<^1^[^^, 
 
 '^^\ 
 
 BL  240  .L44  1867 
 Leitch,  William. 
 God's  glory  in  the  heavens 
 
(page  25 !'' 
 
GOD'S   GLORY   IN    THE 
 HEAVENS 
 
 By  WILLIAM  LEITCH,  d.d. 
 
 LATE  PRINCIPAL  AND  PRIMARIUS  PROFESSOR  OF  THEOLOGY 
 queen's  college,  CANADA 
 
 THIRD   EDITION- 
 
 X^,  of  P.,.,, -.,.  ^ 
 
 ALEXANDER  STRAHAN,   PUBLISHER 
 
 56  LUDGATE  HILL,  LONDON 
 
 1867 
 
PEEFACE. 
 
 Some  of  tlie  following  chapters  were  originally 
 published  in  Good  Words,  The  subjects  were 
 selected  without  much  regard  to  system,  the 
 progress  of  astronomical  research  usually  deter- 
 mining the  order  in  which  the  papers  appeared. 
 To  give  greater  completeness,  much  new  matter 
 is  added ;  so  that  nearly  one-half  of  the  volume 
 is  published  for  the  first  time.  The  object  of 
 the  work  is  to  present  a  survey  of  recent 
 astronomical  discovery  and  speculation,  in  con- 
 nexion with  the  religious  questions  to  which 
 they  give  rise.  These  questions  impart  a  new 
 interest  to  astro-theology,  and  the  present  con- 
 tribution is  intended  to  meet,  in  some  measure, 
 the  felt  necessity  of  a  better  adjustment  between 
 
vi  PREFACE. 
 
 the  aimiments  of  the  theoloo;ian  and  the  dis- 
 coveries  of  the  astronomer.  Synoptical  tables, 
 which  the  student  may  find  useful  for  reference, 
 are  added.  They  give  a  condensed  summary 
 of  the  principal  facts  of  astronomy. 
 
CONTENTS. 
 
 L  A  JOURNEY  THROUGH  SPACE, 
 n.   THE  MOON — IS  IT  INHABITED  ? 
 
 III.  THE  moon's  invisible  SIDE, 
 
 IV.  LUNAR  LANDSCAPE, 
 
 V.   THE  USES  OF  THE  MOON,     . 
 VI.   DISCOVERY  OF  THE  NEW  PLANET  VULCAN, 
 Vn.   TOTAL  ECLIPSE  OF  THE  SUN, 
 VIIL   THE  SUN  :  ITS  WORK  AND  STRUCTURE, 
 IX.   THE  CHEMISTRY  OF  THE  SUN, 
 X.  THE  STRUCTURE  OF  COMETS, 
 XL   THE  HISTORY  OF  COMETS,    . 
 XII.   THE  STRUCTURE  OF  THE  PLANETS, 
 
 XIII.  THE  STRUCTURE  OP  SATURN's  RINGS, 
 
 XIV.  THE  NEBULAR  HYPOTHESIS, 
 XV.  STELLAR  GROUPING, 
 
 XVI.    THE  OBSERVATORY, 
 XVIL   ASTRONOMY  IN  AMERICA,   . 
 XVIII.  THE  STABILITY  OF  THE  SOLAR  SYSTEM, 
 XIX.   THE  ETERNITY  OF  MATTER, 
 XX.   THE  PLURALITY  OF  WORLDS, 
 
 PAG8 
 
 1 
 
 25 
 
 36 
 
 48 
 
 65 
 
 81 
 
 98 
 
 113 
 
 130 
 
 142 
 
 159 
 
 176 
 
 193 
 
 212 
 
 227 
 
 237 
 
 253 
 
 274 
 
 290 
 
 299 
 
Vlll 
 
 CONTENTS. 
 
 SYNOPTICAL  TABLES. 
 
