ve x :5 =m$4          
,pr(essor ,newcomb consid]s1 f ! numb]s 
( ! />s 9 all directions t[>ds ! ,milky 
,way be+ approximately equal1 t !re _c  
be mu* diff]5ce 9 our di/ance f x 9     
v>i\s directions4 ,x w\ld foll[ t its   
plan is approximately circul> or broadly

 elliptic4 ,! exi/5ce ( r+-nebul may be 
held to r5d] su* a =m probable4  ,sir   
,norman ,locky] gives facts :i* t5d 9 ! 
same direction4 ,9 an article 9 ,nature 
( ,novemb] #h?1 #aijj1 he says3 ',we f9d
 t ! gase\s />s are n only conf9$ to !  
,milky ,way1 b !y are ! mo/ remote 9 e  
direction1 9 e galactic longitude2 all (
 !m h ! smalle/ prop] motion4' ,& aga91 
ref]r+ to ! hotte/ />s be+ equally      
remote on all sides ( u1 he says3 ',x is
 because we are 9 ! c5tre1 because !    
sol> sy/em is 9 ! c5tre1 t ! obs]v$     
effect arises4' ,he also consid]s t !   
r+-nebula 9 ,lyra ne>ly repres5ts ! =m (
 our :ole sy/em2 & he adds3 ',we        
practically "k t 9 our sy/em ! c5tre is 
! region ( lea/ di/urbance1 & !re=e     
cool] conditions4'  ,^! v>i\s facts &   
conclusions ( "s ( ! mo/ em95t a/ronom]s
 all po9t to "o def9ite inf]5ce1 t our  
position1 or t ( ! sol> sy/em1 is n v f>
 f ! c5tre ( ! va/ r+ ( />s con/itut+ ! 
,milky ,way1 :ile ! same facts imply a  
ne>ly circul> =m to ?is r+4 ,"h1 m ?an z

 reg>ds our position 9 ! plane ( !      
,galaxy1 !re is no possibility ( precise
 det]m9ation2 b x is q c]ta9 t if we 7  
situat$ v f> away f ! c5tre1 say1 =     
in/ance1 "o-f\r? ( its diamet] f "o side
 ( x & ?ree-f\r?s f ! o!r1 ! appe>ances 
w\ld n be :at !y are1 & we %\ld easily  
detect ! exc5tricity ( our position4    
,ev5 if we 7 "o-?ird ! diamet] f "o side
 & two-?irds f ! o!r1 x w1 ,i ?9k1 be   
admitt$ t ?is also w\ld h be5 asc]ta9$  
by ! v>i\s me?ods ( rese>* n[ available4
 ,we mu/1 !re=e1 be some:]e betwe5 !    
actual c5tre & a circle ^: radius is    
"o-?ird ( ! di/ance to ! ,milky ,way4 ,b
 if we are ab\t midway betwe5 ^! two    
positions1 we %all only be "o-six? ( !  
radius or "o-twelf? ( ! diamet] ( !     
,milky ,way f its exact c5tre2 & if we  
=m "p ( a clu/] or gr\p ( />s sl[ly     
revolv+ ar\nd t c5tre1 we %\ld probably 
obta9 all ! advantages1 if any1 t may   
arise f a ne>ly c5tral position 9 !     
entire />-sy/em4  ,?is "q ( our         
situation )9 ! great circle ( ! ,milky  

,way is ( consid]able importance f !    
po9t ( view ,i am "h sugge/+1 s t e fact
 be>+ ^u x %\ld be not$2 & !re is "o :i*
 has n1 ,i ?9k1 be5 giv5 ! full weight  
due to x4 ,x is g5]ally admitt$ t !     
great] brilliancy ( "s p>ts ( ! ,milky  
,way is no indication ( ne>ness1 because
 surfaces possess equal brilliancy f    
:atev] di/ance !y are se54 ,?us ea*     
planet has its special brilliancy or    
reflective p[]1 te*nically t]m$ its     
'alb$o1' & ?is rema9s ! same at all     
di/ances if ! o!r conditions are simil>4
 ,b not)/&+ ?is well-kn[n fact1 ,sir    
,john ,h]s*el's rem>k t ! great]        
brightness ( ! s\!rn ,milky ,way        
'conveys /rongly ! impression ( great]  
proximity1' & !re=e1 t we are           
exc5trically plac$ 9 its plane1 has be5 
adopt$ by _m writ]s z if x 7 ! /atem5t (
 a fact1 or at lea/ a cle>ly express$   
op9ion1 in/ead ( be+ a m]e 'impression1'
 & really a mislead+ "o4 ,i !re=e wi% to
 adduce a ph5om5on :i* has a real be>+  
on ! "q4 ,x is evid5t t1 if ! ,milky    

,way 7 actually ( uni=m wid? ?r\gh\t1 !n
 diff]5ces ( app>5t wid? w\ld indicate  
diff]5ces ( di/ance4 ,9 ! p>ts ne>] to u
 x w\ld appe> wid]1 :]e m remote1 n>r[]2
 b 9 ^! opposite directions !re w\ld n  
necess>ily be any diff]5ces 9           
brightness4 ,we %\ld1 h[ev]1 expect t 9 
! p>ts ne>] to u ! lucid />s1 z well z  
^? )9 any def9ite limits ( magnitude1   
w\ld be ei!r m num]\s or m wide ap>t on 
! av]age4 ,no su* diff]5ce z ?is1 h[ev]1
 has be5 record$2 b !re is a peculi>    
correspond5ce 9 ! opposite portions ( ! 
,galaxy :i* is v sugge/ive4 ,9 !        
beautiful *>ts ( ! ,nebul & ,/> ,clu/]s 
by ! late ,mr4 ,sidney ,wat]s1 publi%$  
by ! ,royal ,a/ronomical ,society & "h  
reproduc$ by _! p]mission 7see end (    
volume71 ! ,milky ,way is del9eat$ 9 its
 :ole ext5t ) great detail & f ! be/    
au?orities4 ,^! *>ts %[ u t1 9 bo?      
hemisph]es1 x rea*es its maximum        
ext5sion on ! "r & left m>g9s ( ! *>ts1 
:]e x is almo/ equal 9 ext5t2 :ile 9 !  
c5tre ( ea* *>t1 t is at its ne>e/ po9ts

 to ! nor? & s\? poles respectively1 x  
is at its n>r[e/ portion2 &1 al?\gh ?is 
"p 9 ! s\!rn hemisph]e is brighte/ & mo/
 /rongly def9$1 yet ! actual ext5t1     
includ+ ! fa9t] portions1 is1 aga91 n v 
unequal 9 ! opposite segm5ts4 ,"h we h a
 rem>kable & significant symmetry 9 !   
proportions ( ! ,milky ,way1 :i*1 tak5 9
 connection ) ! ne>ly symmetrical       
scatt]+ ( ! />s 9 all p>ts ( ! va/ r+1  
is /rongly sugge/ive ( a ne>ly circul>  
=m & ( our ne>ly c5tral position )9 its 
plane4 ,!re is "o o!r feature 9 ?is     
del9eation ( ! ,milky ,way :i* is wor?y 
( notice4 ,x has be5 ! univ]sal practice
 to speak ( x z be+ d\ble ?r\gh a       
consid]able portion ( its ext5t1 & all !
 usual />-maps %[ ! division greatly    
exagg]at$1 especially 9 ! nor!rn        
hemisph]e2 & ?is division 0 consid]$ s  
important z to lead to ! clov5-disc !ory
 ( its =m1 or t x consi/$ ( two sep>ate 
irregul> r+s1 ! ne>] "o p>tly hid+ ! m  
di/ant2 :ile v>i\s spiral comb9ations 7 
held by o!rs to be ! be/ way ( expla9+  

its complex appe>ance4 ,b ?is new] map1 
r$uc$ f a l>ge "o by ,"l ,rosse's       
a/ronom]1 ,dr4 ,bo$dick]1 :o devot$ five
 ye>s to its del9eation1 %[s u t !re is 
no actual division 9 any portion ( x 9 !
 nor!rn hemisph]e1 b t ev]y:]e1 ?r\gh\t 
its :ole wid?1 x consi/s ( num]\s       
int]m+l$ /reams & bran*es1 v>y+ greatly 
9 lum9osity1 & ) _m fa9t or b>ely       
di/+ui%able ext5sions along its m>g9s1  
yet =m+ "o unmi/akable nebul\s belt2 & !
 same g5]al "* applies to x 9 ! s\!rn   
hemisph]e z del9eat$ by ,dr4 ,g\ld4     
,ano!r feature1 :i* is well %[n to ! eye
 by ^! m accurate maps1 is ! regul>     
curvature ( ! c5tral l9e ( ! ,milky     
,way4 ,we c judge ( ?is almo/           
suffici5tly by ! eye2 b if1 ) a pair (  
compasses1 we f9d ! prop] radius & c5tre
 ( curvature1 we %all see t ! true      
circul> curve is always 9 ! v c5tre ( ! 
nebul\s mass1 & ! same radius appli$ 9 !
 same mann] to ! opposite hemisph]e     
gives a simil> result4 ,x w be not$ t z 
! ,milky ,way is obliquely situat$ on ^!

 *>ts1 ! c5tre ( ! curve w be ab\t 9    
,r4,a4 #j;h4 #djm4 9 ! map ( ! s\!rn    
hemisph]e1 & 9 ,r4,a4 #ab;h4 #djm4 9 t (
 ! nor!rn hemisph]e2 :ile ! radius (    
curvature w be ab\t ! l5g? ( ! *ord (   
eight h\rs ( ,r4,a4 z measur$ on ! m>g9 
( ! maps4 ,?is great regul>ity ( curve (
 ! c5tral l9e ( ! ,galaxy /rongly       
sugge/s rotation z ! only means by :i* x
 c\ld h orig9at$ & be ma9ta9$4   ,,!    
,,sol> ,,clu/]  ,a/ronom]s are n[       
g5]ally agre$ t !re is a clu/] ( />s (  
:i* our sun =ms a "p1 ?\gh its exact    
dim5sions1 =m1 & limits are /ill "u     
discussion4 ,sir ,william ,h]s*el long  
ago arriv$ at ! conclusion t ! ,milky   
,way 'consi/s ( />s v diff]5tly scatt]$ 
f ^? imm$iately ar\nd u4' ,dr4 ,g\ld    
believ$ t !re 7 ab\t five hundr$ bright 
/>s mu* ne>] to u ?an ! ,milky ,way1 :i*
 he t]m$ ! sol> clu/]4 ,& ,miss ,cl]ke  
obs]ves t ! actual exi/5ce ( su* a clu/]
 is indicat$ by ! fact t 'an enum]ation 
( ! />s 9 photometric ord] discloses a  
sy/ematic excess ( />s bright] ?an ! #d?

 magnitude1 mak+ x c]ta9 t !re is an    
actual cond5sation 9 ! neighb\rhood ( ! 
sun--t ! av]age all[ance ( cubical space
 p] /> is small] )9 a sph]e enclos+ him 
) a radius1 say1 ( #adj light-ye>s1 ?an 
fur!r away4'#e  ,b ! mo/ int]e/+ inquiry
 into ?is subject is t by ,pr(essor     
,kapteyn ( ,grn+51 "o ( ! mo/ pa9/ak+   
/ud5ts ( ! di/ribution ( ! />s4 ,he     
f\nds 8 conclusions ma9ly on ! prop]    
motions ( ! />s1 ?is be+ ! be/ g5]al    
indication ( di/ance 9 ! abs5ce ( actual
 det]m9ation ( p>allax4 ,he made use ( !
 prop] motions & ! spectra ( m ?an two  
?\s& />s1 & he f9ds t a consid]able body
 ( />s hav+ l>ge prop] motions1 & also  
pres5t+ ! sol> type ( spectra1 surr\nd  
our sun 9 all directions1 & %[ no       
increas$ d5sity1 z ! m di/ant />s d1    
t[>ds ! ,milky ,way4 ,he f9ds also t    
t[>ds ! c5tre ( ?is clu/] />s are f>    
clos] toge!r ?an ne> its out] limits 7he
 says !re are n9ety-eight times z _m71 t
 x is r\ghly sph]ical 9 %ape1 & t !     
maximum compression is1 z ne>ly z c be  

asc]ta9$1 at ! c5tre ( ! circle ( !     
,milky ,way1 :ile ! sun is at "s di/ance
 away f ?is c5tral po9t4#f  ,x is a v   
sugge/ive fact t mo/ ( ! />s belong+ to 
?is clu/] h spectra ( ! sol> type1 :i*  
indicates t !y are ( ! same g5]al       
*emical con/itution z our sun1 & are    
also at ab\t ! same /age ( evolution2 & 
?is may well h aris5 f _! orig9 9 a     
great nebul\s mass situat$ at or ne> !  
c5tre ( ! galactic plane1 & probably    
revolv+ r\nd _! common c5tre ( gravity4 
,z ,kapteyn's result 0 bas$ on mat]ials 
:i* 7 n s full or reliable z ^? n[      
available1 ,pr(essor ,s4 ,newcomb has   
exam9$ ! "q himself1 us+ two rec5t li/s 
( />s1 "o limit$ to ^? hav+ prop]       
motions ( #aj a c5tury1 ( :i* !re are   
#bie1 & ! o!r ( ne>ly #aejj />s )       
'appreciable prop] motions4' ,!y are    
situat$ 9 two zones1 ea* ab\t #e 9      
bread? & cutt+ across ! ,milky ,way 9   
diff]5t p>ts ( its c\rse4 ,!y af=d1     
!re=e1 a good te/ ( ! di/ribution ( ^!  
ne>] />s ) reg>d to ! ,galaxy4 ,! result

 is1 t on ! av]age ^! />s are n m num]\s
 9 or ne> ! ,milky ,way ?an else:]e2 &  
,pr(essor ,newcomb expresses himself on 
?is po9t z foll[s3--',! conclusion is   
int]e/+ & important4 ,if we %\ld blot   
out f ! sky all ! />s hav+ no prop]     
motion l>ge en\gh to be detect$1 we %\ld
 f9d rema9+ />s ( all magnitudes2 b !y  
w\ld be scatt]$ almo/ uni=mly ov] ! sky1
 & %[ little or no t5d5cy to cr[d t[>ds 
! ,galaxy1 unless1 p]haps1 9 ! region   
ne> #ai;h4 ( ,"r ,asc5sion4'#g  ,a      
little consid]ation w %[ t1 z ! />s (   
all magnitudes :i* are1 on ! av]age1    
ne>e/ to u are spread ov] ! sky 9 'all  
directions' & 'almo/ uni=mly1' ?is      
necess>ily implies t !y =m a clu/] or   
gr\p1 & t our sun is some:]e n v f> f ! 
c5tre ( ?is gr\p4 ,aga91 ,pr(essor      
,newcomb ref]s to '! rem>kable equality 
9 ! numb] ( />s 9 opposite directions f 
u4 ,we d n detect any m>k$ diff]5ce     
betwe5 ! numb]s ly+ r\nd ! opposite     
poles ( ! ,galaxy1 nor1 s f> z kn[n1    
betwe5 ! />-d5sity 9 diff]5t regions at 

equal di/ances f ! ,milky ,way' 7,!     
,/>s1 p4 #cae74 ,& aga9 he ref]s to !   
same "q at p4 #cag1 :]e he says3 ',s f> 
z we c judge f ! enum]ation ( ! />s 9   
all directions1 & f ! aspect ( ! ,milky 
,way1 our sy/em is ne> ! c5tre ( ! /ell>
 univ]se4'  ,x w1 ,i ?9k1 n[ be cle> to 
my read]s t ! f\r ma9 a/ronomical       
propositions /at$ 9 my article :i*      
appe>$ 9 ! ,new ,york ,indep5d5t & 9 !  
,=tnightly ,review1 & :i* 7 ei!r d5i$ or
 decl>$ to be unprov$ by my a/ronomical 
critics1 h be5 %[n to be support$ by s  
_m conv]g+ l9es ( evid5ce1 t x is no    
long] possible to d5y t !y are1 at lea/ 
provisionally1 fairly well e/abli%$4 ,^!
 facts are1 7#a7 t ! /ell> univ]se is n 
( inf9ite ext5t2 7#b7 t our sun is      
situat$ 9 ! c5tral plane ( ! ,milky     
,way2 7#c7 t x is also situat$ ne> to ! 
c5tre ( t plane2 7#d7 t we are surr\nd$ 
by a gr\p or clu/] ( />s ( unkn[n ext5t1
 :i* occupy a place n f> remov$ f !     
c5tre ( ! galactic plane1 & !re=e1 ne>  
to ! c5tre ( our univ]se ( />s4  ,n only

 are ^! f\r propositions ea* support$ by
 conv]g+ l9es ( evid5ce1 includ+ "s :i* 
,i believe h n be=e be5 adduc$ 9 _!     
support1 b a numb] ( a/ronom]s1         
admitt$ly ( ! fir/ rank1 h arriv$ at !  
same conclusions z to ! be>+ ( !        
evid5ce1 & h express$ _! convictions 9 !
 cle>e/ mann]1 z quot$ by me4 ,x is _!  
conclusions :i* ,i appeal to & adopt2   
yet my two *ief a/ronomical critics     
positively d5y t !re is any valid       
evid5ce ( ! f9it5ess ( ! /ell> univ]se1 
:i* "o ( !m t]ms 'a my?1' & he ev5      
accuses me ( hav+ />t$ x4 ,bo? ( !m1    
h[ev]1 agree 9 /at+ v /rongly "o        
objection to my ma9 !sis--t our c5tral  
position 7n necess>ily at ! precise     
c5tre7 9 ! /ell> univ]se has a mean+ & a
 purpose1 9 connection ) ! developm5t ( 
life & ( man ^u ?is e>?1 &1 s f> z we   
"k1 "h only4 ,) ?is "o objection1 ! only
 "o t 9 my op9ion has ! slighte/ weight1
 ,i w n[ proce$ to deal4   ,,! ,,sun',s 
,,motion ,,?r\gh ,,space  ,! two        
a/ronom]s :o did me ! hon\r to criticise

 my orig9al article laid ! greate/ /ress
 on ! fact1 t ev5 if ,i _h prov$ t ! sun
 n[ occupi$ a ne>ly c5tral position 9 ! 
great />-sy/em1 x 0 really ( no         
importance :atev]1 because1 at ! rate ! 
sun 0 travell+1 'five million ye>s ago  
we 7 deep 9 ! actual /ream ( ! ,milky   
,way2 five million ye>s h5ce we %all h  
completely cross$ ! gulf :i* x          
encircles1 & aga9 be a memb] ( "o ( its 
con/itu5t gr\ps1 b on ! opposite side4  
,& t5 million ye>s are reg>d$ by        
geologi/s & biologi/s z b a trifle on   
acc\nt to meet _! dem&s ^u ! bank (     
,"t4' ,?us speaks "o ( my critics4 ,!   
o!r is equally cru%+4 ,he says3--',if   
!re is a c5tre to ! visible univ]se1 &  
if we occupy x to-day1 we c]ta9ly did n 
d s ye/]day1 & %all n d s to-morr[4 ,!  
,sol> ,sy/em is kn[n to be mov+ among ! 
/>s ) a velocity :i* w\ld c>ry u to     
,sirius )9 #ajj1jjj ye>s1 if we happ5$  
to be travell+ 9 8 direction1 z we are  
n4 ,9 ! #ej or #ajj million ye>s dur+   
:i*1 accord+ to geologi/s1 ?is e>? has  

be5 a habitable globe1 we mu/ h pass$ by
 ?\s&s ( />s on ! "r h& & on ! left4444 
,9 8 eag]ness to limit ! univ]se 9      
space1 ,dr4 ,wallace has surely =gott5 t
 x is equally important1 = 8 purpose1 to
 limit x 9 "t2 b incomp>ably m difficult
 9 ! face ( asc]ta9$ facts4444 ,inde$1 s
 f> f our hav+ tranquilly enjoy$ a      
c5tral position 9 unbrok5 cont9uity =   
scores or p]haps hundr$s ( millions (   
ye>s1 we %\ld 9 t "t h trav]s$ ! univ]se
 f b\nd>y to b\nd>y4'#h  ,n[ ! av]age   
read] ( ^! two criticisms1 tak+ acc\nt (
 ! high (ficial position ( bo? writ]s1  
w\ld accept _! /atem5ts ( ! case z be+  
demon/rat$ facts1 requir+ no            
qualification :atev]1 & w\ld conclude t 
my :ole argum5t _h be5 !reby r5d]$      
wor?less1 & all t ,i f\nd$ ^u x a       
fanta/ic dream4 ,b if1 on ! o!r h&1 ,i c
 %[ t _! /at$ facts z to ! sun's motion 
are by no means demon/rat$1 because     
f\nd$ ^u assumptions :i* may be q       
errone\s2 & fur!r1 t if ! facts %\ld    
turn out to be sub/antially correct1 !y 

h bo? omitt$ to /ate well-kn[n & admitt$
 qualifications :i* r5d] ! conclusions  
!y d]ive f ! facts v d\btful1 !n !      
av]age read] w le>n ! valuable lesson t 
(ficial advocacy1 :e!r 9 m$ic9e1 law1 or
 sci5ce is nev] to be accept$ till ! o!r
 side ( ! case has be5 he>d4 ,let u see1
 !re=e1 :at ! facts really are4         
,pr(essor ,simon ,newcomb calculates t1 
if !re are "o hundr$ million />s 9 !    
/ell> univ]se ea* five times ! mass (   
our sun1 & spread ov] a space :i* light 
w\ld require ?irty ?\s& ye>s to cross1  
!n any mass trav]s+ su* a sy/em ) a     
velocity ( m ?an tw5ty-five miles a     
second1 w\ld fly (f into inf9ite space  
nev] to return4 ,n[ z !re are _m />s :i*
 h1 app>5tly1 v mu* m ?an ?is velocity1 
x w\ld foll[ t ! visible univ]se is     
un/able4 ,x also implies t ^! great     
velocities 7 n acquir$ 9 ! sy/em itself1
 b t ! bodies :i* possess !m mu/ h ent]$
 x f )\t1 ?us requir+ o!r univ]ses z !  
fe$]s ( our univ]se4  ,= ! accuracy ( ! 
above /atem5t ! au?ority ( ,pr(essor    

,newcomb is an ample gu>antee2 b !re may
 be modifications requir$ 9 ! data on   
:i* x is f\nd$1 & ^! may greatly alt] ! 
result4 ,if ,i d n mi/ake1 ! e/imate ( a
 hundr$ million />s is f\nd$ on actual  
c\nts or e/imates ( />s ( successive    
magnitudes 9 diff]5t p>ts ( ! heav5s1 & 
x does n include ei!r ^? ( ! d5s] />    
clu/]s nor ! c\ntless millions j beyond 
! rea* ( telescopes 9 ! ,milky ,way4    
,nei!r does x make all[ance = ! d>k />s 
suppos$ by "s a/ronom]s to be _m times m
 num]\s ?an ! bright ones1 nor = ! va/  
numb] ( ! nebul1 great & small1 9       
calculat+ ! total mass ( ! /ell>        
sy/em4#i ,9 8 late/ "w ,pr(essor        
,newcomb says1 ',! total numb] ( />s is 
to be c\nt$ by hundr$s ( millions'2 &   
h5ce ! controll+ p[] ( ! sy/em on bodies
 )9 x w be _m times great] ?an t giv5   
above1 & might ev5 be ample to reta9 )9 
its b\nds su* a rapidly mov+ /> z       
,arcturus1 :i* is believ$ to be travell+
 at ! rate ( m ?an ?ree hundr$ miles a  
second4 ,b !re is ano!r v important     

limitation to ! conclusions to be drawn 
f ,pr(essor ,newcomb's calculation4 ,x  
assumes ! />s to be ne>ly uni=mly       
di/ribut$ ?r\gh ! :ole ( ! space to :i* 
! sy/em ext5ds4 ,b ! facts are v        
diff]5t4 ,! exi/5ce ( clu/]s1 "s ( :i*  
comprise _m ?\s&s ( />s1 is "o example (
 irregul>ity ( di/ribution1 & any "o (  
^! l>g] clu/]s w\ld probably be able to 
*ange ! c\rse ( ev5 ! swifte/ />s pass+ 
ne> x4 ,! l>g] nebul might h ! same     
effect1 s9ce ! late ,mr4 ,rany>d1 tak+  
all 8 data s z to produce a m9imum      
result1 calculat$ ! probable mass ( !   
,orion nebula to be f\r & a half million
 times t ( ! sun1 & !re may be _m o!r   
nebul equally l>ge4 ,b f> m important is
 ! fact ( ! va/ r+ ( ! ,milky ,way1 :i* 
is n[ univ]sally held by a/ronom]s to   
be1 n only app>5tly b really1 m d5sely  
cr[d$ ) />s & also ) va/ masses (       
nebul\s matt] ?an any o!r "p ( ! heav5s1
 s t x may possibly comprise )9 itself a
 v l>ge proportion ( ! :ole ( ! matt] ( 
! visible univ]se4 ,?is is r5d]$ m      

probable by ! fact t ! great majority ( 
/>-clu/]s lie along its c\rse1 mo/ ( !  
huge gase\s />s belong to x1 :ile !     
occurr5ce !re only ( 'new />s' is       
evid5ce ( a sup]abundance ( matt] 9     
v>i\s =ms lead+ to frequ5t heat-produc+ 
collisions1 j z ! frequ5t occurr5ce (   
meteoric %[]s on our e>? is evid5ce ( ! 
sup]abundance ( meteoric matt] 9 ! sol> 
sy/em4  ,x is recognis$ by ma!maticians 
t )9 any great sy/em ( bodies subject to
 ! law ( gravitation !re c be no su* ?+ 
z motion ( any ( !m 9 a /raight l9e2    
nei!r c any am\nt ( motion arise )9 su* 
a sy/em ?r\gh ! action ( gravitation    
alone capable ( c>ry+ any ( its masses  
out ( ! sy/em4 ,! ultimate t5d5cy mu/ be
 t[>ds conc5tration r ?an t[>ds         
disp]sal4  ,x seems1 !re=e1 only        
reasonable to consid] :atev] motions &  
:atev] velocities we f9d among ! />s1 z 
hav+ be5 produc$ by ! gravitative p[] ( 
! l>g] aggregations1 modifi$ p]haps by  
electrical repulsive =ces1 by           
collisions1 & by ! results ( ^?         

collisions2 & we may look to ! *anges n[
 visibly go+ on 9 "s ( ! nebul & clu/]s 
z indications ( ! =ces t h probably     
br\ght ab\t ! actual condition ( ! :ole 
/ell> univ]se4  ,if we exam9e !         
beautiful photographs ( nebul by ,dr4   
,rob]ts & o!r obs]v]s1 we f9d t !y are (
 _m =ms4 ,"s are extremely irregul> &   
almo/ l pat*es ( cirrus cl\ds1 b a l>ge 
numb] are ei!r di/9ctly spiral 9 =m1 or 
%[ indications ( becom+ spiral1 & ?is   
has be5 f\nd to be ! case ev5 ) "s ( !  
l>ge irregul> nebula4 ,!n aga9 we h     
num]\s r+-=m$ nebul1 usually ) a />     
involv$ 9 d5se nebulosity 9 ! c5tre1    
sep>at$ by a d>k space ( v>i\s wid?s f !
 out] r+4 ,all ^! k9ds ( nebul h />s    
involv$ 9 !m1 & app>5tly =m+ "p ( _!    
/ructure1 :ile o!rs :i* d n diff] 9     
appe>ance f ord9>y />s are believ$ by   
,dr4 ,rob]ts to lie betwe5 u & ! nebula4
 ,9 ! case ( _m ( ! spiral nebul1 />s   
are (t5 /rung along ! coils ( ! spiral1 
:ile o!r curv$ l9es ( />s are se5 j     
outside ! nebula1 s t x is impossible to

 avoid ! conclusion t bo? are really    
connect$ ) x1 ! out] l9es ( />s indicat+
 a =m] great] ext5sion ( ! nebula ^:    
mat]ial has be5 us$ up 9 ! gr[? ( ^!    
/>s4 ,"s ( ^! spiral nebul %[           
beautifully regul> convolutions1 & ^!   
usually h a l>ge c5tral /> l mass1 z 9  
,m4 #ajj ,com & ,i4 #hd ,com1 9 ,vol4   
,,ii4 ,pl4 #ad ( ,dr4 ,rob]ts's         
photographs4 ,! /raight :ite /reaks     
across ! nebula ( ! ,pleiades & "s o!rs 
are believ$ by ,dr4 ,rob]ts to be       
indications ( spiral nebul se5 edgewise4
 ,9 o!r cases1 clu/]s ( />s are m or    
less nebul\s1 & ! arrangem5t ( ! />s    
seems to indicate _! developm5t f a     
spiral nebula4 ,x is to be not$ t _m ( !
 objects class$ z planet>y nebul by ,sir
 ,john ,h]s*el are %[n by ! be/         
photographs to be really ( ! r+-type1   
?\gh (t5 ) a v n>r[ division betwe5 ! r+
 & ! c5tral mass4 ,?is =m may !re=e be (
 frequ5t occurr5ce4  ,b if ?is annul> =m
 ) "s k9d ( c5tral nucleus1 (t5 v l>ge1 
is produc$ "u c]ta9 conditions by !     

action ( ! ord9>y laws ( motion ^u m or 
less ext5sive masses ( discrete matt]1  
:y may n ! same laws act+ ^u simil>     
matt] once disp]s$ ov] ! :ole ext5t ( ! 
exi/+ /ell> univ]se1 or ev5 beyond :at  
are n[ its f>!/ limits1 h l$ to !       
aggregation ( ! va/ annul> =mation ( !  
,milky ,way1 ) all ! subord9ate c5tres (
 conc5tration or disp]sal to be f\nd )9 
or ar\nd x8 ,& if ?is is a reasonable   
conception1 may we n hope t by a        
conc5tration ( att5tion ^u a few ( ! be/
 m>k$ & mo/ fav\rably situat$ annul> &  
spiral sy/ems1 suffici5t k ( _! int]nal 
motions may be obta9$ :i* may s]ve z a  
guide to ! k9d ( motion we may expect to
 f9d 9 ! great galactic r+ & its        
subord9ate />s8 ,we may !n p]haps       
discov] :i* n[ seem s erratic1 are      
really all p>ts ( a s]ies ( orbital     
movem5ts limit$ & controll$ by ! =ces ( 
! great sy/em to :i* !y belong1 s t1 if 
n ma!matically /able1 !y may yet be     
suffici5tly s to endure = "s ?\s&       
millions ( ye>s4  ,x is a sugge/ive fact

 t ! calculat$ position ( ! 'sol>       
apex'--! po9t t[>ds :i* our sun appe>s  
to move--is n[ f\nd to be mu* m ne>ly 9 
! plane ( ! ,milky ,way ?an ! position  
fir/ assign$ to x1 & ,pr(essor ,newcomb 
adopts1 z mo/ likely to be accurate1 a  
po9t ne> ! bright /> ,vega 9 !          
con/ellation ,lyra4 ,o!r calculators h  
plac$ x /ill f>!r ea/1 :ile ,ranck5 &   
,otto ,/umpe assign x a position        
actually 9 ! ,milky ,way2 & ,mr4 ,g4,c4 
,bompas concludes t ! sun's plane (     
motion ne>ly co9cides ) t ( ! ,galaxy4  
,m4 ,ranck5 f\nd t #ajf />s ne> ! ,milky
 ,way %[$1 9 _! v small prop] motions1 a
 drift along x 9 a direction f          
,cassiopei t[>ds ,orion1 & ?is1 x is    
suppos$1 may be p>tly due to our sun's  
motion 9 an opposite direction4  ,9 _m  
o!r p>ts ( ! heav5s !re are gr\ps ( />s 
:i* h almo/ id5tical prop] motions--a   
ph5om5on :i* ! late ,r4,a4 ,proctor t]m$
 '/>-drift'2 & he especially po9t$ out t
 five ( ! />s ( ! ,great ,be> 7 all     
drift+ 9 ! same direction2 & al?\gh ?is 

has be5 d5i$ by lat] writ]s1 ,pr(essor  
,newcomb1 9 8 rec5t book on ,! ,/>s1    
decl>es t ,proctor 0 "r1 & expla9s t !  
error ( 8 critics 0 due to n mak+       
all[ance = ! div]g5ce ( ! circles ( "r  
asc5sion4 ,! ,pleiades are ano!r gr\p1 !
 />s ( :i* drift 9 ! same direction1 & x
 is a mo/ sugge/ive fact t photographs  
n[ %[ ?is clu/] to be emb$d$ 9 a va/    
nebula1 :i*1 !re=e1 has also a prop]    
motion2 b "s ( ! small] />s d n p>take (
 x4 ,?ree />s 9 ,cassiopei also move    
toge!r1 & no d\bt _m o!r simil>ly       
connect$ gr\ps rema9 to be discov]$4    
,^! facts h a v important be>+ on ! "q (
 ! motion ( our sun 9 space4 ,= ?is     
motion has be5 det]m9$ by comp>+ !      
motions ( l>ge numb]s ( />s :i* are     
assum$ to be :olly indep5d5t ( ea* o!r1 
& to move1 z x 71 at r&om4 ,miss ,a4,m4 
,cl]ke1 9 h] ,sy/em ( ! ,/>s1 puts ?is  
po9t v cle>ly1 z foll[s3 ',= !          
assumption t ! absolute movem5ts ( ! />s
 h no pref]5ce = "o direction ov] ano!r1
 =ms ! basis ( all inve/igations hi!rto 

conduct$ into ! translatory advance ( ! 
sol> sy/em4 ,! little fabric (          
labori\sly acquir$ k reg>d+ x at once   
crumbles if t basis has to be remov$4 ,9
 all inve/igations ( ! sun's movem5t1 ! 
movem5ts ( ! />s h be5 reg>d$ z casual  
irregul>ities2 %\ld !y prove to be 9 any
 visible degree sy/ematic1 ! mode (     
treatm5t adopt$ 7& !re is no o!r at     
pres5t op5 to u7 becomes invalid1 & its 
results null & void4 ,! po9t is !n (    
s+ul> int]e/1 & ! evid5ce be>+ ^u x     
des]ves our utmo/ att5tion4'  ,mr4      
,w4,h4,s4 ,monck1 a well-kn[n a/ronom]1 
takes ! same view4 ,he says3 ',! pro( ( 
?is motion re/s on ! assumption t if we 
take a suffici5t numb] ( />s1 _! real   
motions 9 all directions w be equal1 & t
 !re=e ! app>5t prepond]ances :i* we    
obs]ve 9 p>ticul> directions result f ! 
real motion ( ! sun4 ,b !re is no       
impossibility 9 a sy/ematic motion ( !  
majority ( ! />s us$ 9 ^! rese>*es :i*  
might reconcile ! obs]v$ facts ) a      
motionless sun4 ,&1 9 ! second place1 if

 ! sun is n 9 ! exact c5tre ( gravity ( 
! univ]se1 we might expect him to be    
mov+ 9 an orbit ar\nd ?is c5tre (       
gravity1 & our obs]vations on 8 actual  
motion are n suffici5tly num]\s or      
accurate to enable u to affirm t he is  
mov+ 9 a "r l9e r ?an su* an orbit4'    
,n[ ?is 'sy/ematic motion1' :i* w\ld    
r5d] all calculations z to ! sun's      
motion inaccurate or ev5 altoge!r       
wor?less1 is by _m a/ronom]s held to be 
an obs]v$ reality4 ,! />-drift1 fir/    
po9t$ out by ,proctor1 has be5 %[n to   
exi/ 9 _m o!r gr\ps ( />s1 :ile ! curi\s
 arrangem5ts ( />s all ov] ! heav5s 9   
/raight l9es1 or regul> curves1 or      
spirals1 /rongly sugge/s a wide ext5sion
 ( ! same k9d ( relation4 ,b ev5 m      
ext5sive sy/ematic movem5ts h be5 obs]v$
 or sugge/$ by a/ronom]s4 ,sir ,d4      
,gill1 by an ext5sive rese>*1 believes t
 he has f\nd indications ( a rotation ( 
! bright] fix$ />s z a :ole 9 reg>d to !
 fa9t] fix$ />s z a :ole4 ,mr4 ,maxwell 
,hall has also f\nd indications ( a     

movem5t ( a l>ge gr\p ( />s1 includ+ our
 sun1 ar\nd a common c5tre1 situat$ 9 a 
direction t[>ds ,epsilon ,&rom$1 & at a 
di/ance ( ab\t #dij ye>s ( light-travel4
 ,^! la/ two motions are n yet e/abli%$2
 b !y seem to prove two important       
facts--7a7 t em95t a/ronom]s believe t  
"s sy/ematic motions mu/ exi/ among !   
/>s1 or !y w\ld n devote s mu* lab\r to 
! se>* = !m2 & 7b7 t ext5sive sy/ematic 
motions ( "s k9d d exi/1 or ev5 ^!      
results w\ld n h be5 obta9$4  ,mr4      
,w4,w4 ,campbell1 ( ! ,lick ,obs]vatory1
 ?us rem>ks on ! unc]ta9ty (            
det]m9ations ( ! sun's motions3 ',!     
motion ( ! sol> sy/em is a purely       
relative quantity4 ,x ref]s to specifi$ 
gr\ps ( />s4 ,! results = v>i\s gr\ps   
may diff] widely1 & all be correct4 ,x  
w\ld be easy to select a gr\p ( />s )   
ref]5ce to :i* ! sol> motion w\ld be    
rev]s$ #ahj f ! values assign$ above'   
7,a/rophysical ,j\rnal1 vol4 xiii4 p4   
#hg4 #aija74  ,x mu/ be rememb]$ t1 )9 a
 uni=m clu/] ( />s1 ea* mov+ r\nd !     

common c5tre ( gravity ( ! :ole clu/]1  
,kepl]'s laws d n prevail1 ! law be+ t !
 angul> velocities are all id5tical1 s t
 ! m di/ant />s move fa/] ?an ^? ne>] ! 
c5tre1 subject to modifications1 h[ev]1 
due to ! v>y+ d5sity ( ! clu/]4 ,b if ! 
clu/] is ne>ly globul>1 !re mu/ be />s  
mov+ r\nd ! c5tre 9 e plane1 & ?is w\ld 
lead to app>5t motions 9 _m directions z
 view$ by u1 al?\gh ^? :i* 7 mov+ 9 !   
same plane z ourselves w\ld1 :5 comp>$ )
 remote />s outside ! clu/]1 appe> to be
 all mov+ 9 ! same direction & at ! same
 rate1 =m+1 9 fact1 "o ( ^? drift+      
sy/ems ( />s already ref]r$ to4 ,aga91  
if 9 ! process ( =mation ( our clu/]1   
small] aggregations already hav+ a      
rotatory motion 7 drawn into x1 ?is     
might lead to _! revolv+ 9 an opposite  
direction to ^? :i* 7 =m$ f ! orig9al   
nebula1 ?us increas+ ! div]sities (     
app>5t motion4  ,! evid5ce n[ briefly   
set =? fully ju/ifies1 ,i submit1 !     
rem>ks z to ! /atem5ts ( my a/ronomical 
critics at ! beg9n+ ( ?is section4 ,!y h

 bo? giv5 ! accept$ views z to direction
 & rate ( movem5t ( our sun )\t any     
qualification :atev]1 z if !y 7         
a/ronomical facts ( ! same c]ta9ty & !  
same degree ( accuracy z ! sun's di/ance
 f ! e>?2 & !y w assur$ly h be5 s       
und]/ood by ! great body (              
non-ma!matical read]s4 ,x appe>s1 h[ev]1
 if ! au?orities ,i h quot$ are "r1 t ! 
:ole calculation re/s ^u c]ta9          
assumptions1 :i* are c]ta9ly to "s      
ext5t1 & may be to a v l>ge ext5t1      
errone\s4 ,?is is my reply to "o "p ( _!
 criticism4  ,9 ! next place1 !y bo?    
ass]t1 or imply1 n only t ! sun's motion
 is n[ 9 a /raight l9e1 b t x has be5 9 
a /raight l9e f "s enorm\sly remote     
p]iod :5 x fir/ ent]$ ! /ell> sy/em on  
"o side1 & w s cont9ue to move till x   
rea*es ! utmo/ b\nds ( t sy/em on ! o!r 
side4 ,& ?is is /at$ by !m bo?1 n z a   
possibility1 b z a c]ta9ty4 ,!y use su* 
t]ms z 'mu/' & 'w be1' leav+ no room =  
any d\bt :atev]4 ,b su* a result implies
 ! abrogation ( ! law ( gravitation1    

s9ce "u its action motion 9 a /raight   
l9e 9 ! mid/ ( ?\s&s or millions ( suns 
( v>i\s sizes is an absolute            
impossibility2 :ile x also implies t !  
sun mu/ h be5 />t$ on its c\rse f "s o!r
 sy/em outside ! ,milky ,way1 ) su* a   
precise det]m9ation ( direction z n to  
collide )1 or ev5 make a ne> approa* to1
 any "o ( ! suns or clu/]s ( suns1 or   
va/ nebul\s masses1 dur+ its passage    
?r\gh ! v mid/ ( ! /ell> univ]se4  ,?is 
is my reply to ! ma9 po9t ( _!          
criticism1 & ,i ?9k ,i am ju/ifi$ 9 say+
 t no?+ 9 my :ole article is s          
demon/rably baseless z ! /atem5ts ,i h  
n[ exam9$4         99       99       99 
99       99  ,consid]+ !n ! :ole be>+ ( 
! evid5ce1 ,i refuse to accept !        
unsupport$ dicta ( ^? :o w\ld h u       
believe t our admitt$ position n f> f ! 
c5tre ( ! /ell> univ]se is a m]e        
tempor>y co9cid5ce ( no significance    
:atev]2 or t our sun & ho/s ( o!r simil>
 orbs ne> to u h come toge!r by an      
accid5t1 & are be+ disp]s$ into surr\nd+

 space1 nev] to meet aga94 ,until ?is is
 prov$ by indisputable evid5ce1 x seems 
to me f> m probable t we are mov+ 9 an  
orbit ( "s k9d ar\nd ! c5tre ( gravity (
 a va/ clu/]1 z det]m9$ by !            
inve/igations ( ,kapteyn1 ,newcomb1 &   
o!r a/ronom]s2 &1 consequ5tly1 t ! ne>ly
 c5tral position we n[ occupy may be a  
p]man5t "o4 ,= ev5 if our sun's orbit   
%\ld h a diamet] a ?\s& times t (       
,neptune1 x w\ld be b a small fraction (
 ! diamet] ( ! ,milky ,way2 :ile s va/  
is ! scale ( our univ]se1 t x might be  
ev5 a hundr$ ?\s& times z great & /ill  
leave u deeply imm]s$ 9 ! sol> clu/]1 & 
v mu* ne>] to ! d5se c5tral portion ?an 
to its m diffus$ out] regions4  ,"h !   
subject may be left = ! pres5t4 ,aft]   
hav+ /udi$ ! evid5ce af=d$ by ! ess5tial
 conditions ( life-developm5t on ! e>?1 
& ! num]\s indications t ^! conditions d
 n exi/ on any ( ! o!r planets ( ! sol> 
sy/em1 x may be aga9 t\*$ ^u 9 a g5]al  
review ( ! conclusions arriv$ at4       
,,footnotes3  #d ,nature1 ,octob] #bf1  