 THE  SOLAR  SYSTEM — 
 
 Laws  of  Motion, 
 
 Kepler's  Laws, 
 
 Law  of  Gravitation, 
 
 Elements  of  Elliptical  Motion, 
 
 Secular  Variations  in  Orbit, 
 
 Number  of  Bodies  of  Solar  System 
 
 Laws  of  Light, 
 
 Bocle's  Law  of  Planetary  Distances 
 
 Exterior  and  Interior  Planets, 
 
 Kirkwood's  Law, 
 
 Planetary  Elements, 
 
 THE  SUN,   . 
 
 MERCURY, 
 
 VENUS, 
 
 THE  EARTH,  • 
 
 THE  MOON, 
 
 MARS, 
 
 ASTEROIDS, 
 
 JUPITER,     . 
 
 JUPITER'S  SATELLITES, 
 
 SATURN,      . 
 
 saturn's  rings,   . 
 Saturn's  satellites, 
 
 URANUS,     . 
 
 URANUS'  SATELLITES, 
 
 NEPTUNE, 
 
 NEPTUNE'S  SATELLITES, 
 
 COMETS,     . 
 
 DOUBLE  STARS,      . 
 
 NEBULiE,  . 
 
 METEORIC  ZONES, 
 
 FIXED  STARS, 
 
 TELESCOPE, 
 
Structure  of  Milky  Way. 
 I 
 
 A  JOUENEY  THROUGH  SPACE. 
 
 We  are  accustomed  to  survey  the  universe  from  the 
 stand  point  of  our  globe,  and,  consequently,  as  far  as 
 the  mere  evidence  of  sense  is  concerned,  all  else  ap- 
 pears little  compared  to  man's  abode;  and  so  great  is 
 the  mastery  of  sense  over  reason,  that,  for  ages,  man 
 resisted  the  conclusive  force  of  the  latter.  It  was  an 
 agreeable  delusion,  that  the  whole  universe  centred 
 in' man;  and  when  Galileo  was  persecuted  by  papal 
 
 A 
 
2       A   JOURNEY  THROUGH  SPACE. 
 
 authority,  tlie  motive  may  perhaps  as  much  be  traced 
 to  human  pride,  as  to  orthodox  zeal.  The  whole  sub- 
 sequent history  of  astronomy  is,  simply,  the  record  of 
 the  way  in  which  man  has  been  brought  to  his  level,  as 
 far,  at  least,  as  his  dignity  depends  on  the  abode  in 
 which  he  dwells.  But  the  grand  lesson  of  astronomy 
 is,  that  man's  true  dignity  does  not  consist  in  the 
 mere  outward  and  physical.  The  more  that  the  dis- 
 coveries of  astronomy  make  this  world  shrink  into 
 insignificance,  the  more  amazing  is  the  view  we  ob- 
 tain of  man's  spiritual  dignity.  It  is  the  immensity 
 of  the  universe,  contrasted  with  the  humble  abode  of 
 man,  that  brings  out  most  strikingly  the  value  of  the 
 human  soul,  as  redeemed  by  the  death  of  the  Cross. 
 When  you  attempt  to  plumb  the  depths  of  space,  or 
 number  the  orbs  of  heaven,  your  feeling  is,  How 
 little  is  man !  And,  yet,  how  great,  when  measured 
 by  the  price  of  his  redemption !  How  little  are 
 worlds  and  systems  to  a  God-loving  spirit!  The 
 holy  breathings  of  one  devout  heart,  give  to  God 
 more  glory  than  the  loudest  anthems  of  the  heavenly 
 hosts.  And  the  starry  firmament  has  not  been  created 
 in  vain,  while  it  teaches  this  great  truth  to  all  spi- 
 ritual intelligences.  There  is  something  that  urges  us 
 to  find  some  use  or  adaptation  for  all  God's  works, 
 but  we  too  often  restrict  the  naiure  of  the  use ;  and 
 unless  we  find  some  physical  adaptation,  we  think 
 that  we  have  failed.  Is  it  not  use  enough  for  the 
 innumerable  hosts  of  heaven  to  be  the  silent  teachers 
 
A   JOURNEY  THROUGH  SPACE.       3 
 
 of  immortal  spirits,  emphasising  the  great  redemptive 
 actj  and  proclaiming  that,  in  the  estimate  of  heaven, 
 there  is  nothing  greater  than  the  soul  of  man  ?  The 
 deeper  we  penetrate  into  the  abyss  of  space,  the  more 
 will  we  comprehend  the  significance  of  the  inquiry, 
 "What  shall  it  profit  a  man,  though  he  gain  the 
 whole  world,  and  lose  his  own  soul  ?  or  what  shall  a 
 man  give  in  exchange  for  his  soul?" 
 
 Though  the  facts  and  deductions  of  astronomy 
 sufficiently  bring  out  the  immensity  of  the  universe, 
 as  contrasted  with  our  world,  still  it  is  difficult  to 
 realise  the  truth ;  our  thoughts  will  obstinately  cling 
 to  our  globe,  and  the  images  of  grandeur  will  still 
 be,  our  terrestrial  seas  and  mountains.  Let  us,  how- 
 ever, attempt  to  escape  from  the  narrow  confines  of 
 our  globe,  and  see  it,  as  others  see  it,  from  a  different 
 point  of  view.  Let  us  take  a  nearer  survey  of  other 
 orbs  and  systems,  and  see  what  impressions  they  pro- 
 duce, as  compared  with  that  received  from  the  plat- 
 form  of  the  earth. 
 
 But  what  vehicle  can  we  avail  ourselves  of  for  our 
 excursion  ?  Must  we  be  altogether  dependent  on  the 
 fairy  wings  of  imagination,  or  can  we  derive  aid 
 from  some  less  ethereal  agencies  ?  It  was  long  the 
 fond  wish  of  man  to  soar  above  this  terrestrial  scene, 
 and  visit  other  planets.  In  the  infancy  of  physical 
 science,  it  was  hoped  that  some  discovery  might  be 
 made  that  would  enable  us  to  emancipate  ourselves 
 from  the  bondage  of  gravity,  and,  at  least,  pay  a 
 
4       A   JO  URNE  Y  THR  0  UGH  SPA  CE. 
 
 visit  to  our  neighbour  the  moon.  The  poor  attempts 
 of  the  aeronaut  have  shewn  the  hoplessness  of  the 
 enterprise.  The  success  of  his  achievement  depends  on 
 the  buoyant  power  of  the  atmosphere,  but  the  atmo- 
 sphere extends  only  a  few  miles  above  the  earth,  and 
 its  action  cannot  reach  beyond  its  own  limits.  The 
 only  machine,  independent  of  the  atmosphere,  we  can 
 conceive  of,  would  be  one  on  the  principle  of  the 
 rocket.  The  rocket  rises  in  the  air,  not  from  the 
 resistance  offered  by  the  atmosphere  to  its  fiery 
 stream,  but  from  the  internal  reaction.  The  velocity 
 would,  indeed,  be  greater  in  a  vacuum  than  in  the 
 atmosphere,  and  could  we  dispense  with  the  comfort 
 of  breathing  air,  we  might,  with  such  a  machine, 
 transcend  the  boundaries  of  our  globe,  and  visit  other 
 orbs. 
 
 Instead,  however,  of  torturing  our  imagination  to 
 conceive  of  a  rocket  device,  which  would  eclipse  the 
 performances  of  all  flying  machines,  let  us  take  one 
 of  nature's  rockets  as  the  material  aid  to  our  imagin- 
 ary flight.  Let  us  follow  the  course  of  some  comet 
 in  its  wanderings  across  our  system.  A  rocket,  held 
 fast,  with  its  fiery  stream  directed  against  a  strong 
 wind,  very  well  represents  the  telescopic  appearance 
 of  a  comet,  when  in  the  neighbourhood  of  the  sun. 
 The  luminous  particles  shoot  out  from  the  nucleus  of 
 the  comet,  precisely  as  the  sparks  issue  from  the 
 rocket-tube,  and  they  are  thrown  back  as  a  strong 
 wind  would  throw  back  the  fiery  stream  of  the  rocket. 
 