#ahii4  #e ,! ,sy/em ( ! ,/>s1 p4 #che4 
#f ,?is acc\nt ( ,pr(essor ,kapteyn's   
rese>* is tak5 f an article by ,miss    
,a4,m4 ,cl]ke 9 ,k1 ,april #ahic4  #g ,!
 ,/>s1 p4 #bef4 ,! region "h ref]r$ to  
is t :]e ! ,milky ,way has its greate/  
wid? 7?\gh ne>ly z wide 9 ! "p exactly  
opposite71 & :]e x may p]haps ext5d     
some:at 9 our direction4 ,miss ,a4,m4   
,cl]ke in=ms me t 9 ,april #aija        
,kapteyn )drew ! conclusions arriv$ at 9
 #ahic1 z be+ f\nd$ on illegitimate     
reason+ z to ! relation ( p>allaxes to  
prop] motions4 ,b z ?is relation is /ill
 accept$1 "u c]ta9 limitations1 by      
,pr(essor ,newcomb & o!r a/ronom]s1 :o h
 arriv$ indep5d5tly at v simil> results1
 x seems n improbable t1 aft] all1      
,pr(essor ,kapteyn's conclusions may n  
require v mu* modification4 ,pr(essor   
,newcomb also tells u 7,! ,/>s1 p4 #bad1
 footnote7 t he has se5 ! late/ (       
,pr(essor ,kapteyn's pap]s1 d[n to      
#aija2 b he does n !re=e express any    
d\bt z to 8 own conclusions z "h ref]r$ 

to4  #h ,see ,k & ,! ,=tnightly ,review 
( ,april #aijc4  #i ,sir ,r4 ,ball 9 an 
article 9 ,good ,words 7,april #aijc7   
says t lum9osity is an exceptional      
ph5om5on 9 nature1 & t lum9\s />s are b 
! gl[-worms & fire-flies ( ! univ]se1 z 
comp>$ ) ! myriads ( o!r animals4       
,,*apt] ,,ix  ,,! ,,uni=mity ,,( ,,matt]
 ,,& ,,its ,,laws ,,?r\gh\t ,,! ,,/ell> 
,,univ]se   ,i h %[n 9 ! second *apt] ( 
?is "w t none ( ! previ\s writ]s on ! "q
 ( ! habitability ( ! o!r planets h     
really dealt ) ! subject 9 any adequate 
mann]1 s9ce n only d !y appe> to be q   
unaw>e ( ! delicate balance ( conditions
 :i* alone r5d]s organic life possible  
on any planet1 b !y h altoge!r omitt$   
any ref]5ce to ! fact t n only mu/ !    
conditions be su* z to r5d] life        
possible n[1 b ^! conditions mu/ h      
p]si/$ dur+ ! long geological epo*s ne$$
 = ! sl[ developm5t ( life f its mo/    
rudim5t>y =ms4 ,x w !re=e be necess>y to
 ent] into "s details bo? z to !        
physical & *emical ess5tials = a        

cont9u\s developm5t ( organic life1 &   
also into ! comb9ation ( me*anical &    
physical conditions :i* are requir$ on  
any planet to r5d] su* life possible4   
,,! ,,uni=mity ,,( ,,matt]  ,"o ( ! mo/ 
important & f>-rea*+ ( ! discov]ies due 
to ! spectroscope is t ( ! wond]ful     
id5tity ( ! elem5ts & mat]ial comp\nds 9
 e>? & sun1 />s & nebul1 & also ( !     
id5tity ( ! physical & *emical laws t   
det]m9e ! /ates & =ms assum$ by matt]4  
,m ?an half ! total numb] ( ! kn[n      
elem5ts h be5 already detect$ 9 ! sun1  
includ+ all ^? :i* compose ! bulk ( !   
e>?'s solid mat]ial1 ) ! "o exception ( 
oxyg54 ,?is is a v l>ge proportion :5 we
 consid] ! v peculi> conditions :i*     
enable u to detect !m4 ,= we c only     
recognise an elem5t 9 ! sun :5 x exi/s  
at its surface 9 an inc&esc5t /ate1 &   
also above its surface 9 ! =m ( a       
some:at cool] gas4 ,_m ( ! elem5ts may  
r>ely or nev] be br\ght to ! surface ( s
 va/ a body1 or if !y d sometimes appe> 
!re1 x may n be 9 suffici5t quantity or 

9 suffici5t purity to produce any b&s 9 
! spectroscope1 :ile ! cool] gas or     
vap\r may ei!r n be pres5t1 or be s     
disp]s$ z n to produce suffici5t        
absorption to r5d] its spectral l9es    
visible4 ,aga91 x is believ$ t _m       
elem5ts are dissociat$ by ! int5se heat 
( ! sun1 & may n be recognisable by u1  
or !y may only exi/ at its surface 9 a  
comp\nd =m unkn[n on ! e>?2 & 9 "s su*  
way ^? l9es ( ! sol> spectrum :i* rema9 
/ill unrecognis$ may h be5 produc$4 ,"o 
( ^! unkn[n l9es 0 t ( ,helium1 a gas   
f\nd soon aft]w>ds 9 ! r>e m9]al        
',cleveite1' & s9ce detect$ frequ5tly 9 
_m />s4 ,"s ( ! />s h spectra v closely 
resembl+ t ( ! sun4 ,! d>k l9es are     
almo/ z num]\s1 & mo/ ( !m correspond   
accurately ) sol> l9es1 s t we _c d\bt  
_! hav+ almo/ exactly ! same *emical    
con/itution1 & be+ also 9 ! same        
condition z reg>ds heat & /age (        
developm5t4 ,o!r />s1 z we h already    
/at$1 exhibit ma9ly l9es ( hydrog51     
sometimes comb9$ ) f9e metallic l9es4 ,(

 ! spectra ( ! nebul comp>atively little
 is kn[n1 b _m are decid$ly gase\s1 :ile
 o!rs %[ a cont9u\s spectrum indicat+ a 
m complex con/itution4  ,b we also obta9
 consid]able k ( ! matt] ( non-t]re/rial
 bodies by ! analysis ( ! num]\s        
meteorites :i* fall ^u ! e>?4 ,mo/ ( ^! 
belong to "s ( ! _m meteoric /reams :i* 
circulate r\nd ! sun1 & :i* may be      
suppos$ to give u samples ( planet>y    
matt]4 ,b z x is n[ believ$ t _m ( !m   
are produc$ by ! debris ( comets1 & !   
orbits ( "s ( ^! indicate t !y h come f 
/ell> space & h be5 drawn into our sy/em
 by ! attractive p[] ( ! l>g] planets1 x
 is almo/ c]ta9 t ! meteoric /ones n    
infrequ5tly br+ u matt] f ! remot]      
regions ( space1 & probably af=d u      
samples ( ! solid con/itu5ts ( nebula2  
or ! cool] />s4 ,x is1 !re=e1 a mo/     
sugge/ive fact t none ( ^! meteorites h 
be5 f\nd to conta9 a s+le non-t]re/rial 
elem5t1 al?\gh no less ?an tw5ty-f\r    
elem5ts h be5 f\nd 9 !m1 & x w be (     
int]e/ to give ! li/ ( ^!1 z            

foll[s3--,oxyg51 ,hydrog51 ,*lor9e1     
,sulphur1 ,phosphorus1 ,c>bon1 ,silicon1
 ,iron1 ,nickel1 ,cobalt1 ,magnesium1   
,*romium1 ,manganese1 ,copp]1 ,t91      
,antimony1 ,alum9ium1 ,calcium1         
,potassium1 ,sodium1 ,li?ium1 ,titanium1
 ,ars5ic1 & ,vanadium4 ,sev5 ( ! above1 
pr9t$ 9 italics1 h n yet be5 f\nd 9 !   
sun1 su* z ,oxyg51 ,*lor9e1 ,sulphur1 & 
,phosphorus1 :i* =m ! con/itu5ts ( _m   
widespread m9]als1 & !y supply important
 gaps 9 ! s]ies ( sol> & /ell> elem5ts4 
,x may be not$ t al?\gh meteorites h    
suppli$ no new elem5ts1 !y h furni%$    
examples ( "s new comb9ations ( ^!      
elem5ts =m+ m9]als di/9ct f any f\nd 9  
our rocks4  ,! fact ( ! occurr5ce 9     
meteorites n only ( m9]als :i* are      
peculi> to !m or are f\nd on ! e>?1 b   
also ( /ructures resembl+ our breccias1 
ve9s1 & ev5 slick5-side surfaces1 has   
be5 held to be oppos$ to ! meteoritic   
!ory ( ! orig9 ( suns & planets1 because
 meteorites seem to be ?us prov$ to be !
 fragm5ts ( suns or worlds1 n _! prim>y 

con/itu5ts4 ,b ^! cases are exceptional1
 & ,mr4 ,sorby1 :o made a special /udy (
 meteorites1 conclud$ t _! mat]ials h   
usually be5 9 a /ate ( fusion or ev5 (  
vap\r1 z !y n[ exi/ 9 ! sun1 & t !y     
became cond5s$ into m9ute globul>       
p>ticles1 :i* aft]w>ds collect$ into    
l>g] masses1 & may h be5 brok5 up by    
mutual impact1 & aga9 & aga9 become     
aggregat$ toge!r--?us pres5t+ features  
:i* are completely 9 accordance ) !     
meteoritic !ory4  ,b1 q rec5tly1 ,mr4   
,t4,c4 ,*amb]l9 has appli$ ! !ory (     
tidal di/ortion to %[+ h[ solid bodies 9
 space1 )\t ev] com+ into actual        
contact1 mu/ sometimes be torn ap>t or  
disrupt$ into num]\s fragm5ts by pass+  
ne> to ea* o!r4 ,especially :5 a small  
body passes ne> a mu* l>g] "o1 !re is a 
c]ta9 di/ance ( approa* 7t]m$ ! ,ro*e   
limit7 :5 ! increas+ diff]5tial =ce (   
gravity w be suffici5t to te> asund] !  
small] body & cause ! fragm5ts ei!r to  
circulate ar\nd x or to be disp]s$ 9    
space4#aj ,9 ?is way1 !re=e1 ^? l>g]    

meteorites :i* exhibit planet>y /ructure
 may h be5 produc$4 ,( c\rse !y w\ld    
r>ely h be5 true planets atta*$ to a    
sun1 b m frequ5tly "s ( ! small] d>k    
suns1 :i* may possess _m ( ! physical   
*>act]i/ics ( planets1 & ( :i* !re may  
be myriads 9 ! /ell> spaces4  ,on !     
:ole1 !n1 we h positive k ( ! exi/5ce1 9
 ! sun1 />s1 & planet>y & /ell> spaces1 
( su* a l>ge proportion ( ! elem5ts (   
our globe1 & s few indications ( any n  
=m+ "p ( x1 t we are ju/ifi$ 9 !        
/atem5t1 t ! :ole /ell> univ]se is1     
broadly speak+1 con/ruct$ ( ! same s]ies
 ( elem5t>y sub/ances z ^? we c /udy ^u 
our e>?1 & ( :i* ! :ole realm ( nature1 
animal1 vegetable1 & m9]al1 is compos$4 
,! evid5ce ( ?is id5tity ( sub/ance is  
really f> m complete ?an we c\ld expect1
 consid]+ ! v limit$ means ( inquiry t  
we possess2 & we %all1 !re=e1 n be      
ju/ifi$ 9 assum+ t any important        
diff]5ce exi/s4  ,:5 we pass f ! elem5ts
 ( matt] to ! laws :i* gov]n x1 we also 
f9d ! cle>e/ pro(s ( id5tity4 ,t !      

fundam5tal law ( gravitation ext5ds to !
 :ole physical univ]se is r5d]$ almo/   
c]ta9 by ! fact t d\ble />s move r\nd _!
 common c5tre ( gravity 9 elliptical    
orbits :i* correspond well ) bo?        
obs]vation & calculation4 ,t ! laws (   
light are ! same bo? "h & 9             
int]-planet>y space is indicat$ by !    
fact t ! actual measurem5t ( ! velocity 
( light on ! e>?'s surface gives a      
result s completely id5tical ) t        
prevail+ to ! limits ( ! sol> sy/em1 t !
 measurem5t ( ! sun's di/ance1 by means 
( ! eclipses ( ,jupit]'s satellites     
comb9$ ) ! measur$ velocity ( light1    
agrees almo/ exactly ) t obta9$ by means
 ( ! transits ( ,v5us1 or ?r\gh our     
ne>e/ approa* to ! planets ,m>s or      
,eros4  ,aga91 ! m recondite laws (     
light are f\nd to be id5tical 9 sun &   
/>s ) ^? obs]v$ )9 ! n>r[ b\nds (       
laboratory exp]im5ts4 ,! m9ute *ange (  
position ( spectral l9es caus$ by !     
s\rce ( light mov+ t[>ds or away f u    
enables u to det]m9e ?is k9d ( motion 9 

! mo/ di/ant />s1 9 ! planets1 or 9 !   
moon1 & ^! results c be te/$ by ! motion
 ( ! e>? ei!r 9 its orbit or 9 its      
rotation2 & ^! latt] te/s agree ) !     
!oretical det]m9ation ( :at mu/ occur1  
dep5d5t on ! wave-l5g?s ( ! diff]5t d>k 
l9es ( ! sol> spectrum det]m9$ by       
measurem5ts 9 ! laboratory4  ,9 l mann]1
 m9ute *anges 9 ! wid5+ or n>r[+ (      
spectral l9es1 _! splitt+ up1 _!        
increase or decrease 9 numb]1 & _!      
arrangem5t s z to =m flut+s1 c all be   
int]pret$ by exp]im5ts 9 ! laboratory1  
%[+ t su* ph5om5a are due to alt]ations 
( temp]ature1 ( pressure1 or ( !        
magnetic field1 ?us prov+ t ! v same    
physical & *emical laws act 9 ! same way
 "h & 9 ! remote/ dep?s ( space4  ,^!   
v>i\s discov]ies give u ! c]ta9         
conviction t ! :ole mat]ial univ]se is  
ess5tially "o1 bo? z reg>ds ! action (  
physical & *emical laws1 & also 9 its   
me*anical relations ( =m & /ructure4 ,x 
consi/s ?r\gh\t ( ! v same elem5ts ) :i*
 we are s famili> on our e>?2 ! same e!r

 ^: vibrations br+ u light & heat1      
electricity & magnetism1 & a :ole ho/ ( 
o!r my/]i\s & z yet imp]fectly kn[n     
=ces2 gravitation acts ?r\gh\t its va/  
ext5t2 & 9 :atev] direction & by :atev] 
means we obta9 a k ( ! /ell> univ]se1 we
 f9d ! same me*anical1 physical1 &      
*emical laws prevail+ z ^u our e>?1 s t 
we h 9 "s cases be5 actually enabl$ to  
reproduce 9 our laboratories ph5om5a )  
:i* we _h fir/ become acqua9t$ 9 ! sun  
or among ! />s4  ,we may !re=e feel x to
 be an almo/ c]ta9 conclusion t--!      
elem5ts be+ ! same1 ! laws :i* act ^u1 &
 comb9e1 & modify ^? elem5ts be+ !      
same--organis$ liv+ be+s :]ev] !y may   
exi/ 9 ?is univ]se mu/ be1 fundam5tally1
 & 9 ess5tial nature1 ! same also4 ,!   
outw>d =ms ( life1 if !y exi/ else:]e1  
may v>y almo/ inf9itely1 z !y d v>y on !
 e>?2 b1 ?r\gh\t all ?is v>iety ( =m--f 
fungus or moss to rose-bu%1 palm or oak2
 f mollusc1 worm1 or butt]fly to        
humm+-bird1 elephant1 or man--! biologi/
 recognises a fundam5tal unity (        

sub/ance & ( /ructure1 dep5d5t on !     
absolute requirem5ts ( ! gr[+1 mov+1    
develop+1 liv+ organism1 built up ( !   
same elem5ts1 comb9$ 9 ! same           
proportions1 & subject to ! same laws4  
,we d n say t organic life c\ld n exi/  
"u altoge!r div]se conditions f ^? :i*  
we "k or c conceive1 conditions :i* may 
prevail 9 o!r univ]ses con/ruct$ q      
diff]5tly f ours1 :]e o!r sub/ances     
replace ! matt] & e!r ( our univ]se1 &  
:]e o!r laws prevail4 ,b1 )9 ! univ]se  
we "k1 !re is n ! slighte/ reason to    
suppose organic life to be possible1    
except "u ! same g5]al conditions & laws
 :i* prevail "h4 ,we w1 !re=e1 n[ proce$
 to describe1 v g5]ally1 :at are !      
conditions ess5tial to ! exi/5ce & !    
cont9u\s developm5t ( vegetable & animal
 life4  ,,footnote3  #aj ,!             
,a/rophysical ,j\rnal1 vol4 xiv41 ,july 
#aija1 p4 #ag4     ,,*apt] ,x  ,,!      
,,ess5tial ,,*>act]s ,,( ,,! ,,liv+     
,,organism   ,be=e try+ to compreh5d !  
physical conditions on any planet :i*   

are ess5tial = ! developm5t & ma9t5ance 
( a v>i$ & complex sy/em ( organic life 
comp>able to t ( our e>?1 we mu/ obta9  
"s k ( :at life is1 & ( ! fundam5tal    
nature & prop]ties ( ! liv+ organism4   
,physiologi/s & philosoph]s h made _m   
attempts to def9e 'life1' b 9 mo/ cases 
9 aim+ at absolute g5]ality !y h be5    
vague & un9/ructive4 ,?us ,de ,bla9ville
 def9$ x z ',! tw(old int]nal movem5t ( 
composition & decomposition1 at once    
g5]al & cont9u\s'2 :ile ,h]b]t ,sp5c]'s 
late/ def9ition 0 ',life is ! cont9u\s  
adju/m5t ( int]nal relations to ext]nal 
relations4' ,b nei!r ( ^! is suffici5tly
 precise1 explanatory1 or di/9ctive1 &  
!y might almo/ be appli$ to ! *anges    
occurr+ 9 a sun or planet1 or to !      
elevation & gradual =mation ( a cont95t4
 ,"o ( ! olde/ def9itions1 t (          
,ari/otle1 seems to come ne>] ! m>k3    
',life is ! assemblage ( ! op]ations (  
nutrition1 gr[?1 & de/ruction4' ,b ^!   
def9itions ( 'life' are unsatisfactory1 
because !y apply to an ab/ract idea r   

?an to ! actual liv+ organism4 ,! m>vel 
& my/]y ( life1 z we "k x1 resides 9 !  
body :i* manife/s x1 & ?is liv+ body !  
def9itions ignore4  ,! ess5tial po9ts 9 
! liv+ body1 z se5 9 its high]          
developm5ts1 are1 fir/1 t x consi/s     
?r\gh\t ( highly complex b v un/able =ms
 ( matt]1 e p>ticle ( :i* is 9 a        
cont9ual /ate ( gr[? or decay2 t x      
absorbs or appropriates dead matt] f    
)\t2 takes ?is matt] into ! int]ior (   
its body2 acts ^u x me*anically &       
*emically1 reject+ :at is useless or    
hurtful2 & s trans=m+ ! rema9d] z to    
r5ew e atom ( its own /ructure int]nal &
 ext]nal1 at ! same "t ?r[+ (f1 p>ticle 
by p>ticle1 all ! worn-out or dead      
portions ( its own sub/ance4 ,secondly1 
9 ord] to be able to d all ?is1 its :ole
 body is p]meat$ ?r\gh\t by bran*+      
vessels or por\s tissues1 by :i* liquids
 & gases c rea* e "p & c>ry on ! v>i\s  
processes ( nutrition & excretion above 
ref]r$ to4 ,z ,pr(essor ,burdon ,s&]son 
well puts x3 ',! mo/ di/9ctive          

peculi>ity ( liv+ matt] z comp>$ )      
non-liv+ is1 t x is ev] *ang+ :ile ev] !
 same4' ,& ^! *anges are ! m rem>kable  
because !y are accompani$1 & ev5        
produc$1 by a v l>ge am\nt ( me*anical  
"w--9 animals by means ( _! normal      
activities 9 se>* ( food1 9 assimilat+ t
 food1 9 cont9ually r5ew+ & build+ up _!
 :ole organism1 & 9 _m o!r ways2 9      
plants by build+ up _! /ructure1 :i* (t5
 involves rais+ tons ( mat]ial high into
 ! air1 z 9 =e/ trees4 ,z a rec5t writ] 
puts x3 ',! mo/ prom95t1 & p]haps ! mo/ 
fundam5tal1 ph5om5on ( life is :at may  
be describ$ z ! ,en]gy ,traffic or !    
function ( trad+ 9 en]gy4 ,! *ief       
physical function ( liv+ matt] seems to 
consi/ 9 absorb+ en]gy1 /or+ x 9 a high]
 pot5tial /ate1 & aft]w>ds p>tially     
exp5d+ x 9 ! k9etic or active =m4'#aa   
,?irdly--& p]haps mo/ m>vell\s (        
all--all liv+ organisms h ! p[] (       
reproduction or increase1 9 ! l[e/ =ms  
by a process ( self-division or         
'fission1' z x is t]m$1 9 ! high] by    

means ( reproductive cells1 :i*1 ?\gh 9 
_! e>lie/ /age q indi/+ui%able          
physically or *emically 9 v diff]5t     
species1 yet possess ! my/]i\s p[] (    
develop+ a p]fect organism1 id5tical )  
its p>5ts 9 all its p>ts1 %apes1 &      
organs1 & s wond]fully resembl+ !m1 t ! 
m9ute/ di/9ctive details ( size1 =m1 &  
col\r1 9 hair or fea!rs1 9 tee? or      
claws1 9 scales1 sp9es1 or cre/s1 are   
reproduc$ ) v close accuracy1 ?\gh (t5  
involv+ metamorphic *anges dur+ gr[? ( s
 /range a nature t1 if !y 7 n famili> to
 u b 7 n>rat$ z occurr+ only 9 "s di/ant
 & almo/ inaccessible region1 w\ld be   
treat$ z travell]s' tales1 incr$ible &  
impossible z ^? ( ,s9dbad ! ,sailor4  ,9
 ord] t ! sub/ance ( liv+ bodies %\ld be
 able to und]go ^! con/ant *anges :ile  
pres]v+ ! same =m & /ructure 9 m9ute    
details--t !y %\ld be1 z x 71 9 a       
con/ant /ate ( flux :ile rema9+ s5sibly 
un*ang$1 x is necess>y t ! molecules (  
:i* !y are built up %\ld be s comb9$ z  
to be easily sep>at$ & z easily         

unit$--be1 z x is t]m$1 labile or fl[+2 
& ?is is br\ght ab\t by _! *emical      
composition1 :i*1 :ile consi/+ ( few    
elem5ts1 is yet highly complex 9        
/ructure1 a l>ge numb] ( *emical atoms  
be+ comb9$ 9 an endless v>iety ( ways4  
,! physical basis ( life1 z ,huxley t]m$
 x1 is protoplasm1 a sub/ance :i*       
consi/s ess5tially ( only f\r common    
elem5ts1 ! ?ree gases1 nitrog51 hydrog51
 & oxyg51 ) ! non-metallic solid1 c>bon2
 h5ce all ! special products ( plants & 
animals are t]m$ c>bon-comp\nds1 & _!   
/udy con/itutes "o ( ! mo/ ext5sive &   
intricate bran*es ( mod]n *emi/ry4 ,_!  
complexity is indicat$ by ! fact t !    
molecule ( sug> conta9s #de1 & t ( /e>9e
 no less ?an #agc1 con/itu5t atoms4 ,!  
*emical comp\nds ( c>bon are f> m num]\s
 ?an ^? ( all ! o!r *emical elem5ts     
comb9$2 & x is ?is wond]ful v>iety & !  
complexity ( its possible comb9ations   
:i* expla9 ! fact1 t all ! v>i\s animal 
tissues--sk91 horn1 hair1 nails1 tee?1  
muscle1 n]ve1 etc41 consi/ ( ! same f\r 

elem5ts 7) occasionally m9ute quantities
 ( sulphur1 phosphorus1 lime1 or silica1
 9 "s ( !m71 z prov$ by ! m>vell\s fact 
t ^! tissues are all produc$ z well by !
 grass-eat+ %eep or ox z by ! fi% or    
fle%-eat+ seal or tig]4 ,& ! m>vel is   
/ill fur!r increas$ :5 we consid] t !   
innum]able div]se sub/ances produc$ by  
plants & animals are all =m$ out ( !    
same ?ree or f\r elem5ts4 ,su* are !    
endless v>iety ( organic acids1 f       
prussic acid to ^? ( ! v>i\s fruits2 !  
_m k9ds ( sug>s1 gums1 & />*es2 ! numb] 
( diff]5t k9ds ( oil1 wax1 etc42 !      
v>iety ( ess5tial oils :i* are mo/ly =ms
 ( turp5t9es1 ) su* sub/ances z camphor1
 res9s1 ca\t*\c1 & gutta-p]*a2 & !      
ext5sive s]ies ( vegetable alkaloids1   
su* z nicot9e f tobacco1 morph9e f      
opium1 /ry*n9e1 cur>9e1 & o!r poisons2  
qu99e1 belladonna1 & simil> m$ic9al     
alkaloids2 toge!r ) ! ess5tial pr9ciples
 ( our refre%+ dr9ks1 tea1 c(fee1 &     
cocoa1 & o!rs too num]\s to be nam$     
"h--all alike consi/+ solely ( ! f\r    

common elem5ts f :i* almo/ our :ole     
organism is built up4 ,if ?is 7 n       
indisputably prov$1 x w\ld sc>cely be   
cr$it$4  ,pr(essor ,f4,j4 ,all5 consid]s
 t ! mo/ important elem5t 9 protoplasm1 
& t :i* conf]s ^u x its mo/ ess5tial    
prop]ties 9 ! liv+ organism--its extreme
 mobility & transposibility--is nitrog54
 ,?is elem5t1 ?\gh in]t 9 itself1       
readily ent]s into comp\nds :5 en]gy is 
suppli$ to x1 ! mo/ /rik+ illu/ration ( 
:i* is ! =mation ( ammonia1 a comp\nd ( 
nitrog5 & hydrog51 produc$ by electric  
dis*>ges ?r\gh ! atmosph]e4 ,ammonia1 & 
c]ta9 oxides ( nitrog5 produc$ 9 !      
atmosph]e 9 ! same way1 are ! *ief      
s\rces ( ! nitrog5 assimilat$ by plants1
 & ?r\gh !m by animals2 = al?\gh plants 
are cont9ually 9 contact ) ! free       
nitrog5 ( ! atmosph]e1 !y are unable to 
absorb x4 ,by _! leaves !y absorb oxyg5 
& c>bon-dioxide to build up _! woody    
tissues1 :ile by _! roots !y absorb wat]
 9 :i* ammonia & oxides ( nitrog5 are   
dissolv$1 & f ^! !y produce ! protoplasm

 :i* builds up ! :ole sub/ance ( !      
animal _w4 ,! en]gy requir$ to produce  
^! nitrog5-comp\nds is giv5 up by !m :5 
und]go+ fur!r *anges1 & ?us ! production
 ( ammonia by electricity 9 ! atmosph]e1
 & its be+ c>ri$ by ra9 into ! soil1    
con/itute ! fir/ /eps 9 t long s]ies (  
op]ations :i* culm9ates 9 ! production (
 ! high] =ms ( life4  ,b ! rem>kable    
trans=mations & comb9ations cont9ually  
go+ on 9 e liv+ body1 :i* are1 9 fact1 !
 ess5tial conditions ( its life1 are    
!mselves dep5d5t on c]ta9 physical      
conditions :i* mu/ be always pres5t4    
,pr(essor ,all5 rem>ks3 ',! s5sitiv5ess 
( nitrog51 its pron5ess to *ange its    
/ate ( comb9ation & en]gy1 appe> to     
dep5d on c]ta9 conditions ( temp]ature1 
pressure1 etc41 :i* exi/ at ! surface ( 
?is e>?4 ,mo/ vital ph5om5a occur betwe5
 ! temp]ature ( freez+ wat] & #ajd ,f4  
,if ! g5]al temp]ature ( ! e>?'s surface
 rose or fell #gb ,f4 7a small am\nt    
relatively71 ! :ole c\rse ( life w\ld be
 *ang$1 ev5 p]*ance to ext9ction4'      

,ano!r important1 & ev5 m ess5tial fact1
 9 connection ) life1 is ! exi/5ce 9 !  
atmosph]e ( a small b ne>ly con/ant     
proportion ( c>bonic acid gas1 ?is be+ !
 s\rce f :i* ! :ole ( ! c>bon 9 !       
vegetable & animal k+doms is prim>ily   
d]iv$4 ,! leaves ( plants absorb c>bonic
 acid gas f ! atmosph]e1 & ! peculi>    
sub/ance1 *lorophyll1 f :i* !y d]ive _! 
gre5 col\r1 has ! p[]1 "u ! influ5ce (  
sunlight1 to decompose x1 us+ ! c>bon to
 build up its own /ructure & giv+ out ! 
oxyg54 ,9 ! laboratory ! c>bon c only be
 sep>at$ f ! oxyg5 by ! application (   
heat1 "u :i* c]ta9 metals burn by comb9+
 ) ! oxyg51 ?us sett+ free ! c>bon4     
,*lorophyll has a highly complex *emical
 /ructure v imp]fectly kn[n1 b x is said
 to be only produc$ :5 !re is iron 9 !  
soil4  ,! leaves ( plants1 s (t5 look$  
^u z m]e ornam5tal app5dages1 are among 
! mo/ m>vell\s /ructures 9 liv+         
organisms1 s9ce 9 decompos+ c>bonic acid
 at ord9>y temp]atures !y d :at no o!r  
ag5cy 9 nature c p]=m4 ,9 do+ ?is !y    

utilise a special gr\p ( e!r-waves :i*  
alone appe> to h ?is p[]4 ,! complexity 
( ! processes go+ on 9 leaves is well   
indicat$ 9 ! foll[+ quotation3--  ',we h
 se5 h[ gre5 leaves are suppli$ ) gases1
 wat]1 & dissolv$ salts1 & h[ !y c trap 
special e!r-waves4 ,! active en]gy ( ^! 
waves is us$ to transmute ! simple      
inorganic comp\nds into complex organic 
ones1 :i* 9 ! process ( respiration are 
r$uc$ to simpl] sub/ances aga91 & !     
pot5tial en]gy trans=m$ into k9etic4 ,^!
 metabolic *anges take place 9 liv+     
cells full ( int5se activities4 ,curr5ts
 c\rse ?r\gh ! protoplasm & cell-sap 9 e
 direction1 & betwe5 ! cells :i* are    
also unit$ by /r&s ( protoplasm4 ,!     
gases us$ & giv5 (f 9 respiration &     
assimilation are float$ 9 & out1 & ea*  
protoplasm p>ticle burn$ or unburn$ is !
 c5tre ( an area ( di/urbance4 ,pure    
protoplasm is influ5c$ equally by all   
rays3 t associat$ ) *lorophyll is       
affect$ by c]ta9 r$ & violet rays 9     
p>ticul>4 ,^!1 especially ! r$ ones1 br+

 ab\t ! dissociation ( ! elem5ts ( !    
c>bonic acid1 ! assimilation ( ! c>bon1 
& ! excretion ( ! oxyg54'#ab  ,x is ?is 
vigor\s life-activity ev] at "w 9 !     
leaves1 ! roots1 & ! sap-cells1 t builds
 up ! plant1 9 all its wondr\s beauty ( 
bud & foliage1 fl[] & fruit2 & at ! same
 "t produces1 ei!r z useful or          
wa/e-products1 all t weal? ( od\rs &    
flav\rs1 ( col\rs & textures1 ( fibres &
 v>i$ woods1 ( roots & tub]s1 ( gums &  
oils & res9s innum]able1 t1 tak5        
altoge!r1 r5d] ! _w ( vegetable life    
p]haps m v>i$1 m beautiful1 m enjoyable1
 m indisp5sable to our high] nature ?an 
ev5 t ( animals4 ,b !re is really no    
comp>ison betwe5 !m4 ,we c\ld h plants  
)\t animals2 we c\ld n h animals )\t    
plants4 ,& all ?is m>vel & my/]y (      
vegetable life1 a my/]y :i* we r>ely    
pond] ov] because its effects are s     
famili>1 is usually held to be          
suffici5tly expla9$ by ! /atem5t t x is 
all due to ! special prop]ties (        
protoplasm4 ,well might ,huxley say1 t  

protoplasm is n only a sub/ance b a     
/ructure or me*anism1 a me*anism kept at
 "w by sol> heat & light1 & capable (   
produc+ a ?\s& times m v>i$ & m>vell\s  
results ?an all ! human me*anism ev]    
inv5t$4  ,b besides absorb+ c>bonic acid
 f ! atmosph]e1 sep>at+ & utilis+ !     
c>bon & giv+ out ! oxyg51 plants z well 
z animals cont9ually absorb oxyg5 f !   
atmosph]e1 & ?is is s univ]sally ! case 
t oxyg5 is said to be ! food (          
protoplasm1 )\t :i* x _c cont9ue to     
live2 & x is ! peculi> b q invisible    
/ructure ( ! protoplasm :i* enables x to
 d ?is1 & also 9 plants to absorb an    
enorm\s am\nt ( wat] z well4  ,b al?\gh 
protoplasm is s complex *emically z to  
defy exact analysis1 be+ an elaborate   
/ructure ( atoms built up into a        
molecule 9 :i* ea* atom mu/ occupy its  
true place 7l e c>v$ /one 9 a ,go?ic    
ca!dral71 yet x is1 z x 71 only !       
/>t+-po9t or mat]ial out ( :i* !        
inf9itely v>i$ /ructures ( liv+ bodies  
are =m$4 ,! extreme mobility &          

*angeability ( ! /ructure ( ^! molecules
 enables ! protoplasm to be cont9ually  
modifi$ bo? 9 con/itution & =m1 &1 by ! 
sub/itution or addition ( o!r elem5ts1  
to s]ve special purposes4 ,?us :5       
sulphur 9 small quantities is absorb$ & 
built into ! molecul> /ructure1 proteids
 are =m$4 ,^! are mo/ abundant 9 animal 
/ructures1 & give ! n\ri%+ prop]ties to 
meat1 *eese1 eggs1 & o!r animal foods2 b
 !y are also f\nd 9 ! vegetable k+dom1  
especially 9 nuts & se$s su* z gra91    
peas1 etc4 ,^! are g5]ally kn[n z       
nitrog5\s foods1 & are v nutriti\s1 b n 
s easily dige/ible z meat4 ,proteids    
exi/ 9 v v>i$ =ms & (t5 conta9          
phosphorus z well z sulphur1 b _! ma9   
*>act]i/ic is ! l>ge proportion (       
nitrog5 !y conta91 :ile _m o!r animal & 
vegetable products1 z mo/ roots1 tub]s1 
& gra9s1 & ev5 fats & oils1 are ma9ly   
compos$ ( />* & sug>4 ,9 its *emical &  
physiological aspects prote9 is ?us     
describ$ by ,pr(essor ,w4,d4            
,haliburton3--',proteids are produc$    

only 9 ! liv+ laboratory ( animals &    
plants2 proteid matt] is ! all-important
 mat]ial pres5t 9 protoplasm4 ,?is      
molecule is ! mo/ complex t is kn[n2 x  
always conta9s five & (t5 six or ev5    
sev5 elem5ts4 ,! task ( ?or\ghly und]/&+
 its composition is necess>ily va/1 &   
advance sl[4 ,b1 little by little1 !    
puzzle is be+ solv$1 & ?is f9al conque/ 
( organic *emi/ry1 :5 x does arrive1 w  
furni% physiologi/s ) new light on _m ( 
! d>k places ( physiological sci5ce4'#ac
  ,:at makes protoplasm & its           
modifications /ill m m>vell\s is ! p[] x
 possesses ( absorb+ & m\ld+ a numb] (  
o!r elem5ts 9 v>i\s p>ts ( liv+         
organisms = special uses4 ,su* are      
silica 9 ! /ems ( ! grass family1 lime &
 magnesia 9 ! bones ( animals1 iron 9   
blood1 & _m o!rs4 ,besides ! f\r elem5ts
 con/itut+ protoplasm1 mo/ animals &    
plants conta9 also 9 "s p>ts ( _!       
/ructure sulphur1 phosphorus1 *lor9e1   
silicon1 sodium1 potassium1 calcium1    
magnesium1 & iron2 :ile1 less frequ5tly1

 fluor9e1 iod9e1 brom9e1 li?ium1 copp]1 
manganese1 & alum9ium are also f\nd 9   
special organs or /ructures2 & !        
molecules ( all ^! are c>ri$ by !       
protoplasmic fluids to ! places :]e !y  
are requir$ & built into ! liv+         
/ructure1 ) ! same precision & = simil> 
ends z brick & /one1 iron1 slate1 wood1 
& glass are ea* utilis$ 9 _! prop]      
places 9 any l>ge build+4#ad ,!         
organism1 h[ev]1 is n built1 b gr[s4 ,e 
organ1 e fibre1 cell1 or tissue is =m$ f
 div]se mat]ials1 :i* are fir/ decompos$
 into _! elem5t>y molecules1 trans=m$ by
 ! protoplasm or by special solv5ts =m$ 
f x1 c>ri$ to ! places :]e !y are ne$$  
by ! vital fluids1 & !re built up atom  
by atom or molecule by molecule into !  
special /ructures ( :i* !y are to =m a  
"p4  ,b ev5 ?is m>vel ( gr[? & repair ( 
e individual organism is f> surpass$ by 
! great] m>vel ( reproduction4 ,e liv+  
?+ ( ! high] ord]s arises f a s+le      
microscopic cell1 :5 f]tilis$1 z x is   
t]m$1 by ! absorption ( ano!r           

microscopic cell d]iv$ f a diff]5t      
individual4 ,^! cells are (t51 ev5 "u ! 
highe/ p[]s ( ! microscope1 h>dly       
di/+ui%able f o!r cells :i* occur 9 all 
animals & plants & ( :i* _! /ructure is 
built up2 yet ^! special cells beg9 to  
gr[ 9 a totally diff]5t mann]1 & in/ead 
( =m+ "o p>ticul> "p ( ! organism1      
develop inevitably into a complete liv+ 
?+ ) all ! organs1 p[]s1 & peculi>ities 
( its p>5ts1 s z to be recognisably ( ! 
same species4 ,if ! simple gr[? ( !     
fully =m$ organism is a my/]y1 :at ( ?is
 gr[? ( ?\s&s ( complex organisms ea* ) 
all its special peculi>ities1 yet all   
aris+ f m9ute g]ms or cells ! div]se    
natures ( :i* are :olly indi/+ui%able by
 ! highe/ p[]s ( ! microscope8 ,?is1    
too1 is said to be ! "w ( protoplasm "u 
! influ5ce ( heat & moi/ure1 & mod]n    
physiologi/s hope "s day to le>n 'h[ x  
is done4' ,x may be well "h to give !   
views ( a mod]n writ] on ?is po9t4      
,ref]r+ to a difficulty :i* _h be5 /at$ 
by ,cl]k-,maxwell tw5ty-five ye>s ago1 t

 !re 0 n room 9 ! reproductive cell = ! 
millions ( molecules ne$$ to s]ve z !   
units ( gr[? = all ! diff]5t /ructures 9
 ! body ( ! high] animals1 ,pr(essor    
,m',k5drick says3--',b to-day1 x is     
reasonable f exi/+ data to suppose t !  
g]m9al vesicle might conta9 a million ( 
millions ( organic molecules4 ,complex  
arrangem5ts ( ^! molecules suit$ = !    
developm5t ( all ! p>ts ( a highly      
complicat$ organism1 might satisfy all !
 dem&s ( ! !ory ( h]$ity4 ,d\btless !   
g]m 0 a mat]ial sy/em ?r\gh & ?r\gh4 ,! 
conception ( ! physici/ 01 t molecules 7
 9 v>i\s /ates ( movem5t2 & ! ?9k]s 7   
/riv+ t[>d a k9etic !ory ( molecules & (
 atoms ( solid matt]1 :i* might be z    
fruitful z ! k9etic !ory ( gases4 ,!re 7
 motions atomic & molecul>4 ,x 0        
conceivable t ! peculi>ities ( vital    
action might be det]m9$ by ! k9d (      
motion t took place 9 ! molecules ( :at 
we call liv+ matt]4 ,x might be diff]5t 
9 k9d f "s ( ! motions dealt ) by       
physici/s4 ,life is cont9ually be+      

creat$ f non-liv+ mat]ial--su*1 at lea/1
 is ! exi/+ view ( gr[? by !            
assimilation ( food4 ,! creation ( liv+ 
matt] out ( non-liv+ may be !           
transmission to ! dead matt] ( molecul> 
motions :i* are sui g5]is 9 =m4' ,?is is
 ! mod]n physiological view ( 'h[ x may 
be done1' & x seems h>dly m intelligible
 ?an ! v old !ory ( ! orig9 ( /one axes1
 giv5 by ,adrianus ,tollius 9 #afdi1 &  
quot$ by ,mr4 ,e4,b4 ,tylor1 :o         
says3--',he gives draw+s ( "s ord9>y    
/one axes & hamm]s & tells h[ naturali/s
 say t !y are g5]at$ 9 ! sky by a       
fulgure\s exhalation conglob$ 9 a cl\d  
by ! circumfix$ hum\r1 & are1 z x 71    
bak$ h>d by int5se heat1 & ! weapon     
becomes po9t$ by ! damp mix$ ) x fly+ f 
! dry "p1 & leav+ ! o!r end d5s]1 b !   
exhalations press x s h>d t x breaks    
?r\gh ! cl\d & makes ?und] & lightn+4   
,b--he says--if ?is is really ! way 9   
:i* !y are g5]at$1 x is odd !y are n    
r\nd1 & t !y h holes ?r\gh !m4 ,x is    
h>dly to be believ$1 he ?9ks4'#ae ,& s1 

:5 ! physiologi/s1 det]m9$ to avoid !   
assumption ( any?+ beyond matt] & motion
 9 ! g]m1 impute ! :ole developm5t &    
gr[? ( ! elephant or ( man f m9ute cells
 int]nally alike1 by means ( 'k9ds (    
motion' & ! 'transmission ( motions :i* 
are sui g5]is 9 =m1' _m ( u w be incl9$ 
to say ) ! old au?or--',x is h>dly to be
 believ$1 ,i ?9k4'  ,?is brief /atem5t (
 ! conclusions arriv$ at by *emi/s &    
physiologi/s z to ! composition &       
/ructure ( organis$ liv+ ?+s has be5    
?\ght advisable1 because ! non-sci5tific
 read] has (t5 no conception ( !        
incomp>able m>vel & my/]y ( !           
life-processes he has always se5 go+ on1
 sil5tly & almo/ unnotic$1 9 ! _w ar\nd 
him4 ,& ?is is /ill m ! case n[ t       
two-?irds ( our population are cr[d$    
into cities :]e1 remov$ f all !         
occupations1 ! *>ms1 & ! int]e/s (      
c\ntry life1 !y are driv5 to seek       
occupation & excitem5t 9 ! !atre1 !     
music-hall1 or ! tav]n4 ,h[ little d ^! 
"k :at !y lose by be+ ?us %ut out f all 

quiet int]c\rse ) nature2 its soo?+     
sights & s\nds2 its exquisite beauties (
 =m & col\r2 its endless my/]ies ( bir?1
 & life1 & dea?4 ,mo/ p give sci5tific  
m5 cr$it = mu* great] k ?an !y possess 9
 ^! matt]s2 & _m educat$ read]s w1 ,i   
feel sure1 be surpris$ to f9d t ev5 su* 
app>5tly simple ph5om5a z ! rise ( ! sap
 9 trees are n yet completely expla9$4  
,z to ! deep] problems ( life1 & gr[?1 &
 reproduction1 ?\gh our physiologi/s h  
le>n$ an inf9ite am\nt ( curi\s or      
in/ructive facts1 !y c give u no        
intelligible explanation ( !m4  ,!      
endless complexities & confus+ am\nt (  
detail 9 all treatises on ! physiology (
 animals & plants are su*1 t ! av]age   
read] is ov]:elm$ ) ! mass ( k pres5t$  
to him1 & concludes t aft] su* elaborate
 rese>*es ev]y?+ mu/ be kn[n1 & t !     
almo/ univ]sal prote/s aga9/ ! ne$ ( any
 causes b ! me*anical1 physical1 &      
*emical laws & =ces are well f\nd$4 ,i  
h1 !re=e1 ?\ght x advisable to pres5t a 
k9d ( bird's-eye view ( ! subject1 & to 

%[1 9 ! words ( ! greate/ liv+          
au?orities on ^! matt]s1 bo? h[ complex 
are ! ph5om5a & h[ f> our tea*]s are f  
be+ able to give u any adequate         
explanation ( !m4  ,i v5ture to hope t !
 v brief sket* ( ! subject ,i h be5 able
 to give w enable my read]s to =m "s    
fa9t g5]al conception ( ! inf9ite       
complexity ( life & ! v>i\s problems    
connect$ ) x2 & t !y w ?us be ! bett]   
enabl$ to appreciate ! extreme delicacy 
( ^? adju/m5ts1 ^? =ces1 & ^? complex   
conditions ( ! environm5t1 t alone r5d] 
life1 & above all ! gr& age-long        
panorama ( ! developm5t ( life1 9 any   
way possible4 ,x is to ^! conditions1 z 
!y prevail 9 ! _w ar\nd u1 t we w n[    
direct our att5tion4  ,,footnotes3  #aa 
,pr(essor ,f4,j4 ,all53 ,:at is ,life8  
#ab ,art4 ',vegetable ,physiology' 9    
,*amb]s's ,encyclopdia4  #ac ,address to
 ! ,briti% ,association1 #aijb1 ,section
 ,physiology4  #ad ,?is enum]ation ( !  
elem5ts t ent] into ! /ructure ( plants 
& animals is tak5 f ,pr(essor ,f4,j4    

,all5's pap] already ref]r$ to4  #ae    
,e>ly ,hi/ory ( ,mank9d1 #bnd ed4 p4    
#bbg4     ,,*apt] ,,xi  ,,! ,,physical  
,,conditions ,,ess5tial ,,= ,,organic   
,,life   ,! physical conditions on !    
surface ( our e>? :i* appe> to be       
necess>y = ! developm5t & ma9t5ance (   
liv+ organisms may be dealt ) "u !      
foll[+ head+s3--  #a4 ,regul>ity (      
heat-supply1 result+ 9 a limit$ range ( 
temp]ature4  #b4 ,a suffici5t am\nt (   
sol> light & heat4  #c4 ,wat] 9 great   
abundance1 & univ]sally di/ribut$4  #d4 
,an atmosph]e ( suffici5t d5sity1 &     
consi/+ ( ! gases :i* are ess5tial =    
vegetable & animal life4 ,^! are ,oxyg51
 ,c>bonic-acid gas1 ,aque\s vap\r1      
,nitrog51 & ,ammonia4 ,^! mu/ all be    
pres5t 9 suitable proportions4  #e4     
,alt]nations ( day & night4   ,,small   
,,range ,,( ,,temp]ature ,,requir$ ,,=  
,,gr[? ,,& ,,developm5t  ,vital ph5om5a 
= ! mo/ "p occur betwe5 ! temp]atures ( 
freez+ wat] & #ajd ,fahr41 & ?is is     
suppos$ to be due ma9ly to ! prop]ties (

 nitrog5 & its comp\nds1 :i* betwe5 ^!  
temp]atures only c ma9ta9 ^?            
peculi>ities :i* are ess5tial to        
life--extreme s5sitiv5ess & lability2   
facility ( *ange z reg>ds *emical       
comb9ation & en]gy2 & o!r prop]ties :i* 
alone r5d] nutrition1 gr[?1 & cont9ual  
repair possible4 ,a v small increase or 
decrease ( temp]ature beyond ^! limits1 
if cont9u$ = any consid]able "t1 w\ld   
c]ta9ly de/roy mo/ exi/+ =ms ( life1 &  
w\ld n improbably r5d] any fur!r        
developm5t ( life impossible except 9 "s
 ( its l[e/ =ms4  ,z "o example ( !     
direct effects ( increas$ temp]ature1 we
 may adduce ! coagulation ( album54 ,?is
 sub/ance is "o ( ! proteids1 & plays an
 important "p 9 ! vital ph5om5a ( bo?   
plants & animals1 & its fluidity & p[] (
 easy comb9ation & *ange ( =m are lo/ by
 any degree ( coagulation :i* takes     
place at ab\t #afj ,fahr4  ,! extreme   
importance to all ! high] organisms ( a 
mod]ate temp]ature is /rik+ly %[n by !  
complex & successful arrangem5ts =      

ma9ta9+ a uni=m degree ( heat 9 !       
int]ior ( ! body4 ,! normal blood-heat 9
 a man is #ih ,fahr41 & ?is is con/antly
 ma9ta9$ )9 "o or two degrees ?\gh !    
ext]nal temp]ature may be m ?an fifty   
degrees bel[ ! freez+-po9t4 ,high       
temp]atures ^u ! e>?'s surface d n range
 s f> f ! mean z d ! l[4 ,9 ! great] "p 
( ! tropics ! air-temp]ature seldom     
rea*es #if ,fahr41 ?\gh 9 arid di/ricts 
& des]ts1 :i* occur *iefly along ! m>g9s
 ( ! nor!rn & s\!rn tropics1 x n        
unfrequ5tly surpasses #aaj ,fahr41 & ev5
 occasionally rises to #aae or #abj 9   
,au/ralia & ,c5tral ,india4 ,yet )      
suitable food & mod]ate c>e !           
blood-temp]ature ( a heal?y man w\ld n  
rise or fall m ?an "o or at mo/ two     
degrees4 ,! great importance ( ?is      
uni=mity ( temp]ature 9 all ! vital     
organs is di/9ctly %[n by ! fact t :51  
dur+ fev]s1 ! temp]ature ( ! pati5t     
rises six degrees above ! normal am\nt1 
8 condition is critical1 :ile an        
increase ( sev5 or eight degrees is an  

almo/ c]ta9 indication ( a fatal result4
 ,ev5 9 ! vegetable k+dom se$s w n      
g]m9ate "u a temp]ature ( f\r or five   
degrees above ! freez+-po9t4  ,n[ ?is   
extreme s5sibility to v>iations (       
int]nal temp]ature is q intelligible :5 
we consid] ! complexity & in/ability (  
protoplasm1 & ( all ! proteids 9 ! liv+ 
organism1 & h[ important x is t !       
processes ( nutrition & gr[?1 involv+   
con/ant motion ( fluids & incessant     
molecul> decompositions & recomb9ations1
 %\ld be effect$ ) ! greate/ regul>ity4 
,& ?\gh a few ( ! high] animals1 includ+
 man1 are s p]fectly organis$ t !y c    
adapt or protect !mselves s z to be able
 to live "u v extreme conditions z      
reg>ds temp]ature1 yet ?is is n ! case )
 ! great majority1 or ) ! l[] types1 z  
evid5c$ by ! almo/ complete abs5ce (    
reptiles f ! arctic regions4  ,x mu/    
also be rememb]$ t extreme cold &       
extreme heat are n[h]e p]petual4 ,!re is
 always "s div]sity ( seasons1 & !re is 
no l& animal :i* passes its :ole life   

:]e ! temp]ature nev] rises above !     
freez+ po9t4   ,,! ,,necessity ,,(      
,,sol> ,,light  ,:e!r ! high] animals & 
man c\ld h be5 develop$ ^u ! e>? )\t    
sol> light1 ev5 if all ! o!r ess5tial   
conditions 7 pres5t1 is d\btful4 ,t1    
h[ev]1 is n ! po9t ,i am at pres5t      
consid]+1 b "o t is mu* m fundam5tal4   
,)\t plant life l& animals at all ev5ts 
c\ld nev] h come into exi/5ce1 because  
!y h n ! p[] ( mak+ protoplasm out (    
inorganic matt]4 ,! plant alone c take !
 c>bon out ( ! small proportion (       
c>bonic acid 9 ! atmosph]e1 & ) x1 & !  
o!r necess>y elem5ts1 z already         
describ$1 build up ^? wond]ful c>bon    
comp\nds :i* are ! v f\ndation ( animal 
life4 ,b x does ?is solely by ! ag5cy ( 
sol> light1 & ev5 uses a special portion
 ( t light4 ,n only1 !re=e1 is a sun    
ne$$ to give light & heat1 b x is q     
possible t any sun w\ld n answ] !       
purpose4 ,a sun is requir$ ^: light     
possesses ^? special rays :i* are       
effective = ?is op]ation1 & z we "k t ! 

/>s diff] greatly 9 _! spectra1 & !re=e 
9 ! nature ( _! light1 all might n be   
able to effect ?is great trans=mation1  
:i* is "o ( ! v fir/ /eps 9 r5d]+ animal
 life possible on our e>?1 & !re=e      
probably on all e>?s4   ,,wat] ,a ,,fir/
 ,,ess5tial ,,( ,,organic ,,life  ,x is 
h>dly necess>y to po9t out ! absolute   
necessity ( wat]1 s9ce x actually       
con/itutes a v l>ge proportion ( !      
mat]ial ( e liv+ organism1 & ab\t       
?ree-f\r?s ( our own bodies4 ,wat]1     
!re=e1 mu/ be pres5t ev]y:]e1 9 "o =m or
 ano!r1 on any globe :]e life is        
possible4 ,nei!r animal nor plant c exi/
 )\t x4 ,x mu/ also be pres5t 9 su*     
quantity & s di/ribut$ z to be con/antly
 available on e "p ( a globe :]e life is
 to be ma9ta9$2 & x is equally necess>y 
t x %\ld h p]si/$ 9 equal pr(usion      
?r\gh\t ^? enorm\s geological epo*s dur+
 :i* life has be5 develop+4 ,we %all see
 lat] on h[ v special are ! conditions t
 h secur$ ?is cont9u\s di/ribution (    
wat] on our e>?1 & we %all also le>n t  

?is l>ge am\nt ( wat]1 its wide         
di/ribution1 & its arrangem5t ) reg>d to
 ! l&-surface1 is an ess5tial factor 9  
produc+ t limit$ range ( temp]ature :i*1
 z we h se51 is a prim>y condition = !  
developm5t & ma9t5ance ( life4   ,,!    
,,atmosph]e ,,mu/ ,,be ,,( ,,suffici5t  
,,d5sity ,,& ,,compos$ ,,( ,,suitable   
,,gases  ,! atmosph]e ( any planet on   
:i* life c be develop$ mu/ h sev]al     
qualities :i* are unconnect$ ) ea* o!r1 
& ! co9cid5ce ( :i* may be a r>e        
ph5om5on 9 ! univ]se4 ,! fir/ ( ^! is a 
suffici5t d5sity1 :i* is requir$ = two  
purposes--z a /or] ( heat1 & 9 ord] to  
supply ! oxyg51 c>bonic acid1 & aque\s  
vap\r 9 suffici5t quantities = !        
requirem5ts ( vegetable & animal life4  
,z a res]voir ( heat & a regulator (    
temp]ature1 a r d5se atmosph]e is a fir/
 necessity1 9 co-op]ation ) ! l>ge      
quantity & wide di/ribution ( wat]      
ref]r$ to 9 ! la/ section4 ,! v diff]5t 
"* ( our s\?-we/ f our nor?-ea/ w9ds is 
a good illu/ration ( its p[] ( di/ribut+

 heat & moi/ure4 ,?is x does ow+ to !   
peculi> prop]ty x possesses ( all[+ !   
sun's rays to pass freely ?r\gh x to !  
e>? :i* x w>ms1 b act+ l a blanket 9    
prev5t+ ! rapid escape ( ! non-lum9\s   
heat s produc$4 ,b ! heat /or$ up dur+ !
 day is giv5 out at night1 & ?us secures
 a uni=mity ( temp]ature :i* w\ld n     
o!rwise exi/4 ,?is effect is /rik+ly se5
 at high altitudes1 :]e ! temp]ature    
becomes l[] & l[]1 till at a n v great  
elevation1 ev5 9 ! tropics1 sn[ lies on 
! gr\nd all ! ye> r\nd4 ,?is is almo/   
:olly due to ! r>ity ( ! air1 :i*1 on t 
acc\nt1 has n s mu* capacity = heat4 ,x 
also all[s ! heat x acquires to radiate 
m freely ?an d5s] air1 s t ! nights are 
mu* cold]4 ,at ab\t #ah1jjj feet high   
our atmosph]e is exactly half its d5sity
 at ! sea-level4 ,?is is consid]ably    
high] ?an ! usual sn[-l9e1 ev5 "u !     
equator1 :5ce x foll[s t if our         
atmosph]e 0 only half its pres5t d5sity 
x w\ld r5d] ! e>? unsuitable = ! high]  
=ms ( animal life4 ,x is n easy to say  

exactly :at w\ld be ! result z reg>ds   
climate2 b x seems likely t1 except     
p]haps 9 limit$ areas 9 ! tropics1 :]e  
conditions 7 v fav\rable1 ! :ole        
l&-surface w\ld become buri$ 9 sn[ &    
ice4 ,?is appe>s inevitable1 because    
evaporation f ! oceans by direct        
sun-heat w\ld be m rapid ?an n[2 b z !  
vap\r rose 9 ! r>e atmosph]e x w\ld     
rapidly become froz51 & sn[ w\ld fall   
almo/ p]petually1 al?\gh x might n lie  
p]man5tly on ! gr\nd 9 ! equatorial     
l[l&s4 ,x appe>s c]ta91 !re=e1 t ) half 
our pres5t bulk ( atmosph]e life w\ld be
 h>dly possible on ! e>? on acc\nt (    
l[]$ temp]ature alone4 ,& z !re w\ld    
c]ta9ly be an add$ difficulty 9 ! ne$ful
 supply ( oxyg5 to animals & c>bonic    
acid to plants1 x seems highly probable 
t a r$uction ( d5sity ( ev5 "o-f\r?     
might be suffici5t to r5d] a l>ge       
portion ( ! globe a sn[ & ice-clad wa/e1
 & ! rema9d] liable to su* extremes (   
climate t only l[ =ms ( life c\ld h     
aris5 & be5 p]man5tly ma9ta9$4   ,,!    

,,gases ,,( ,,! ,,atmosph]e  ,com+ n[ to
 consid] ! con/itu5t gases ( !          
atmosph]e1 !re is reason to believe t !y
 =m a mixture z nicely balanc$ 9 reg>d  
to animal & vegetable life z are !      
d5sity & ! temp]ature4 ,at a fir/ view (
 ! subject we might conclude t oxyg5 is 
! "o great ess5tial = animal life1 & t  
all else is ( little importance4 ,b     
fur!r consid]ation %[s u t nitrog51     
al?\gh m]ely a dilu5t ( ! oxyg5 z reg>ds
 ! respiration ( animals1 is ( ! fir/   
importance to plants1 :i* obta9 x f !   
ammonia =m$ 9 ! atmosph]e & c>ri$ d[n   
into ! soil by ! ra94 ,al?\gh !re is    
only "o "p ( ammonia to a million ( air1
 yet ^u ?is m9ute proportion ! v exi/5ce
 ( ! animal _w dep5ds1 because nei!r    
animals nor plants c assimilate ! free  
nitrog5 ( ! air into _! tissues4  ,ano!r
 fundam5tally important gas 9 !         
atmosph]e is c>bonic acid1 :i* =ms ab\t 
f\r p>ts 9 t5 ?\s& p>ts ( air1 &1 z     
already /at$1 is ! s\rce f :i* plants   
build up ! great bulk ( _! tissues1 z   

well z ^? protoplasms & proteids s      
absolutely necess>y z food = animals4   
,an important fact to notice "h is1 t   
c>bonic acid1 s ess5tial to plants1 & to
 animals ?r\gh plants1 is yet a poison  
to animals4 ,:5 pres5t 9 mu* m ?an !    
normal quantity1 z x (t5 is 9 cities & 9
 badly v5tilat$ build+s1 x becomes      
highly prejudicial to heal?2 b ?is is   
believ$ to be p>tly due to ! v>i\s      
corporeal emanations & o!r impurities   
associat$ ) x4 ,pure c>bonic acid gas to
 ! am\nt ( ev5 "o p] c5t4 9 o!rwise pure
 air c1 x is said1 be brea!d = a "t )\t 
bad effects1 b any?+ m ?an ?is          
proportion w soon produce suffocation4  
,x is probable1 !re=e1 t a v mu* small] 
proportion ?an "o p] c5t41 if con/antly 
pres5t1 w\ld be dang]\s to life2 ?\gh no
 d\bt1 if ?is _h always be5 !           
proportion1 life might h be5 develop$ 9 
adaptation to x4 ,consid]+1 h[ev]1 t ?is
 poison\s gas is l>gely giv5 out by !   
high] animals z a product ( respiration1
 x w\ld evid5tly be dang]\s to !        

p]man5ce ( life if ! quantity =m+ a     
con/ant con/itu5t ( ! atmosph]e 7 mu*   
great] ?an x is4   ,,aque\s ,,vap\r ,,9 
,,! ,,atmosph]e  ,?is wat]-gas1 al?\gh x
 occurs 9 ! atmosph]e 9 l>gely v>y+     
quantities1 is yet1 9 two di/9ct ways1  
ess5tial to organic life4 ,x prev5ts !  
too rapid loss ( moi/ure f ! leaves (   
plants :5 expos$ to ! sun1 & x is also  
absorb$ by ! upp] surface ( ! leaf & by 
! "y %oots1 :i* ?us obta9 bo? wat] &    
m9ute quantities ( ammonia :5 ! supply  
by ! roots is insuffici5t4 ,b x is ( ev5
 m vital importance 9 supply+ ! hydrog5 
:i*1 :5 unit$ ) ! nitrog5 ( ! atmosph]e 
by electrical dis*>ges1 produces !      
ammonia1 :i* is ! ma9 s\rce ( all !     
proteids ( ! plant1 :i* proteids are ! v
 f\ndation ( animal life4  ,f ?is brief 
/atem5t ( ! purposes s]v$ by ! v>i\s    
gases =m+ our atmosph]e1 we see t !y are
 to "s ext5t antagoni/ic1 & t any       
consid]able increase ( "o or ! o!r w\ld 
lead to results t might be injuri\s ei!r
 directly or 9 _! ultimate results4 ,& z

 ! elem5ts :i* con/itute ! bulk ( all   
liv+ matt] possess prop]ties :i* r5d] !m
 alone suitable = ! purpose1 we may     
conclude t ! proportions 9 :i* !y exi/ 9
 our atmosph]e _c be v widely dep>t$ f  
:]ev] organic =ms are develop$4   ,,!   
,,alt]nation ,,( ,,day ,,& ,,night      
,al?\gh x is difficult to decide        
positively :e!r alt]nations ( light &   
d>kness at %ort int]vals are absolutely 
ess5tial = ! developm5t ( ! v>i\s high] 
=ms ( life1 or :e!r a _w 9 :i* light 0  
con/ant might d z well1 yet on ! :ole x 
seems probable t day & night are really 
important factors4 ,all nature is full (
 rhy?mic movem5ts ( inf9itely v>i$ k9ds1
 degrees1 & durations4 ,all ! motions & 
functions ( liv+ ?+s are p]iodic2 gr[? &
 repair1 assimilation & wa/e1 g on      
alt]nately4 ,all our organs are subject 
to fatigue & require re/4 ,all k9ds (   
/imulus mu/ be ( %ort duration or       
injuri\s results foll[4 ,h5ce !         
advantage ( d>kness1 :5 ! /imuli ( light
 & heat are p>tially remov$1 & we       

welcome 'tir$ nature's sweet re/or]1    
balmy sleep'--giv+ re/ to all ! s5ses & 
faculties ( body & m9d1 & end[+ u )     
r5ew$ vig\r = ano!r p]iod ( activity &  
enjoym5t ( life4  ,plants z well z      
animals are invigorat$ by ?is nightly   
repose2 & all alike b5efit by ^! long]  
p]iods ( great] & less am\nts ( "w caus$
 by summ] & w9t]1 dry & wet seasons4 ,x 
is a sugge/ive fact1 t :]e ! influ5ce ( 
heat & light is greate/--)9 ! tropics--!
 days & nights are ( equal l5g?1 giv+   
equal p]iods ( activity & re/4 ,b 9 cold
 & ,arctic regions :]e1 dur+ ! %ort     
summ]1 light is ne>ly p]petual1 & all ! 
functions ( life1 9 vegetation          
especially1 g on ) extreme rapidity1 ?is
 is foll[$ by ! long re/ ( w9t]1 ) its  
%ort days & greatly l5g!n$ p]iods (     
d>kness4  ,( c\rse1 all ?is is r        
sugge/ion ?an pro(4 ,x is possible t 9 a
 _w ( p]petual day or 9 "o ( p]petual   
night1 life might h be5 develop$4 ,b on 
! o!r h&1 consid]+ ! great v>iety (     
physical conditions :i* are se5 to be   

necess>y = ! developm5t & pres]vation ( 
life 9 its endless v>ieties1 any        
prejudicial influ5ces1 h[ev] slight1    
might turn ! scale1 & prev5t t h>moni\s 
& cont9u\s evolution :i* we "k mu/ h    
occurr$4  ,s f> ,i h only consid]$ ! "q 
( day & night z reg>ds ! pres5ce or     
abs5ce ( light4 ,b x is probably f> m   
important 9 its heat aspect2 & "h its   
p]iod becomes ( great1 p]haps vital1    
importance4 ,) its pres5t duration (    
twelve h\rs day & twelve night on !     
av]age1 !re is n "t1 ev5 betwe5 !       
tropics1 = ! e>? to become s excessively
 heat$ z to be inimical to life2 :ile a 
consid]able portion ( ! heat1 /or$ up 9 
! soil1 ! wat]1 & ! atmosph]e1 is giv5  
out at night1 & ?us prev5ts a too sudd5 
& injuri\s contra/ ( heat & cold4 ,if ! 
day & night 7 ea* v mu* long]--say #ej  
or #ajj h\rs--x is q c]ta9 t1 dur+ a day
 ( t duration1 ! heat w\ld become s     
great z to be inimical1 p]haps          
prohibitive1 to mo/ =ms ( life2 :ile !  
abs5ce ( all sun-heat = an equally long 

p]iod w\ld result 9 a temp]ature f> bel[
 ! freez+ po9t ( wat]4 ,x is d\btful    
:e!r any high =ms ( animal life c\ld h  
aris5 "u su* great & cont9ual contra/s (
 temp]ature4  ,we w n[ proce$ to po9t   
out ! special features :i*1 9 our e>?1 h
 comb9$ to br+ ab\t & to ma9ta9 ! v>i\s 
& complex conditions we h se5 to be     
ess5tial = life z x exi/s ar\nd u4      
,,*apt] ,,xii  ,,! ,,e>? ,,9 ,,its      
,,relation ,,to ,,! ,,developm5t ,,&    
,,ma9t5ance ,,( ,,life   ,! fir/        
circum/ance to be consid]$ 9 relation to
 ! habitability ( a planet is its       
di/ance f ! sun4 ,we "k t ! heat+ p[] ( 
! sun ^u our e>? is ample = ! developm5t
 ( life 9 an almo/ inf9ite v>iety ( =ms2
 & we h a l>ge am\nt ( evid5ce to %[ t1 
7 x n = ! equalis+ p[] ( air & wat]1    
di/ribut$ z !y are ) u1 ! heat receiv$ f
 ! sun w\ld be sometimes too great &    
sometimes too little4 ,9 "s p>ts (      
,africa1 ,au/ralia1 & ,india1 ! s&y soil
 becomes s hot t an egg c be cook$ by   
plac+ x j bel[ ! surface4 ,on ! o!r h&1 

at an elevation ( ab\t #ab1jjj feet 9   
lat4 #dj x freezes e night1 & ?r\gh\t ! 
day 9 all places %elt]$ f ! sun4 ,n[1   
bo? ^! temp]atures are adv]se to life1 &
 if ei!r ( !m p]si/$ ov] a consid]able  
portion ( ! e>?1 ! developm5t ( life    
w\ld h be5 impossible4 ,b ! heat d]iv$ f
 ! sun is inv]sely z ! squ>e ( !        
di/ance1 s t at half ! di/ance we %\ld h
 f\r times z mu* heat1 & at twice !     
di/ance only "o-f\r? ( ! heat4 ,ev5 at  
two-?irds ( ! di/ance we %\ld receive m 
?an twice z mu* heat2 &1 consid]+ !     
facts z to ! extreme s5sitiv5ess (      
protoplasm & ! coagulation ( album51 x  
seems c]ta9 t we are situat$ 9 :at has  
be5 t]m$ ! temp]ate zone ( ! sol> sy/em1
 & t we c\ld n be remov$ f> f our pres5t
 position )\t endang]+ a consid]able    
portion ( ! life n[ exi/+ ^u ! e>?1 & 9 
all probability r5d]+ ! actual          
developm5t ( life1 ?r\gh all its phases 
& gradations1 impossible4   ,,!         
,,obliquity ,,( ,,! ,,ecliptic  ,!      
effect ( ! obliquity ( ! e>?'s equator  

to its pa? r\nd ! sun1 ^u :i* dep5d our 
v>y+ seasons & ! inequality ( day &     
night ?r\gh\t all ! temp]ate zones1 is v
 g5]ally kn[n4 ,b x is n usually        
consid]$ t ?is obliquity is ( any great 
importance z reg>ds ! suitability ( !   
e>? = ! developm5t & ma9t5ance ( life2 &
 x seems to h be5 pass$ ov] z an accid5t
 h>dly wor? notice1 because almo/ any   
o!r obliquity or none at all w\ld h be5 
equally advantage\s4 ,b if we consid]   
:at ! direction ( ! e>?'s axis might    
possibly h be51 we %all f9d t x is      
really a matt] ( great importance f our 
pres5t po9t ( view4  ,let u suppose1    
fir/1 t ! e>?'s axis 01 l t ( ,uranus1  
almo/ exactly 9 ! plane ( its orbit or  
direct$ t[>ds ! sun4 ,!re c be little   
d\bt t su* a position w\ld h r5d]$ our  
_w unfitt$ = ! developm5t ( life4 ,= !  
result w\ld be ! mo/ trem5d\s contra/s (
 ! seasons2 at mid-w9t]1 on "o half !   
globe1 arctic night & m ?an arctic cold 
w\ld prevail2 :ile on ! o!r half !re    
w\ld be a midsumm] ( cont9u\s day ) a   

v]tical sun & su* an am\nt ( heat z     
n[h]e exi/s ) u4 ,at ! two equ9oxes !   
:ole globe w\ld enjoy equal day & night1
 all our pres5t tropics & "p ( !        
sub-tropical zone hav+ ! sun at noon s  
ne> to ! z5i? z to h ! ess5tial ( a     
tropical climate4 ,b ! *ange to ab\t a  
mon? ( con/ant sun%9e or a mon? (       
cont9u\s night w\ld be s rapid1 t x     
seems almo/ impossible t ei!r vegetable 
or animal life w\ld ev] h develop$ "u   
su* t]rible conditions4  ,! o!r extreme 
direction ( ! e>?'s axis1 exactly at "r 
angles to ! plane ( ! orbit1 w\ld be mu*
 m fav\rable1 b w\ld /ill h its         
disadvantages4 ,! :ole surface f equator
 to poles w\ld enjoy equal day & night1 
& e "p w\ld receive ! same am\nt (      
sun-heat all ! ye> r\nd1 s t !re w\ld be
 no *ange ( seasons2 b ! heat receiv$   
w\ld v>y ) ! latitude4 ,9 our latitude !
 sun's altitude at noon all ! ye> w\ld  
be less ?an #dj1 ! same z n[ occurs at !
 equ9oxes1 & we might !re=e h a p]petual
 spr+ z reg>ds temp]ature4 ,b ! con/ancy

 ( ! heat 9 ! equatorial & tropical     
regions & ( cold t[>ds ! poles w\ld lead
 to a m con/ant & m rapid circulation ( 
air1 & we %\ld probably exp]i5ce su*    
cont9u\s nor?-we/]ly w9ds z to r5d] our 
climate always cold & probably v damp4  
,ne> ! poles ! sun w\ld always be on1 or
 close to1 ! horizon1 & w\ld give s     
little heat t ! sea might be p]petually 
froz5 & ! l& deeply sn[-buri$2 & ^!     
conditions w\ld probably ext5d into !   
temp]ate zone1 & possibly s f> s\? z to 
r5d] life impossible 9 our latitudes1   
s9ce :atev] results arose w\ld be due to
 p]man5t causes1 & we "k h[ p[]ful are  
sn[ & ice to ext5d _! sway ov] adjac5t  
areas if n c\nt]act$ by summ] heat or   
w>m moi/ w9ds4 ,on ! :ole1 !re=e1 x     
seems probable t ?is position ( ! e>?'s 
axis w\ld result 9 a mu* small] portion 
( its surface be+ capable ( support+ a  
luxuriant & v>i$ vegetable & animal life
 ?an is n[ ! case2 :ile ! extreme       
uni=mity ( conditions ev]y:]e pres5t    
might be s antagoni/ic to ! great law ( 

rhy?m t seems to p]vade ! univ]se1 & be 
9 o!r ways s unfav\rable1 t             
life-developm5t w\ld probably h tak5 q a
 diff]5t c\rse f t :i* x has tak54  ,x  
appe>s almo/ c]ta91 !re=e1 t "s         
int]m$iate position ( ! axis w\ld be !  
mo/ fav\rable2 & t :i* actually exi/s   
seems to comb9e ! advantage ( *ange (   
seasons ) good climatical conditions ov]
 ! l>ge/ possible area4 ,we "k t dur+ ! 
great] "p ( ! epo* ( life-developm5t ?is
 area 0 mu* great] ?an at pres5t1 s9ce a
 luxuriant vegetation ( decidu\s &      
ev]gre5 trees & %rubs ext5d$ up to & )9 
! ,arctic ,circle1 lead+ to ! =mation ( 
coal-b$s bo? 9 palozoic & t]ti>y times2 
! extremely fav\rable conditions =      
organic life :i* !n prevail$ ov] s l>ge 
a portion ( ! globe's surface1 & :i*    
p]si/$ d[n to a comp>atively rec5t epo*1
 lead to ! conclusion t no m fav\rable  
degree ( obliquity 0 possible ?an t :i* 
we actually possess4 ,a %ort acc\nt ( ! 
evid5ce on ?is int]e/+ subject w n[ be  
giv54   ,,p]si/5ce ,,( ,,mild ,,climates

 ,,?r\gh ,,geologic ,,"t  ,! :ole ( !   
geological evid5ce goes to %[ t 9 remote
 ages ! climate ( ! e>? 0 g5]ally m     
uni=m1 ?\gh p]haps n w>m]1 ?an x is n[1 
& ?is c be be/ expla9$ by a slightly    
diff]5t di/ribution ( sea & l&1 :i*     
all[$ ! w>m wat]s ( ! tropical oceans to
 p5etrate into v>i\s p>ts ( ! cont95ts  
7:i* 7 !n m brok5 up ?an !y are n[71 &  
also to ext5d m freely into ! ,arctic   
regions4 ,s soon z we g back into !     
t]ti>y p]iod1 we f9d indications ( a    
w>m] climate 9 ! nor? temp]ate zone2 &  
:5 we rea* ! middle ( t p]iod1 we f9d   
abundant indications1 bo? 9 plant &     
animal rema9s1 ( mild climates ne> to ! 
,arctic ,circle1 or actually )9 x4  ,on 
! we/ coa/ ( ,gre5l&1 9 #gj ,n4 lat41   
!re are f\nd abundance ( fossil plants v
 beautifully pres]v$1 among :i* are _m  
diff]5t species ( oaks1 bee*es1 popl>s1 
plane-trees1 v9es1 walnuts1 plums1      
*e/nuts1 sequoias1 & num]\s %rubs--#acg 
species 9 all1 indicat+ a vegetation su*
 z n[ gr[s 9 ! nor? temp]ate p>ts (     

,am]ica & ,ea/]n ,asia4 ,& ev5 fur!r    
nor?1 9 ,spitzb]g51 9 ,n4 lat4 #gh &    
#gi1 a some:at simil> flora is f\nd1 n q
 s v>i$1 b ) oaks1 popl>s1 bir*es1      
planes1 limes1 hazels1 p9es1 & _m       
aquatic plants su* z may n[ be f\nd 9   
,we/ ,norway & 9 ,alaska1 ne>ly tw5ty   
degrees fur!r s\?4  ,/ill m remote1 9 ! 
,cretace\s p]iod1 fossil plants h be5   
f\nd 9 ,gre5l&1 consi/+ ( f]ns1 cycads1 
conif]s1 & su* trees & %rubs z popl>s1  
sassafras1 &rom$as1 magnolias1 myrtles1 
& _m o!rs1 simil> 9 "* & (t5 id5tical 9 
species ) fossils ( ! same p]iod f\nd 9 
,c5tral ,europe & ! ,unit$ ,/ates1      
indicat+ a widespread uni=mity (        
climate1 su* z w\ld be br\ght ab\t by ! 
great ocean-curr5ts c>ry+ ! w>m wat]s ( 
! tropics into ! ,arctic seas4  ,/ill   
fur!r back1 9 ! ,jurassic p]iod1 we h   
pro(s ( a mild climate 9 ,ea/ ,sib]ia & 
at ,& 9 ,norway j )9 ! ,arctic ,circle1 
9 num]\s plant rema9s1 & also rema9s (  
great reptiles alli$ to ^? f\nd 9 ! same
 /rata 9 all p>ts ( ! _w4 ,simil>       

ph5om5a occur 9 ! /ill e>li] ,triassic  
p]iod2 b we w pass on to ! mu* m remote 
,c>bonif]\s p]iod1 dur+ :i* mo/ ( !     
great coal-b$s ( ! _w 7 =m$ f a         
luxuriant vegetation1 consi/+ mo/ly (   
f]ns1 giant horse-tails1 & primitive    
conif]s4 ,! luxuriance ( ^! plants1 :i* 
are (t5 f\nd beautifully pres]v$ & 9    
imm5se quantities1 is suppos$ to        
indicate an atmosph]e 9 :i* c>bonic acid
 gas 0 mu* m abundant ?an n[2 & ?is is  
r5d]$ probable by ! small numb] & l[    
type ( t]re/rial animals1 consi/+ ( a   
few insects & amphibia4  ,b ! int]e/+   
po9t is1 t true coal-b$s1 ) simil>      
fossils to ^? ( our own coal-measures1  
are f\nd at ,spitzb]g5 & at ,be> ,isl& 9
 ,ea/ ,sib]ia1 bo? f> )9 ! ,arctic      
,circle1 aga9 indicat+ a great uni=mity 
( climate1 & probably a d5s] & m        
vap\r-lad5 atmosph]e1 :i* w\ld act z a  
blanket ov] ! e>? & pres]ve ! heat      
br\ght to ! ,arctic seas by ! ocean     
curr5ts f ! w>m] regions4  ,! /ill e>li]
 ,silurian rocks are also f\nd          

abundantly 9 ! ,arctic regions1 b _!    
fossils are entirely ( m>9e animals4    
,yet !y %[ ! same ph5om5a z reg>ds      
climate1 s9ce ! corals & cephalopod\s   
mollusca f\nd 9 ! ,arctic b$s closely   
resemble ^? ( all o!r p>ts ( ! e>?4#af  
,_m o!r facts indicate t ?r\gh\t !      
enorm\s p]iods requir$ = ! developm5t ( 
! v>i$ =ms ( life ^u ! e>?1 ! great     
ph5om5a ( nature 7 b little diff]5t f ^?
 t prevail 9 our own times4 ,! sl[ &    
g5tle processes by :i* ! v>i\s vegetable
 & animal rema9s 7 pres]v$ are %[n by ! 
p]fect /ate 9 :i* _m ( ! fossils exi/4  
,(t5 trunks ( trees1 cycads1 & tree-f]ns
 are f\nd /&+ erect1 ) _! roots /ill    
imb$d$ 9 ! soil !y grew 94 ,l>ge leaves 
( popl>s1 maples1 oaks1 & o!r trees are 
(t5 pres]v$ 9 z p]fect a /ate z if ga!r$
 by a botani/ & dri$ betwe5 pap] = 8    
h]b>ium1 & ! same is especially ! case )
 ! beautiful f]ns ( ! ,p]mian &         
,c>bonif]\s p]iods4 ,?r\gh\t ^! & mo/   
o!r =mations well-pres]v$ ripple-m>ks   
are f\nd 9 ! solidifi$ mud or s& ( old  

sea%ores1 diff]+ 9 no respect f simil>  
m>ks to be f\nd on almo/ e coa/ to-day4 
,equally int]e/+ are ! m>ks ( ra9-drops 
pres]v$ 9 ! rocks ( almo/ all ages4 ,sir
 ,*>les ,lyell has giv5 illu/rations (  
rec5t impressions ( ra9-drops on !      
ext5sive mud-flats ( ,nova ,scotia1 &   
also an illu/ration ( ra9-drops on a    
slab ( %ale f ! c>bonif]\s =mation ( !  
same c\ntry2 & ! two are z mu* alike z !
 pr9ts ( two diff]5t %[]s a few days    
ap>t4 ,! g5]al size & =m ( ! drops are  
almo/ id5tical1 & imply a great         
simil>ity 9 ! g5]al atmosph]ic          
conditions4  ,we mu/ n =get t ?is       
pres5ce ( ra9 ?r\gh\t geological "t     
implies1 z we h se5 9 our la/ *apt]1 a  
con/ant & univ]sal di/ribution (        
atmosph]ic du/4 ,! two *ief s\rces ( ?is
 du/--! total quantity ( :i* 9 !        
atmosph]e mu/ be enorm\s--are volcanoes 
& des]ts1 & we are !re=e sure t ^! two  
great natural ph5om5a h always be5      
pres5t4 ,( volcanoes we h ample         
indep5d5t evid5ce 9 ! pres5ce ( lavas & 

volcanic a%es1 z well z actual /umps or 
cores ( old volcanoes1 ?r\gh all        
geological =mations2 & we c h little    
d\bt t des]ts also 7 pres5t1 ?\gh p]haps
 n always s ext5sive z !y are n[4 ,x is 
a v sugge/ive fact t ^! two ph5om5a1    
usually held to be blots on ! fair face 
( nature1 & ev5 to be oppos$ to belief 9
 a b5efic5t ,creator1 %\ld n[ be prov$  
to be really ess5tial to ! e>?'s        
habitability4  ,not)/&+ ?is preval5ce ( 
w>m & uni=m conditions1 !re is also     
evid5ce ( consid]able *anges ( climate2 
& at two p]iods--9 ! ,eoc5e & 9 ! remote
 ,p]mian--!re are ev5 indications (     
ice-action1 s t "s geologi/s believe t  
!re 7 !n actual glacial epo*s4 ,b x     
seems m probable t !y imply only local  
glaciation1 ow+ to !re hav+ be5 high l& 
& o!r suitable conditions = ! production
 ( glaci]s 9 c]ta9 areas4  ,! :ole be>+ 
( ! geological evid5ce indicates !      
wond]ful cont9uity ( conditions         
fav\rable = life1 & = ! mo/ "p (        
climatal conditions m fav\rable ?an ^?  