A  JO  URNE  V  THR  O  UGH  SPA  CE.       5 
 
 The  sector  or  fan^  so  well  seen  in  the  comet  which 
 lately  (1861)  burst  upon  us  with  such  astonishing 
 brilliancy,  is  the  form  which  the  gush  of  luminous 
 particles  assumes  under  some  unknown  repelling 
 power.  The  revolution  of  the  comet  is  determined 
 by  the  laws  of  gravitation,  but  there  are  perplexing 
 movements  in  the  tail  and  nucleus,  which  likely  will 
 receive  an  explanation  from  this  rocket-like  action. 
 
 We  have,  however,  to  do  at  present,  not  with  the 
 theory  of  the  constitution  of  the  comet,  but  with  its 
 character,  as  a  vehicle  for  surveying  the  solar  system. 
 We  may  be  pardoned  in  using  it  as  a  vehicle  for  our 
 imagination,  when  some  advocates  for  the  plurality  of 
 inhabited  worlds  have  gravely  argued,  that  the  most 
 ethereal  comets  may  have  their  inhabitants — that 
 even  each  particle  may  have  its  adhering  element  of 
 life.  An  inexorable  logic  has  driven  them  to  this 
 conclusion,  from  the  assumed  position,  that  the  very 
 matter  of  planets,  apart  from  their  proved  adaptation, 
 implies  life.  The  densest  comet  would  afford  but 
 insecure  footing  to  beings  of  almost  spiritual  essence, 
 as  the  matter  of  which  it  is  composed  must  be  so  light 
 that  the  atmosphere  of  our  earth  is  as  lead  compared 
 to  it.  But  we  shall  overlook  this  difficulty,  and  ven- 
 ture, in  thought,  to  follow  the  fortunes  of  some  cometic 
 wanderer.  The  difficulty  of  reaching  some  suitable 
 comet,  is  lessened  by  the  consideration  that  the  comet 
 may  come  to  us.  It  has  been  surmised  that  the  above 
 comet  touched  at  our  earth,  as  one  of  its  stations^  in 
 
6       A  y^O  URNE  Y  THR  0  UGH  SPA  CE. 
 
 its  line  of  transit  across  the  system.  The  surmise 
 needs  corroboration,  but  it  is  quite  a  legitimate  one. 
 There  is  no  physical  reason  why  we  should  not 
 pass  through  the  tail  of  a  comet  without  ever  know- 
 ing it.  The  phosphorescent  light,  seen  by  Mr 
 Hind,  and  noticed  by  others,  may  have  had  no  con- 
 nexion with  the  matter  of  the  comet ;  but  still,  it  is 
 possible  that  we  may  have  been  immersed  in  this 
 cometary  medium,  without  any  appreciable  effects 
 being  produced. 
 
 The  great  advantage  of  the  comet,  as  a  convenient 
 vehicle  for  an  excursion,  is,  that  it  gives  near,  as  well 
 as  extensive  views  of  the  system.  The  drawback  of 
 our  own  globe  is,  that  it  always  keeps  at  the  same 
 distance,  or  nearly  so,  from  all  the  bodies  of  the  sys- 
 tem ;  so  that,  although  it  is  constantly  moving  on- 
 wards, we  are  kept  at  such  a  distance,  that  we  see 
 but  little  change  in  the  celestial  scenery.  It  is  like 
 an  excursion  steamer  constantly  sailing,  in  a  narrow 
 circuit,  round  a  buoy  moored  in  the  middle  of  a 
 v/ide  lake.  The  view  of  the  surrounding  scenery 
 never  changes,  and  the  minute  objects  of  the  land- 
 scape are  never  seen.  The  comet,  on  the  other  hand, 
 is  like  the  steamer  that  sails  up  the  whole  length  of 
 the  lake  on  one  side,  and  comes  down  along  the 
 other.  Every  object  is  seen  minutely,  and  from  dif- 
 ferent points  of  view.  Most  comets,  too,  rise  above 
 the  plane  of  the  solar  system,  so  that  we  may  have  a 
 clear  view  of  the  relation  of  one  planet  to  the  other. 
 