n[ prevail+1 s9ce a l>g] ext5t ( l&     
t[>ds ! ,nor? ,pole 0 available = an    
abundant vegetation1 & 9 all probability
 = an equally abundant animal life4 ,we 
"k1 too1 t !re 0 nev] any total break 9 
life-developm5t2 no epo* ( su* l[]+ or  
rais+ ( temp]ature z to de/roy all life2
 no su* g5]al subsid5ce z to subm]ge !  
:ole l&-surface4 ,al?\gh ! geological   
record is 9 p>ts v imp]fect1 yet x is1  
on ! :ole1 wond]fully complete2 & x     
pres5ts to our view a cont9u\s progress1
 f simple to complex1 f l[] to high]4   
,type aft] type becomes highly          
specialis$ 9 adaptation to local or     
climatal conditions1 & !n dies out1 giv+
 room = "s o!r type to arise & be       
specialis$ 9 h>mony ) ! *ang$           
conditions4 ,! g5]al "* ( ! inorganic   
*ange appe>s to h be5 f m insul> to m   
cont95tal conditions1 accompani$ by a   
*ange f m uni=m to less uni=m climates1 
f an almo/ sub-tropical w>m? & moi/ure1 
ext5d+ up to ! ,arctic ,circle1 to t    
div]sity ( tropical1 temp]ate1 & cold   

areas1 capable ( support+ ! greate/     
possible v>iety 9 ! =ms ( life1 & :i*   
seems especially adapt$ to /imulate     
mank9d to civilisation & social         
developm5t by means ( ! necess>y /ruggle
 aga9/1 & utilisation (1 ! v>i\s =ces ( 
nature4   ,,wat]1 ,,its ,,am\nt ,,&     
,,di/ribution ,,on ,,! ,,e>?  ,al?\gh x 
is g5]ally kn[n t ! oceans occupy m ?an 
two-?irds ( ! :ole surface ( ! globe1 ! 
enorm\s bulk ( ! wat] 9 proportion to ! 
l& t rises above its surface is h>dly   
ev] appreciat$4 ,b z ?is is a matt] ( ! 
greate/ importance1 bo? z reg>ds !      
geological hi/ory ( ! globe & ! special 
subject we are "h discuss+1 x w be      
necess>y to ent] into "s details 9 reg>d
 to x4  ,accord+ to ! be/ rec5t         
e/imates1 ! l& area ( ! globe is #j4bh (
 ! :ole surface1 & ! wat] area #j4gb4 ,b
 ! mean height ( ! l& above ! sea-level 
is f\nd to be #bbej feet1 :ile ! mean   
dep? ( ! seas & oceans is #ac1hfj feet2 
s t ?\gh ! wat] area is two & a half    
times t ( ! l&1 ! mean dep? ( ! wat] is 

m ?an six times ! mean height ( ! l&4   
,?is is1 ( c\rse1 due to ! fact t l[l&s 
occupy mo/ ( ! l&-area1 ! plateaus &    
high m\nta9s a comp>atively small       
portion ( x2 :ile1 ?\gh ! greate/ dep?s 
( ! oceans ab\t equal ! greate/ heights 
( ! m\nta9s1 yet ov] enorm\s areas !    
oceans are deep en\gh to subm]ge all !  
m\nta9s ( ,europe & temp]ate ,nor?      
,am]ica1 except ! extreme summits ( "o  
or two ( !m4 ,h5ce x foll[s t ! bulk ( !
 oceans1 ev5 omitt+ all ! %all[ seas1 is
 m ?an ?irte5 times t ( ! l& above      
sea-level2 & if all ! l&-surface &      
ocean-floors 7 r$uc$ to "o level1 t is1 
if ! solid mass ( ! globe 7 a true      
oblate sph]oid1 ! :ole w\ld be cov]$ )  
wat] ab\t two miles deep4 ,! diagram "h 
giv5 w r5d] ?is m intelligible & w s]ve 
to illu/rate :at foll[s4  ,illu/ration3 
,diagram ( proportionate mean height (  
,l& & dep? ( ,oceans4 ,l& ,area4 4#bh ( 
area ( ,globe4 ,ocean ,area 4#gb ( area 
( ,globe4  ,9 ?is diagram ! l5g?s ( !   
sections repres5t+ l& & ocean are       

proportionate to _! areas1 :ile !       
?ickness ( ea* is proportionate to _!   
mean height & mean dep? respectively4   
,h5ce ! two sections are 9 correct      
proportion to _! cubic cont5ts4  ,a m]e 
inspection ( ?is diagram is suffici5t to
 disprove ! old idea1 /ill held by a few
 geologi/s & by _m biologi/s1 t oceans &
 cont95ts h repeat$ly *ang$ places dur+ 
geological times1 or t ! great oceans h 
aga9 & aga9 be5 bridg$ ov] to facilitate
 ! di/ribution ( beetles or birds1      
reptiles or mammals4 ,we mu/ rememb] t  
al?\gh ! diagram %[s ! cont95ts & oceans
 z a :ole1 yet x also %[s1 ) q suffici5t
 accuracy1 ! proportions ( ea* ( ! great
 cont95ts to ! oceans :i* are adjac5t to
 !m4 ,x mu/ also be borne 9 m9d t !re c 
be no elevation on a l>ge scale )\t a   
correspond+ subsid5ce else:]e2 because  
if !re 7 n a va/ unsupport$ holl[ w\ld  
be left b5ea? ! ris+ l& or 9 "s "p      
adjac5t to x4  ,n[1 look+ at ! diagram &
 at a *>t or globe1 try to imag9e !     
ocean-bottom ris+ gradually1 to =m a    

cont95t jo9+ ,africa ) ,s\? ,am]ica or )
 ,au/ralia 7bo? ( :i* are dem&$ by _m   
biologi/s73 x is cle> t1 :ile su* an    
elevation 0 go+ on1 ei!r "s cont95tal l&
 or "s o!r "p ( ! ocean-b$ mu/ s9k to a 
correspond+ am\nt4 ,we %all !n see1 t if
 su* *anges ( elevation on a cont95tal  
scale h tak5 place aga9 & aga9 at       
diff]5t p]iods1 x w\ld h be5 almo/      
impossible1 on e occasion1 to avoid a   
:ole cont95t be+ subm]g$ 7or ev5 all !  
cont95ts7 9 ord] to equalise subsid5ce )
 elevation :ile new cont95ts 7 be+ rais$
 up f ! abyssal dep?s ( ! ocean4 ,we    
conclude1 !re=e1 t ) ! exception ( a    
comp>atively n>r[ belt ar\nd ! cont95ts1
 :i* may be r\ghly indicat$ by ! ?\s&   
fa?om l9e ( s\nd+s1 ! great ocean dep?s 
are p]man5t features ( ! e>?'s surface4 
,x is ?is /ability ( ! g5]al di/ribution
 ( l& & wat] t has secur$ ! cont9uity ( 
life ^u ! e>?4 ,_h ! great oceanic      
bas9s1 on ! o!r h&1 be5 un/able1 *ang+  
places ) ! l& at v>i\s p]iods (         
geological "t1 !y w\ld1 almo/ c]ta9ly1  

aga9 & aga9 h swall[$ up ! l& 9 _! va/  
abysses1 & h ?us de/roy$ all ! organic  
life ( ! _w4  ,!re are _m confirmatory  
pro(s ( ?is view 7:i* is n[ widely      
accept$ by geologi/s & physici/s71 & a  
few ( !m may be briefly /at$4  #a4 ,none
 ( ! cont95ts pres5t u ) m>9e deposits (
 any "o geological age & occupy+ a l>ge 
"p ( ! surface ( ea*1 z mu/ h be5 ! case
 _h !y ev] be5 sunk deep b5ea? ! ocean &
 aga9 elevat$2 nei!r d any ( !m conta9  
ext5sive =mations correspond+ to ! deep 
oceanic clays & oozes1 :i* aga9 !y mu/ h
 done _h !y be5 at any "t rais$ up f !  
ocean dep?s4  #b4 ,all ! cont95ts pres5t
 an almo/ complete & cont9u\s s]ies (   
rocks ( all geological ages1 & 9 ea* ( !
 great geological p]iods !re are f\nd   
fre% wat] & e/u>9e deposits1 & ev5 old  
l&-surfaces1 demon/rat+ cont9uity (     
cont95tal or insul> conditions4  #c4    
,all ! great oceans possess1 scatt]$ ov]
 !m1 a few or _m isl&s t]m$ 'oceanic1' &
 *>act]is$ by a volcanic or corall9e    
/ructure1 ) no anci5t /ratifi$ rocks 9  

anyone ( !m2 & 9 none ( ^! is !re f\nd a
 s+le indig5\s l& mammal or amphibian4  
,x is incr$ible t1 if ^! oceans _h ev]  
conta9$ ext5sive cont95ts1 & if ^!      
oceanic isl&s are--z ev5 n[ !y are (t5  
alleg$ to be--p>ts ( ^! n[ subm]g$      
cont95ts1 n "o fragm5t ( any ( ! old    
/ratifi$ rocks1 :i* *>act]ise all exi/+ 
cont95ts1 %\ld rema9 to %[ _! orig94 ,9 
! ,atlantic we f9d ! ,azores1 ,madeira1 
& ,/4 ,hel5a2 9 ! ,indian ,ocean1       
,mauritius1 ,b\rbon1 & ,k]guel5 ,isl&2 9
 ! ,pacific1 ! ,fiji1 ,samoan1 ,society1
 ,s&wi*1 & ,galapagos ,isl&s1 all )\t   
exception tell+ u ! same tale1 t !y h   
be5 built up f ! ocean dep?s by subm>9e 
volcanoes & corall9e gr[?s1 b h nev] =m$
 "p ( cont95tal areas4  #d4 ,! cont\rs (
 ! floors ( all ! great oceans1 n[      
fairly well kn[n ?r\gh ! s\nd+s (       
explor+ vessels & = subm>9e telegraph   
l9es1 also give confirmatory evid5ce t  
!y h nev] be5 cont95tal l&4 ,= if any "p
 ( !m 7 a sunk5 cont95t1 t "p mu/ h     
reta9$ "s impress ( its orig94 ,"s ( !  

num]\s m\nta9 ranges :i* *>act]ise e    
cont95t w\ld h rema9$4 ,we %\ld f9d     
slopes ( f #bj to #ej n uncommon1 :ile  
valleys bord]$ by rocky precipices1 z 9 
,lake ,luc]ne & a hundr$ o!rs1 or       
isolat$ rock-wall$ m\nta9s l ,roraima1  
or ranges ( precipices z 9 ! ,ghts (    
,india or ! ,fiords ( ,norway1 w\ld     
frequ5tly be met )4 ,b n a s+le feature 
( ?is k9d has ev] be5 f\nd 9 ! ocean    
abysses4 ,in/ead ( ^! we h va/ pla9s1   
:i*1 if ! wat] 7 remov$1 w\ld appe>     
almo/ exactly level1 ) no abrupt slopes 
any:]e4 ,:5 we consid] t deposits f ! l&
 nev] rea* ^! remote ocean dep?s1 & t   
!re is no wave-action bel[ a few hundr$ 
feet1 ^! cont95tal features once subm]g$
 w\ld be inde/ructible2 & _! total      
abs5ce is1 !re=e1 itself a demon/ration 
t none ( ! great oceans are on ! sites (
 subm]g$ cont95ts4   ,,h[ ,,ocean       
,,dep?s ,,7 ,,produc$  ,x is a v        
difficult problem to det]m9e h[ ! va/   
bas9s :i* are fill$ by ! great oceans1  
especially t ( ! ,pacific1 7 fir/       

produc$4 ,:5 ! e>?'s surface 0 /ill 9 a 
molt5 /ate1 x w\ld necess>ily take ! =m 
( a true oblate sph]oid1 ) a compression
 at ! poles due to its spe$ ( rotation1 
:i* is suppos$ to h be5 v great4 ,! cru/
 =m$ by ! gradual cool+ ( su* a globe   
w\ld be ( ! same g5]al =m1 &1 be+ ?91   
w\ld easily be fractur$ or b5t s z to   
accommodate itself to any unequal       
/resses f ! int]ior4 ,z ! cru/ ?ick5$ & 
! :ole mass sl[ly cool$ & contract$1    
fissures & crumpl+ w\ld occur1 ! =m]    
s]v+ z outlets = volcanic activities ^: 
results are f\nd ?r\gh\t all geological 
ages2 ! latt] produc+ m\nta9 *a9s 9 :i* 
! rocks are almo/ always curv$1 fold$1  
or ev5 ?ru/ ov] ea* o!r1 indicat+ !     
mighty =ces due to ! adju/m5ts ( a solid
 cru/ ^u a %r9k+ fluid or semi-fluid    
int]ior4  ,b dur+ ?is :ole process !re  
seem to be no =ces at "w t c\ld lead to 
! production ( su* a feature z !        
,pacific1 a va/ depression cov]+ ne>ly  
"o-?ird ( ! :ole surface ( ! globe4 ,!  
,atlantic ,ocean1 be+ small] & ne>ly    

opposite to ! ,pacific1 b approximately 
( equal dep?1 may be look$ ^u z a       
complem5t>y ph5om5on :i* w be probably  
expla9$ z a result ( ! same causes z !  
va/] cavity4  ,s f> z ,i am aw>e1 !re is
 only "o sugge/$ cause ( ! =mation ( ^! 
great oceans t seems adequate2 & z t    
cause is to "s ext5t support$ by q      
indep5d5t a/ronomical evid5ce1 & also   
directly be>s ^u ! ma9 subject ( !      
pres5t volume1 x mu/ be briefly         
consid]$4  ,a few ye>s ago1 ,pr(essor   
,george ,d>w91 ( ,cambridge1 arriv$ at a
 c]ta9 conclusion z to ! orig9 ( ! moon1
 :i* is n[ comp>atively well kn[n by    
,sir ,rob]t ,ball's popul> acc\nt ( x 9 
8 small volume1 ,"t & ,tide4 ,briefly   
/at$1 x is z foll[s4 ,! tides produce   
friction on ! e>? & v sl[ly increase !  
l5g? ( our day1 & also cause ! moon to  
rec$e fur!r f u4 ,! day is l5g!n$ only  
by a small fraction ( a second 9 a ?\s& 
ye>s1 & ! moon is rec$+ at an equally   
imp]ceptible rate4 ,b z ^! =ces are     
con/ant1 & h always act$ on ! e>? &     

moon1 z we g back & back into ! almo/   
inf9ite pa/ we come to a "t :5 !        
rotation ( ! e>? 0 s rapid t gravity at 
! equator c\ld h>dly reta9 its out]     
portion1 :i* 0 spread out s t ! =m ( !  
:ole mass 0 some?+ l a *eese ) r\nd$    
edges4 ,& ab\t ! same epo* ! di/ance ( !
 moon is f\nd to h be5 s small t x 0    
actually t\*+ ! e>?4 ,all ?is is !      
result ( ma!matical calculation f ! kn[n
 laws ( gravitation & tidal effects2 & z
 x is difficult to see h[ s l>ge a body 
z ! moon c\ld h orig9at$ 9 any o!r way1 
x is suppos$ t at a /ill e>li] p]iod !  
moon & e>? 7 "o1 & t ! moon sep>at$ f ! 
p>5t mass ow+ to c5trifugal =ce g5]at$  
by ! e>?'s rapid rotation4 ,:e!r ! e>? 0
 liquid or solid at ?is epo*1 & exactly 
h[ ! sep>ation occurr$1 is n expla9$    
ei!r by ,pr(essor ,d>w9 or ,sir ,rob]t  
,ball2 b x is a v sugge/ive fact t1 q   
rec5tly1 x has be5 %[n1 by means ( !    
spectroscope1 t d\ble />s ( %ort p]iod d
 orig9ate 9 ?is way f a s+le />1 z      
already describ$ 9 our six? *apt]2 b 9  

^! cases x seems probable t ! p>5t /> is
 9 a gase\s /ate4  ,^! inve/igations (  
,pr(essor ,g4 ,d>w9 h be5 made use ( by 
! ,rev4 ,osmond ,fi%] 79 8 v int]e/+ &  
important "w1 ,physics ( ! ,e>?'s ,cru/7
 to acc\nt = ! bas9s ( ! great oceans1 !
 ,pacific be+ ! *asm left :5 ! l>g]     
portion ( ! mass ( ! moon p>t$ f ! e>?4 
,adopt+1 z ,i d1 ! !ory ( ! orig9 ( !   
e>? by meteoric accretion ( solid matt]1
 we mu/ consid] our planet z hav+ be5   
produc$ f "o ( ^? va/ r+s ( meteorites  
:i* 9 great numb]s /ill circulate r\nd !
 sun1 b :i* at ! mu* e>li] p]iod n[     
contemplat$ 7 bo? m num]\s & mu* m      
ext5sive4 ,ow+ to irregul>ities (       
di/ribution 9 su* a r+ & ?r\gh          
di/urbance by o!r bodies1 aggregations (
 v>i\s size w\ld inevitably occur1 & !  
l>ge/ ( ^! w\ld 9 "t draw 9 to itself   
all ! re/1 & ?us =m a planet4 ,dur+ !   
e>ly /ages ( ?is process ! p>ticles w\ld
 be s small & w\ld come toge!r s        
gradually1 t little heat w\ld be        
produc$1 & !re w\ld result m]ely a loose

 aggregation ( cold matt]4 ,b z !       
process w5t on & ! mass ( ! incipi5t    
planet became consid]able--p]haps half t
 ( ! e>?--! re/ ( ! r+ w\ld fall 9 )    
great] & great] velocity2 & ?is1 add$ to
 ! gravitative compression ( ! gr[+ mass
 might1 :5 ne>ly its pres5t size1 h     
produc$ suffici5t heat to liquefy ! out]
 lay]s1 :ile ! c5tral portion rema9$    
solid & to "s ext5t incoh]5t1 ) probably
 l>ge quantities ( heavy gases 9 !      
int]/ices4 ,:5 ! am\nt ( ! meteoric     
accretions became s r$uc$ z to be       
insuffici5t to keep up ! heat to !      
melt+-po9t1 a cru/ w\ld =m1 & might h   
rea*$ ab\t half or ?ree-f\r?s ( its     
pres5t ?ickness :5 ! moon became        
sep>at$4  ,let u n[ try to picture to   
ourselves :at happ5$4 ,we %\ld h a globe
 some:at l>g] ?an our e>? is n[1 bo?    
because x !n conta9$ ! mat]ial ( ! moon 
& also because x 0 hott]1 revolv+ s     
rapidly z to be v greatly flatt5$ at !  
poles2 :ile ! equatorial belt bulg$ out 
enorm\sly1 & w\ld probably h sep>at$ 9 !

 =m ( a r+ ) a v slight increase ( ! "t 
( rotation1 :i* is suppos$ to h be5 ab\t
 f\r h\rs4 ,?is globe w\ld h a          
comp>atively ?9 cru/1 b5ea? :i* !re 0   
molt5 rock to an unkn[n dep?1 p]haps a  
few hundr$s1 p]haps m ?an a ?\s& miles4 
,at ?is "t ! attraction ( ! sun act+ on 
! molt5 int]ior produc$ tides 9 x1 caus+
 ! ?9 cru/ to rise & fall e two h\rs1 b 
to s small an ext5t--only ab\t a foot or
 s--z n necess>ily to fracture x2 b x is
 calculat$ t ?is slight rhy?mic         
undulation co9cid$ ) ! normal p]iod (   
undulation due to su* a l>ge mass (     
heavy liquid1 & s t5d$ to increase !    
in/ability due to rapid rotation4  ,!   
bulk ( ! moon is ab\t "o-fiftie? "p t ( 
! e>?1 & an easy calculation %[s u t1   
tak+ ! area ( ! ,pacific1 ,atlantic1 &  
,indian ,oceans comb9$ z ab\t two-?irds 
t ( ! globe1 x w\ld require a ?ickness  
7or dep?7 ( ab\t =ty miles to furni% !  
mat]ial = ! moon4 ,we mu/1 ( c\rse1     
assume t !re 7 "s inequalities 9 !      
?ickness ( ! cru/ & 9 its comp>ative    

rigidity1 s t :5 ! critical mom5t came &
 ! e>? c\ld no long] reta9 its          
equatorial protub]ance aga9/ !          
c5trifugal =ce due to rotation comb9$ ) 
! tidal undulations caus$ by ! sun1     
in/ead ( a cont9u\s r+ sl[ly deta*+     
itself1 ! cru/ gave way 9 two or m great
 masses :]e x 0 weake/1 & z ! tidal wave
 pass$ "u x & a quantity ( ! liquid     
sub/ratum rose ) x1 ! :ole w\ld break up
 & collect into a sub-globul> mass a    
%ort di/ance f ! e>?1 & cont9ue revolv+ 
) x = "s "t at ab\t ! same rate z !     
surface _h rotat$4 ,b z tidal action is 
always equal on opposite sides ( a      
globe1 !re w\ld be a simil> disruption  
!re1 =m+1 x may be suppos$1 ! ,atlantic 
bas91 :i*1 z may be se5 on a small      
globe1 is almo/ exactly opposite a "p ( 
! ,c5tral ,pacific4 ,s soon z ^! two    
great masses _h sep>at$ f ! e>?1 ! latt]
 w\ld gradually settle d[n into a /ate (
 equilibrium1 & ! molt5 matt] ( !       
int]ior1 :i* w\ld n[ fill ! great       
oceanic bas9s up to a level ( a few mile

 bel[ ! g5]al surface w\ld soon cool    
en\gh to =m a ?9 cru/4 ,! l>g] portion (
 ! nasc5t moon w\ld gradually attract to
 itself ! "o or m small] portions & =m  
our satellite2 & f t "t tidal friction  
by bo? moon & sun w\ld beg9 to op]ate & 
w\ld gradually l5g!n our day &1 m       
rapidly1 our mon? 9 ! way expla9$ 9 ,sir
 ,rob]t ,ball's volume4  ,a v int]e/+   
po9t may n[ be ref]r$ to1 because x     
seems confirmatory ( ?is orig9 ( ! great
 ocean bas9s4 ,9 ,mr4 ,osmond ,fi%]'s "w
 x is expla9$ h[ ! v>iations 9 ! =ce (  
gravity1 at num]\s po9ts all ov] ! _w1 h
 be5 det]m9$ by obs]vations ) ! p5dulum1
 & also h[ ^! v>iations af=d a measure (
 ! ?ickness ( ! solid cru/1 :i* is (    
less specific gravity ?an ! molt5       
int]ior on :i* x re/s4 ,by ?is means a v
 int]e/+ result 0 obta9$4 ,! obs]vations
 on num]\s oceanic isl&s prov$ t !      
sub-oceanic cru/ 0 consid]ably m d5se   
?an ! cru/ "u ! cont95ts1 b also ?9n]1 !
 result be+ to br+ ! av]age mass ( !    
sub-oceanic cru/ & oceans to an equality

 ) t ( ! cont95tal cru/1 & ?is causes ! 
:irl+ e>? to be 9 a /ate ( balance1 or  
equilibrium4 ,n[1 bo? ! ?9ness & !      
increas$ d5sity ( ! cru/ seem to be well
 expla9$ by ?is !ory ( ! orig9 ( !      
oceanic bas9s4 ,! new cru/ w\ld         
necess>ily = a long "t be ?9n] ?an !    
old] portion1 because =m$ s mu* lat]1 b 
x w\ld v soon become cool en\gh to all[ 
! aque\s vap\r ( ! atmosph]e & t giv5 (f
 ?r\gh fissures f ! molt5 int]ior to    
collect 9 ! ocean bas9s1 :i* w\ld !nce=?
 be cool$ m rapidly & kept at a uni=m   
temp]ature & also "u a uni=m pressure1 &
 ^! conditions w\ld lead to ! /eady &   
cont9u\s increase ( ?ickness1 ) a great]
 compactness ( /ructure ?an 9 !         
cont95tal areas4 ,x is no d\bt to ?is   
uni=mity ( conditions1 ) a l[]+ ( !     
bottom temp]ature ?r\gh\t ! great] "p ( 
geological "t1 till x has become only a 
few degrees above ! freez+-po9t1 t we   
owe ! rem>kable p]si/5ce ( ! va/ & deep 
ocean bas9s on :i*1 z we h se51 !       
cont9uity ( life on ! e>? has l>gely    

dep5d$4  ,!re is "o o!r fact :i* l5ds "s
 support to ?is !ory ( ! orig9 ( ! ocean
 bas9s--_! almo/ complete symmetry )    
reg>d to ! equator4 ,bo? ! ,atlantic &  
,pacific bas9s ext5d to an equal di/ance
 nor? & s\? ( ! equator1 an equality :i*
 c\ld h>dly h be5 produc$ by any cause n
 directly connect$ ) ! e>?'s rotation4  
,! pol> seas :i* are cot]m9\s ) ! two   
great oceans are v mu* %all[]1 & _c1    
!re=e1 be consid]$ z =m+ "p ( ! true    
oceanic bas9s4   ,,wat] ,,z ,,an        
,,equalis] ,,( ,,temp]ature  ,!         
importance ( wat] 9 regulat+ !          
temp]ature ( ! e>? is s great t1 ev5 if 
we _h en\gh wat] on ! l& = all ! wants (
 plants & animals1 b _h no great oceans1
 x is almo/ c]ta9 t ! e>? c\ld n h      
produc$ & su/a9$ ! v>i\s =ms ( life :i* 
x n[ possesses4  ,! effect ( ! oceans is
 tw(old4 ,ow+ to ! great specific heat (
 wat]1 t is1 its prop]ty ( absorb+ heat 
sl[ly b to a l>ge am\nt1 & giv+ x out ) 
equal sl[ness1 ! surface-wat]s ( !      
oceans & seas are heat$ by ! sun s t by 

! ev5+ ( a bright day !y h become q w>m 
to a dep? ( sev]al feet4 ,b air has mu* 
less specific heat ?an wat]1 a p\nd (   
wat] 9 cool+ "o degree be+ capable (    
w>m+ f\r p\nds ( air "o degree2 b z air 
is #ggj times z light z wat]1 x foll[s t
 ! heat f "o cubic foot ( wat] w w>m m  
?an #cjjj cubic feet ( air z mu* z x    
cools itself4 ,h5ce ! enorm\s surface ( 
! seas & oceans1 ! l>g] "p ( :i* is )9 !
 tropics1 w>ms ! :ole ( ! l[] & d5s]    
portions ( ! air1 especially dur+ !     
night1 & ?is w>m? is c>ri$ to all p>ts (
 ! e>? by ! w9ds1 & ?us ameliorates !   
climate4 ,ano!r q di/9ct effect is due  
to ! great ocean curr5ts1 l ! ,gulf     
,/ream & ! ,japan ,curr5t1 :i* c>ry !   
w>m wat] ( ! tropics to temp]ate &      
arctic regions1 & ?us r5d] _m c\ntries  
habitable :i* w\ld o!rwise suff] ! rig\r
 ( an almo/ arctic w9t]4 ,^! curr5ts    
are1 h[ev]1 directly due to ! w9ds1 &   
prop]ly belong to ! section on !        
atmosph]e4  ,! o!r equalis+ action1 due 
prim>ily to ! great area ( ! seas &     

oceans1 is a result ( ! va/ evaporat+   
surface f :i* ! l& d]ives almo/ all its 
wat] 9 ! =m ( ra9 & riv]s2 & x is q     
evid5t t if !re 7 n suffici5t           
wat]-surface to produce an ample supply 
( vap\r = ?is purpose1 arid di/ricts    
w\ld occupy m & m ( ! e>?'s surface4 ,h[
 mu* wat]-surface is necess>y = life we 
d n "k2 b if ! proportions ( wat] &     
l&-surfaces 7 rev]s$1 x seems probable t
 ! l>g] proportion ( ! e>? might be     
un9habitable4 ,! vap\r ?us produc$ has  
also a v great effect 9 equalis+        
temp]ature2 b ?is also is a po9t :i* w  
come bett] "u our next *apt] on !       
atmosph]e4         99       99       99 
99       99  ,!re are1 h[ev]1 "s matt]s 
connect$ ) ! wat]-supply ( ! e>?1 & its 
relation to ! developm5t ( life1 t call 
= a few rem>ks "h4 ,:at has det]m9$ !   
total quantity ( wat] on ! e>? or on o!r
 planets does n appe> to be kn[n2 b     
presumably x w\ld dep5d1 p>tially or    
:olly1 on ! mass ( ! planet be+         
suffici5t to enable x to reta9 by its   

gravitative =ce ! oxyg5 & hydrog5 ( :i* 
wat] is compos$4 ,z ! two gases are s   
easily comb9$ to =m wat]1 b c only be   
sep>at$ "u special conditions1 its      
quantity w\ld be dep5d5t on ! supply (  
hydrog51 :i* is b r>ely f\nd on ! e>? 9 
a free /ate4 ,! important fact1 h[ev]1  
is1 t we d possess s great a quantity ( 
wat]1 t if ! :ole surface ( ! globe 0 z 
regul>ly cont\r$ z are ! cont95ts1 &    
m]ely wr9kl$ ) m\nta9 *a9s1 !n ! exi/+  
wat] w\ld cov] ! :ole globe ne>ly two   
miles deep1 leav+ only ! tops ( high    
m\nta9s above its surface z r[s ( small 
isl&s1 ) a few l>g] isl&s =m$ by :at are
 n[ ! high plateaus ( ,tibet & ! ,s\!rn 
,&es4  ,n[ !re seems no reason :y ?is   
di/ribution ( ! wat] %\ld n h occurr$--9
 fact x seems probable t x w\ld h       
occurr$1 _h x n be5 = ! =tunate         
co9cid5ce ( ! =mation ( enorm\sly deep  
ocean bas9s4 ,s f> z ,i am aw>e1 no     
suffici5t explanation ( ! =mation ( ^!  
bas9s has be5 giv5 b t ( ,mr4 ,osmond   
,fi%]1 z "h describ$1 & t dep5ds ^u ?ree

 unique circum/ances3 7#a7 ! =mation ( a
 satellite at a v late p]iod ( !        
planet's developm5t :5 !re 0 already a r
 ?ick cru/2 7#b7 ! satellite be+ f> l>g]
 9 proportion to its prim>y ?an any o!r 
9 ! sol> sy/em2 & 7#c7 its hav+ be5     
produc$ by fission f its prim>y on      
acc\nt ( extremely rapid rotation1      
comb9$ ) sol> tides 9 its molt5 int]ior1
 & a rate ( oscillation ( t molt5       
int]ior co9cid+ ) ! tidal p]iod4#ag     
,:e!r ?is v rem>kable !ory ( ! orig9 (  
our moon is ! true "o1 & if s1 :e!r !   
explanation x seems to af=d ( ! great   
oceanic bas9s is correct1 ,i am n       
ma!matician en\gh to judge4 ,! tidal    
!ory ( ! orig9 ( ! moon1 z work$ out    
ma!matically by ,pr(essor ,g4,h4 ,d>w91 
has be5 support$ by ,sir ,rob]t ,ball & 
accept$ by _m o!r a/ronom]s2 :ile !     
rese>*es ( ! ,rev4 ,osmond ,fi%] into ! 
,physics ( ! ,e>?'s ,cru/1 toge!r ) 8   
ma!matical abilities & 8 practical "w z 
a geologi/1 entitle 8 op9ion on ! "q ( !
 mode ( orig9 ( ! ocean bas9s to !      

highe/ respect4 ,&1 z we h se51 !       
exi/5ce ( ^! va/ & deep ocean bas9s1    
produc$ by ! ag5cy ( a s]ies ( ev5ts s  
rem>kable z to be q unique 9 ! sol>     
sy/em1 play$ an important "p 9 r5d]+ !  
e>? fit = ! developm5t ( ! high] =ms (  
animal life1 :ile )\t !m x seems n      
improbable t ! conditions w\ld h be5 su*
 z to r5d] any v>i$ =ms ( t]re/rial life
 h>dly possible4  ,,footnotes3  #af ,= a
 full] acc\nt ( ?is ,arctic fauna &     
flora see ! works ( ,sir ,c4 ,lyell1    
,sir ,a4 ,geikie1 & o!r geologi/s4 ,a   
full summ>y ( x is also giv5 9 ! au?or's
 ,isl& ,life4  #ag ,pr(essor ,g4,h4     
,d>w9 /ates t x is ne>ly c]ta9 t no o!r 
satellite nor any ( ! planets orig9at$ 9
 ! same way z ! moon4     ,,*apt] ,,xiii
  ,,! ,,e>? ,,9 ,,relation ,,to ,,life3 
,,atmosph]ic ,,conditions   ,we h se5 9 
our t5? *apt] t ! physical basis (      
life--protoplasm--consi/s ( ! f\r       
elem5ts1 oxyg51 nitrog51 hydrog51 &     
c>bon1 & t bo? plants & animals dep5d   
l>gely ^u ! free oxyg5 9 ! air to c>ry  

on _! vital processes2 :ile ! c>bonic   
acid & ammonia 9 ! atmosph]e seem to be 
absolutely ess5tial to plants4 ,:e!r    
life c\ld h aris5 & h be5 highly        
develop$ ) an atmosph]e compos$ (       
diff]5t elem5ts f ours x is1 ( c\rse1   
impossible to say2 b !re are c]ta9      
physical conditions :i* seem absolutely 
ess5tial :atev] may be ! elem5ts :i*    
compose x4  ,! fir/ ( ^! ess5tials is an
 atmosph]e :i* %all be ( su* d5sity at !
 surface ( ! planet1 & ( s great a bulk1
 z to be n too r>e to fulfil its v>i\s  
functions at all altitudes :]e !re is a 
consid]able area ( l&4 ,:at det]m9es !  
total quantity ( gase\s matt] on !      
surface ( a planet w be1 ma9ly1 its     
mass1 toge!r ) ! av]age temp]ature ( its
 surface4  ,! molecules ( gases are 9 a 
/ate ( rapid motion 9 all directions1 & 
! light] gases h ! mo/ rapid motions4 ,!
 av]age spe$ ( ! motion ( ! molecules   
has be5 r\ghly det]m9$ "u v>y+          
conditions ( pressure & temp]ature1 &   
also ! probable maximum & m9imum rates1 

& f ^! data1 & c]ta9 kn[n facts z to    
planet>y atmosph]es1 ,mr4 ,g4 ,john/one 
,/oney1 ,f4,r4,s41 has calculat$ :at    
gases w escape f ! atmosph]es ( ! e>? & 
! o!r planets4 ,he f9ds t all ! gases   
:i* are con/itu5ts ( air h su*          
comp>atively l[ molecul> rates ( motion 
t ! =ce ( gravity at ! upp] limits ( !  
e>?'s atmosph]e is amply suffici5t to   
reta9 !m2 h5ce ! /ability 9 its         
composition4 ,b !re are two o!r gases1  
hydrog5 & helium1 :i* are bo? kn[n to   
ent] ! atmosph]e1 b nev] accumulate s z 
to =m any measurable portion ( x1 & ^!  
are f\nd to h suffici5t molecul> motion 
to escape f x4 ,) reg>d to hydrog51 if !
 e>? 7 mu* l>g] & m massive ?an x is1 s 
z to reta9 ! hydrog51 disa/r\s          
consequ5ces might ensue1 because1 :5ev] 
a suffici5t quantity ( ?is gas          
accumulat$1 x w\ld =m an explosive      
mixture ) ! oxyg5 ( ! atmosph]e1 & a    
fla% ( lightn+ or ev5 ! smalle/ flame   
w\ld lead to explosions s viol5t &      
de/ructive z p]haps to r5d] su* a planet

 unsuit$ = ! developm5t ( life4 ,we     
appe>1 !re=e1 to be j at ! major limit (
 mass to secure habitability1 except 9  
su* planets z may h no cont9u\s supply (
 free hydrog54         99       99      
99       99       99  ,p]haps ! mo/     
important me*anical functions ( !       
atmosph]e dep5d5t on its d5sity are3    
7#a7 ! production ( w9ds1 :i* 9 _m ways 
br+ ab\t an equalisation ( temp]ature1 &
 :i* also produce surface-curr5ts on !  
ocean2 & 7#b7 ! di/ribution ( moi/ure   
ov] ! e>? by means ( cl\ds :i* also h   
o!r important functions4  ,w9ds dep5d   
prim>ily on ! local di/ribution ( heat 9
 ! air1 especially on ! great am\nt (   
heat con/antly pres5t 9 ! equatorial    
zone1 due to ! sun be+ always ne>ly     
v]tical at noon1 & to its be+ simil>ly  
v]tical at ea* tropic once a ye>1 ) a   
long] day1 lead+ to ev5 high]           
temp]atures ?an at ! equator1 & produc+ 
also t cont9u\s belt ( arid l&s or      
des]ts :i* almo/ encircle ! globe 9 !   
region ( ! tropics4 ,heat$ air be+      

light]1 ! cold] air f ! temp]ate zones  
cont9ually fl[s t[>ds x1 lift+ x up &   
caus+ x to fl[ ov]1 z x 71 to ! nor? &  
s\?4 ,b z ! infl[ comes f an area ( less
 rapid to "o ( m rapid rotation1 ! c\rse
 ( ! air is div]t$1 & produces !        
nor?-ea/ & s\?-ea/ trades2 :ile ! ov]fl[
 f ! equator go+ to an area ( less rapid
 rotation1 turns we/w>d & produces !    
s\?-we/ w9ds s preval5t ov] ! nor?      
,atlantic & ! nor? temp]ate zone        
g5]ally1 & ! nor?-we/ 9 ! s\!rn         
hemisph]e4  ,x is outside ! zone ( !    
equable trade-w9ds1 & 9 a region a few  
degrees on ea* side ( ! tropics1 t      
de/ructive hurricanes & typhoons        
prevail4 ,^! are really enorm\s :irlw9ds
 due to ! int5sely heat$ atmosph]e ov] !
 arid regions already m5tion$1 caus+ an 
inru% ( cool air f v>i\s directions1 ?us
 sett+ up a rotatory motion :i*         
increases 9 rapidity till equilibrium is
 re/or$4 ,! hurricanes ( ! ,we/ ,indies 
& ,mauritius1 & ! typhoons ( ! ,ea/]n   
seas1 are ?us caus$4 ,"s ( ^! /orms are 

s viol5t t no human /ructures c resi/   
!m1 :ile ! l>ge/ & mo/ vigor\s trees are
 torn to pieces or ov]turn$ by !m4 ,b if
 our atmosph]e 7 mu* d5s] ?an x is1 its 
increas$ weight w\ld give x /ill great] 
de/ructive =ce2 & if to ?is 7 add$ a    
some:at great] am\nt ( sun-heat--:i*    
might be due ei!r to our great]         
proximity to ! sun or to ! sun's great] 
size or great] heat-int5sity1 ^! tempe/s
 might be s increas$ 9 frequ5cy &       
viol5ce z to r5d] consid]able portions (
 ! e>? un9habitable4  ,! con/ant &      
equable trade-w9ds h a v important      
function 9 initiat+ ^? f>-rea*+         
ocean-curr5ts :i* are ( ! greate/       
importance 9 equalis+ temp]ature4 ,!    
well kn[n ,gulf ,/ream is to u ! mo/    
important ( ^! curr5ts1 because x plays 
! *ief "p 9 giv+ u ! mild climate we    
enjoy 9 common ) ! :ole ( ,we/]n        
,europe1 a mildness :i* is felt to a    
consid]able di/ance )9 ! ,arctic        
,circle2 &1 9 conjunction ) ! ,japan    
curr5t1 :i* does ! same = ! :ole ( !    

temp]ate regions ( ! ,nor? ,pacific1    
r5d]s a l>ge portion ( ! globe bett]    
adapt$ = life ?an x w\ld be )\t ^!      
b5eficial influ5ces4  ,^! equalis+      
curr5ts1 h[ev]1 are almo/ entirely due  
to ! =m & position ( ! cont95ts1 &      
especially to ! fact t !y are s situat$ 
z to leave va/ expanses ( ocean along ! 
equatorial zone1 & ext5d+ nor? & s\? to 
! arctic & ant>ctic regions4 ,if ) !    
same am\nt ( l& ! cont95ts _h be5 s     
gr\p$ z to occupy a consid]able portion 
( ! equatorial oceans--su* z w\ld h be5 
! case _h ,africa be5 turn$ s z to jo9  
,s\? ,am]ica1 & ,asia be5 br\ght to !   
s\?-ea/ s z to take ! place ( "p ( !    
equatorial ,pacific1 !n ! great         
ocean-curr5ts c\ld h be5 b feeble or h  
h>dly exi/$4 ,)\t ^! curr5ts mu* ( !    
nor? & s\? temp]ate l&s w\ld h be5 buri$
 9 ice1 :ile ! l>ge/ portion ( !        
cont95ts w\ld h be5 s int5sely heat$ z  
p]haps to be unsuit$ = ! developm5t ( ! 
high] =ms ( animal life1 s9ce we h %[n  
79 *apt]s ,x4 & ,,xi47 h[ delicate is ! 