A   JOURNEY  TH-ROUGH  SPACE.       7 
 
 The  early  misconception,  as  to  the  arrangement  of 
 the  solar  system,  arose  chiefly  from  the  circumstance 
 that,  from  the  position  of  the  earth,  we  see  it  in  sec- 
 tion, not  in  ^lan.  When  two  armies  meet,  it  is  diffi- 
 cult for  the  one  to  comprehend  the  dispositions  of  the 
 other,  and  hence  the  plan,  sometimes  resorted  to,  of 
 employing  balloons,  to  enable  the  one  party  to  look 
 down  from  above  upon  the  position  taken  up  by  the 
 other.  The  orbit  of  the  comet  is,  in  like  manner, 
 usually  so  situated,  that  it  commands  such  a  view  of 
 the  solar  system ;  and  the  sun  and  its  surrounding 
 planets  are  seen  as  distinctly  as  the  central  body  of 
 an  army,  with  all  its  outlying  forces,  is  seen  from  the 
 balloon.  Comets,  however,  occasionally  move  on 
 the  same  level  with  the  planets,  and  it  is  from  a  comet 
 with  such  an  orbit  that  the  best  view  can  be  obtained 
 of  them  individually.  The  comet  may,  in  this  case, 
 come  so  close  that  the  planetary  orbs  may  be  caught 
 in  the  sweep  of  its  tail.  A  planet  may,  at  one  time, 
 be  seen  so  large  as  to  cover  most  of  the  celestial 
 hemisphere;  at  another,  so  minute  as -to  appear  but  a 
 point  of  light  in  the  dark  concave. 
 
 Then,  again,  let  us  consider  the  rate  at  which  the 
 comet  travels.  This  is  by  no  means  an  equable  one. 
 Sometimes  it  moves  so  slowly,  that  a  child  might 
 keep  up  with  it ;  at  another,  it  speeds  round  with 
 lightning  velocity.  It  is  like  a  coach  going  down  a 
 declivity  without  a  drag.  It  increases  its  velocity 
 till  it  comes  to  the  bottom  of  the  hill,  and  the  mo- 
 
8       A   JO  URNE  V  THR  0  UGH  SPA  CE. 
 
 mentum  acquired  carries  it  up  the  opposite  side,  till 
 it  gradually  slackens  and  assumes  a  snail's  pace. 
 •The  comet  approaching  the  sun  is  going  down  hill, 
 and  when  it  reaches  the  nearest  point  it  wheels  round, 
 and  then  ascends  till  its  speed  is  gradually  arrested. 
 It  is  reined  in  by  the  sun,  from  which  there  are  in- 
 visible lines  of  force  dragging  it  back ;  and,  if  its 
 momentum  be  not  too  great,  it  is  effectually  checked 
 and  brought  back  to  pursue  its  former  course.  Most 
 frequently,  however,  its  course  is  so  impetuous  that 
 all  the  strength  of  the  sun,  in  reining  back,  avails 
 nothing.  It  breaks  loose,  like  a  fiery  steed  from  its 
 master ;  speeds  off  into  space,  and  is  heard  of  no  more. 
 We  shall,  first,  follow  the  fortunes  of  one  of  the  more 
 tractable  comets,  or  those  that  remain  permanent 
 members  of  the  solar  system,  performing  their  revo- 
 lutions regularly  round  the  sun.  Of  these  there  are 
 six  whose  orbits  are  well  determined. 
 