balance & h[ n>r[ ! limits ( temp]ature 
:i* are requir$4  ,!re seems to be no   
reason :atev] :y "s su* di/ribution ( ! 
sea & l& %\ld n h exi/$1 _h x n be5 = ! 
admitt$ly exceptional conditions :i* l$ 
to ! production ( our satellite1 ?us    
necess>ily =m+ va/ *asms along ! region 
( ! equator :]e c5trifugal =ce z well z 
! int]nal sol> tides 7 mo/ p[]ful1 & :]e
 ! ?9 cru/ 0 ?us compell$ to give way4  
,& z ! highe/ au?orities decl>e t !re   
are no indications ( su* an orig9 (     
satellites 9 ! case ( any o!r planet1 ! 
:ole s]ies ( conditions fav\rable to    
life on ! e>? become all ! m rem>kable4 
,,cl\ds1 ,,_! ,,importance ,,& ,,_!     
,,causes  ,few p]sons h any adequate    
conception ( ! real nature ( cl\ds & ( !
 important "p !y take 9 r5d]+ our _w a  
habitable & an enjoyable "o4  ,on !     
av]age1 ! ra9fall ov] ! oceans is mu*   
less ?an ov] ! l&1 ! :ole region ( !    
trade-w9ds hav+ usually a cl\dless sky &
 v little ra92 b 9 ! int]v5+ belt (     
calms1 ne> to ! equator1 a cl\dy sky &  

heavy ra9s are frequ5t4 ,?is arises f ! 
fact t ! w>m1 moi/ air ov] ! ocean is   
rais$ upw>ds1 by ! cold & heavy air f   
nor? & s\?1 into a cool] region :]e x _c
 hold s mu* aque\s vap\r1 :i* is !re    
cond5s$ & falls z ra94 ,g5]ally1 :]ev] !
 w9ds bl[ ov] ext5sive areas ( wat] on  
to ! l&1 especially if !re are m\nta9s  
or elevat$ plateaus :i* cause !         
moi/ure-lad5 air to rise to heights :]e 
! temp]ature is l[]1 cl\ds are =m$ & m  
or less ra9 falls4 ,b if ! l& is ( an   
arid nature & mu* heat$ by ! sun1 ! air 
becomes capable ( hold+ /ill m aque\s   
vap\r1 & ev5 d5se ra9-cl\ds disp]se )\t 
produc+ any ra9fall4 ,f ^! simple       
causes1 ) ! l>ge area ( sea z comp>$ ) !
 l& ^u our e>?1 by f> ! l>g] portion ( !
 surface is well suppli$ ) ra91 :i*1    
fall+ mo/ abundantly 9 ! elevat$ & !re=e
 cool] regions1 p]colates ! soil1 &     
gives rise to ^? innum]able spr+s &     
rivulets :i* moi/5 & beautify ! e>?1 &  
:i*1 unit+ toge!r1 =m /reams & riv]s1   
:i* return to ! seas & oceans :5ce !y 7 

orig9ally d]iv$4   ,,cl\ds ,,& ,,ra9    
,,dep5d ,,^u ,,atmosph]ic ,,du/  ,!     
beautiful sy/em ( aque\s circulation by 
means ( ! atmosph]e z sket*$ above 0    
long ?\ght to expla9 ! :ole process1 &  
to require no fur!r elucidation2 b ab\t 
a qu>t] ( a c5tury back a curi\s        
exp]im5t 0 made :i* indicat$ t !re 0    
ano!r factor 9 ! process :i* _h be5     
entirely ov]look$4 ,if a small jet (    
/eam is s5t into two l>ge glass         
receiv]s1 "o fill$ ) ord9>y air1 ! o!r )
 air :i* has be5 filt]$ by pass+ ?r\gh a
 ?ick lay] ( cotton wool s z to keep    
back all p>ticles ( solid matt]1 ! fir/ 
vessel w be in/antly fill$ ) cond5s$    
cl\dy-look+ vap\r1 :ile 9 ! o!r vessel !
 air & vap\r w rema9 p]fectly transp>5t 
& invisible4 ,ano!r exp]im5t 0 !n made  
to imitate m ne>ly :at occurs 9 nature4 
,! two vessels 7 prep>$ z be=e1 b a     
small quantity ( wat] 0 plac$ 9 ea*     
vessel & all[$ to evaporate till ! air 0
 ne>ly saturat$ ) vap\r1 :i* rema9$     
invisible 9 bo?4 ,bo? vessels 7 !n      

slightly cool$1 :5 in/antly a d5se cl\d 
0 =m$ 9 t fill$ ) unfilt]$ air1 :ile !  
o!r rema9$ q cle>4 ,^! exp]im5ts prov$ t
 ! m]e cool+ ( air bel[ ! dew po9t w n  
cause ! aque\s vap\r 9 x to cond5se into
 drops s z to =m mi/1 fog1 or cl\d1     
unless small p>ticles ( solid or liquid 
matt] are pres5t to act z nuclei ^u :i* 
cond5sation beg9s4 ,! d5sity ( a cl\d w 
!re=e dep5d n only on ! quantity ( vap\r
 9 ! air1 b on ! pres5ce ( an abundance 
( m9ute du/-p>ticles on :i* cond5sation 
c beg94  ,t su* du/ exi/s ev]y:]e 9 !   
air1 ev5 up to great heights1 is n a    
supposition b a prov$ fact4 ,by expos+  
glass plates cov]$ ) glyc]9e 9 diff]5t  
places & at diff]5t altitudes ! numb] ( 
^! p>ticles 9 ea* cubic foot ( air has  
be5 det]m9$2 & x is f\nd t n only are !y
 pres5t ev]y:]e at l[ levels1 b t !re   
are a consid]able numb] ev5 at ! tops ( 
! highe/ m\nta9s4 ,^! solid p>ticles    
also act 9 ano!r way4 ,by radiation 9 ! 
high] atmosph]e !y become v cold1 & ?us 
cond5se ! vap\r by contact1 j z ! po9ts 

( grass-blades cond5se x to =m dew4  ,:5
 /eam is escap+ f an eng9e we see a mass
 ( d5se :ite vap\r1 a m9iature cl\d2 &  
if we are ne> x 9 cold1 damp wea!r1 we  
feel little drops ( ra9 produc$ f x4 ,b 
on a f9e1 w>m day x rises quickly & soon
 melts away1 & entirely disappe>s4      
,exactly ! same ?+ happ5s on a l>g]     
scale 9 nature4 ,9 f9e wea!r we may h   
abundant cl\ds cont9ually pass+ high    
ov]head1 b !y nev] produce ra91 because 
z ! m9ute globules ( wat] sl[ly fall    
t[>ds ! e>?1 ! w>m dry air aga9 turns !m
 into invisible vap\r4 ,aga91 9 f9e     
wea!r1 we (t5 see a small cl\d on a     
m\nta9 top :i* rema9s !re a consid]able 
"t1 ev5 ?\gh a brisk w9d is bl[+4 ,!    
m\nta9 top is cold] ?an ! surr\nd+ air1 
& ! invisible vap\r becomes cond5s$ into
 cl\d by pass+ ov] x1 b ! mom5t ^! cl\d 
p>ticles are c>ri$ pa/ ! summit into !  
w>m] & dri] air !y are aga9 evaporat$ & 
disappe>4 ,on ,table ,m\nta91 ne> ,cape 
,t[n1 ?is ph5om5on occurs on a l>ge     
scale1 & is t]m$ ! table-clo?1 ! mass ( 

:ite fleecy cl\d seem+ to hang ov] !    
flat m\nta9 top to "s di/ance d[n :]e x 
rema9s = sev]al mon?s1 :ile all ar\nd   
!re is bright sun%9e4  ,ano!r ph5om5on t
 indicates ! univ]sal pres5ce ( du/ to  
enorm\s heights 9 ! atmosph]e is ! blue 
col\r ( ! sky4 ,?is is caus$ by !       
pres5ce ( su* excessively m9ute p>ticles
 ( du/ ?r\gh an enorm\s ?ickness ( !    
high] atmosph]e--probably up to a height
 ( tw5ty or ?irty miles1 or m--t !y     
reflect only ! light ( %ort wave-l5g? f 
! blue end ( ! spectrum4 ,?is also has  
be5 prov$ by exp]im5t4 ,if a glass      
cyl9d]1 sev]al feet long1 is fill$ )    
pure air f :i* all solid p>ticles h be5 
remov$ by filt]+ & pass+ ov] r$-hot     
plat9um wires1 & a ray ( electric light 
is pass$ ?r\gh x1 ! int]ior1 :5 view$   
lat]ally1 appe>s q d>k1 ! light pass+   
?r\gh 9 a /raight l9e & n illum9at+ !   
air4 ,b if a little m air is pass$ ?r\gh
 ! filt] s rapidly z to all[ only !     
m9ute/ p>ticles ( du/ to ent] ) x1 !    
vessel becomes gradually fill$ ) a blue 

haze1 :i* gradually deep5s into a       
beautiful blue1 comp>able ) t ( ! sky4  
,if n[ "s ( ! unfilt]$ air is admitt$1 !
 blue fades away into ! ord9>y t9t (    
daylight4  ,s9ce x has be5 kn[n t liquid
 oxyg5 is blue1 _m p h conclud$ t ?is   
expla9s ! blue col\r ( ! sky4 ,b x has  
really no?+ to d ) ! po9t at issue4 ,!  
blue ( ! liquid oxyg5 becomes s         
excessively fa9t 9 ! gas1 fur!r att5uat$
 z x is by ! col\rless nitrog51 t x w\ld
 h no p]ceptible col\r 9 ! :ole ?ickness
 ( our atmosph]e4 ,aga91 if x _h a      
p]ceptible blue t9t we c\ld n see x     
aga9/ ! blackness ( space beh9d x2 b    
:ite objects se5 ?r\gh x1 su* z ! moon &
 cl\ds1 %\ld all appe> blue1 :i* !y d n 
d4 ,! blue we see is f ! :ole sky1 & is 
!re=e reflect$ light2 & z pure air is q 
transp>5t1 !re mu/ be solid or liquid   
p>ticles s m9ute z to reflect blue light
 only4 ,9 ! l[] atmosph]e ! ra9-produc+ 
p>ticles are l>g]1 & reflect all ! rays1
 ?us dilut+ ! blue col\r ne> ! horizon1 
&1 by refraction & reflection comb9$1   

produc+ ! v>i\s beautiful hues ( sunrise
 & sunset4  ,?is production ( exquisite 
col\rs by ! du/ 9 ! atmosph]e1 ?\gh add+
 greatly to ! enjoym5t ( life1 _c be    
consid]$ ess5tial to x2 b !re is ano!r  
circum/ance connect$ ) atmosph]ic du/   
:i*1 ?\gh little appreciat$1 might h    
effects :i* c h>dly be calculat$4 ,if   
!re 7 no du/ 9 ! atmosph]e1 ! sky w\ld  
appe> black ev5 at noon1 except 9 !     
actual direction ( ! sun2 & ! />s w\ld  
be visible 9 ! day z well z at night4   
,?is w\ld foll[ because air does n      
reflect light1 & is n visible4 ,we %\ld 
!re=e receive no light f ! sky itself z 
we d n[1 & ! nor? side ( e hill1 h\se1 &
 o!r solid objects1 w\ld be totally d>k1
 unless !re 7 any surfaces 9 t direction
 to reflect ! light4 ,! surface ( !     
gr\nd at a little di/ance w\ld be 9     
sun%9e1 & ?is w\ld be ! only s\rce (    
light :]ev] direct sunlight 0 cut (f4   
,to get a good am\nt ( pleasant light 9 
h\ses x w\ld be necess>y to h !m built  
on ne>ly level gr\nd1 or on gr\nd ris+  

to ! nor?1 & ) walls ( glass all r\nd & 
d[n to ! floor l9e1 to receive z mu* z  
possible ( ! reflect$ light f ! gr\nd4  
,:at effect ?is k9d ( light w\ld h on   
vegetation x is difficult to say1 b     
trees & %rubs w\ld probably gr[ lat]ally
 t[>ds ! s\?1 ea/1 & we/1 s z to get z  
mu* direct sun%9e z possible4  ,a m     
important result w\ld be t1 z sun%9e    
w\ld be p]petual dur+ ! day1 s mu*      
evaporation w\ld take place t ! soil    
w\ld become arid & almo/ b>e 9 places t 
are n[ cov]$ ) vegetation1 & plants l ! 
cactuses ( ,arizona & ! euphorbias (    
,s\? ,africa w\ld occupy a l>ge portion 
( ! surface4  ,return+ n[ f ?is         
collat]al subject ( light & col\r to ! m
 important aspect ( ! "q--! abs5ce (    
cl\d & ra9--we h to consid] :at w\ld    
happ51 & 9 :at way ! enorm\s quantity ( 
wat] :i* w\ld be evaporat$ "u cont9ual  
sun%9e w\ld be return$ to ! e>?4  ,!    
fir/ & mo/ obvi\s means w\ld be by      
abnormally abundant dews1 :i* w\ld be   
deposit$ almo/ e night on e =m ( leafy  

vegetation4 ,n only w\ld all grass &    
h]bage1 b all ! out] leaves ( %rubs &   
trees1 cond5se s mu* moi/ure z to take !
 place ( ra9 s f> z ! ne$s ( su*        
vegetation 7 conc]n$4 ,b )\t arrangem5ts
 = irrigation cultivation w\ld be almo/ 
impossible1 because ! b>e soil w\ld     
become int5sely heat$ dur+ ! day1 & w\ld
 reta9 s mu* ( its heat ?r\gh ! night s 
z to prev5t any dew =m+ ^u x4  ,"s m    
effective mode1 !re=e1 ( return+ !      
aque\s vap\r ( ! atmosph]e to ! e>? &   
ocean1 w\ld be requir$1 & ?is1 ,i       
believe1 w\ld be done by means ( hills &
 m\nta9s ( suffici5t height to become   
decid$ly cold] ?an ! l[l&s4 ,! air f ov]
 ! oceans w\ld be con/antly load$ )     
moi/ure1 & :5ev] ! w9ds blew on to ! l& 
! air w\ld be c>ri$ up ! slopes ( !     
hills into ! cold] regions1 & !re be    
rapidly cond5s$ ^u ! vegetation1 & also 
on ! b>e e>? & rocks ( nor!rn slopes1 & 
:]ev] !y cool$ suffici5tly dur+ !       
aft]noon or night to be bel[ !          
temp]ature ( ! air4 ,! quantity ( vap\r 

?us cond5s$ w\ld r$uce ! atmosph]ic     
pressure1 :i* w\ld lead to an inru% (   
air f bel[1 br++ ) x m vap\r1 & ?is     
might give rise to p]petual torr5ts1    
especially on nor!rn & ea/]n slopes4 ,b 
z ! evaporation w\ld be mu* great] ?an  
at ! pres5t "t1 ow+ to p]petual sun%9e1 
s ! wat] return$ to ! e>? w\ld be       
great]1 & z x w\ld n be s uni=mly       
di/ribut$ ov] ! l& z x is n[1 ! result  
w\ld p]haps be t ext5sive m\nta9 sides  
w\ld become deva/at$ by viol5t torr5ts1 
r5d]+ p]man5t vegetation almo/          
impossible2 :ile o!r & m ext5sive areas1
 9 ! abs5ce ( ra91 w\ld become arid     
wa/es t w\ld support only ! few peculi> 
types ( vegetation t are *>act]i/ic (   
su* regions4  ,:e!r su* conditions z "h 
suppos$ w\ld prev5t ! developm5t ( !    
high] =ms ( life x is impossible to say1
 b x is c]ta9 t !y w\ld be v            
unfav\rable1 & might h mu* m disa/r\s   
consequ5ces ?an any we h "h sugge/$4 ,we
 c h>dly suppose t1 ) w9ds &            
rock-=mations at all l :at !y are n[1   

any _w c\ld be :olly free f atmosph]ic  
du/4 ,if1 h[ev]1 ! atmosph]e itself 7   
mu* less d5se ?an x is1 say "o-half1 :i*
 might v easily h be5 ! case1 !n ! w9ds 
w\ld h less c>ry+ p[]1 & at ! elevations
 at :i* cl\ds are usually =m$ !re w\ld n
 be en\gh du/-p>ticles to assi/ 9 _!    
=mation4 ,h5ce fogs close to ! e>?'s    
surface w\ld l>gely take ! place ( cl\ds
 float+ f> above x1 & ^! w\ld c]ta9ly be
 less fav\rable to human life & to t (  
_m ( ! high] animals ?an exi/+          
conditions4  ,! _w-wide di/ribution (   
atmosph]ic du/ is a rem>kable ph5om5on4 
,z ! blue col\r ( ! sky is univ]sal1 !  
:ole ( ! high] atmosph]e mu/ be p]vad$  
by myriads ( ultra-microscopical        
p>ticles1 :i*1 by reflect+ ! blue rays  
only1 give u n only ! azure vault (     
heav51 b 9 comb9ation ) ! co>s] du/ (   
l[] altitudes1 diffus$ daylight1 ! gr&  
=ms & motions ( ! fleecy cl\ds1 & !     
'g5tle ra9 f heav5' to refre% ! p>*$ e>?
 & make x beautiful ) foliage & fl[]s4  
,ov] e "p ( ! va/ ,pacific ,ocean1 ^:   

isl&s mu/ produce a m9imum ( du/1 ! sky 
is always blue1 & its ?\s& isles d n    
suff] = want ( ra94 ,ov] ! great        
=e/-pla9 ( ! ,amazon valley1 :]e !      
production ( du/ mu/ be v small1 !re is 
yet abundance ( ra9-cl\ds & ( ra94 ,?is 
is due prim>ily to ! two great natural  
s\rces ( du/--! active volcanoes1 toge!r
 ) ! des]ts & m arid regions ( ! _w2 &1 
9 ! second place1 to ! d5sity & wond]ful
 mobility ( ! atmosph]e1 :i* n only     
c>ries ! f9e/ du/-p>ticles to an enorm\s
 height1 b di/ributes !m ?r\gh its :ole 
ext5t ) su* wond]ful uni=mity4  ,e      
du/-p>ticle is ( c\rse mu* heavi] ?an   
air1 & 9 a comp>atively %ort "t1 if !   
atmosph]e 7 /ill1 w\ld fall to ! gr\nd4 
,tyndall f\nd t ! air ( a cell> "u !    
,royal ,in/itution 9 ,albem>le ,/reet1  
:i* _h n be5 op5$ = sev]al mon?s1 0 s   
pure t ! pa? ( a beam ( electric light  
s5t ?r\gh x 0 q invisible4 ,b c>eful    
exp]im5ts %[ t n only is ! air 9        
cont9ual motion1 b ! motion is          
excessively irregul>1 be+ h>dly ev] q   

horizontal1 b upw>ds & d[nw>ds & 9 e    
int]m$iate direction1 z well z 9        
c\ntless :irls & eddies2 & ?is          
complexity ( motion mu/ ext5d to a va/  
height1 probably to fifty miles or m1 9 
ord] to provide a suffici5t ?ickness (  
^? m9ute/ p>ticles :i* produce ! blue ( 
! sky4  ,all ?is complexity ( motion is 
due to ! action ( ! sun 9 heat+ !       
surface ( ! e>?1 & ! extreme irregul>ity
 ( t surface bo? z reg>ds cont\r & its  
capacity = heat-absorption4 ,9 "o area  
we h s& or rock or b>e clay1 :i*1 :5    
expos$ to bright sun%9e1 become scor*+  
hot2 9 ano!r area we h d5se vegetation1 
:i*1 ow+ to evaporation caus$ by !      
sun%9e1 rema9s comp>atively cool1 & also
 ! /ill cool] surfaces ( riv]s & ,alp9e 
lakes4 ,b if ! air 7 mu* less d5se ?an x
 is1 ^! movem5ts w\ld be less en]getic1 
:ile all ! du/ t 0 rais$ to any         
consid]able height w\ld1 by its own     
weight1 fall back aga9 to ! e>? mu* m   
rapidly ?an x does n[4 ,!re w\ld ?us be 
mu* less du/ p]man5tly 9 ! atmosph]e1 & 

?is w\ld inevitably lead to dim9i%$     
ra9fall &1 p>tially1 to ! o!r injuri\s  
effects already describ$4   ,,atmosph]ic
 ,,electricity  ,we h already se5 t     
vegetable organisms obta9 ! *ief "p ( ! 
nitrog5 9 _! tissues f ammonia produc$ 9
 ! atmosph]e & c>ri$ into ! e>? by ra94 
,?is sub/ance c only be ?us produc$ by !
 ag5cy ( electrical dis*>ges1 or        
lightn+1 :i* cause ! comb9ation ( !     
hydrog5 9 ! aque\s vap\r ) ! free       
nitrog5 ( ! air4 ,b cl\ds are important 
ag5ts 9 ! accumulation ( electricity 9  
suffici5t am\nt to produce ! viol5t     
dis*>ges we "k z lightn+1 & x is d\btful
 :e!r )\t !m !re w\ld be any dis*>ges   
?r\gh ! atmosph]e capable ( decompos+ ! 
aque\s vap\r 9 x4 ,n only are cl\ds     
b5eficial 9 ! production ( ra91 & also 9
 mod]at+ ! int5sity ( cont9u\s sun-heat1
 b !y are also requisite = ! =mation (  
*emical comp\nds 9 vegetables :i* are ( 
! highe/ importance to ! :ole animal    
k+dom4 ,s f> z we "k1 animal life c\ld n
 exi/ on ! e>?'s surface )\t ?is s\rce (

 nitrog51 & !re=e )\t cl\ds & lightn+2 &
 ^!1 we h j se51 dep5d prim>ily on a due
 proportion ( du/ 9 ! atmosph]e4  ,b ?is
 due proportion ( du/ is ma9ly suppli$  
by volcanoes & des]ts1 & its di/ribution
 & con/ant pres5ce 9 ! air dep5ds ^u !  
d5sity ( ! atmosph]e4 ,?is aga9 dep5ds  
on two o!r factors3 ! =ce ( gravity due 
to ! mass ( ! planet1 & ! absolute      
quantity ( ! free gases con/itut+ !     
atmosph]e4  ,we ?us f9d t ! va/1        
invisible ocean ( air 9 :i* we live1 &  
:i* is s important to u t deprivation ( 
x = a few m9utes is de/ructive ( life1  
produces also _m o!r b5eficial effects (
 :i* we usually take little acc\nt1     
except at times :5 /orm or tempe/1 or   
excessive heat or cold1 rem9d u h[      
delicate is ! balance ( conditions on   
:i* our com=t1 & ev5 our lives1 dep5d4  
,b ! sket* ,i h "h attempt$ to give (   
its v>i$ functions %[s u t x is really a
 mo/ complex /ructure1 a wond]ful piece 
( ma*9]y1 z x 71 :i* 9 its v>i\s        
compon5t gases1 its actions & reactions 

^u ! wat] & ! l&1 its production (      
electrical dis*>ges1 & its furni%+ !    
elem5ts f :i* ! :ole fabric ( organic   
life is compos$ & p]petually r5ew$1 may 
be truly consid]$ to be ! v s\rce &     
f\ndation ( life itself4 ,?is is se51 n 
only 9 ! fact ( our absolute dep5d5ce ^u
 x e m9ute ( our lives1 b 9 ! t]rible   
effects produc$ by ev5 a slight degree (
 impurity 9 ?is vital elem5t4 ,yet x is 
among ^? nations t claim to be ! mo/    
civilis$1 ^? t pr(ess to be guid$ by a k
 ( ! laws ( nature1 ^? t mo/ glory 9 !  
advance ( sci5ce1 t we f9d ! greate/    
apa?y1 ! greate/ recklessness1 9        
cont9ually r5d]+ impure ?is             
all-important necess>y ( life1 to su* a 
degree t ! heal? ( ! l>g] portion ( _!  
populations is injur$ & _! vitality     
l[]$1 by conditions :i* compel !m to    
brea! m or less f\l & impure air = !    
great] "p ( _! lives4 ,! huge &         
ev]-increas+ cities1 ! va/ manufactur+  
t[ns bel*+ =? smoke & poison\s gases1 ) 
! cr[d$ dwell+s1 :]e millions are =c$ to

 live "u ! mo/ t]rible insanit>y        
conditions1 are ! witnesses to ?is      
crim9al apa?y1 ?is incr$ible            
recklessness & inhumanity4  ,= ! la/    
fifty ye>s & m ! inevitable results (   
su* conditions h be5 fully kn[n2 yet to 
?is day no?+ ( importance has be5 done1 
no?+ is be+ done4 ,9 ?is beautiful l&   
!re is ample space & a sup]abundance (  
pure air = e individual4 ,yet our weal?y
 & our le>n$ classes1 our rul]s &       
law-mak]s1 our religi\s tea*]s & our m5 
( sci5ce1 all alike devote _! lives &   
en]gies to any?+ or ev]y?+ b ?is4 ,yet  
?is is ! "o great & prim>y ess5tial ( a 
p's heal? & well-be+1 to :i* ev]y?+     
%\ld1 = ! "t1 be subord9ate4 ,till ?is  
is done1 & done ?or\ghly & completely1  
our civilisation is naught1 our sci5ce  
is naught1 our religion is naught1 & our
 politics are less ?an naught--are      
utt]ly despicable2 are bel[ contempt4   
,x has be5 ! consid]ation ( our wond]ful
 atmosph]e 9 its v>i\s relations to     
human life1 & to all life1 :i* has      

compell$ me to ?is cry = ! *ildr5 & =   
outrag$ humanity4 ,w no body ( humane m5
 & wom5 b& !mselves toge!r1 & take no   
re/ till ?is cry+ evil is aboli%$1 & ) x
 n9e-t5?s ( all ! o!r evils t n[ afflict
 u8 ,let ev]y?+ give way to ?is4 ,z 9 a 
w> ( conque/ or aggression no?+ is all[$
 to /& 9 ! way ( victory1 & all private 
rights are subord9at$ to ! alleg$ public
 weal1 s1 9 ?is w> aga9/ fil?1 disease1 
& mis]y let no?+ /& 9 ! way--nei!r      
private int]e/s nor ve/$ rights--& we   
%all c]ta9ly conqu]4 ,?is is ! gospel t 
%\ld be prea*$1 9 season & out ( season1
 till ! nation li/5s & is conv9c$4 ,let 
?is be our claim3 ,pure air & pure wat] 
= e inhabitant ( ! ,briti% ,isles4 ,vote
 = no "o :o says ',x c't be done4' ,vote
 only = ^? :o decl>e ',x %all be done4' 
,x may take five or t5 or tw5ty ye>s1 b 
all petty ameliorations1 all piecemeal  
re=ms1 mu/ wait till ?is fundam5tal re=m
 is effect$4 ,!n1 :5 we h enabl$ our p  
to brea! pure air1 & dr9k pure wat]1 &  
live ^u simple food1 & "w & play & re/  

"u heal?y conditions1 !y w be 9 a       
position to decide 7= ! fir/ "t7 :at o!r
 re=ms are really ne$$4  ,rememb]6 ,we  
claim to be a p ( high civilisation1 (  
advanc$ sci5ce1 ( great humanity1 (     
enorm\s weal?6 ,= v %ame d n let u say  
',we _c arrange matt]s s t our p may all
 brea! unpollut$1 unpoison$ air6'       
,,*apt] ,,xiv  ,,! ,,e>? ,,is ,,! ,,only
 ,,habitable ,,planet ,,9 ,,! ,,sol>    
,,sy/em   ,hav+ %[n 9 ! la/ ?ree *apt]s 
h[ num]\s & h[ complex are ! conditions 
:i* alone r5d] life possible on our e>?1
 h[ nicely balanc$ are oppos+ =ces1 & h[
 curi\s & delicate are ! means by :i* ! 
ess5tial comb9ations ( ! elem5ts are    
br\ght ab\t1 x w be a comp>atively easy 
task to %[ h[ totally unfitt$ are all ! 
o!r planets ei!r to develop or to       
pres]ve ! high] =ms ( life1 &1 9 mo/    
cases1 any =ms above ! l[e/ & mo/       
rudim5t>y4 ,9 ord] to make ?is cle> we w
 take ! mo/ important ( ! conditions 9  
ord]1 & see h[ ! v>i\s planets fulfil   
!m4   ,,mass ,,( ,a ,,planet ,,& ,,its  

,,atmosph]e  ,! height & d5sity ( !     
atmosph]e ( a planet is important z     
reg>ds life 9 sev]al ways4 ,on its      
d5sity dep5ds its p[] ( c>ry+ moi/ure2 (
 hold+ a suffici5t supply ( du/-p>ticles
 = ! =mation ( cl\ds2 ( c>ry+           
ultra-microscopic p>ticles to su* a     
height & 9 su* quantity z to diffuse !  
light ( ! sun by reflection f ! :ole    
sky2 ( rais+ waves 9 ! ocean & ?us a]at+
 its wat]s1 & ( produc+ ! ocean curr5ts 
:i* s greatly equalise temp]ature4 ,n[  
?is d5sity dep5ds on two factors3 ! mass
 ( ! planet & ! quantity ( ! atmosph]ic 
gases4 ,b !re is good reason to ?9k t ! 
latt] dep5ds directly ^u ! =m]1 because 
x is only :5 a c]ta9 mass is atta9$ t   
any ( ! light] p]man5t gases c be held  
on ! surface ( a planet4 ,?us1 accord+  
to ,dr4 ,g4 ,john/one ,/oney1 :o has    
specially /udi$ ?is subject1 ! moon _c  
reta9 ev5 su* a heavy gas z c>bonic     
acid1 or ! /ill heavi] c>bon disulphide2
 :ile no p>ticle ( oxyg51 nitrog51 or   
wat]-vap\r c possibly rema9 on x1 ow+ to

 ! fact ( its mass be+ only ab\t        
"o-eightie? t ( ! e>?4 ,x is believ$ t  
!re are consid]able quantities ( gases 9
 ! /ell> spaces1 & probably also )9 !   
sol> sy/em1 b p]haps 9 ! liquid or solid
 =m4 ,9 t /ate !y might be attract$ by  
any small mass su* z ! moon1 b ! heat ( 
its surface :5 expos$ to ! sol> rays    
w\ld quickly re/ore !m to ! gase\s      
condition1 :5 !y w\ld at once escape4   
,x is only :5 a planet atta9s a mass at 
lea/ a qu>t] t ( ! e>? t x is capable ( 
reta9+ wat]-vap\r1 "o ( ! mo/ ess5tial (
 ! gases2 b ) s small a mass z ?is1 its 
:ole atmosph]e w\ld probably be s limit$
 9 am\nt & s r>e at ! planet's surface t
 x w\ld be q unable to fulfil ! v>i\s   
purposes = :i* an atmosph]e is requir$ 9
 ord] to support life4 ,= _! adequate   
fulfilm5t ! mass ( a planet _c be mu*   
less ?an t ( ! e>?4 ,"h we come to "o ( 
^? nice adju/m5ts ( :i* s _m h be5      
already po9t$ out4 ,dr4 ,john/one ,/oney
 arrives at ! conclusion t hydrog5      
escapes f ! e>?4 ,x is cont9ually       

produc$ 9 small quantities by subm>9e   
volcanoes1 by fissures 9 volcanic       
regions1 f decay+ vegetation1 & f "s o!r
 s\rces2 yet1 ?\gh sometimes f\nd 9     
m9ute quantities1 x =ms no regul>       
con/itu5t ( our atmosph]e4#ah  ,!       
quantity ( hydrog5 comb9$ ) oxyg5 to =m 
! mass ( wat] 9 our va/ & deep oceans is
 enorm\s4 ,yet if x _h be5 only "o-t5? m
 ?an x actually is1 ! pres5t l&-surface 
w\ld h be5 almo/ all subm]g$4 ,h[ !     
adju/m5ts occurr$ s t !re 0 exactly     
en\gh hydrog5 to fill ! va/ ocean bas9s 
) wat] to su* a dep? z to leave en\gh   
l&-surface = ! ample developm5t (       
vegetable & animal life1 & yet n s mu* z
 to be injuri\s to climate1 x is        
difficult to imag9e4 ,yet ! adju/m5t    
/>es u 9 ! face4 ,fir/1 we h a satellite
 unique 9 size z comp>$ ) its prim>y1 & 
app>5tly 9 lat5ess ( orig92 !n we h a   
mode ( orig9 = t satellite said to be   
c]ta9ly unique 9 ! sol> sy/em2 z a      
consequ5ce ( ?is orig91 x is believ$1 we
 h enorm\sly deep ocean bas9s           

symmetrically plac$ ) reg>d to !        
equator--an arrangem5t :i* is v         
important = ocean circulation2 !n we mu/
 h _h ! "r quantity ( hydrog51 obta9$ 9 
"s unkn[n way1 :i* =m$ wat] en\gh to    
fill ^! *asms1 s z to leave an ample    
area ( dry l&1 b :i* "o-t5? m wat] w\ld 
h +ulf$2 &1 la/ly1 we h oxyg5 en\gh left
 to =m an atmosph]e ( suffici5t d5sity =
 all ! requirem5ts ( life4 ,x c\ld n be 
t ! surplus hydrog5 escap$ :5 ! wat] _h 
be5 produc$1 because x escapes v sl[ly1 
& x comb9es s easily ) free oxyg5 by    
means ( ev5 a sp>k1 z to make x c]ta9 t 
all ! available hydrog5 0 us$ up 9 !    
oceanic wat]s1 & t ! supply f ! e>?'s   
int]ior has be5 s9ce comp>atively small 
9 am\nt4  ,!re is yet "o m adju/m5t to  
be notic$4 ,all ! facts n[ ref]r$ to %[ 
t ! e>?'s mass is suffici5t to br+ ab\t 
! conditions fav\rable = life4 ,b if our
 globe _h be5 a little l>g]1 &          
proportionately d5s]1 9 all probability 
no life w\ld h be5 possible4 ,betwe5 a  
planet ( #hjjj & "o ( #iejj miles       

diamet] is n a l>ge diff]5ce1 :5 comp>$ 
) ! enorm\s range ( size ( ! o!r        
planets4 ,yet ?is slight increase 9     
diamet] w\ld give two-?irds increase 9  
bulk1 &1 ) a correspond+ increase (     
d5sity due to ! great] gravitative =ce1 
! mass w\ld be ab\t d\ble :at x is4 ,b )
 d\ble ! mass ! quantity ( gases ( all  
sorts attract$ & reta9$ by gravity w\ld 
probably h be5 d\ble2 & 9 t case !re    
w\ld h be5 d\ble ! quantity ( wat]      
produc$1 z no hydrog5 c\ld !n escape4 ,b
 ! surface ( ! globe w\ld only be "o    
half great] ?an at pres5t1 9 :i* case ! 
wat] w\ld h suffic$ to cov] ! :ole      
surface sev]al miles deep4              
,,habitability ,,( ,,o!r ,,planets  ,:5 
we look to ! o!r planets ( our sy/em we 
see ev]y:]e illu/rations ( ! relation ( 
size & mass to habitability4 ,! small]  
planets1 ,m]cury & ,m>s1 h n suffici5t  
mass to reta9 wat]-vap\r1 &1 )\t x1 !y  
_c be habitable4 ,all ! l>g] planets c h
 v little solid matt]1 z indicat$ by _! 
v l[ d5sity not)/&+ _! enorm\s mass4    

,!re is1 !re=e1 v good reason = ! belief
 t ! adaptability ( a planet = a full   
developm5t ( life is prim>ily dep5d5t1  
)9 v n>r[ limits1 on its size &1 m      
directly1 on its mass4 ,b if ! e>? owes 
its specially con/itut$ atmosph]e & its 
nicely adju/$ quantity ( wat] to su*    
g5]al causes z "h indicat$1 & ! same    
causes apply to ! o!r planets ( ! sol>  
sy/em1 !n ! only planet on :i* life c be
 possible is ,v5us4 ,z1 h[ev]1 x may be 
urg$ t exceptional causes may h giv5 o!r
 planets an equal advantage 9 ! matt] ( 
air & wat]1 we w briefly consid] "s ( ! 
o!r conditions :i* we h f\nd to be      
ess5tial 9 ! case ( ! e>?1 b :i* x is   
almo/ impossible to conceive z exi/+1 to
 ! requir$ ext5t1 on any ( ! o!r planets
 ( ! sol> sy/em4   ,a ,,small ,,&       
,,def9ite ,,range ,,( ,,temp]ature  ,we 
h already se5 )9 :at n>r[ limits !      
temp]ature on a planet's surface mu/ be 
ma9ta9$ 9 ord] to develop & support     
life4 ,we h also se5 h[ num]\s & h[     
delicate are ! conditions1 su* z d5sity 

( atmosph]e1 ext5t & p]man5ce ( oceans1 
& di/ribution ( sea & l&1 :i* are       
requisite1 ev5 ) u1 9 ord] to r5d]      
possible ! cont9u\s pres]vation ( a     
suffici5tly uni=m temp]ature4 ,slight   
alt]ations "o way or ano!r might r5d] ! 
e>? almo/ un9habitable1 ?r\gh its be+   
liable to alt]nations ( too great heat  
or excessive cold4 ,h[ !n c we suppose t
 any o!r ( ! planets1 :i* h ei!r v mu* m
 or v mu* less sun-heat ?an we receive1 
c\ld1 by any possible modification (    
conditions1 be r5d]$ capable ( produc+ &
 support+ a full & v>i$ life-developm5t8
  ,m>s receives less ?an half ! am\nt ( 
sun-heat p] unit ( surface t we d4 ,& z 
x is almo/ c]ta9 t x conta9s no wat]    
7its pol> sn[s be+ caus$ by c>bonic acid
 or "s o!r heavy gas7 x foll[s t1 al?\gh
 x may produce vegetable life ( "s l[   
k9ds1 x mu/ be q unsuit$ = t ( ! high]  
animals4 ,its small size & mass1 ! latt]
 only "o-n9? t ( ! e>?1 may probably    
all[ x to possess a v r>e atmosph]e (   
oxyg5 & nitrog51 if ^? gases exi/ !re1 &