 Let  us  enter  the  cometary  vehicle  at  some  point 
 beyond  the  confines  of  the  solar  system ;  and  Halley's 
 comet  makes  an  excursion  three  hundred  millions  of 
 miles  beyond  Neptune — the  most  distant  planet  in 
 the  system.  Here  the  comet  is  a  globular  mass, 
 lazily  floating  along  like  a  filmy  cloud  in  the  heavens. 
 It  is  on  its  way  to  the  sun,  and  we  shall  suppose  that 
 the  planets  are  so  many  stations  on  the  line.  When 
 we  near  Neptune,  his  attraction  is  powerfully  felt. 
 The  sun  would  have  us  go  straight  on,  but  our  mo- 
 tion is  so  slow,  and  the  sun  so  distant,  that  Neptune 
 
A   JOURNEY  THROUGH  SPACE.       9 
 
 readily  drags  us  out  of  our  course.  Here  we  may 
 discover  objects  that  have  escaped  the  keen  eye  of 
 astronomers.  No  astronomer  has  ever  detected  more 
 than  one  satellite;  but  we  may  well  suppose  that 
 this  arises,  not  from  their  non-existence,  but  from 
 their  invisibility  at  such  a  distance.  As  planets 
 recede  from  the  sun,  distance  from  the  centre  of 
 light  is  compensated  for,  in  some  measure,  by  the 
 number  of  satellites.  If  the  day  wants  brilliancy, 
 the  loss  is  made  up  by  the  magnificence  of  the  moon- 
 light scenery.  There  are  probably  crowds  of  moons 
 studding  the  ISTeptunian  skies,  and  giving  cheer- 
 ing light  when  the  tiny  sun  has  set — the  sun  being 
 only  a  thousandth  pjtrt  as  large  as  it  appears  from 
 our  globe.  It  is  not  improbable  that  Neptune  has 
 rings  like  Saturn.  Some  astronomers  have  pretty 
 confidently  asserted  that  they  have  sometimes  got 
 glimpses  of  a  ring.  The  rings  may  be  invisible,  not 
 merely  from  distance,  but  from  the  dimness  of  the 
 matter  of  which  they  are  composed.  The  dark  ring 
 of  Saturn  would  not  be  seen  by  the  best  telescope  at 
 the  distance  of  Neptune.  When  we  alight  on  the 
 surface  of  Neptune,  we  find  a  little  more  difficulty  in 
 locomotion.  A  man  who  w^eighs  twelve  stones  on 
 the  earth,  would  here  weigh  sixteen  stones;  and 
 having  this  additional  weight,  with  the  same  muscu- 
 lar strength,  difficulty  of  movement  would  necessarily 
 be  the  result.  This  does  not  arise  from  the  density 
 of  the  planet,  but  from  its  superior  mass.     So  far 
 
10     A   JOURNEY  THROUGH  SPACE. 
 
 from  the  matter  being  dense,  it  is  on  the  whole  no 
 heavier  than  water.  This,  however,  is  on  the  sup- 
 position that  we  see  the  solid  surface  of  the  planet. 
 What  we  see,  however,  may  be  only  an  envelope  far 
 above  the  surface  of  the  nucleus,  which  may  have  a 
 much  greater  density.  Though  the  sun  has  dwindled 
 down  to  one-thousandth  its  size,  its  light  is  by  no 
 means  so  dim  as  might  be  supposed.  We  have  a 
 proof  of  this  in  the  case  of  eclipses.  If  the  most 
 slender  crescent  be  left  uncovered  by  the  moon,  the 
 diminution  of  light  is  by  no  means  startling.  It  is 
 only  at  the  moment  of  totality  that  the  dread  effects 
 of  an  eclipse  are  produced.  We  can  conceive  of  the 
 Neptunians  thriving  very  well,  notwithstanding  their 
 stinted  supply  of  light ;  and  we  can  suppose  that  all 
 unpleasant  effects  might  be  completely  obviated,  by 
 having  the  pupil  of  the  eye  enlarged,  and  the  sensi- 
 bility of  the  retina  increased.  The  diminution  of 
 heat  would  be  more  difficult  to  endure,  but,  with  a 
 properly  constituted  atmosphere,  and  with  the  central 
 heat  of  the  planet  itself,  w^e  can  have  no  difficulty  in 
 conceiving  of  its  being  inhabited.  The  human  frame 
 proves  how  low  a  temperature  is  compatible  with  the 
 functions  of  life.  In  this  climate,  the  sinking  of  the 
 temperature  ten  degrees  below  the  freezing-point,  is 
 more  keenly  felt  than  a  sinking  of  twenty  degrees 
 below  zero  during  a  Canadian  winter.  The  reaction 
 of  the  vital  powers  seems  to  come  more  into  play  at 
 
A   JO  URNE  Y  THR  0  UGH  SPA  CE.      1 1 
 
 very  low  temperatures,  and  hence  the  wide  range 
 through  which  life  is  possible. 
 
 The  next  station  is  Uranus,  but  the  interval  be- 
 tween is  vast.  The  stage  from  the  one  orbit  to  that 
 of  the  other  is  about  one-third  of  the  whole  journey 
 to  the  sun.  In  a  railway  train,  running  at  the  or- 
 dinary speed,  this  distance  could  not  be  done  under  less 
 than  six  thousand  years  ;  so  that,  if  the  train  started 
 at  the  creation  of  man,  it  would  not  have  yet  reached 
 this  first  station  on  the  way  to  the  sun.  The  planets, 
 however,  are  closer  as  you  approach  the  sun,  just  as 
 on  a  railway  the  stations  become  more  numerous  as 
 you  approach  the  metropolis.  In  our  cometary 
 vehicle,  the  speed  is  always  increasing,  so  that, 
 although  slow  as  a  railway  train  at  first,  it  soon 
 acquires  immensely  greater  speed  as  it  rushes  on 
 towards  its  distant  goal.  The  comet  of  Halley, 
 though  starting  so  far  beyond  the  verge  of  the  sys- 
 tem, takes  only  about  forty  years  to  reach  the  sun. 
 The  railway  train,  going  always  at  the  same  rate, 
 would  take  10,000  years  from  the  remotest  orbit  of 
 the  system  to  the  centre. 
 
 With  our  increased  velocity,  Uranus  has  less  in- 
 fluence in  drawing  us  out  of  our  course.  Here  we 
 find  numerous  satellites.  Sir  William  Herschel  dis- 
 covered six,  but  only  four  have  been  detected  by 
 others.  It  is,  however,  highly  probable  that  the 
 number  is  greater  even  than  that  assigned  by  Hers- 
 
12     ^   y (9  URNE  Y  THR  0  UGH  SPA  CE. 
 
 chel.  In  Uranus,  as  far  as  weight  is  concerned,  we 
 would  find  ourselves  more  at  home  than  in  any  other 
 planet.  Our  power  of  locomotion  would  be  very 
 much  the  same  as  here.  The  most  notable  fact  con- 
 nected with  Uranus  is,  that  his  satellites  revolve  in  a 
 direction  the  opposite  to  that  of  all  the  planets  ^d 
 satellites  of  the  solar  system.  The  nebular  hypothesis 
 is  very  much  founded  upon  the  uniformity  of  the 
 system  in  this  respect ;  and  this  breach  of  uniformity 
 presents  a  rather  baffling  discrepancy. 
 
 Our  next  stage  is  somewhat  shorter  than  the  last, 
 still  the  interval  between  Uranus  and  Saturn  ig 
 immense ;  but  when  we  reach  this  station,  we  have 
 only  a  third  of  our  journey  before  us.  Here  we  are 
 in  danger  of  being  completely  drawn  out  of  our 
 course,  the  attraction  of  the  planet  being  so  powerful. 
 Its  size  is  such  that  it  could  contain  within  its  sphere 
 772  terrestrial  globes.  It  is,  however,  as  light  as 
 cork;  and  the  consequence  is,  that  standing  on  its 
 surface,  you  do  not  feel  yourself  dragged  down  by  its 
 attraction;  you  feel  no  material  difference,  in  this 
 respect,  between  it  and  our  own  globe.  An  opportu- 
 nity is  now  afforded  of  inspecting  the  mystery  of  the 
 rings.  You  will  probably  discover  many  more  rings, 
 or,  rather,  what  appears  a  single  ring  will  be  found 
 to  consist  of  many  smaller  ones.  Ton  can  see 
 through  the  dusky  ring,  and  have  an  opportunity  of 
 detecting  its  nature.  You  will  find  it  to  be  different 
 from  vapour  or  gas,  and  to  consist  of  meteorites  of  con- 
 