 ?is lack ( d5sity w\ld r5d] x unable to
 reta9 dur+ ! night ! v mod]ate am\nt ( 
heat x might absorb dur+ ! day4 ,?is    
conclusion is support$ by its l[        
reflect+ p[]1 %[+ t x has h>dly any     
cl\ds 9 its scanty atmosph]e4 ,dur+ !   
great] "p ( ! tw5ty-f\r h\rs1 !re=e1 its
 surface-temp]ature w\ld probably be mu*
 bel[ ! freez+ po9t ( wat]2 & ?is1 tak5 
9 conjunction ) ! total abs5ce ( aque\s 
vap\r or liquid wat]1 w\ld add /ill     
fur!r to its unsuitability = animal     
life4  ,9 ,v5us ! conditions are equally
 adv]se 9 ! o!r direction4 ,x receives f
 ! sun almo/ d\ble ! am\nt ( heat t we  
receive1 & ?is alone w\ld r5d] necess>y 
"s extraord9>y comb9ation ( modify+     
ag5cies 9 ord] to r$uce & r5d] uni=m !  
excessively high temp]ature4 ,b x is n[ 
kn[n t ,v5us has "o peculi>ity :i* is 9 
itself almo/ prohibitive ( animal life1 
& probably ( ev5 ! l[e/ =ms ( vegetable 
life4 ,?is peculi>ity is1 t ?r\gh tidal 
action caus$ by ! sun1 its day has be5  
made to co9cide ) its ye>1 or1 m        

prop]ly1 t x rotates on its axis 9 !    
same "t t x revolves r\nd ! sun4 ,h5ce x
 always pres5ts ! same face to ! sun2 & 
:ile "o half has a p]petual day1 ! o!r  
half has p]petual night1 ) p]petual     
twilight ?r\gh refraction 9 a n>r[ belt 
adjo9+ ! illum9at$ half4 ,b ! side t    
nev] receives ! direct rays ( ! sun mu/ 
be int5sely cold1 approximat+1 9 !      
c5tral portions1 to ! z]o ( temp]ature1 
:ile ! half expos$ to p]petual sun%9e ( 
d\ble int5sity to ours mu/ almo/ c]ta9ly
 rise to a temp]ature f> too great = !  
exi/5ce ( protoplasm1 & probably1 !re=e1
 ( any =m ( animal life4  ,v5us appe>s  
to h a d5se atmosph]e1 & its brilliancy 
sugge/s t we see ! upp] surface ( a     
cl\d-canopy1 & ?is w\ld no d\bt greatly 
r$uce ! excessive sol> heat4 ,its mass1 
be+ a little m ?an ?ree-f\r?s t ( ! e>?1
 w\ld enable x to reta9 ! same gases z  
we possess4 ,b "u ! extraord9>y         
conditions t prevail on ! surface ( ?is 
planet1 x is h>dly possible t !         
temp]ature ( ! illum9at$ side c be      

pres]v$ 9 a suffici5t /ate ( uni=mity = 
! developm5t ( life 9 any ( its high]   
=ms4  ,m]cury possesses ! same          
peculi>ity ( keep+ "o face always t[>ds 
! sun1 & z x is s mu* small] & s mu*    
ne>] ! sun its contra/s ( heat & cold   
mu/ be /ill m excessive1 & we ne$ h>dly 
discuss ! possibility ( ?is planet be+  
habitable4 ,its mass be+ only "o-?irtie?
 t ( ! e>?1 wat]-vap\r w c]ta9ly escape 
f x1 &1 mo/ probably1 nitrog5 & oxyg5   
also1 s t x c possess v little          
atmosph]e2 & ?is is indicat$ by its l[  
reflect+ p[]1 no less ?an #hc p] c5t4 ( 
! sun's light be+ absorb$1 & only #ag p]
 c5t4 reflect$1 :]eas cl\ds reflect #gb 
p] c5t4 ,?is planet is !re=e int5sely   
heat$ on "o side & froz5 on ! o!r2 x has
 no wat] & h>dly any atmosph]e1 & is    
!re=e1 f e po9t ( view1 totally unfitt$ 
= support+ liv+ organisms4  ,ev5 if x is
 suppos$ t1 9 ! case ( ,v5us1 its       
p]petual cl\d-canopy may keep d[n !     
surface temp]ature )9 ! limits necess>y 
= animal life1 ! extraord9>y turmoil 9  

its atmosph]e caus$ by ! excessively    
contra/$ temp]atures ( its d>k & light  
hemisph]es mu/ be extremely inimical to 
life1 if n absolutely prohibitive ( x4  
,= on ! great] "p ( ! hemisph]e t nev]  
receives a ray ( light or heat f ! sun  
all ! wat] & aque\s vap\r mu/ be turn$  
into ice or sn[1 & x seems almo/        
impossible t ! air itself c escape      
congelation4 ,x c\ld only d s by a v    
rapid circulation ( ! :ole atmosph]e1 & 
?is w\ld c]ta9ly be produc$ by ! enorm\s
 & p]man5t diff]5ce ( temp]ature betwe5 
! two hemisph]es4 ,indications (        
refraction by a d5se atmosph]e are      
visible dur+ ! planet's transit ov] !   
sun's disc1 & also :5 x is 9 conjunction
 ) ! sun1 & ! refraction is s great t   
,v5us is believ$ to h an atmosph]e mu*  
high] ?an ours4 ,b dur+ ! rapid         
circulation ( su* an atmosph]e1 heat$ on
 "o half ! planet & cool$ on ! o!r1 mo/ 
( ! aque\s vap\r mu/ be tak5 out ( x on 
! d>k side z fa/ z x is produc$ on !    
heat$ side1 ?\gh suffici5t may rema9 to 

produce a canopy ( v l(ty cl\ds analog\s
 to our cirri4 ,! occasional visibility 
( ! d>k side ( ,v5us may be caus$ by an 
electrical gl[ due to ! friction ( !    
p]petually ov]fl[+ & infl[+ atmosph]e1  
?is be+ increas$ by reflection f a va/  
surface ( p]petual sn[4 ,if we consid]  
all ! exceptional features ( ?is planet1
 x appe>s c]ta9 t ! conditions z reg>ds 
climate _c n[ be su* z to ma9ta9 a      
temp]ature )9 ! n>r[ limits ess5tial =  
life1 :ile !re is little probability t  
at any e>li] p]iod x c h possess$ &     
ma9ta9$ ! necess>y /ability dur+ ! long 
epo*s :i* are requisite = its           
developm5t4  ,be=e consid]+ ! condition 
( ! l>g] planets1 x w be well to ref] to
 an argum5t :i* has be5 suppos$ to      
m9imise ! difficulties already /at$ z to
 ^? planets :i* approa* ne>e/ to ! e>? 9
 size & di/ance f ! sun4   ,,! ,,argum5t
 ,,f ,,extreme ,,conditions ,,on ,,!    
,,e>?  ,9 reply to ! evid5ce %[+ h[ nice
 are ! adaptations requir$ =            
life-developm5t1 x is (t5 object$ t life

 does n[ exi/ "u v extreme              
conditions--"u tropic heat & arctic     
sn[s2 9 ! burnt-up des]t z well z 9 !   
moi/ tropical =e/2 9 ! air z well z 9 ! 
wat]2 on l(ty m\nta9s z well z on !     
level l[l&s4 ,?is is no d\bt true1 b x  
does n prove t life c\ld h be5 develop$ 
9 a _w :]e any ( ^! extremes ( climate  
*>act]is$ ! :ole surface4 ,! des]ts are 
inhabit$ because !re are oases :]e wat] 
is atta9able1 z well z 9 ! surr\nd+     
f]tile areas4 ,! arctic regions are     
inhabit$ because !re is a summ]1 & dur+ 
t summ] !re is vegetation4 ,if ! surface
 ( ! gr\nd 7 always froz51 !re w\ld be  
no vegetation & no animal life4  ,! late
 ,mr4 ,r4,a4 ,proctor put ?is argum5t ( 
! div]sity ( conditions "u :i* life     
actually does exi/ on ! e>? z well      
probably z x c be put4 ,he says3 ',:5 we
 consid] ! v>i\s conditions "u :i* life 
is f\nd to prevail1 t no diff]5ce (     
climatic relations1 or ( elevation1 (   
l&1 or ( air1 or ( wat]1 ( soil 9 l&1 ( 
fre%ness or saltness 9 wat]1 ( d5sity 9 

air1 appe>s 7s f> z our rese>*es h      
ext5d$7 to r5d] life impossible1 we are 
compell$ to inf] t ! p[] ( support+ life
 is a quality :i* has an exce$+ly wide  
range 9 nature4'  ,?is is true1 b )     
c]ta9 res]vations4 ,! only species (    
animal :i* does really exi/ "u ! mo/    
v>i$ conditions ( climate is man1 & he  
does s because 8 intellect r5d]s him to 
"s ext5t ! rul] ( nature4 ,none ( ! l[] 
animals h su* a wide range1 & ! div]sity
 ( conditions is n really s great z x   
appe>s to be4 ,! /rict limits are n[h]e 
p]man5tly ov]pass$1 & !re is always !   
*ange f w9t] to summ]1 & ! possibility (
 migration to less inhospitable areas4  
,,! ,,great ,,planets ,,all             
,,un9habitable  ,hav+ already %[n t !   
condition ( ,m>s1 bo? z reg>ds wat]1    
atmosph]e1 & temp]ature1 is q unfitt$ to
 ma9ta9 life1 a view 9 :i* bo? g5]al    
pr9ciples & telescopic exam9ation       
p]fectly agree1 we may pass on to ! out]
 planets1 :i*1 h[ev]1 h long be5 giv5 up
 z adapt$ = life ev5 by ! mo/ ard5t     

advocates = 'life 9 o!r worlds4' ,_!    
remot5ess f ! sun--ev5 ,jupit] be+ five 
times z f> z ! e>?1 & !re=e receiv+ only
 "o tw5ty-fif? ( ! light & heat t we    
receive p] unit ( surface--r5d]s x almo/
 impossible1 ev5 if o!r conditions 7    
fav\rable1 t !y %\ld possess            
surface-temp]atures adequate to !       
necessities ( organic life4 ,b _! v l[  
d5sities1 comb9$ ) v l>ge size1 r5d]s x 
c]ta9 t !y none ( !m h a solidifi$      
surface1 or ev5 ! elem5ts f :i* su* a   
surface c\ld be =m$4  ,x is suppos$ t   
,jupit] & ,saturn1 z well z ,uranus &   
,neptune1 reta9 a consid]able am\nt (   
int]nal heat1 b c]ta9ly n suffici5t to  
keep ! metallic & o!r elem5ts ( :i* !   
sun & e>? consi/ 9 a /ate ( vap\r1 = if 
s !y w\ld be planet>y />s & w\ld %9e by 
_! own light4 ,& if any consid]able     
portion ( _! bulk consi/$ ( ^! elem5ts1 
:e!r 9 a solid or a liquid /ate1 _!     
d5sities w\ld necess>ily be mu* great]  
?an t ( ! e>? in/ead ( v mu*            
less--,jupit] is "u "o-f\r? ! d5sity ( !

 e>?1 ,saturn "u an eigh?1 :ile ,uranus 
& ,neptune are ( int]m$iate d5sities1   
?\gh mu* less 9 bulk ev5 ?an ,saturn4   
,x ?us appe>s t ! sol> sy/em consi/s (  
two gr\ps ( planets :i* diff] widely f  
ea* o!r4 ,! out] gr\p ( f\r v l>ge      
planets are almo/ :olly gase\s1 &       
probably consi/ ( ! p]man5t gases--^?   
:i* c only be liquefi$ or solidifi$ at a
 v l[ temp]ature4 ,9 no o!r way c _!    
small d5sity comb9$ ) enorm\s bulk be   
acc\nt$ =4  ,! inn] gr\p also ( f\r     
planets are totally unlike ! prec$+4 ,!y
 are all ( small size1 ! e>? be+ !      
l>ge/4 ,!y are all ( a d5sity r\ghly    
proportionate to _! bulk4 ,! e>? is bo? 
! l>ge/ & ! d5se/ ( ! gr\p2 n only is x 
situat$ at t di/ance f ! sun :i*1 ?r\gh 
sol> heat alone1 all[s wat] to rema9 9 !
 liquid /ate ov] almo/ ! :ole ( its     
surface1 b x possesses num]\s           
*>act]i/ics :i* secure a v equable      
temp]ature1 & :i* h secur$ to x v ne>ly 
! same temp]ature dur+ ^? enorm\s       
geological p]iods 9 :i* t]re/rial life  

has exi/$4 ,we h already %[n t no o!r   
planet possesses ^! *>act]i/ics n[1 & x 
is almo/ equally c]ta9 t !y nev] h      
possess$ !m 9 ! pa/1 & nev] w possess !m
 9 ! future4   ,a ,,la/ ,,argum5t ,,=   
,,habitability ,,( ,,! ,,planets        
,al?\gh x has be5 admitt$ by ! late ,mr4
 ,proctor & "s o!r a/ronom]s t mo/ ( !  
planets are n n[ habitable1 yet1 x is   
(t5 urg$1 !y may h be5 s 9 ! pa/ or may 
become s 9 ! future4 ,"s are n[ too hot1
 o!rs are n[ too cold2 "s h n[ no wat]1 
o!rs h too mu*2 b all g ?r\gh _! appo9t$
 s]ies ( /ages1 & dur+ "s ( ^! /ages    
life may be or may h be5 possible4 ,?is 
argum5t1 al?\gh vague1 w appeal to "s   
read]s1 & x may1 !re=e1 be necess>y to  
reply to x4 ,?is is ! m necess>y z x is 
/ill made use ( by a/ronom]s4 ,9 a      
criticism ( my article 9 ,! ,=tnightly  
,review1 ,m4 ,camille ,flamm>ion1 ( !   
,p>is ,obs]vatory1 dramatically rem>ks3 
',yes1 life is univ]sal1 & et]nal1 = "t 
is "o ( its factors4 ,ye/]day ! moon1   
to-day ! e>?1 to-morr[ ,jupit]4 ,9 space

 !re are bo? cradles & tombs4'#ai  ,x is
 ?us sugge/$ t ! moon 0 once inhabit$ & 
t ,jupit] w be inhabit$ 9 "s remote     
future2 b no attempt is made to deal ) !
 ess5tial physical conditions ( ^! v    
div]se objects1 r5d]+ !m n only n[1 b   
always1 unfitt$ to develop & to ma9ta9  
t]re/rial or a]ial life4 ,?is vague     
supposition--x c h>dly be t]m$ an       
argum5t--z reg>ds pa/ or future         
adaptability = life1 ( all ! planets &  
"s ( ! satellites 9 ! sol> sy/em1 is1   
h[ev]1 r5d]$ invalid by an equally g5]al
 objection to :i* its uphold]s appe>    
nev] to h giv5 a mom5t's consid]ation2 &
 z x is an objection :i* /ill fur!r     
en=ces ! view z to ! unique position ( !
 e>? 9 ! sol> sy/em1 x w be well to     
submit x to ! judgm5t ( our read]s4     
,,limitation ,,( ,,! ,,sun',s ,,heat  ,x
 is well kn[n t !re is1 & has be5 =     
ne>ly half a c5tury1 a pr(\nd diff]5ce (
 op9ion betwe5 geologi/s & physici/s z  
to ! actual or possible duration 9 ye>s 
( life ^u ! e>?4 ,! geologi/s1 be+      

greatly impress$ ) ! va/ results produc$
 by ! sl[ processes ( ! we>+ away ( !   
rocks & ! deposit ( ! mat]ial 9 seas or 
lakes1 to be aga9 upheav$ to =m dry l&1 
& to be aga9 c>v$ out by ra9 & w9d1 by  
heat & cold1 by sn[ & ice1 into hills & 
valleys & gr& m\nta9 ranges2 & fur!r1 by
 ! fact t ! highe/ m\nta9s 9 e "p ( !   
globe v (t5 exhibit on _! l(tie/ summits
 /ratifi$ rocks :i* conta9 m>9e         
organisms1 & 7 !re=e orig9ally laid d[n 
b5ea? ! sea2 &1 yet aga91 by ! fact t ! 
l(tie/ m\nta9s are (t5 ! mo/ rec5t1 & t 
^! gr& features ( ! e>?'s surface are b 
! late/ examples ( ! action ( =ces t h  
be5 at "w ?r\gh\t all geological        
"t--/udy+ all _! lives ! detail$        
evid5ces ( all ^! *anges1 h come to !   
conclusion t !y imply enorm\s p]iods    
only to be measur$ by scores or hundr$s 
( millions ( ye>s4  ,& ! collat]al /udy 
( fossil rema9s 9 ! long s]ies (        
rock-=mations en=ces ?is view4 ,9 ! :ole
 epo* ( human hi/ory1 & f> back into    
prehi/oric times dur+ :i* man exi/$ on !

 e>?1 al?\gh sev]al animals h become    
ext9ct1 yet !re is no pro( t any new "o 
has be5 develop$4 ,b ?is human era1 s f>
 z yet kn[n1 go+ back c]ta9ly to !      
glacial epo* & almo/ c]ta9ly to         
pre-glacial times1 _c be e/imat$ at less
 ?an a million1 "s ?9k ev5 sev]al       
million ye>s2 & z !re h c]ta9ly be5 "s  
consid]able alt]ations ( level1         
excavation ( valleys1 deposits ( great  
b$s ( gravel1 & o!r sup]ficial *anges   
dur+ ?is p]iod1 "s k9d ( a scale (      
measurem5t ( geological "t has be5      
obta9$1 by comp>ison ) ! v m9ute *anges 
t h occurr$ dur+ ! hi/orical p]iod4 ,?is
 scale is admitt$ly a v imp]fect "o1 b x
 is bett] ?an none at all2 & x is by    
comp>+ ^! small *anges ) ! f> great]    
ones :i* h occurr$ dur+ e successive /ep
 backw>d 9 geological hi/ory t ^!       
e/imates ( geological "t h be5 arriv$   
at4 ,!y are also support$ by !          
palontologi/s1 to :om ! va/ panorama (  
successive =ms ( life is an ev]-pres5t  
reality4 ,directly !y pass into ! late/ 

/age ( ! ,t]ti>y p]iod--! ,plioc5e (    
,sir ,*>les ,lyell--all ov] ! _w new =ms
 ( life appe> :i* are evid5tly ! =]unn]s
 ( _m ( our /ill exi/+ species2 & z !y g
 a little fur!r back1 into ! ,mioc5e1   
!re are indications ( a w>m] climate 9  
,europe1 & l>ge numb]s ( mammals        
resembl+ ^? :i* n[ inhabit ! tropics1 b 
( q di/9ct species & (t5 ( di/9ct g5]a &
 families4 ,& "h1 ?\gh we h only rea*$  
to ab\t ! middle ( ! ,t]ti>y p]iod1 !   
*anges 9 ! =ms ( life1 9 ! climate1 & 9 
! l&-surfaces are s great :5 comp>$ ) ! 
v m9ute *anges dur+ ! human epo*1 z to  
require u to multiply ! "t elaps$ _m    
times ov]4 ,yet ! :ole ( ! ,t]ti>y      
p]iod1 dur+ :i* all ! great gr\ps ( !   
high] animals 7 develop$ f a            
comp>atively few g5]alis$ ance/ral =ms1 
is yet ! %orte/ by f> ( ! ?ree great    
geological p]iods--! ,mesozoic or       
,second>y1 hav+ be5 mu* long]1 ) /ill   
va/] *anges bo? 9 ! e>?'s cru/ & 9 ! =ms
 ( life2 :ile ! ,palozoic or ,prim>y1   
:i* c>ries u back to ! e>lie/ =ms ( life

 z repres5t$ by fossilis$ rema9s1 is    
always e/imat$ by geologi/s to be at    
lea/ z long z ! o!r two comb9$1 &       
probably v mu* long]4  ,f ^! v>i\s      
consid]ations mo/ geologi/s :o h made   
any e/imates ( geological "t f ! p]iod (
 ! e>lie/ fossilif]\s rocks1 h arriv$ at
 ! conclusion t ab\t #bjj millions (    
ye>s are requir$4 ,b f ! v>iety ( ! =ms 
( life at ?is e>ly p]iod x is conclud$ t
 a v mu* great] duration is ne$$ = !    
:ole epo* ( life4 ,speak+ ( ! v>i$ m>9e 
fauna ( ! ,cambrian p]iod1 ! late       
,pr(essor ,ramsay says3--',9 ?is e>lie/ 
kn[n v>i$ life we f9d no evid5ce ( its  
hav+ liv$ ne> ! beg9n+ ( ! zoological   
s]ies4 ,9 a broad s5se1 comp>$ ) :at mu/
 h gone be=e1 bo? biologically &        
physically1 all ! ph5om5a connect$ ) ?is
 old p]iod seem1 to my m9d1 to be ( q a 
rec5t description2 & ! climates ( seas &
 l&s 7 ( ! v same k9d z ^? ! _w enjoys  
at ! pres5t day4' ,& ,pr(essor ,huxley  
held v simil> views :5 he decl>$3 ',if !
 v small diff]5ces :i* are obs]vable    

betwe5 ! crocodiles ( ! old] ,second>y  
=mations & ^? ( ! pres5t day furni% any 
sort ( an approximation t[>ds an e/imate
 ( ! av]age rate ( *ange among reptiles1
 x is almo/ appall+ to reflect h[ f>    
back 9 ,palozoic times we mu/ g be=e we 
c hope to arrive at t common /ock f :i* 
! crocodiles1 liz>ds1 ,orni?oscelida1 & 
,plesiosauria1 :i* _h atta9$ s great a  
developm5t 9 ! ,triassic epo*1 mu/ h be5
 d]iv$4'  ,n[1 9 opposition to ^! dem&s 
( ! geologi/s1 9 :i* !y are almo/       
unanim\s1 ! mo/ celebrat$ physici/s1    
aft] full consid]ation ( all possible   
s\rces ( ! heat ( ! sun1 & kn[+ ! rate  
at :i* x is n[ exp5d+ heat1 decl>e1 )   
complete conviction1 t our sun _c h     
exi/$ z a heat-giv+ body = s long a     
p]iod1 & !y w\ld !re=e r$uce ! "t dur+  
:i* life c possibly h exi/$ on ! e>? to 
ab\t "o-f\r? ( t dem&$ by geologi/s4 ,9 
"o ( 8 late/ articles1 ,"l ,kelv9       
says3--',n[ we h irrefragable dynamics  
prov+ t ! :ole life ( our sun z a lum9>y
 is a v mod]ate numb] ( million ye>s1   

probably less ?an #ej million1 possibly 
betwe5 #ej & #ajj' 7,phil4 ,mag41 vol4  
ii41 ,six? ,s]41 p4 #age1 ,aug4 #aija74 
,9 my ,isl& ,life 7*ap4 ,x47 ,i h myself
 giv5 reasons = ?9k+ t bo? !            
/ratigraphical & biological *anges may h
 gone on m quickly ?an has be5 suppos$1 
& t geological "t 7mean+ !reby ! "t dur+
 :i* ! developm5t ( life ^u ! e>? has   
be5 go+ on7 may be r$uc$ s z possibly to
 be br\ght )9 ! maximum p]iod all[$ by  
physici/s2 b !re w c]ta9ly be no "t to  
sp>e1 & any planets dep5d5t on our sun  
^: p]iod ( habitability is ei!r pa/ or  
to come1 _c possibly h1 or h _h1        
suffici5t "t = ! necess>ily sl[         
evolution ( ! high] life-=ms4 ,aga91 all
 physici/s hold t ! sun is n[ cool+1 & t
 its future life w be mu* less ?an its  
pa/4 ,9 a lecture at ! ,royal           
,in/itution 7publi%$ 9 ,nature ,s]ies1 9
 #ahhi71 ,"l ,kelv9 says3--',x w\ld1 ,i 
?9k1 be exce$+ly ra% to assume z        
probable any?+ m ?an tw5ty million ye>s 
( ! sun's light 9 ! pa/ hi/ory ( ! e>?1 

or to reckon m ?an five or six million  
ye>s ( sunlight = "t to come4'  ,^!     
extracts s]ve to %[ t1 unless ei!r      
geologi/s or physici/s are v f> f any   
approa* to accuracy 9 _! e/imates ( pa/ 
or future age ( ! sun1 !re is v great   
difficulty 9 br++ !m into h>mony or 9   
acc\nt+ = ! actual facts ( ! geological 
hi/ory ( ! e>? & ( ! :ole c\rse (       
life-developm5t ^u x4 ,we are1 !re=e1   
aga9 br\ght to ! conclusion t !re has   
be51 & is1 no "t to sp>e2 t ! :ole ( !  
available pa/ life-p]iod ( ! sun has be5
 utilis$ = life-developm5t on ! e>?1 & t
 ! future w be n mu* m ?an may be ne$$ =
 ! completion ( ! gr& drama ( human     
hi/ory1 & ! developm5t ( ! full         
possibilities ( ! m5tal & moral nature (
 man4  ,we h "h1 !n1 a v p[]ful argum5t1
 f a diff]5t po9t ( view ?an any        
previ\sly consid]$1 = ! conclusion t    
man's place 9 ! sol> sy/em is altoge!r  
unique1 & t no o!r planet ei!r has      
develop$ or c develop su* a full &      
complete life-s]ies z t :i* ! e>? has   

actually develop$4 ,ev5 if ! conditions 
_h be5 m fav\rable ?an !y are se5 to be 
on o!r planets1 ,m]cury1 ,v5us1 & ,m>s  
c\ld n possibly h pres]v$ equability (  
conditions long en\gh = life-developm5t1
 s9ce = unkn[n ages !y mu/ h be5 pass+  
sl[ly t[>ds _! pres5t :olly unsuitable  
conditions2 :ile ,jupit] & ! planets    
beyond him1 ^: epo* ( life-developm5t is
 suppos$ to be 9 ! remote future :5 !y  
%all h sl[ly cool$ d[n to habitability1 
w !n be /ill m fa9tly illum9at$ &       
scantily w>m$ by a rapidly cool+ sun1 & 
may ?us become1 at ! be/1 globes ( solid
 ice4 ,?is is ! tea*+ ( sci5ce--( ! be/ 
sci5ce ( ! tw5tie? c5tury4 ,yet we f9d  
ev5 a/ronom]s :o1 m ?an any o!r expon5ts
 ( sci5ce1 %\ld give he$ to ! tea*+s ( !
 si/] sci5ces to :i* !y owe s mu*1      
indulg+ 9 su* rhapsodies z !            
foll[+3--',9 our sol> sy/em1 ?is little 
e>? has n obta9$ any special privileges 
f ,nature1 & x is /range to wi% to      
conf9e life )9 ! circle ( t]re/rial     
*emi/ry4' ,& aga93 ',inf9ity encompasses

 u on all sides1 life ass]ts itself1    
univ]sal & et]nal1 our exi/5ce is b a   
fleet+ mom5t1 ! vibration ( an atom 9 a 
ray ( ! sun1 & our planet is b an isl&  
float+ 9 ! cele/ial ar*ipelago1 to :i*  
no ?\ght w ev] place any b\nds4'#bj  ,9 
place ( su* 'wild & :irl+ words1' ,i h  
endeav\r$ to /ate ! sob] conclusions ( !
 be/ work]s & ?9k]s z to ! nature &     
orig9 ( ! _w 9 :i* we live1 & ( !       
univ]se :i* on all sides surr\nds u4 ,i 
leave x to my read]s to decide :i* is ! 
m tru/wor?y guide4   ,,footnotes3  #ah  
,transactions ( ,royal ,dubl9 ,society1 
vol4 vi4 7s]4 ii471 "p xiii4 ',(        
,atmosph]es ^u ,planets & ,satellites4' 
,by ,g4 ,john/one ,/oney1 ,f4,r4,s41    
etc4 etc4  #ai ,k1 ,june #aijc4  #bj ,m4
 ,camille ,flamm>ion1 9 ,k1 ,june #aijc4
     ,,*apt] ,,xv  ,,! ,,/>s--,,h ,,!y  
,,planet>y ,,sy/ems8 ,,are ,,!y         
,,b5eficial ,,to ,,u8   ,mo/ ( ! writ]s 
on ! ,plurality ( ,worlds1 f ,font5elle 
to ,proctor1 tak+ into consid]ation !   
enorm\s numb] ( ! />s & _! app>5t       

uselessness to our _w1 h assum$ t _m (  
!m mu/ h sy/ems ( planets circl+ r\nd   
!m1 & t "s ( ^! planets1 at all ev5ts1  
mu/ possess inhabitants1 "s1 p]haps1    
l[]1 b o!rs no d\bt high] ?an ourselves4
 ,"o ( our well-kn[n mod]n a/ronom]s1   
writ+ only t5 ye>s ago1 adopts ! same   
view4 ,he says3 ',! suns :i* we call />s
 7 cle>ly n creat$ = our b5efit4 ,!y are
 ( v little practical use to ! e>?'s    
inhabitants4 ,!y give u v little light2 
an additional small satellite--"o       
consid]ably small] ?an ! moon--w\ld h   
be5 mu* m useful 9 ?is respect ?an !    
millions ( />s reveal$ by ! telescope4  
,!y mu/ !re=e h be5 =m$ = "s o!r        
purpose4444 ,we may !re=e conclude1 ) a 
high degree ( probability1 t ! />s--at  
lea/ ^? ) spectra ( ! sol> type--=m     
c5tres ( planet>y sy/ems some:at simil> 
to our own4'#ba ,! au?or !n discusses ! 
conditions necess>y = life analog\s to t
 ( our e>?1 z reg>ds temp]ature1        
rotation1 mass1 atmosph]e1 wat]1 etc41 &
 he is ! only writ] ,i h met ) :o has   

consid]$ ^! conditions2 b he t\*es on !m
 v briefly1 & he arrives at ! conclusion
 t1 9 ! case ( ! />s ( sol> type1 x is  
probable t "o planet1 situat$ at a prop]
 di/ance1 w\ld be fitt$ to support life4
 ,he e/imates r\ghly t !re are ab\t t5  
million />s ( ?is type1 t is1 closely   
resembl+ our sun1 & t if only "o 9 t5 ( 
^! has a planet at ! prop] di/ance &    
prop]ly con/itut$ 9 o!r respects1 !re w 
be "o million worlds fitt$ = ! support (
 animal life4 ,he !re=e concludes t !re 
are probably _m />s hav+ life-be>+      
planets revolv+ r\nd !m4  ,!re are1     
h[ev]1 _m consid]ations n tak5 acc\nt ( 
by ?is writ] :i* t5d to r$uce v         
consid]ably ! above e/imate4 ,x is n[   
kn[n t imm5se numb]s ( ! />s ( small]   
magnitudes are ne>] to u ?an are !      
majority ( ! />s ( ! fir/ & second      
magnitudes1 s t x is probable t ^!1 z   
well z a consid]able proportion ( ! v   
fa9t telescopic />s1 are really ( small 
dim5sions4 ,we h evid5ce t _m ( !       
brighte/ />s are mu* l>g] ?an our sun1 b

 !re are probably t5 times z _m t are   
mu* small]4 ,we h se5 t ! :ole ( ! pa/  
light & heat-giv+ duration ( our sun    
has1 accord+ to ! be/ au?orities1 be5   
only j suffici5t = ! developm5t ( life  
^u ! e>?4 ,b ! duration ( a sun's       
heat-giv+ p[] w dep5d ma9ly ^u its mass1
 toge!r ) its con/itu5t elem5ts4 ,suns  
:i* are mu* small] ?an ours are1 !re=e1 
f t cause alone1 unsuit$ to give        
adequate light & heat = a suffici5t "t1 
& ) suffici5t uni=mity1 =               
life-developm5t on planets1 ev5 if !y   
possess any at ! "r di/ance1 & ) !      
ext5sive s]ies ( nicely adju/$          
conditions :i* ,i h %[n to be necess>y4 
,aga91 we mu/1 probably1 rule out z     
unfitt$ = life-developm5t ! :ole region 
( ! ,milky ,way1 on acc\nt ( ! excessive
 =ces !re 9 action1 z %[n by ! imm5se   
size ( _m ( ! />s1 _! enorm\s heat-giv+ 
p[]1 ! cr[d+ ( />s & nebul\s matt]1 !   
great numb] ( />-clu/]s1 &1 especially1 
because x is ! region ( 'new />s1' :i*  
imply collisions ( masses ( matt]       

suffici5tly l>ge to become visible f !  
imm5se di/ance we are f !m1 b yet       
excessively small z comp>$ ) suns !     
duration ( ^: light is to be measur$ by 
millions ( ye>s4 ,h5ce ! ,milky ,way is 
! !atre ( extreme activity & motion2 x  
is comp>atively cr[d$ ) matt] und]go+   
cont9ual *ange1 & is !re=e n suffici5tly
 /able = long p]iods to be at all likely
 to possess habitable worlds4  ,we mu/1 
!re=e1 limit our possible planet>y      
sy/ems suitable = life-developm5t1 to   
/>s situat$ inside ! circle ( ! ,milky  
,way & f> remov$ f x--t is1 to ^?       
compos+ ! sol> clu/]4 ,^! h be5 v>i\sly 
e/imat$ to consi/ ( a few hundr$ or _m  
?\s& />s--at all ev5ts to a v small     
numb] z comp>$ ) ! 'hundr$s ( millions' 
9 ! :ole /ell> univ]se4 ,b ev5 "h we f9d
 t only a portion are probably suitable4
 ,pr(essor ,newcomb arrives at !        
conclusion--z h "s o!r a/ronom]s--t !   
/>s 9 g5]al h a mu* small] mass 9       
proportion to ! light !y give ?an our   
sun has2 &1 aft] an elaborate           

discussion1 he f9ally concludes t !     
bright] />s are1 on ! av]age1 mu* less  
d5se ?an our sun4 ,9 all probability1   
!re=e1 !y _c give light & heat = s long 
a p]iod1 & z ?is p]iod 9 ! case ( our   
sun has only be5 j suffici5t1 ! numb] ( 
suns ( ! sol> type & ( a suffici5t mass 
may be v limit$4 ,yet fur!r1 ev5 among  
/>s hav+ a simil> physical con/itution  
to our sun & ( an equal or great] mass1 
only a portion ( _! p]iod ( lum9osity   
w\ld be suitable = ! support ( planet>y 
life4 ,:ile !y are 9 process ( =mation  
by accretions ( solid or gase\s masses1 
!y w\ld be subject to su* fluctuations (
 temp]ature1 & to su* cata/rophic       
outbur/s :5 any l>g] mass ?an usual 0   
drawn t[>ds !m1 t ! :ole ( ?is          
p]iod--p]haps by f> ! longe/ portion (  
_! exi/5ce--mu/ be left out ( ! acc\nt (
 planet-produc+ suns4 ,yet all ^! are to
 u />s ( v>i\s degrees ( brilliancy4 ,x 
is almo/ c]ta9 t x is only :5 ! gr[? ( a
 sun is ne>ly complet$1 & its heat has  
atta9$ a maximum1 t ! epo* (            

life-developm5t is likely to beg9 ^u any
 planets x may possess at ! mo/ suitable
 di/ance1 & ^u :i* all ! requisite      
conditions %\ld be pres5t4  ,x may be   
said t !re are great numb]s ( />s beyond
 our sol> clu/] & yet )9 ! circle ( !   
,milky ,way1 z well z o!rs t[>ds ! poles
 ( ! ,milky ,way1 :i* ,i h n "h ref]r$  
to4 ,b ( ^! regions v little is kn[n1   
because x is impossible to tell :e!r />s
 9 ^! directions are situat$ 9 ! out]   
portion ( ! sol> clu/] or 9 ! regions   
beyond x4 ,"s a/ronom]s appe> to ?9k t  
^! regions may be ne>ly empty ( />s1 &  
,i h endeav\r$ to repres5t :at seems to 
be ! g5]al view on ?is v difficult      
subject 9 ! two diagrams ( ! /ell>      
univ]se at pp4 #cjj1 #cja4 ,! regions   
beyond our clu/] & above or bel[ ! plane
 ( ! ,milky ,way are ^? :]e ! small     
irresolvable nebul ab\nd1 & ^! may      
indicate t sun-=mation is n yet active 9
 ^? regions4 ,! two *>ts ( ,nebul &     
,clu/]s at ! end ( ! volume illu/rate1 &
 p]haps t5d to support ?is view4        

,,d\ble ,,& ,,multiple ,,/> ,,sy/ems    
,we h already se51 9 our six? *apt]1 h[ 
rapid & extraord9>y has be5 ! discov]y (
 :at are t]m$ spectroscopic             
b9>ies--pairs ( />s s close toge!r z to 
appe> l a s+le /> 9 ! mo/ p[]ful        
telescopes4 ,! sy/ematic se>* = su* />s 
has only be5 c>ri$ on = a few ye>s1 yet 
s _m h be5 already f\nd1 & _! numb]s are
 increas+ s rapidly1 z to q />tle       
a/ronom]s4 ,"o ( ! *ief work]s 9 ?is    
field1 ,pr(essor ,campbell ( ! ,lick    
,obs]vatory1 has /at$ 8 op9ion t1 z     
accuracy ( measurem5t increases1 ^!     
discov]ies w g on till--'! /> t is n a  
spectroscopic b9>y w prove to be ! r>e  
exception1'--& o!r a/ronom]s ( em95ce h 
express$ simil> views4 ,b ^! close      
revolv+ />-sy/ems are g5]ally admitt$ to
 be out ( ! category ( life-produc+     
suns4 ,! tidal di/urbances mutually     
produc$ mu/ be enorm\s1 & ?is mu/ be    
inimical to ! developm5t ( planets1     
unless !y 7 v close to ea* sun1 & ?us 9 
! mo/ unfav\rable position = life4  ,we 

?us see t ! result ( ! mo/ rec5t        
rese>*es among ! />s is entirely oppos$ 
to ! old idea t ! c\ntless myriads ( />s
 all _h planets circulat+ r\nd !m1 & t !
 ultimate purpose ( _! exi/5ce 01 t !y  
%\ld be support]s ( life1 z our sun is !
 support] ( life ^u ! e>?4 ,s f> is ?is 
f be+ ! case1 t va/ numb]s ( />s h to be
 put aside z :olly unfitt$ = su* a      
purpose2 & :5 by successive elim9ations 
( ?is nature we h r$uc$ ! numb]s :i* may
 possibly be available to a few         
millions1 or ev5 to a few ?\s&s1 !re    
comes ! la/ />tl+ discov]y1 t ! entire  
ho/ ( />s is f\nd to conta9 b9>y sy/ems 
9 su* rapidly increas+ numb]s1 z to lead
 "s ( ! v fir/ a/ronom]s ( ! day to !   
conclusion t s+le />s may som$ay be f\nd
 to be ! r>e exception6 ,b ?is trem5d\s 
g5]alisation w\ld1 at "o /roke1 sweep   
away a l>ge proportion ( ! />s :i* o!r  
successive disqualifications _h sp>$1 & 
?us leave our sun1 :i* is c]ta9ly s+le1 
& p]haps two or ?ree companion orbs1    
alone among ! />ry ho/ z possible       

support]s ( life on "s "o ( ! planets   
:i* circulate ar\nd !m4  ,b we d n      
really "k t any su* suns exi/4 ,if !y   
exi/ we d n "k t !y possess planets4 ,if
 any d possess planets ^! may n be at ! 
prop] di/ance1 or be ( ! prop] mass1 to 
r5d] life possible4 ,if ^! prim>y       
conditions %\ld be fulfill$1 & if !re   
%\ld possibly be n only "o or two1 b a  
doz5 or m t s f> fulfil ! fir/ few      
conditions :i* are ess5tial1 :at        
probability is !re t all ! o!r          
conditions1 all ! o!r nice adaptations1 
all ! delicate balance ( oppos+ =ces t  
we h f\nd to prevail ^u ! e>?1 & ^:     
comb9ation "h is due to exceptional     
conditions :i* exi/ 9 ! case ( no o!r   
kn[n planet--%\ld all be aga9 comb9$ 9  
"s ( ! possible planets ( ^! possibly   
exi/+ suns8  ,i submit t ! probability  
is n[ all ! o!r way4 ,s long z we c\ld  
assume t all ! />s might be1 9 all      
ess5tials1 l our sun1 x seem$ almo/     
ludicr\s to suppose t our sun alone %\ld
 be 9 a position to support life4 ,b :5 

we f9d t enorm\s classes l ! gase\s />s 
( small d5sity1 ! sol> />s :ile increas+
 9 size & temp]ature1 ! />s :i* are mu* 
small] ?an our sun1 ! nebul\s />s1      
probably all ! />s ( ! ,milky ,way1 &   
la/ly t enorm\s class ( spectroscopic   
d\bles--v]itable ,a>on's rods :i* ?reat5
 to swall[ up all ! re/--t all ^! are = 
v>i\s reasons unlikely to h att5dant    
planets adapt$ to develop life1 !n !    
probabilities seem to be enorm\sly aga9/
 !re be+ any consid]able numb] ( suns   
possess+ att5dant habitable e>?s4 ,j z !
 habitability ( all ! planets & l>g]    
satellites1 once assum$ z s extremely   
probable z to am\nt almo/ to a c]ta9ty1 
is n[ g5]ally giv5 up1 s t 9 speculat+  
on life 9 /ell> sy/ems ,mr4 ,gore       
assumes t only "o planet to ea* sun c be
 habitable2 9 l mann] x may1 & ,i       
believe w1 turn out1 t ( all ! myriad   
/>s1 ! m we le>n ab\t !m1 ! small] &    
small] w become ! scanty residue :i*1 ) 
any probability1 we c suppose to        
illum9ate & vivify habitable e>?s4 ,& :5

 ) ?is scanty probability we comb9e !   
/ill scanti] probability t any su*      
planet w possess simultane\sly1 & = a   
suffici5tly long p]iod1 all ! highly    
complex & delicately balanc$ conditions 
kn[n to be ess5tial = a full            
life-developm5t1 ! conception t on ?is  
e>? alone has su* developm5t be5        
complet$ w n seem s wildly improbable a 
conjecture z x has hi!rto be5 held to   
be4   ,,are ,,! ,,/>s ,,b5eficial ,,to  
,,u8  ,:5 ,i sugge/$ 9 my fir/          
publication on ?is subject t "s         
emanations f ! />s might be b5eficial or
 injuri\s1 & t a c5tral position might  
be ess5tial 9 ord] to r5d] ^! emanations
 equable1 "o ( my a/ronomical critics   
laugh$ ! idea to scorn1 & decl>$ t 'we  
might w&] into out] space )\t los+ any?+
 m s]i\s ?an we lose :5 ! night is cl\dy
 & we _c see ! />s4'#bb ,h[ my critic   
kn[s t ?is is s he does n tell u4 ,he   
/ates x positively1 ) no qualification1 
z if x 7 an e/abli%$ fact4 ,x may be z  
well to inquire1 !re=e1 if !re is any   

evid5ce be>+ ^u ! po9t at issue4        
,a/ronom]s are s fully occupi$ ) ! va/  
numb] & v>iety ( ! ph5om5a pres5t$ by ! 
/ell> univ]se & ! v>i\s difficult       
problems aris+ !refrom1 t _m less] b    
/ill int]e/+ inquiries h necess>ily     
receiv$ little att5tion4 ,su* a m9or    
problem is ! det]m9ation ( h[ mu* heat  
or o!r active radiation we receive f !  
/>s2 yet a few obs]vations h be5 made ) 
results t are ( consid]able int]e/4  ,9 
! ye>s #aijj & #aija ,mr4 ,e4,f4 ,ni*ols
 ( ! ,y]kes ,obs]vatory made a s]ies (  
exp]im5ts ) a radiomet] ( special       
con/ruction1 to det]m9e ! heat emitt$ by
 c]ta9 />s4 ,! result arriv$ at 01 t    
,vega gave ab\t #a_/bjjjjjjjj ( ! heat (
 a c&le at "o metre di/ance1 & ,arcturus
 ab\t #b4b times z mu*4  ,9 #ahie &     
#ahif ,mr4 ,g4,m4 ,m9*9 made a s]ies (  
exp]im5ts on ! ,electrical ,measurem5t (
 ,/>light1 by means ( a photo-electric  
cell ( peculi> con/ruction :i* is       
s5sitive to ! :ole ( ! rays 9 !         
spectrum1 & also to "s ( ! ultra-r$ &   

ultra-violet rays4 ,comb9$ ) ?is 0 a v  
delicate electromet]4 ,! telescope      
employ$ to conc5trate ! light 0 a       
reflector ( two feet ap]ture4 ,mr4 ,m9*9
 0 assi/$ 9 ! exp]im5ts by ! late       
,pr(essor ,g4,f4 ,fitzg]ald1 ,f4,r4,s41 
( ,tr9ity ,college1 ,dubl91 :i* may be  
consid]$ gu>antee ( ! accuracy ( !      
obs]vations4 ,! foll[+ are ! *ief       
results obta9$3--                       
----------------------------------------
-------------------------------         
----------------------------------------
----------------------------            
,deflection    ,light                   
,s\rce ( ,light4                 9      
9      ,e4 ,m4 ,f4                      
,millimetres  ,c&les4    ,volts4        
----------------------------------------
----------------------------     #ahif  
,c&le at #aj feet di/ance     #ah4gj    
,betelgeuse 7#j4i mag47          #ab4hj 
#j4fhe      #j4jbf           ,aldeb>an  
7#a4a mag47            #e4ba            
#j4bgi      #j4jab           ,procyon   

7#j4e mag7               #d4hi          
#j4bfa      #j4jaa           ,alpha     
,cygni 7#a4c mag47          #d4ij       
#j4bfb      #j4jaa           ,pol>is    
7#b4a mag47              #c4aj          
#j4aff      #j4jjg                      
----------------------------------------
----------------------------            
#a volt4              #dcb4jj           
#ahie  ,arcturus 7#j4c mag47            
#h4b        #a4ja       #j4jai          
,vega 7#j4a mag7                 #aa4e  
#a4db       #j4jbf           ,c&le at   
#aj feet               #h4a             
----------------------------------------
----------------------------            
,n4,b4--,! /&>d c&le %one directly on ! 
cell1 :]eas      ! />'s light 0         
conc5trat$ by a #b-;foot mirror4  ,!    
s5sitive surface on :i* ! light ( ! />s 
0 conc5trat$ 0 #a_/bj in* 9 diamet]4 ,we
 mu/ !re=e dim9i% ! am\nt ( c&le light 9
 ?is table 9 ! proportion ( ! squ>e ( ! 
diamet] ( ! mirror 79 #a_/bj ( an in*7  
to "o1 equal to #a_/bcjdjj4 ,if we make 

! necess>y r$uction 9 ! case ( ,vega1 & 
also equalise ! di/ance at :i* ! c&le 0 
plac$1 we f9d ! foll[+ result3--        
,obs]v]4        ,/>4               ,c&le
 p[] at #aj ft4      ,m9*94             
,vega                #a_/afbbej         
,ni*ols4                                
#a_/bbjjjjjj  ,?is enorm\s diff]5ce 9 ! 
result is no d\bt l>gely due to ! fact t
 ,mr4 ,ni*ols's app>atus measur$ heat   
alone1 :]eas ,mr4 ,m9*9's cell measur$  
almo/ all ! rays4 ,& ?is is fur!r %[n by
 ! fact t1 :]eas ,mr4 ,ni*ols f\nd      
,arcturus a r$ />1 hott] ?an ,vega a    
:ite "o1 ,mr4 ,m9*91 measur+ also !     
light-giv+ & "s ( ! *emical rays1 f\nd  
,vega consid]ably m en]getic ?an        
,arcturus4 ,^! comp>isons also sugge/ t 
o!r modes ( measurem5t might give yet   
high] results1 b x w no d\bt be urg$ t  
su* m9ute effects mu/ necess>ily be q   
inop]ative ^u ! organic _w4  ,!re are1  
h[ev]1 "s consid]ations :i* t5d ! o!r   
way4 ,mr4 ,m9*9 rem>ks on ! unexpect$   
fact t ,betelgeuse produces m ?an d\ble 

! electrical en]gy ( ,procyon1 a mu*    
bright] />4 ,?is indicates t _m ( ! />s 
( small] visual magnitudes may give out 
a l>ge am\nt ( en]gy1 & x is ?is en]gy1 
:i* we n[ "k c take _m /range & v>i$    
=ms1 t w\ld be likely to influ5ce       
organic life4 ,& z to ! quantity be+ too
 m9ute to h any effect1 we "k t !       
excessively m9ute am\nt ( light f ! v   
smalle/ telescopic />s produces su*     
*emical *anges on a photographic plate z
 to =m di/9ct images1 ) comp>atively    
small l5ses or reflectors & ) an        
exposure ( two or ?ree h\rs4 ,& if x 7 n
 t ! diffus$ light ( ! surr\nd+ sky also
 acts ^u ! plate & blurs ! fa9t images1 
mu* small] />s c\ld be photograph$4  ,we
 "k t n all ! rays1 b a portion only1   
are capable ( produc+ ^! effects2 we "k 
also t !re are _m k9ds ( radiation f !  
/>s1 & probably "s yet undiscov]$       
comp>able ) ! ,x rays & o!r new =ms (   
radiation4 ,we mu/ also rememb] !       
endless v>iety & ! extreme in/ability ( 
! protoplasmic products 9 ! liv+        

organism1 _m ( :i* are p]haps z s5sitive
 to special rays z is ! photographic    
plate4  ,& we are n "h limit$ to action 
= a few m9utes or a few h\rs1 b ?r\gh\t 
! :ole night & day1 & cont9u$ :5ev] !   
sky is cle> = mon?s or ye>s4 ,?us !     
cumulative effect ( ^! v weak radiations
 may become important4 ,x is probable t 
_! action w\ld be mo/ influ5tial on     
plants1 & "h we f9d all ! conditions    
requisite = its accumulation &          
utilisation 9 ! l>ge am\nt (            
leaf-surface expos$ to x4 ,a l>ge tree  
mu/ pres5t "s hundr$s ( sup]ficial feet 
( receptive surface1 :ile ev5 %rubs &   
h]bs (t5 h a leaf-area ( great]         
sup]ficial ext5t ?an ! object-glasses ( 
our l>ge/ telescopes4 ,"s ( ! highly    
complex *emical processes t g on 9      
plants may be help$ by ^! radiations1 & 
_! action w\ld be increas$ by ! fact t1 
com+ f e direction ov] ! :ole surface ( 
! heav5s1 ! rays f ! />s w\ld be able to
 rea* & act ^u e leaf ( ! d5se/ masses (
 foliage4 ,! l>ge am\nt ( gr[? t takes  

place at night may be 9 "p due to ?is   
ag5cy4  ,( c\rse all ?is is highly      
speculative2 b ,i submit1 9 view ( !    
fact t ! light ( ! v fa9te/ />s does    
produce di/9ct *emical *anges1 t ev5 ! v
 m9ute heat-effects are measureable1 z  
well z ! electro-motive =ces caus$ by   
!m2 & fur!r1 t :5 we consid] ! millions1
 p]haps hundr$s ( millions ( />s1 all   
act+ simultane\sly on any organism :i*  
may be s5sitive to !m1 ! supposition t  
!y d produce "s effect1 & possibly a v  
important effect1 is n "o to be summ>ily
 reject$ z altoge!r absurd & n wor?     
inquir+ into4  ,x is n1 h[ev]1 ^!       
possible direct actions ( ! />s ^u liv+ 
organisms to :i* ,i atta* mu* weight z  
reg>ds our c5tral position 9 ! /ell>    
univ]se4 ,fur!r consid]ation ( ! subject
 has conv9c$ me t ! fundam5tal          
importance ( t position is a physical   
"o1 z has already be5 sugge/$ by ,sir   
,norman ,locky] & "s o!r a/ronom]s4     
,briefly1 ! c5tral position appe>s to be
 ! only "o :]e suns c be suffici5tly    

/able & long-liv$ to be capable (       
ma9ta9+ ! long process ( life-developm5t
 9 any ( ! planets !y may possess4 ,?is 
po9t w be fur!r develop$ 9 ! next 7&    
conclud+7 *apt]4  ,,footnotes3  #ba ,!  
,worlds ( ,space1 by ,j4,e4 ,gore1 *apt]
 iii4  #bb ,! ,=tnightly ,review1 ,april
 #aijc1 p4 #fj4     ,,*apt] ,,xvi       
,,/ability ,,( ,,! ,,/>-,,sy/em3        
,,importance ,,( ,,our ,,c5tral         
,,position3 ,,summ>y ,,& ,,conclusion   
,"o ( ! greate/ difficulties ) reg>d to 
! va/ sy/em ( />s ar\nd u is ! "q ( its 
p]man5ce & /ability1 if n absolutely &  
indef9itely1 yet = p]iods suffici5tly   
long to all[ = ! _m millions ( ye>s t h 
c]ta9ly be5 requir$ = our t]re/rial     
life-developm5t4 ,?is p]iod1 9 ! case ( 
! e>?1 z ,i h suffici5tly %[n1 has be5  
*>act]is$ ?r\gh\t by extreme uni=mity1  
:ile a cont9uance ( t uni=mity = a few  
millions ( ye>s 9 ! future is almo/     
equally c]ta94  ,b our ma!matical       
a/ronom]s c f9d no indications ( su*    
/ability ( ! /ell> univ]se z a :ole1 if 

subject to ! law ( gravitation alone4 ,9
 reply to "s que/ions on ?is po9t1 my   
fri5d ,pr(essor ,george ,d>w9 writes z  
foll[s3--',a symmetrical annul> sy/em ( 
bodies might revolve 9 a circle ) or )\t
 a c5tral body4 ,su* a sy/em w\ld be    
un/able4 ,if ! bodies are ( unequal     
masses & n symmetrically dispos$1 !     
break-up ( ! sy/em w\ld probably be m   
rapid ?an 9 ! ideal case ( symmetry4'   
,?is w\ld imply t ! great annul> sy/em (
 ! ,milky ,way is un/able4 ,b if s1 its 
exi/5ce at all is a great] my/]y ?an    
ev]4 ,al?\gh 9 detail its /ructure is v 
irregul>1 z a :ole x is wond]fully      
symmetrical2 & x seems q impossible t   
its g5]ally circul> r+-l =m c be !      
result ( ! *ance aggregation ( matt] f  
any pre-exi/+ diff]5t =m4 ,/>-clu/]s are
 equally un/able1 or1 r1 no?+ is kn[n or
 c be pr$icat$ ab\t _! /ability or      
in/ability1 accord+ to ,pr(essors       
,newcomb & ,d>w94  ,mr4 ,e4,t4 ,:ittak] 
7,secret>y to ! ,royal ,a/ronomical     
,society71 to :om ,pr(essor ,g4 ,d>w9   

s5t my que/ions1 writes3--',i d\bt :e!r 
! pr9cipal ph5om5a ( ! /ell> univ]se are
 consequ5ces ( ! law ( gravitation at   
all4 ,i h be5 work+ myself at spiral    
nebul1 & h got a fir/ approximation to  
an explanation--b x is electro-dynamical
 & n gravitational4 ,9 fact1 x may be   
que/ion$ :e!r1 = bodies ( su* trem5d\s  
ext5t z ! ,milky ,way or nebul1 ! effect
 :i* we call gravitation is giv5 by     
,newton's law2 j z ! ord9>y =mul (      
electro/atic attraction break d[n :5 we 
consid] *>ges mov+ ) v great            
velocities4'  ,accept+ ^! /atem5ts &    
op9ions ( two ma!maticians :o h giv5    
special att5tion to simil> problems1 we 
ne$ n limit ourselves to ! laws (       
gravitation z hav+ det]m9$ ! pres5t =m (
 ! /ell> univ]se2 & ?is is ! m important
 because we may ?us escape f a          
conclusion :i* _m a/ronom]s seem to ?9k 
inevitable1 viz4 t ! obs]v$ prop]       
motions ( ! />s _c be expla9$ by !      
gravitative =ces ( ! sy/em itself4 ,9   
*apt] ,,viii4 ( ?is "w ,i h quot$       

,pr(essor ,newcomb's calculation z to ! 
effect ( gravitation 9 a univ]se ( #ajj 
million />s1 ea* five times ! mass ( our
 sun1 & spread ov] a sph]e :i* x w\ld   
take light #cj1jjj ye>s to cross2 !n1 a 
body fall+ f its out] limits to ! c5tre 
c\ld at ! utmo/ acquire a velocity (    
tw5ty-five miles a second2 & !re=e1 any 
body 9 any "p ( su* a univ]se hav+ a    
great] velocity w\ld pass away into     
inf9ite space4 ,n[1 z sev]al />s h1 x is
 believ$1 mu* m ?an ?is velocity1 x     
foll[s n only t !y w inevitably escape f
 our univ]se1 b t !y d n belong to x1 z 
_! great velocity mu/ h be5 acquir$     
else:]e4 ,?is seems to h be5 ! idea ( ! 
a/ronom] :o /at$ t1 ev5 at ! v mod]ate  
spe$ ( our sun1 we %\ld 9 five million  
ye>s be deep 9 ! actual /ream ( ! ,milky
 ,way4 ,to ?is ,i h already suffici5tly 
repli$2 b ,i n[ wi% to br+ be=e my      
read]s an excell5t illu/ration ( !      
importance ( ! late ,pr(essor ,huxley's 
rem>k1 t ! results y got out ( !        
'ma!matical mill' dep5d entirely on :at 

y put into x4  ,9 ! ,philosophical      
,magaz9e 7,janu>y #aijb7 is a rem>kable 
article by ,"l ,kelv91 9 :i* he         
discusses ! v same problem z t :i*      
,pr(essor ,newcomb _h discuss$ at a mu* 
e>li] date1 b1 />t+ f diff]5t           
assumptions1 equally bas$ on asc]ta9$   
facts & probabilities d$uc$ f !m1 br+s  
out a v diff]5t result4  ,"l ,kelv9     
po/ulates a sph]e ( su* a radius t a /> 
at its conf9es w\ld h a p>allax (       
"o-?\s&? "p ( a second 7#j4jja71        
equival5t to #cbae light-ye>s4 ,uni=mly 
di/ribut$ ?r\gh ?is sph]e !re is matt]  
equal 9 mass to #ajjj million suns l    
ours4 ,if ?is matt] becomes subject to  
gravitation1 x all beg9s to move at fir/
 ) almo/ inf9ite sl[ness1 especially ne>
 its c5tre2 b nev]!less1 9 tw5ty-five   
million ye>s _m ( ^! suns w\ld h acquir$
 velocities ( f twelve to tw5ty miles a 
second1 :ile "s w\ld h less & "s        
probably m ?an sev5ty miles a second4   
,n[ su* velocities z ^! agree g5]ally ) 
! measur$ velocities ( ! />s1 h5ce ,"l  

,kelv9 ?9ks !re may be z mu* matt] z    
#ajjj million suns )9 ! above-nam$      
di/ance4 ,he !n /ates t if we suppose   
!re to be #aj1jjj million suns )9 ! same
 sph]e1 velocities w\ld be produc$ v mu*
 great] ?an ! kn[n />-velocities2 h5ce x
 is probable t !re is v mu* less matt]  
?an #aj1jjj million times ! sun's mass4 
,he also /ates t if ! matt] 7 n uni=mly 
di/ribut$ )9 ! sph]e1 !n1 :atev] 0 !    
irregul>ity1 ! acquir$ motions w\ld be  
great]2 aga9 indicat+ t ! #ajjj million 
suns w\ld be ample to produce ! obs]v$  
effects ( /ell> motion4 ,he !n          
calculates ! av]age di/ance ap>t ( ea* (
 ! #ajjj million />s1 :i* he f9ds to be 
ab\t #cjj millions ( millions ( miles4  
,n[ ! ne>e/ /> to our sun is ab\t       
tw5ty-six million million ( miles       
di/ant1 &1 z ! evid5ce %[s1 is situat$ 9
 ! d5s] "p ( ! sol> clu/]4 ,?is gives   
ample all[ance = ! comp>ative empt9ess (
 ! space betwe5 our clu/] & ! ,milky    
,way1 z well z ( ! :ole region t[>ds !  
poles ( ! ,milky ,way 7z %[n by !       

diagrams 9 *apt] ,,iv471 :ile !         
comp>ative d5sity ( ext5sive portions ( 
! ,galaxy itself may s]ve to make up !  
av]age4  ,n[1 previ\s writ]s h come to a
 diff]5t conclusion f ! same g5]al l9e (
 argum5t1 because !y h />t$ ) diff]5t   
assumptions4 ,pr(essor ,newcomb1 ^:     
/atem5t made "s ye>s back is usually    
foll[$1 assum$ #ajj million />s ea* five
 times z l>ge z our sun1 equal to #ejj  
million suns 9 all1 & he di/ribut$ !m   
equally ?r\gh\t a sph]e #cj1jjj         
light-ye>s 9 diamet]4 ,?us he has half !
 am\nt ( matt] assum$ by ,"l ,kelv91 b  
ne>ly five times ! ext5t1 ! result be+ t
 gravity c\ld only produce a maximum    
spe$ ( tw5ty-five miles a second2 :]eas 
on ,"l ,kelv9's assumption a maximum    
spe$ ( sev5ty miles a second w\ld be    
produc$1 or ev5 m4 ,by ?is latt]        
calculation we f9d no insup]able        
difficulty 9 ! spe$ ( any ( ! />s be+   
beyond ! p[] ( gravitation to produce1  
because ! rates "h giv5 are ! direct    
results ( gravitation act+ on bodies    

almo/ uni=mly di/ribut$ ?r\gh space4    
,irregul> di/ribution1 su* z we see     
ev]y:]e 9 ! univ]se1 might lead to bo?  
great] & less velocities2 & if we fur!r 
take acc\nt ( collisions & ne> approa*es
 ( l>ge masses result+ 9 explosive      
disruptions1 we might h almo/ any am\nt 
( motion z ! result1 b z ?is motion w\ld
 be produc$ by gravitation )9 ! sy/em1 x
 c\ld equally well be controll$ by      
gravitation4  ,illu/ration3 ,,diagram   
,,( ,,/ell> ,,univ]se 7,plan74 #a4      
,c5tral "p ( ,sol> ,clu/]4 #b4 ,sun's   
,orbit 7,black spot74 #c4 ,out] limit ( 
,sol> ,clu/]4 #d4 ,milky ,way4  ,9 ord] 
t my read]s may bett] und]/& !          
calculations ( ,"l ,kelv91 & also !     
g5]al conclusions ( a/ronom]s z to ! =m 
& dim5sions ( ! /ell> univ]se1 ,i h     
drawn two diagrams1 "o %[+ a plan on !  
c5tral plane ( ! ,milky ,way1 ! o!r a   
section ?r\gh its poles4 ,bo? are on !  
same scale1 & !y %[ ! total diamet]     
across ! ,milky ,way z be+ #cfjj        
light-ye>s1 or ab\t half t po/ulat$ by  

,"l ,kelv9 = 8 hypo!tical univ]se4 ,i d 
?is because ! dim5sions giv5 by him are 
^? :i* are suffici5t to lead to motions 
ne> ! c5tre su* z ! />s n[ possess 9 a  
m9imum p]iod ( tw5ty-five million ye>s  
aft] ! initial arrangem5t he supposes1  
at :i* lat] epo* :i* we are n[ suppos$  
to h rea*$1 ! :ole sy/em w\ld ( c\rse be
 greatly r$uc$ 9 ext5t by aggregations  
t[>ds & ne> ! c5tre4 ,^! dim5sions also 
seem to accord suffici5tly ) ! actual   
di/ances ( />s z yet measur$4 ,! smalle/
 p>allax :i* has be5 det]m9$ ) any      
c]ta9ty1 accord+ to ,pr(essor ,newcomb's
 li/1 is t ( ,gamma ,cassiopei1 :i* is  
"o-hundr$? ( a second 7#j4ja71 :ile ,"l 
,kelv9 gives none small] ?an #j4jb1 & ^!
 w all be includ$ )9 ! sol> clu/] z ,i h
 %[n x4  ,illu/ration3 ,,diagram ,,(    
,,/ell> ,,univ]se 7,section74 ,section  
?r\gh ,poles ( ,milky ,way4  ,x mu/ be  
cle>ly und]/ood t ^! two illu/rations   
are m]ely diagrams to %[ ! ma9 features 
( ! /ell> univ]se accord+ to ! be/      
in=mation available1 ) ! proportionate  

dim5sions ( ^! features1 s f> z ! facts 
( ! di/ribution ( ! />s & ! views ( ^?  
a/ronom]s :o h paid mo/ att5tion to !   
subject c be h>monis$4 ,( c\rse x is n  
sugge/$ t ! :ole arrangem5t is s regul> 
z "h %[n1 b an attempt has be5 made by  
means ( ! dott$ %ad+ to repres5t !      
comp>ative d5sities ( ! diff]5t portions
 ( space ar\nd u1 & a few rem>ks on ?is 
po9t may be ne$$4  ,! sol> clu/] is %[n 
v d5se at ! c5tral portion1 occupy+     
"o-t5? ( its diamet]1 & x is ne> !      
outside ( ?is d5se c5tre t our sun is   
suppos$ to be situat$4 ,beyond ?is !re  
seems to be almo/ a vacuity1 beyond :i* 
aga9 is ! out] portion ( ! clu/] consi/+
 ( comp>atively ?9ly scatt]$ />s1 ?us   
=m+ a k9d ( r+-clu/]1 resembl+ 9 %ape ! 
beautiful r+-nebula 9 ,lyra1 z has be5  
sugge/$ by sev]al a/ronom]s4 ,!re is "s 
direct evid5ce = ?is r+-=m4 ,pr(essor   
,newcomb 9 8 rec5t book on ,! ,/>s gives
 a li/ ( all />s ( :i* ! p>allax is     
fairly well kn[n4 ,^! are sixty-n9e 9   
numb]2 & on arrang+ !m 9 ! ord] ( !     

am\nt ( _! p>allax1 ,i f9d t no less ?an
 ?irty-five ( !m h p>allaxes betwe5 #j4a
 & #j4d ( a second1 ?us %[+ t !y        
con/itute "p ( ! d5se c5tral mass2 :ile 
?ree o!rs1 f #j4d to #j4ge1 indicate ^? 
:i* are our close/ companions at !      
pres5t "t1 b /ill at an enorm\s di/ance4
 ,^? :i* h p>allaxes ( less ?an ! t5? & 
d[n to "o-hundr$? ( a second are only   
?irty-"o 9 all2 b z !y are spread ov] a 
sph]e t5 times ! diamet]1 & !re=e a ?\s&
 times ! cubic cont5t ( ! sph]e conta9+ 
^? above "o-t5? ( a second1 !y ought to 
be imm5sely m num]\s ev5 if v mu* m ?9ly
 scatt]$4 ,! int]e/+ po9t1 h[ev]1 is1 t 
till we get d[n to a p>allax ( #j4jf1   
!re are only ?ree />s z yet measur$1    
:]eas ^? betwe5 #j4jb & #j4jf1 an equal 
range ( p>allax1 are tw5ty-six 9 numb]1 
& z ^! are scatt]$ 9 all directions !y  
indicate an almo/ vacant space foll[$ by
 a mod]ately d5se out] r+4  ,9 ! enorm\s
 space betwe5 our clu/] & ! ,milky ,way1
 & also above & bel[ its plane to !     
poles ( ! ,galaxy1 />s appe> to be v    

?9ly scatt]$1 p]haps m d5sely 9 ! plane 
( ! ,milky ,way ?an above & bel[ x :]e !
 irresolvable nebul are s num]\s2 & !re 
may n improbably be an almo/ vacant     
space beyond our clu/] = a consid]able  
di/ance1 z has be5 suppos$1 b ?is _c be 
kn[n till "s means are discov]$ (       
measur+ p>allaxes ( f "o-hundr$? to "o  
five-hundr$? ( a second4  ,^! diagrams  
also s]ve to indicate ano!r po9t (      
consid]able importance to ! view "h     
advocat$4 ,by plac+ ! sol> sy/em t[>ds !
 out] m>g9 ( ! d5se c5tral portion ( !  
sol> clu/] 7:i* may v possibly include a
 l>ge proportion ( d>k />s & ?us be mu* 
m d5se t[>ds ! c5tre ?an x appe>s to u71
 x may v well be suppos$ to revolve1 ) !
 o!r />s compos+ x1 ar\nd ! c5tre (     
gravity ( ! clu/]1 z ! =ce ( gravity    
t[>ds t c5tre might be p]haps tw5ty or a
 hundr$ times great] ?an t[>ds ! v mu*  
less d5se & m remote out] portions ( !  
clu/]4 ,! sun1 z indicat$ on ! diagrams1
 is ab\t ?irty light-ye>s f t c5tre1    
correspond+ to a p>allax ( a little m   

?an "o-t5? ( a second1 & an actual      
di/ance ( #aij millions ( millions (    
miles1 equal to ab\t #gj1jjj times !    
di/ance ( ! sun f ,neptune4 ,yet we see 
t ?is position is s little remov$ f !   
exact c5tre ( ! :ole /ell> univ]se1 t if
 any b5eficial influ5ces are due to t   
c5tral position 9 reg>d to ! ,galaxy1 x 
w receive !m p]haps to z full an ext5t z
 if situat$ at ! actual c5tre4 ,b if x  
is situat$ z "h %[n1 !re is no fur!r    
difficulty z to its prop] motion c>ry+ x
 f "o side to ! o!r ( ! ,milky ,way 9   
less "t ?an has be5 requir$ = !         
developm5t ( life ^u ! e>?4 ,& if ! sol>
 clu/] is really sub-globul>1 &         
suffici5tly cond5s$ to s]ve z a c5tre ( 
gravity = ! :ole ( ! />s ( ! clu/] to   
revolve ar\nd1 all ! compon5t />s :i*   
are n situat$ 9 ! plane ( its equator 7&
 t ( ! ,milky ,way7 mu/ revolve         
obliquely at v>i\s angles up to an angle
 ( #ij4 ,^! num]\s div]g+ motions1      
toge!r ) ! motions ( ! ne>] />s outside 
! clu/]1 "s ( :i* may revolve r\nd o!r  

c5tres ( gravity made up l>gely ( d>k   
bodies1 w\ld p]haps suffici5tly acc\nt =
 ! app>5t r&om motions ( s _m ( ! />s4  
,,uni=m ,,heat-,,supply ,,due ,,to      
,,c5tral ,,position  ,we n[ come to a   
po9t ( ! greate/ int]e/ z reg>ds !      
problem we are inve/igat+4 ,we h se5 h[ 
great is ! diff]5ce 9 ! e/imates (      
geologi/s & ^? ( physici/s z to ! "t t  
has elaps$ dur+ ! :ole developm5t (     
life4 ,b ! position we h n[ f\nd = !    
sun1 9 ! out] portion ( ! c5tral        
/>-clu/]1 may af=d a clue to ?is        
problem4 ,:at we require is1 "s mode (  
keep+ up ! sun's heat dur+ ! enorm\s    
geological p]iods 9 :i* we h evid5ce ( a
 wond]ful uni=mity 9 ! e>?'s temp]ature1
 & !re=e 9 ! sun's heat-emission4 ,!    
great c5tral r+-clu/] ) its cond5s$     
c5tral mass1 :i* presumably has be5 =m+ 
= a mu* long] p]iod ?an our sun has be5 
giv+ heat to ! e>?1 mu/ dur+ all ?is "t 
h be5 ex]t+ a p[]ful attraction on !    
diffus$ matt] 9 ! spaces ar\nd x1 n[    
app>5tly almo/ void z comp>$ ) :at !y   

may h be54 ,"s scanty remnants ( t matt]
 we see 9 ! num]\s meteoric sw>ms :i* h 
be5 drawn into our sy/em4 ,a position   
t[>ds ! outside ( ?is c5tral aggregation
 ( suns w\ld evid5tly be v fav\rable = !
 gr[? by accretion ( any consid]able    
mass4 ,! enorm\s di/ance ap>t ( ! out]  
compon5ts 7! out] r+7 ( ! clu/] w\ld    
all[ a l>ge am\nt ( ! infl[+ meteoritic 
matt] to escape !m1 & ! l>g] suns       
situat$ ne> ! surface ( ! inn] d5se     
clu/] w\ld draw to !mselves ! great] "p 
( ?is matt]4#bc ,! v>i\s planets ( our  
sy/em 7 no d\bt built up f a portion ( !
 matt] t fl[$ 9 ne> ! plane ( !         
ecliptic1 b mu* ( t :i* came f all o!r  
directions w\ld be drawn t[>ds ! sun    
itself or to its neighb\r+ suns4 ,"s (  
?is w\ld fall directly into x2 o!r      
masses com+ f diff]5t directions &      
collid+ ) ea* o!r w\ld h _! motion      
*eck$1 & ?us aga9 fall into ! sun2 & s  
long z ! matt] fall+ 9 7 n 9 too l>ge   
masses1 ! sl[ additions to ! sun's bulk 
& increase ( its heat w\ld be           

suffici5tly gradual to be 9 no way      
prejudicial to a planet at ! e>?'s      
di/ance4  ,! ma9 po9t ,i wi% to sugge/  
"h is1 t by f> ! great] portion ( !     
matt] ( ! :ole /ell> univ]se has1 ei!r  
?r\gh gravitation or 9 comb9ation )     
electrical =ces1 z sugge/$ by ,mr4      
,:ittak]1 become drawn toge!r into ! va/
 r+-=m$ sy/em ( ! ,milky ,way1 :i* is1  
presumably1 sl[ly revolv+1 & has ?us be5
 *eck$ 9 its orig9al infl[ t[>d ! c5tre 
( mass ( ! /ell> univ]se4 ,x has also   
probably drawn t[>ds itself ! adjac5t   
portions ( ! scatt]$ mat]ial 9 ! spaces 
ar\nd x 9 all directions4  ,_h ! va/    
mass ( matt] po/ulat$ by ,"l ,kelv9     
acquir$ no motion ( revolution1 b h     
fall5 cont9u\sly t[>ds ! c5tre ( mass1 !
 motions develop$ :5 ! m di/ant bodies  
approa*$ t c5tre w\ld h be5 extremely   
rapid2 :ile1 z !y mu/ h fall5 9 f e     
direction1 !y w\ld h become m & m d5sely
 aggregat$1 & collisions ( ! mo/        
cata/rophic nature w\ld frequ5tly h     
occurr$1 & ?is w\ld h r5d]$ ! c5tral    

portion ( ! univ]se ! lea/ /able & !    
lea/ fitt$ to develop life4  ,b1 "u !   
conditions t actually prevail1 ! v      
rev]se is ! case4 ,! quantity ( matt]   
rema9+ betwe5 our clu/] & ! ,milky ,way 
be+ comp>atively small1 ! aggregation   
into suns has gone on m regul>ly & m    
sl[ly4 ,! motions acquir$ by our sun &  
its neighb\rs h be5 r5d]$ mod]ate by two
 causes3 7#a7 _! ne>ness to ! c5tre ( ! 
v sl[ly aggregat+ clu/] :]e ! motion due
 to gravitation is lea/ 9 am\nt2 & 7#b7 
! slight diff]5tial attraction away f ! 
c5tre by ! ,milky ,way on ! side ne>e/  
to u4 ,aga91 ?is protective action ( !  
,milky ,way has be5 repeat$1 on a small]
 scale1 by ! =mation ( ! out] r+ ( !    
sol> clu/]1 :i* has ?us pres]v$ ! inn]  
c5tral clu/] itself f a too abundant    
direct infl[ ( l>ge masses ( matt]4  ,b 
al?\gh ! matt] compos+ ! out] portion ( 
! orig9al univ]se has be5 to a l>ge     
ext5t aggregat$ into ! va/ sy/em ( !    
,milky ,way1 x seems probable1 p]haps   
ev5 c]ta91 t "s portion w\ld escape its 

attractive =ces & w\ld pass ?r\gh its   
num]\s op5 spaces--indicat$ by ! d>k    
rifts1 *annels1 & pat*es1 z already     
describ$--& ?us fl[ on un*eck$ t[>ds !  
c5tre ( mass ( ! :ole sy/em4 ,! quantity
 ( matt] ?us rea*+ ! c5tral clu/] f !   
enorm\sly remote spaces beyond ! ,milky 
,way might be v small 9 comp>ison ) :at 
0 reta9$ to build up t wond]ful         
/>-sy/em2 b x might yet be s l>ge 9     
total am\nt z to play an important "p 9 
! =mation ( ! c5tral gr\p ( suns4 ,x    
w\ld probably fl[ inw>ds almo/          
cont9u\sly1 & :5 x ultimately rea*$ !   
sol> clu/]1 x w\ld h atta9$ a v high    
velocity4 ,if1 !re=e1 x 7 widely        
diffus$1 & consi/$ ( masses ( small or  
mod]ate size z comp>$ ) planets or />s1 
x w\ld furni% ! en]gy requisite = br++  
^! sl[ly aggregat+ />s to ! requir$     
int5sity ( heat = =m+ lum9\s suns4  ,"h1
 !n1 ,i ?9k1 we h f\nd an adequate      
explanation ( ! v long-cont9u$ light &  
heat-emitt+ capacity ( our sun1 &       
probably ( _m o!rs 9 ab\t ! same        

position 9 ! sol> clu/]4 ,^! w\ld at    
fir/ gradually aggregate into           
consid]able masses f ! sl[ly mov+       
diffus$ matt] ( ! c5tral portions ( !   
orig9al univ]se2 b at a lat] p]iod !y   
w\ld be re9=c$ by a con/ant & /eady     
inru% ( matt] f its v out] regions1 &   
!re=e possess+ su* high velocities z to 
mat]ially aid 9 produc+ & ma9ta9+ !     
requisite temp]ature ( a sun su* z ours1
 dur+ ! long p]iods dem&$ = cont9u\s    
life-developm5t4 ,! enorm\s ext5sion &  
mass ( ! orig9al univ]se ( diffus$ matt]
 7z po/ulat$ by ,"l ,kelv97 is ?us se5  
to be ( ! greate/ importance z reg>ds   
?is ultimate product ( evolution1       
because1 )\t x1 ! comp>atively sl[-mov+ 
& cool c5tral regions might n h be5 able
 to produce & ma9ta9 ! requisite en]gy 9
 ! =m ( heat2 :ile ! aggregation ( by f>
 ! l>g] portion ( its matt] 9 ! great   
revolv+ r+ ( ! galaxy 0 equally         
important1 9 ord] to prev5t ! too great 
& too rapid infl[ ( matt] to ^! fav\r$  
regions4  ,x appe>s1 !n1 t if we admit z

 probable "s su* process ( developm5t z 
,i h "h indicat$1 we c dimly see ! be>+ 
( all ! great features ( ! /ell> univ]se
 ^u ! successful developm5t ( life4 ,^! 
are1 its va/ dim5sions2 ! =m x has      
acquir$ 9 ! mighty r+ ( ! ,milky ,way2 &
 our position ne> to1 b n exactly 91 its
 c5tre4 ,we "k t ! />-sy/em has acquir$ 
^! =ms1 presumably f "s simple & m      
diffus$ condition4 ,we "k t we are      
situat$ ne> ! c5tre ( ?is va/ sy/em4 ,we
 "k t our sun has emitt$ light & heat1  
almo/ uni=mly1 = p]iods incompatible )  
rapid aggregation & ! equally rapid     
cool+ :i* physici/s consid] inevitable4 
,i h "h sugge/$ a mode ( developm5t :i* 
w\ld lead to a v sl[ b cont9u\s gr[? ( !
 m c5tral suns2 to an excessively long  
p]iod ( ne>ly /ation>y heat-giv+ p[]2 & 
la/ly1 an equally long p]iod ( v gradual
 cool+--a p]iod ! comm5cem5t ( :i* our  
sun may h j ent]$ ^u4  ,desc5d+ n[ to   
t]re/rial physics1 ,i h %[n t1 ow+ to ! 
highly complex nature ( ! adju/m5ts     
requir$ to r5d] a _w habitable & to     

reta9 its habitability dur+ ! ons ( "t  
requisite = life-developm5t1 x is 9 !   
highe/ degree improbable t ! requir$    
conditions & adaptations %\ld h occurr$ 
9 any o!r planets ( any o!r suns1 :i*   
might occupy an equally fav\rable       
position ) our own1 & :i* 7 ( !         
requisite size & heat-giv+ p[]4  ,la/ly1
 ,i submit t ! :ole ( ! evid5ce ,i h "h 
br\ght toge!r leads to ! conclusion t   
our e>? is almo/ c]ta9ly ! only inhabit$
 planet 9 our sol> sy/em2 &1 fur!r1 t   
!re is no inconceivability--no          
improbability ev5--9 ! conception t1 9  
ord] to produce a _w t %\ld be precisely
 adapt$ 9 e detail = ! ord]ly developm5t
 ( organic life culm9at+ 9 man1 su* a   
va/ & complex univ]se z t :i* we "k     
exi/s ar\nd u1 may h be5 absolutely     
requir$4   ,,summ>y ,,( ,,argum5t  ,z ! 
la/ t5 *apt]s ( ?is volume embody a     
connect$ argum5t lead+ to ! conclusion  
above /at$1 x may be useful to my read]s
 to summ>ise r fully ! successive /eps (
 ?is argum5t1 ! facts on :i* x re/s1 & !

 v>i\s subsidi>y conclusions arriv$ at4 
7#a7 ,"o ( ! mo/ important results (    
mod]n a/ronomy is to h e/abli%$ ! unity 
( ! va/ /ell> univ]se :i* we see ar\nd  
u4 ,?is re/s ^u a great mass (          
obs]vations1 :i* demon/rate ! wond]ful  
complexity 9 detail ( ! arrangem5t &    
di/ribution ( />s & nebul1 comb9$ ) a no
 less rem>kable g5]al symmetry1 indicat+
 ?r\gh\t a s+le int]-dep5d5t sy/em1 n a 
numb] ( totally di/9ct sy/ems s f> ap>t 
z to h no physical relations ) ea* o!r1 
z 0 once suppos$4  7#b7 ,?is view is    
support$ by num]\s conv]g+ l9es (       
evid5ce1 all t5d+ to %[ t ! />s are n   
inf9ite 9 numb]1 z 0 once g5]ally       
believ$1 & :i* view is ev5 n[ advocat$  
by "s a/ronom]s4 ,! v rem>kable         
calculations ( ,"l ,kelv91 ref]r$ to 9 !
 e>ly "p ( ?is *apt]1 give a fur!r      
support to ?is view1 s9ce !y %[ t if !  
/>s ext5d$ mu* beyond ^? we see or c    
obta9 direct k (1 & ) no v great *ange 9
 _! av]age di/ance ap>t1 !n ! =ce (     
gravitation t[>ds ! c5tre w\ld h produc$

 on ! av]age m rapid motions ?an ! />s  
g5]ally possess4  7#c7 ,an ov]:elm+     
cons5sus ( op9ion among ! be/ a/ronom]s 
e/abli%es ! fact ( our ne>ly c5tral     
position 9 ! /ell> univ]se4 ,!y all     
agree t ! ,milky ,way is ne>ly circul> 9
 =m4 ,!y all agree t our sun is situat$ 
almo/ exactly 9 its m$ial plane4 ,!y all
 agree t our sun1 al?\gh n situat$ at ! 
exact c5tre ( ! galactic circle1 is yet 
n v f> f x1 because !re are no          
unmi/akable signs ( our be+ ne>] to x at
 any "o po9t & f>!r away f ! opposite   
po9t4 ,?us ! ne>ly c5tral position ( our
 sun 9 ! great />-sy/em is almo/        
univ]sally admitt$4  ,on ! "q ( !       
sol>-clu/] !re is m diff]5ce ( op9ion2  
?\gh "h1 aga91 all are agre$ t !re is   
su* a clu/]4 ,its size1 =m1 d5sity1 &   
exact position are some:at unc]ta91 b ,i
 h1 z f> z possible1 be5 guid$ by ! be/ 
available evid5ce4 ,if we adopt ,"l     
,kelv9's g5]al idea ( ! gradual         
cond5sation ( an enorm\s diffus$ mass ( 
matt] t[>ds its common c5tre ( gravity1 

t c5tre w\ld be approximately ! c5tre ( 
?is clu/]4 ,also1 z gravitational =ce at
 & ne> ?is c5tre w\ld be comp>atively   
small1 ! motions produc$ !re w\ld be    
sl[1 & collisions1 be+ due only to      
diff]5tial motions1 :5 !y did occur w\ld
 be v g5tle4 ,we might !re=e expect _m  
d>k aggregations ( matt] "h1 :i* may    
expla9 :y we d n f9d any special cr[d+ (
 visible />s 9 ! direction ( ?is c5tre2 
:ile1 z no /> has a s5sible disc1 ! d>k 
/>s if at great di/ances w\ld h>dly ev] 
be se5 to occult ! bright ones4 ,?us1 x 
seems to me1 ! controll+ =ce may be     
expla9$ :i* has reta9$ our sun 9        
approximately ! same orbit ar\nd ! c5tre
 ( gravity ( ?is c5tral clu/] dur+ !    
:ole p]iod ( its exi/5ce z a sun & our  
exi/5ce z a planet2 & has ?us sav$ u f !
 possibility--p]haps ev5 ! c]ta9ty--(   
disa/r\s collisions or disruptive       
approa*es to :i* suns1 9 or ne> ! ,milky
 ,way1 & to a less ext5t else:]e1 are or
 h be5 expos$4 ,x seems q probable t 9 t
 region ( m rapid & less controll$      

motions & m cr[d$ masses ( matt]1 no /> 
c rema9 9 a ne>ly /able condition z     
reg>ds temp]ature = suffici5tly long    
p]iods to all[ ( a complete sy/em (     
life-developm5t on any planet x may     
possess4  7#d7 ,! v>i\s pro(s are next  
/at$ t assure u ( ! almo/ complete      
uni=mity ( matt]1 & ( mat]ial physical &
 *emical laws1 ?r\gh\t our univ]se4 ,?is
 ,i believe no "o s]i\sly disputes2 & x 
is a po9t ( ! greate/ importance :5 we  
come to consid] ! conditions requir$ = !
 developm5t & ma9t5ance ( life1 s9ce x  
assures u t v simil>1 if n id5tical1    
conditions mu/ prevail :]ev] organic    
life is or c be develop$4  7#e7 ,?is    
leads u on to ! consid]ation ( !        
ess5tial *>act]i/ics ( ! liv+ organism1 
consi/+ z x does ( "s ( ! mo/ abundant &
 mo/ widely di/ribut$ ( ^! mat]ial      
elem5ts1 & be+ always subject to ! g5]al
 laws ( matt]4 ,! be/ au?orities 9      
physiology are quot$1 z to ! extreme    
complexity ( ! *emical comp\nds :i*     
con/itute ! physical basis = !          

manife/ation ( life2 z to _! great      
in/ability2 _! wond]ful mobility comb9$ 
) p]man5ce ( =m & /ructure2 & ! altoge!r
 m>vell\s p[]s !y possess ( br++ ab\t   
unique *emical trans=mations & ( build+ 
up ! mo/ complicat$ /ructures f simple  
elem5ts4  ,i h endeav\r$ to put ! broad 
ph5om5a ( vegetable & animal life 9 a   
way t w enable my read]s to =m "s fa9t  
conception ( ! intricacy1 ! delicacy1 & 
! my/]y ( ! myriad liv+ =ms !y see      
ev]y:]e ar\nd !m4 ,su* a conception w   
enable !m to realise h[ supremely gr& is
 organic life1 & to appreciate bett]1   
p]haps1 ! absolute necessity = ! num]\s1
 complex & delicate adaptations (       
inorganic nature1 )\t :i* x is          
impossible = life ei!r to exi/ n[1 or to
 h be5 develop$ dur+ ! immeasurable pa/4
  7#f7 ,! g5]al conditions :i* are      
absolutely ess5tial = life ?us manife/$ 
on our planet are !n discuss$1 su* z1   
sol> light & heat2 wat] univ]sally      
di/ribut$ on ! planet's surface & 9 !   
atmosph]e2 an atmosph]e ( suffici5t     

d5sity1 & compos$ ( ! sev]al gases f :i*
 alone protoplasm c be =m$2 "s          
alt]nations ( light & d>kness1 & a few  
o!rs4  7#g7 ,hav+ treat$ ^! conditions  
broadly1 & expla9$ :y !y are important &
 ev5 indisp5sable = life1 we next proce$
 to %[ h[ !y are fulfill$ ^u ! e>?1 & h[
 num]\s1 h[ complex1 & (t5 h[ exact are 
! adju/m5ts ne$$ to br+ !m ab\t1 &      
ma9ta9 !m almo/ un*ang$ ?r\gh\t ! va/   
ons ( "t occupi$ 9 ! developm5t ( life4 
,two *apt]s are devot$ to ?is subject2 &
 x is believ$ t !y conta9 facts t w be  
new to _m ( my read]s4 ,! comb9ations ( 
causes :i* lead to ?is result are s     
v>i$1 & 9 sev]al cases dep5d5t on su*   
exceptional peculi>ities ( physical     
con/itution1 t x seems 9 ! highe/ degree
 improbable t !y c all be f\nd aga9     
comb9$ ei!r 9 ! sol> sy/em or ev5 9 !   
/ell> univ]se4 ,x w be well "h j to     
enum]ate ^! conditions1 :i* are all     
ess5tial )9 m or less n>r[ limits3--    
,di/ance ( planet f ! sun4       ,mass (
 planet4       ,obliquity ( its         

ecliptic4       ,am\nt ( wat] z comp>$ )
 l&4       ,surface di/ribution ( l& &  
wat]4       ,p]man5ce ( ?is di/ribution1
 dep5d5t probably on !      unique orig9
 ( our moon4       ,an atmosph]e (      
suffici5t d5sity1 & ( suitable compon5t 
gases4       ,an adequate am\nt ( du/ 9 
! atmosph]e4       ,atmosph]ic          
electricity4  ,_m ( ^! act & react on   
ea* o!r1 & lead to results ( great      
complexity4  7#h7 ,pass+ on to o!r      
planets ( ! sol> sy/em1 x is %[n t none 
( !m comb9e all ! complex conditions :i*
 are f\nd to "w h>moni\sly toge!r on !  
e>?2 :ile 9 mo/ cases !re is "s "o      
defect :i* alone removes !m f ! category
 ( possible life-produc+ & life-support+
 planets4 ,among ^! are ! small size &  
mass ( ,m>s1 be+ su* t x _c reta9 aque\s
 vap\r2 & ! fact t ,v5us rotates on its 
axis 9 ! same "t z x takes to revolve   
r\nd ! sun4 ,nei!r ( ^! facts 0 kn[n :5 
,proctor wrote ^u ! "q ( ! habitability 
( ! planets4 ,all ! o!r planets are n[  
giv5 up--& 7 giv5 up by ,proctor        

himself--z possible life-be>]s 9 _!     
pres5t /age2 b he & o!rs h held t1 if n 
suitable n[1 "s ( !m may h be5 ! sc5e ( 
life-developm5t 9 ! pa/1 :ile o!rs w be 
s 9 ! future4  ,9 ord] to %[ ! futility 
( ?is supposition1 ! problem ( !        
duration ( ! sun z a /able heat-giv] is 
discuss$2 & x is %[n t x is only by     
r$uc+ ! p]iods claim$ by geologi/s &    
biologi/s = life-developm5t ^u ! e>?1 & 
by ext5d+ ! "t all[$ by physici/s to its
 utmo/ limits1 t ! two claims c be      
h>monis$4 ,x foll[s t ! :ole p]iod ( !  
sun's duration z a light & heat-giv] has
 be5 requir$ = ! developm5t ( life ^u ! 
e>?2 & t x is only ^u planets ^: phases 
( developm5t syn*ronise ) t ( ! e>? t ! 
evolution ( life is possible4 ,= ^? ^:  
mat]ial evolution has gone on quick] or 
sl[]1 !re has n be51 or w n be1 "t en\gh
 = ! developm5t ( life4  7#i7 ,! problem
 ( ! />s z possibly hav+ life-support+  
planets is next dealt )1 & reasons are  
giv5 :y 9 only a m9ute portion ( ! :ole 
is ?is possible4 ,ev5 9 t m9ute portion1

 r$uc$ probably to a few ( ! compon5t   
suns ( ! sol>-clu/]1 a l>ge proportion  
seems likely to be rul$ out by be+ close
 b9>y sy/ems1 & ano!r l>ge portion by   
be+ 9 process ( aggregation4 ,9 ^?      
rema9+1 :e!r !y may be reckon$ by t5s or
 by hundr$s we _c say1 ! *ances aga9/ ! 
same complex comb9ation ( conditions z  
^? :i* we f9d on ! e>? occurr+ on any   
planet ( any o!r sun are enorm\sly      
great4  7#aj7 ,i !n ref]1 briefly1 to "s
 rec5t measurem5ts ( />-radiation1 &    
sugge/ t !y may ?us possibly h important
 effects on ! developm5t ( vegetable &  
animal life2 &1 f9ally1 ,i discuss !    
problem ( ! /ability ( ! /ell> univ]se &
 ! special advantage we d]ive f our     
c5tral position1 sugge/$ by "s ( ! late/
 rese>*es ( our great ma!matician &     
physici/--,"l ,kelv94   ,,conclusions   
,hav+ ?us br\ght toge!r ! :ole ( !      
available evid5ce be>+ ^u ! que/ions    
treat$ 9 ?is volume1 ,i claim t c]ta9   
def9ite conclusions h be5 rea*$ & prov$1
 & t c]ta9 o!r conclusions h enorm\s    

probabilities 9 _! fav\r4  ,!           
conclusions rea*$ by mod]n a/ronom]s    
are3 7#a7 ,t ! /ell> univ]se =ms "o     
connect$ :ole2 &1 ?\gh ( enorm\s ext5t1 
is yet f9ite1 & its ext5t det]m9able4   
7#b7 ,t ! sol> sy/em is situat$ 9 !     
plane ( ! ,milky ,way1 & n f> remov$ f !
 c5tre ( t plane4 ,! e>? is !re=e ne>ly 
9 ! c5tre ( ! /ell> univ]se4  7#c7 ,t   
?is univ]se consi/s ?r\gh\t ( ! same    
k9ds ( matt]1 & is subject$ to ! same   
physical & *emical laws4  ,! conclusions
 :i* ,i claim to h %[n to h enorm\s     
probabilities 9 _! fav\r are--  7#d7 ,t 
no o!r planet 9 ! sol> sy/em ?an our e>?
 is inhabit$ or habitable4  7#e7 ,t !   
probabilities are almo/ z great aga9/   
any o!r sun possess+ inhabit$ planets4  
7#f7 ,t ! ne>ly c5tral position ( our   
sun is probably a p]man5t "o1 & has be5 
specially fav\rable1 p]haps absolutely  
ess5tial1 to life-developm5t on ! e>?4  
99       99       99       99       99  
,^! latt] conclusions dep5d ^u !        
comb9ation ( a l>ge numb] ( special     

conditions1 ea* ( :i* mu/ be 9 def9ite  
relation to _m ( ! o!rs1 & mu/ all h    
p]si/$ simultane\sly dur+ enorm\s p]iods
 ( "t4 ,! weight to be giv5 to ?is k9d (
 reason+ dep5ds ^u a full & fair        
consid]ation ( ! :ole evid5ce z ,i h    
endeav\r$ to pres5t x 9 ! la/ sev5      
*apt]s ( ?is book4 ,to ?is evid5ce ,i   
appeal4         99       99       99    
99       99  ,?is completes my "w z a   
connect$ argum5t1 f\nd$ :olly on ! facts
 & pr9ciples accumulat$ by mod]n sci5ce2
 & x leads1 if my facts are sub/antially
 correct & my reason+ s\nd1 to "o great 
& def9ite conclusion--t man1 !          
culm9ation ( consci\s organic life1 has 
be5 develop$ "h only 9 ! :ole va/       
mat]ial univ]se we see ar\nd u4 ,i claim
 t ?is is ! logical outcome ( ! evid5ce1
 if we consid] & weigh ?is evid5ce )\t  
any prepossessions :atev]4 ,i ma9ta9 t x
 is a "q z to :i* we h no "r to =m a    
priori op9ions n f\nd$ ^u evid5ce4 ,&   
evid5ce oppos$ to ?is conclusion1 or ev5
 z to its improbability1 we h absolutely

 none :atev]4  ,b1 if we admit !        
conclusion1 no?+ t ne$ al>m ei!r !      
sci5tific or ! religi\s m9d necess>ily  
foll[s1 because x c be expla9$ or       
acc\nt$ = 9 ei!r ( two di/9ct ways4 ,"o 
consid]able body1 includ+ probably !    
majority ( m5 ( sci5ce1 w admit t !     
evid5ce does app>5tly lead to ?is       
conclusion1 b w expla9 x z due to a     
=tunate co9cid5ce4 ,!re might h be5 a   
hundr$ or a ?\s& life-be>+ planets1 _h !
 c\rse ( evolution ( ! univ]se be5 a    
little diff]5t1 or !re might h be5 none 
at all4 ,!y w\ld probably add1 t1 z life
 & man h be5 produc$1 t %[s t _!        
production 0 possible2 & !re=e1 if n n[ 
!n at "s o!r "t1 if n "h !n 9 "s o!r    
planet ( "s o!r sun1 we %\ld be sure to 
h come into exi/5ce2 or if n precisely !
 same z we are1 !n some?+ a little bett]
 or a little worse4  ,! o!r body1 &     
probably mu* ! l>ge/1 w\ld be repres5t$ 
by ^? :o1 hold+ t m9d is ess5tially     
sup]ior to matt] & di/9ct f x1 _c       
believe t life1 consci\sness1 m9d1 are  

products ( matt]4 ,!y hold t ! m>vell\s 
complexity ( =ces :i* appe> to control  
matt]1 if n actually to con/itute x1 are
 & mu/ be m9d-products2 & :5 !y see life
 & m9d app>5tly ris+ out ( matt] & giv+ 
to its myriad =ms an add$ complexity &  
unfa?omable my/]y1 !y see 9 ?is         
developm5t an additional pro( ( !       
supremacy ( m9d4 ,su* p]sons w\ld be    
incl9$ to ! belief ( ! great eighte5?   
c5tury s*ol>1 ,dr4 ,b5tley1 t ! s\l ( "o
 virtu\s man is ( great] wor? &         
excell5cy ?an ! sun & all 8 planets &   
all ! />s 9 ! heav5s2 & :5 !y are %[n t 
!re are /rong reasons = ?9k+ t man is ! 
unique & supreme product ( ?is va/      
univ]se1 !y w see no difficulty 9 go+ a 
little fur!r1 & believ+ t ! univ]se 0   
actually br\ght into exi/5ce = ?is v    
purpose4  ,) inf9ite space ar\nd u &    
inf9ite "t be=e & beh9d u1 !re is no    
incongruity 9 ?is conception4 ,a univ]se
 z l>ge z ours = ! purpose ( br++ into  
exi/5ce _m myriads ( liv+1 intellectual1
 moral1 & spiritual be+s1 ) unlimit$    

possibilities ( life & happ9ess1 is     
surely n m out ( proportion ?an is !    
complex ma*9]y1 ! life-long lab\r1 !    
+5uity & inv5tion :i* we h be/[$ ^u !   
production ( ! humble1 ! trivial1 p94   
,nei!r is ! app>5t wa/e ( en]gy s great 
9 su* a univ]se1 comp>atively1 z !      
millions ( acorns1 produc$ dur+ its life
 by an oak1 e "o ( :i* might gr[ to be a
 tree1 b ( :i* only "o does actually1   
aft] sev]al hundr$ ye>s1 produce ! "o   
tree :i* is to replace ! p>5t4 ,& if x  
is said t ! acorns are food = bird &    
bea/1 yet ! spores ( f]ns & ! se$s (    
or*ids are n s1 & c\ntless millions ( ^!
 g to wa/e = e "o :i* reproduces ! p>5t 
=m4 ,& all ?r\gh ! animal _w1 especially
 among ! l[] types1 ! same ?+ is se54 ,=
 ! great majority ( ^! entities we c see
 no use :atev]1 ei!r ( ! enorm\s v>iety 
( ! species1 or ! va/ hordes (          
individuals4 ,( beetles alone !re are at
 lea/ a hundr$ ?\s& di/9ct species n[   
liv+1 :ile 9 "s p>ts ( sub-arctic       
,am]ica mosquitoes are sometimes s      

excessively abundant t !y obscure ! sun4
 ,& :5 we ?9k ( ! myriads t h exi/$     
?r\gh ! va/ ages ( geological "t1 ! m9d 
reels "u ! imm5sity (1 to u1 app>5tly   
useless life4  ,all nature tells u !    
same /range1 my/]i\s /ory1 ( ! exub]ance
 ( life1 ( endless v>iety1 ( unimag9able
 quantity4 ,all ?is life ^u our e>? has 
l$ up to & culm9at$ 9 t ( man4 ,x has   
be51 ,i believe1 a common & n unpopul>  
idea t dur+ ! :ole process ( ! rise &   
gr[? & ext9ction ( pa/ =ms1 ! e>? has   
be5 prep>+ = ! ultimate--,man4 ,mu* ( ! 
weal? & luxuriance ( liv+ ?+s1 ! inf9ite
 v>iety ( =m & /ructure1 ! exquisite    
grace & beauty 9 bird & insect1 9       
foliage & fl[]1 may h be5 m]e           
by-products ( ! gr& me*anism we call    
nature--! "o & only me?od ( develop+    
humanity4  ,& is x n 9 p]fect h>mony )  
?is gr&eur ( design 7if x be design71   
?is va/ness ( scale1 ?is m>vell\s       
process ( developm5t ?r\gh all ! ages1 t
 ! mat]ial univ]se ne$$ to produce ?is  
cradle ( organic life1 & ( a be+ de/9$  

to a high] & a p]man5t exi/5ce1 %\ld be 
on a correspond+ scale ( va/ness1 (     
complexity1 ( beauty8 ,ev5 if !re 7 no  
su* evid5ce z ,i h "h adduc$ = ! unique 
position & ! exceptional *>act]i/ics :i*
 di/+ui% ! e>?1 ! old idea t all !      
planets 7 inhabit$1 & t all ! />s exi/$ 
= ! sake ( o!r planets1 :i* planets     
exi/$ to develop life1 w\ld1 9 ! light (
 our pres5t k1 seem utt]ly improbable & 
incr$ible4 ,x w\ld introduce monotony   
into a univ]se ^: gr& "* & tea*+ is     
endless div]sity4 ,x w\ld imply t to    
produce ! liv+ s\l 9 ! m>vell\s &       
glori\s body ( man--man ) 8 faculties1 8
 aspirations1 8 p[]s = good & evil--t   
?is 0 an easy matt] :i* c\ld be br\ght  
ab\t any:]e1 9 any _w4 ,x w\ld imply t  
man is an animal & no?+ m1 is ( no      
importance 9 ! univ]se1 ne$$ no great   
prep>ations = 8 adv5t1 only1 p]haps1 a  
second-rate demon1 & a ?ird or f\r?-rate
 e>?4 ,look+ at ! long & sl[ & complex  
gr[? ( nature t prec$$ 8 appe>ance1 !   
imm5sity ( ! /ell> univ]se ) its ?\s&   

million suns1 & ! va/ ons ( "t dur+ :i* 
x has be5 develop+--all ^! seem only !  
appropriate & h>moni\s surr\nd+s1 !     
necess>y supply ( mat]ial1 ! suffici5tly
 spaci\s work%op = ! production ( t     
planet :i* 0 to produce fir/1 ! organic 
_w1 & !n1 ,man4  ,9 "o ( 8 f9e/ passages
 our great _w-poet gives u 8 conception 
( ! gr&eur ( human nature--',:at a piece
 ( "w is man6 ,h[ noble 9 reason6 ,h[   
inf9ite 9 faculty6 ,9 =m & mov+1 h[     
express & admirable6 ,9 action h[ l an  
angel6 ,9 appreh5sion h[ l a god6' ,& = 
! developm5t ( su* a be+ :at is a       
univ]se su* z ours8 ,h[ev] va/ x may    
seem to our faculties1 x is z a m]e no?+
 9 ! ocean ( ! inf9ite4 ,9 inf9ite space
 !re may be inf9ite univ]ses1 b ,i h>dly
 ?9k !y w\ld be all univ]ses ( matt]4 ,t
 w\ld inde$ be a l[ conception ( inf9ite
 p[]6 ,"h1 on e>?1 we see millions (    
di/9ct species ( animals1 millions (    
diff]5t species ( plants1 & ea* & e     
species consi/+ (t5 ( _m millions (     
individuals1 no two individuals exactly 

alike2 & :5 we turn to ! heav5s1 no two 
planets1 no two satellites alike2 &     
outside our sy/em we see ! same law     
prevail+--no two />s1 no two clu/]s1 no 
two nebul alike4 ,:y !n %\ld !re be o!r 
univ]ses ( ! same matt] & subject to !  
same laws--z is impli$ by ! conception t
 ! />s are inf9ite 9 numb]1 & ext5d     
?r\gh inf9ite space8  ,( c\rse !re may  
be1 & probably are1 o!r univ]ses1 p]haps
 ( o!r k9ds ( matt] & subject to o!r    
laws1 p]haps m l our conceptions ( !    
e!r1 p]haps :olly non-mat]ial1 & :at we 
c only conceive ( z spiritual4 ,b1      
unless ^! univ]ses1 ev5 ?\gh ea* ( !m 7 
a million times va/] ?an our /ell>      
univ]se1 7 also inf9ite 9 numb]1 !y c\ld
 n fill inf9ite space1 :i* w\ld ext5d on
 all sides beyond !m1 s t ev5 a million 
million su* univ]ses w\ld %r9k to       
imp]ceptibility :5 comp>$ ) ! va/       
beyond6  ,( inf9ity 9 any ( its aspects 
we c really "k no?+1 b t x exi/s & is   
inconceivable4 ,x is a ?\ght t oppresses
 & ov]:elms4 ,yet _m speak ( x glibly z 

if !y knew :at x conta9s1 & ev5 use t   
assum$ k z an argum5t aga9/ views t are 
unacceptable to !mselves4 ,to me its    
exi/5ce is absolute b un?9kable--t way  
madness lies4      ',o night6 ,o />s1   
too rudely j>s     ,! f9ite ) !         
inf9ite6'  ,i w conclude ) "o ( ! f9e/  
passages relat+ to ! inf9ite t ,i am    
acqua9t$ )1 f ! p5 ( ! late ,r4,a4      
,proctor3  ',inconceivable1 d\btless1   
are ^! inf9ities ( "t & space1 ( matt]1 
( motion1 & ( life4 ,inconceivable t !  
:ole univ]se c be = all "t ! sc5e ( !   
op]ation ( inf9ite p[]1 omnipres5t1     
all-kn[+4 ,utt]ly incompreh5sible h[    
,inf9ite ,purpose c be associat$ )      
endless mat]ial evolution4 ,b x is no   
new ?\ght1 no mod]n discov]y1 t we are  
?us utt]ly p[]less to conceive or       
compreh5d ! idea ( an ,inf9ite ,be+1    
,almighty1 ,all-kn[+1 ,omnipres5t1 &    
,et]nal1 ( ^: inscrutable purpose !     
mat]ial univ]se is ! unexpla9$          
manife/ation4 ,sci5ce is 9 pres5ce ( !  
old1 old my/]y2 ! old1 old que/ions are 

ask$ ( h]--,can/ ?\ by se>*+ f9d out    
,god8 ,can/ ?\ f9d out ! ,almighty unto 
p]fection8 ,x is z high z heav52 :at    
can/ ?\ d8 deep] ?an hell2 :at can/ ?\  
"k8 ,& sci5ce answ]s ^! que/ions z !y 7 
answ]$ ( old--,z t\*+ ! ,almighty we _c 
f9d ,him out4'         99       99      
99       99       99  ,! foll[+         
beautiful l9es--among ! late/ products (
 ,t5nyson's g5ius--s completely h>monise
 ) ! subject-matt] ( ! pres5t volume1 t 
no apology is ne$$ = quot+ !m "h3--  7,!
 ,"q7      ,w my t9y sp>k ( be+         
,:olly vani% 9 y\r deeps & heights8     
,mu/ my day be d>k by reason1       ,o  
ye ,heav5s1 ( y\r b\ndless nights1      
,ru% ( ,suns & roll ( sy/ems1       ,&  
y\r fi]y cla% ( meteorites8  7,! ,answ]7
      ',_s1 ne>+ yon d>k portal         
,at ! limit ( ?y human /ate1     ,fe> n 
?\ ! hidd5 purpose       ,( t ,p[] :i*  
alone is great1     ,nor ! myriad _w1 ,8
 %ad[1       ,nor ! sil5t ,op5] ( !     
,gate4'  ,,footnote3  #bc ,s9ce writ+   
?is *apt] ,i h se5 a pap] by ,luigi     

d',auria deal+ ma!matically ) ',/ell>   
,motion1 etc41' & am pleas$ to see t1 f 
q diff]5t consid]ations1 he has f\nd x  
necess>y to place ! sol> sy/em at a     
di/ance f ! c5tre n v mu* m remote ?an !
 position ,i h giv5 x4 ,he says3 ',we h 
good reasons to suppose t ! sol> sy/em  
is r ne> ! c5tre ( ! ,milky ,way1 & z   
?is c5tre w\ld1 accord+ to our hypo!sis1
 co9cide ) ! c5tre ( ! ,univ]se1 !      
di/ance ( #aei light ye>s assum$ is n   
too great1 nor c x be v mu*             
small]4'--,j\rnal ( ! ,frankl9          
,in/itute1 ,m>* #aijc4     ,,index      
,adrianus ,tollius on /one axes1 #bjc4  
,air crim9ally poison$ by u1 #bfj4      
,alb$o expla9$1 #afb4      ,algol & its 
companion1 #ci2       *ange ( col\r (1  
#da4      ,all51 ,pr(4 ,f4,j41 on liv+  
matt]1 #aic2       on importance (      
nitrog51 #aie2       on physical        
conditions ess5tial = life1 #aif4       
,alpha ,c5tauri1 ne>e/ />1 #gd4         
,ammonia1 importance (1 to life1 #aie4  
,anaxim&]'s cosmic !ory1 #b4            

,angles ( a m9ute & second1 #hj4        
,arcturus1 rapid motion (1 #agb4        
,argum5t ( book1 summ>y (1 #caj4        
,a/ronom]s1 ! fir/1 #b4      ,a/ronomy1 
! new1 #bd4      ,a/rophysics1 a new    
sci5ce1 #cb4      ,atmosph]e1 qualities 
requisite = life1 #baj2       requisite 
composition (1 #bab2       aque\s vap\r 
91 #bad2       & life1 #bdc2            
effects ( d5sity (1 #bde2       a       
complex /ructure1 #bei2       its vital 
importance to u1 #bfj4       ,ball1 ,sir
 ,r41 on d>k />s1 #adc2       ,"t &     
,tide1 #bcc4      ,b>nham1 ,s4,w41 on   
d\ble />s1 #abc4      ,blue ( sky due to
 du/1 #bea4      ,bo$dick]'s map (      
,milky ,way1 #afd4      ,brew/]1 ,sir   
,d41 aga9/ ,:ewell1 #ae4                
,campbell1 ,pr(41 on spectroscopic      
b9>ies1 #abe2       on unc]ta9ty ( sun's
 motions1 #agi2       on numb] ( b9>y   
sy/ems1 #bhf4      ,c>bon comp\nds1 va/ 
numb]s (1 #aid4      ,c>bonic acid gas  
ess5tial = life1 #aif4      ,c5tral     
position ( sun1 importance (1 #cje4     

,*aldeans ! fir/ a/ronom]s1 #b4         
,*alm]s ,dr41 on plurality ( worlds1    
#ac4      ,*amb]l91 ,t4,c41 orig9 (     
nebul1 #abj2       on /ell> disruption1 
#ahf4      ,*romosph]e1 ! sun's1 #ajg4  
,cl]ke1 ,miss ,a4,m41 on limits ( />    
sy/em1 #ach2       on ,milky ,way1 #aeh1
 #afj2       on sol> clu/]1 #afe2       
on unc]ta9ty ( ! sun's motion1 #agg4    
,climate1 p]si/5ce ( mild1 #bbb4        
,cl\ds1 importance (1 to life1 #bdh4    
,clu/]s 9 relation to ,galaxy1 #fg4     
,comte1 on impossibility ( real k ( !   
/>s1 #be4      ,conclusions ( ! book1   
#cag2       be>+ (1 on sci5ce & on      
religion1 #cai4      ,corona ( sun1     
#ajh4      ,criticisms ( article 9      
,=tnightly ,review1 #afh1 #ahj4         
,d>w91 ,pr(4 ,g41 on meteoritic         
hypo!sis1 #acc2       on orig9 ( moon1  
#bcc2       on in/ability ( annul>      
sy/ems1 #bie4      ,day & night1 uses (1
 #bae4      ,diagrams ( />-di/ribution1 
#fb1 #ff4      ,diffraction-grat+s1 #cj4
      ,disruption ( /ell> bodies1 #ahg4 

,doppl] pr9ciple1 !1 #cg4      ,d\ble   
/>s1 evolution (1 #abc2       n fitt$ = 
life1 #bhf4      ,du/1 importance (1    
#bdi4      ,du/-free air1 results (1    
#bed4       ,e>?1 fir/ measur$1 #e2     
9 relation to life1 #bah2       ! only  
habitable planet1 #bfb2       _c reta9  
hydrog51 #bfd2       suppos$ extreme    
conditions (1 #bga4      ,e>?'s mass1 h[
 relat$ to life1 #bfe4      ,ecliptic1  
obliquity (1 9 relation to life1 #bai4  
,electricity1 effects ( atmosph]ic1     
#beg2       atmosph]ic1 h[ caus$1 #beh4 
,elem5ts1 *ange 9 spectra (1 #abi2      
9 ! sun1 #ahd2       9 meteorites1 #ahe2
       9 organic /ructures1 #bja4       
,emp$ocles an e>ly a/ronom]1 #c4        
,eudoxus on motions ( planets1 #c4      
,evolution ( ! />s1 #abh4               
,explanations ( life-processes1 #bjb4   
,facul ( sun1 #aje4      ,fi%]1 ,rev4   
,o41 on oceanic bas9s1 #bcd2       on ?9
 sub-oceanic cru/1 #bcg4      ,fizeau   
measures spe$ ( light1 #gi4             
,flamm>ion1 ,c41 on univ]sality ( life1 

#bgd1 #bha4      ,font5elle on plurality
 ( worlds1 #i4       ,galileo on />     
measurem5t1 #gd4      ,geological       
climates1 #bbb4      ,geologi/s on      
duration ( sun's heat1 #bge4            
,g]m9al vesicle1 ,m',k5drick on1 #bjb4  
,gill1 ,sir ,d41 on sy/ematic           
/>-motions1 #agh4      ,globul> clu/]s1 
/ability (1 #abf2       & v>iables1     
#abg4      ,gore1 ,mr4 ,j4,e41 on />s 9 
,galaxy1 #fj2       on mass ( b9>y />s1 
#ig2       on remot5ess ( bright />s1   
#adj2       on limits ( /> sy/em1 #ade2 
on limit$ numb] ( />s1 #aea2       on   
life on planets ( o!r suns1 #bhb1 #bhi4 
,g\ld on sol> clu/]1 #afe4      ,g\ld's 
map ( ,milky ,way1 #afd4                
,gravitation1 motions produc$ by1 on ,"l
 ,kelv9's hypo!sis1 #bih4               
,haliburton1 ,pr(essor ,w4,d41 on       
proteids1 #bjj4      ,heat & cold on    
e>?'s surface1 #bjg4      ,heat-supply1 
our long-cont9u$1 acc\nt$ =1 #cje4      
,h]s*el1 ,sir ,j41 on ,milky ,way1 #ej2 
on limits ( ! />-sy/em1 #adg4           

,heliomet]1 description (1 #hi4         
,hugg9s1 ,sir ,w41 on spectra ( />s1    
#cb2       measures radial motion1 #cg4 
,huxley1 ,pr(41 on protoplasm1 #aih2    
on duration ( life1 #bgh4      ,hydrog51
 :y n 9 atmosph]e1 #bdj2       escapes f
 e>?1 #bfd4       ,inf9ity1 unkn[able1  
#cbc2       ,proctor on1 #cbd4          
,jupit]'s satellites %[ spe$ ( light1   
#gi4       ,kapteyn on sol> clu/]1 #aff4
      ,kelv91 ,"l1 on ! sun's age1 #bgi2
       on a sugge/$ primitive =m (      
/>-sy/em1 #bih4      ,kir*h(f1 discov]s 
spectrum-analysis1 #bh4       ,laws (   
matt] uni=m ?r\gh\t univ]se1 #ahg4      
,leaves1 importance (1 #aig4      ,lee1 
,dr41 on orig9 ( d\ble />s1 #abc4       
,lewis1 on remote bright />s1 #ada4     
,life1 unity ( organic1 #ahi2           
def9itions (1 #aia2       conditions    
ess5tial =1 #bjf2       wat] ess5tial =1
 #baj2       atmosph]e =1 #baj2         
dep5d5t on temp]ature1 #bah2       n[   
improbable 9 />s1 #bhh2       conditions
 ess5tial =1 summ>is$1 #cad4            

,life-processes1 explanations (1 #bjb4  
,light1 velocity ( measur$1 #gi2        
necessity ( sol>1 #bji2       f sky due 
to du/1 #beb4      ,light-j\rney        
expla9$1 #ge4      ,light-ratio %[s />s 
to be limit$1 #aeb4      ,liv+ bodies1  
ess5tial po9ts 91 #aib4      ,locky]1   
,sir4 ,n41 on inorganic evolution1 #aag2
       on evolution ( />s1 #acj2        
on ,milky ,way1 #aei2       on position 
( sol> sy/em1 #afa4      ,luigi d',auria
 on /ell> motion1 #cjf4                 
,m',k5drick1 ,pr(41 on g]m9al vesicle1  
#bjb4      ,magnetism & sun-spots1 #ajf4
      ,man1 ,%akespe>e on1 #cbb4        
,m>s1 has no wat]1 #bff2       excessive
 temp]atures on1 #bfg4      ,matt] (    
univ]se uni=m1 #ahc4      ,maund] on d>k
 />s1 #adc4      ,maxwell ,hall1 ,mr41  
on />-motions1 #agh4      ,measurem5t ( 
/>-di/ances1 #he2       difficulty (1   
#hf4      ,m]cury n habitable1 #bff4    
,meteorites1 elem5ts 91 #ahe2       n   
primitive bodies1 #ahf4      ,meteoritic
 hypo!sis1 #aac2       ,proctor on1     

#aad2       expla9s nebul1 #aaf2        
,dr4 ,rob]ts on1 #aai4      ,milky ,way1
 !1 #dh2       =m (1 #ea1 #aei2         
description (1 #eb2       telescopic    
view (1 #eg2       />s 9 relation to1   
#ei2       ,mr4 ,gore on1 #fj2          
d5sity ( />s 91 #fa2       clu/]s &     
nebul 9 relation to1 #fg2       probable
 di/ance (1 #if2       =ms a great      
circle1 #aeg1 #afb2       ,pr(4 ,newcomb
 on1 #aeh2       probably no life 91    
#bhd2       diagrams (1 #cjj2           
revolution (1 important to u1 #cjg4     
,million1 h[ to appreciate a1 #hb4      
,m9*91 ,g4,m41 on radiation f />s1 #bij4
      ,monck1 ,mr4 ,w4,h4,s41 on        
non-inf9ity ( />s1 #add2       on       
unc]ta9ty ( sun's motion1 #agg4         
,moon1 :y no atmosph]e1 #bfc4           
,moon's suppos$ orig91 #bcc4            
,motion1 9 l9e ( sight1 #ce4            
,motions1 imp]ceptible1 #ci4            
,nebul1 ) gase\s spectra1 #dc2       9  
relation to ,galaxy1 #ff2               
di/ribution (1 #fi2       _m =ms (1 #gj2

       gase\s1 #ga2       meteoritic    
!ory (1 #aaf2       planet>y & annul>1  
#age2       ,dr4 ,rob]ts on spiral1     
#aag1 #agd2       ,*amb]l9 on orig9 (1  
#abj4      ,nebul> hypo!sis1 #ih1 #aaa2 
objection to1 #aab4      ,newcomb1 ,pr(4
 ,s41 on /> di/ribution1 #fa2       on  
p>allax ( />s1 #id2       on /ability ( 
/> clu/]s1 #abf2       on sc>city ( s+le
 />s1 #abh2       on limits ( /> sy/em1 
#ach2       on ,milky ,way1 #aeh1 #afj2 
on sol> clu/]1 #afg2       on />        
velocities1 #aga2       on av]age small 
mass ( />s1 #bhe2       on />-motions1  
#big4      ,newton1 ,sir ,isaac1 on     
sun's habitability1 #i4      ,ni*ols1   
,e4,f41 on heat ( />s1 #bij4            
,nitrog51 its importance to life1 #aie4 
,non-habitability ( great planets1 #bgb4
       ,ocean & l&1 diagram (1 #bbh4    
---- bas9s1 p]man5ce (1 #bbi4      ---- 
---- symmetry (1 #bch4      ---- dep?s1 
h[ produc$1 #bcb4      ,oceans1 effect  
(1 on temp]ature1 #bci2       curi\s    
relations (1 #bfd4      ,organic        

products1 div]sity (1 #aie4             
,photographic a/ronomy1 #dc2            
measures ( />-di/ances1 #hi4            
,photosph]e1 !1 #aje4      ,physici/s on
 sun's duration1 #bgh4      ,pick]+'s   
measurem5ts ( ,algol1 #dj4              
,planets1 suppos$ habitability (1 #bff1 
#bfi2       ! great1 un9habitable1 #bgb2
       int]nal heat ( great1 #bgc2      
a la/ argum5t = habitability (1 #bgd2   
h probably no life1 #cae4      ,planets'
 motions fir/ expla9$1 #c2       mass & 
atmosph]e1 #bfb4      ,pleiades1 numb] (
 />s 91 #fg2       a drift+ clu/]1 #agg4
      ,plurality ( worlds1 e>ly writ]s  
on1 #i2       ,proctor on1 #ah4         
,posidonius measures ! e>?1 #e4         
,prit*>d's photographic measures (      
/>-di/ance1 #hi4      ,proctor1 ,r4,a41 
on o!r worlds1 #ah2       on =m (       
,galaxy1 #ea2       on ,h]s*el's views1 
#aja2       on /ell> univ]se1 #ajc2     
on meteoritic !ory1 #aad2       on      
inf9ities1 #acf2       on />-drift1     
#agf2       on life "u v>i$ conditions1 

#bga2       on inf9ity1 #cbd4           
,proctor's ,old & ,new ,a/ronomy1 #df2  
*>t ( />s1 #fj4      ,prom95ces ( sun1  
#ajg4      ,proteids1 =mation (1 #aii2  
,pr(4 ,haliburton on1 #bjj4             
,protoplasm1 complexity (1 #aid2       a
 me*anism1 #aih2       s5sibility (1 to 
heat1 #bjh4      ,ptolemaic sy/em ( !   
heav5s1 #d4       ,radial motion1 #ce4  
,radiation f />s1 #bij4      ,ra9 9 !   
,c>bonif]\s age1 #bbe2       dep5d5t on 
du/1 #bdi4      ,ramsay1 ,pr(41 on      
geological climates1 #bgh4      ,rany>d1
 on />-discs1 #ih2       on inf9ite     
univ]se1 #acg2       on mass ( ,orion   
nebula1 #agc4      ,religi\s be>+ ( my  
conclusions1 #cai4      ,reproduction1  
m>vel (1 #bja4      ,rev]s+ lay] ( sun1 
#ajg4      ,rob]ts1 ,a4,w41 on bir? (   
d\ble />s1 #abc4      ---- ,dr4 ,i41 on 
limits ( />-sy/em1 #adh2       on spiral
 nebul1 #aag2       on meteoritic !ory1 
#aai2       photographs ( nebul1 #de1   
#agd4      ,ro*e limit expla9$1 #abj1   
#ahg4       ,s&]son1 ,pr(4 ,burdon1 on  

liv+ matt]1 #aib4      ,sci5tific &     
agno/ic op9ion on my conclusions1 #cah4 
,sec*i's classification ( />s1 #cc4     
,s+le />s p]haps r>e1 #abh4      ,sol>  
apex1 position (1 #agf4      ,sol>      
clu/]1 !1 #afe2       diagram %[+1 #cjj2
       evid5ce =1 #cjb2       importance
 to u1 #cjf-g1 #cab4      ,sol> sy/em1  
position (1 #cjd4      ,sorby on        
con/itution ( meteorites1 #ahf4         
,spectra1 v>ieties (1 #cd2       (      
elem5ts1 *anges 91 #abi4                
,spectroscopic b9>ies1 abundance (1     
#abe2       great numb]s (1 #bhf4       
,spectrum analysis1 discov]y (1 #bf4    
,sp5c]1 ,h41 on /atus ( nebul1 #ajb4    
,spiral nebul1 orig9 (1 #abj4      ,/>s1
 prov$ to be suns1 #cb2       invisible1
 #ci2       classification (1 #cc2      
spectroscopic d\ble1 #db2               
di/ribution ( !1 #dg2       numb] (     
visible1 #dh2       description ( ,milky
 ,way1 #eb2       9 relation to ,milky  
,way1 #ei2       di/ances (1 #gd2       
measurem5t ( di/ance (1 #he2       mass 

( b9>y1 #ig2       evolution ( d\ble1   
#abb2       spectroscopic d\ble1 #abc2  
clu/]s (1 #abe2       evolution ( !1    
#abh2       classification (1 #acj2     
! hotte/1 #aca2       :5 cool+ give m   
heat1 #acb2       cycle ( evolution &   
decay1 #acc2       suppos$ inf9ite numb]
 (1 #ace2       n inf9ite1 #ach2        
law ( dim9i%+ numb]s (1 #adi2           
sy/ematic motions (1 #agh2       9      
relation to life1 #bhb1 #bhg2           
possible use ( _! emanations1 #bhi4     
,/>-clu/]s & v>iables1 #abg4            
,/>-d5sity1 diagram (1 #ff4             
,/>-drift1 ,proctor on1 #agf4           
,/>light1 electrical measure (1 #bij2   
possible uses (1 #bib4      ,/>-motions1
 ,pr(4 ,newcomb on1 #big4               
,/>-sy/em1 limit$1 #ade2       /ability 
(1 #bie2       suppos$ primitive =m (1  
#big4      ,/ell> motion1 ,luigi        
d',auria on1 #cjf4      ---- univ]se1   
%ape (1 #di2       unity (1 #ajj2       
evolution (1 #ajc2       diagrams (1    
#cjj4      ,/oney1 ,dr41 on atmosph]es &

 gravity1 #bfc4      ,sun1 a typical />1
 #ajd2       brightness (1 #ajd2        
heat (1 #ajd2       surface (1 #aje2    
surr\nd+s (1 #ajf-aaj2       corona (1  
#ajh2       col\r (1 #aaa2       elem5ts
 91 #ahd4      ,sun's di/ance1 measure  
(1 #gf4      ---- heat1 suppos$ limits  
(1 #bge4      ---- life1 all requir$ to 
develop e>?-life1 #bhj4      ---- motion
 ?r\gh space1 #ia1 #afi4      ---- ---- 
unc]ta91 #agg4      ,sun-spots1 nature  
(1 #aje4      ,symmetry ( oceans1 cause 
(1 #bch4       ,temp]ature1 ess5tial =  
life1 #bjf2       equalis$ by wat]1     
#bci2       z reg>ds life on planets1   
#bfg4      ,t5nyson on man & ! univ]se1 
#cbe4       ,uni=mity ( matt]1 #ahc4    
,unity ( /ell> univ]se1 #ajj4           
,univ]se ( />s1 h[ its =m has affect$   
our sun & e>?1 #cjh4      ,univ]se n    
disproportionate if man is its sole     
product1 #cbj4       ,,v5us1 radial     
motions (1 #ch2       diagram ( transit 
(1 #gg2       life b>ely possible on1   
#bff2       adv]se climatic conditions  

(1 #bfh4       ,,wat]1 an ess5tial =    
life1 #baj2       its am\nt &           
di/ribution1 #bbg2       an equalis] (  
temp]ature1 #bci4      ,wave-l5g?s1 h[  
measur$1 #ca4      ,:ewell1 on plurality
 ( worlds1 #h1 #ae2       on man z !    
highe/ product ( ! univ]se1 #ad4        
,:ittak]1 ,mr4 ,e4,t41 on gravitative & 
electro-dynamical =ces1 #bif4           
,w9ds1 importance (1 to life1 #bdf4     
,,zodiacal light1 #aji4      ,pr9t$ by  
,t4 & ,a4 ,,con/able1 ,pr9t]s to ,8     
,maje/y1     at ! ,ed9burgh ,univ]sity  
,press    ,illu/ration3 ,,! ,,nebul ,,& 
,,clu/]s ,,( ,,! ,,nor!rn ,,heav5s4     
,drawn ^u an equal surface projection f 
,dr4 ,,drey]',s catalogue ( #ahhh ,!    
,milky ,way f a ,dr4 ,,bo$dick]',s      
,draw+ by ,,sidney ,,wat]s              
,illu/ration3 ,,! ,,nebul ,,& ,,clu/]s  
,,( ,,! ,,s\!rn ,,heav5s4 ,drawn ^u an  
equal surface projection f ,dr4         
,,drey]',s catalogue ( #ahhh ,! ,milky  
,way f ,,uranometria ,,arg5t9a by       
,,sidney ,,wat]s         ,,works ,,by   

,,! ,,same ,,au?or4     ,,travels ,,on  
,,! ,,amazon ,,& ,,rio-,,negro4         
,,palm-,,trees ,,( ,,! ,,amazon1 ,,&    
,,_! ,,uses 7out ( pr9t74    ,,! ,,malay
 ,,ar*ipelago4    ,,natural ,,selection 
,,& ,,tropical ,,nature4    ,,!         
,,geographical ,,di/ribution ,,(        
,,animals4 #b vols4    ,,isl& ,,life1   
,,or ,,insul> ,,faunas ,,& ,,floras4    
,,d>w9ism4    ,,au/ralasia4 #b vols4    
,,bad ,,times--,,causes ,,( ,,depression
 ,,( ,,trade 7out ( pr9t74    ,,l&      
,,nationalisation1 ,,its ,,necessity ,,&
 ,,its ,,aims4    ,,vacc9ation ,a       
,,delusion4    ,,miracles ,,& ,,mod]n   
,,spiritualism4    ,,! ,,wond]ful       
,,c5tury 7,new & ,illu/rat$ ,edition74  
,,! ,,wond]ful ,,c5tury ,,read]4        
,,/udies ,,sci5tific ,,& ,,social4      
99       99       99       99       99  
,transcrib]'s ,notes3   ,obvi\s         
punctuation & spell+ errors repair$4    
,inconsi/5t hyph5ation has be5 repair$4 
,! oe & ae ligatures 9 ! text has be5   
left z x appe>s 9 ! orig9al book4       

,italic text is d5ot$ by und]scores &   
bold text by equal signs4  ,9 ambigu\s  
cases1 ! text has be5 left z x appe>s 9 
! orig9al book4 ,9 p>ticul>1 _m mismat*$
 quotation m>ks h n be5 *ang$4  ,!      
rema9+ corrections made3    ,page v1    
,=t-nightly *ang$ to ,=tnightly4   ,page
 #ajf1 t]re/ial *ang$ to t]re/rial4