A   JO  URNE  Y  THR  O  UGH  SPA  CE.      1 3 
 
 siderable  size,  though,  at  the  distance  of  the  earth,  it 
 would  appear  as  if  you  were  looking  through  a  cloud 
 of  fine  dust.  It  is  probable,  also,  that  you  will  find 
 the  brighter  rings  to  be  of  a  similar  nature,  though 
 the  bodies  of  which  they  are  composed  may  be  larger 
 and  more  closely  packed  together.  The  rings  have, 
 not  without  reason,  been  suspected  to  be  rows  of  sa- 
 tellites, so  closely  crowded  together  that  they  appear 
 to  be  one  solid  body.  This  accounts  for  the  occa- 
 sional appearance  of  divisions,  and  their  subsequent 
 obliteration.  On  none  of  the  planets  will  the  heavens 
 present  so  grand  a  spectacle.  The  rings,  shining 
 with  the  lustre  of  the  moon,  will  constantly  arch  the 
 heavens.  From  the  efi'ect  of  perspective,  the  arch 
 will  appear  broadest  at  the  summit,  and  gradually  to 
 taper  towards  the  horizon.  The  eight  moons,  some 
 of  them  threading  the  outline  of  the  ring,  will  be  seen 
 in  different  phases  in  the  sky ;  the  stars  will  be  seen 
 setting  behind  the  bright  bars,  and  re-appearing  in 
 the  dark  spaces  between. 
 
 We  next  reach  Jupiter,  nearly  midway  between 
 Saturn  and  the  sun.  It  was  here  that  Lexell's  comet 
 got  entangled  in  the  satellites,  and  was  thrown  quite 
 out  of  its  course  by  the  overpowering  attraction  of 
 the  planet.  A  proof  was,  on  this  occasion,  afforded 
 of  the  almost  ethereal  constitution  of  the  comet. 
 While  the  comet  was  driven  about  at  the  mercy  of 
 every  body  it  met,  it  had  no  power  whatever  to  dis- 
 turb the  course  of  the  smallest  bodies  it  came  in  con- 
 
14     A  JOURNEY  THROUGH  SPACE. 
 
 tact  with ;  and  the  mass  of  the  heavenly  bodies  is 
 determined  by  this  power  of  disturbing  other  bodies. 
 In  the  case  of  the  comets,  no  disturbing  power  has 
 been  detected,  and  no  mass  can  be  assigned  to  them. 
 How  stupendous  an  object  must  Jupiter  have  ap- 
 peared to  an  eye  in  Lexell's  comet,  when  it  swept 
 through  its  satellites.  The  disc  must  have  covered 
 a  great  part  of  the  heavens  as  a  brilliant  canopy,  and 
 the  rotation  would  be  distinctly  sensible,  as  some 
 marked  cloud  would  be  seen  appearing  at  one  edge 
 of  the  disk,  and,  in  five  hours,  disappearing  at  the 
 other.  Jupiter  is  by  far  the  largest  planet  in  the 
 system.  His  dimensions  are  such,  that  it  would 
 take  1491  terrestrial  globes  to  equal  it.  The  density 
 is,  however,  only  that  of  water,  so  that  the  increased 
 weight  of  objects  on  its  surface,  is  not  so  great  as 
 might  be  supposed.  A  man's  weight  would  be  little 
 more  than  doubled. 
 
 In  setting  out  again  on  our  journey,  we  might 
 expect  a  new  station  by  halving  the  distance  between 
 Jupiter  and  the  sun,  as  this  process  served  us  in  the 
 case  of  our  last  two  stages.  We  are  so  far  successful, 
 that  we  find  not  one  large  planet,  but  thousands  of 
 small  ones.  We  have,  from  the  earth,  discovered 
 only  seventy -one,  but,  in  all  probability,  there  are 
 many  yet  to  be  discovered ;  there  may  be  thousands 
 too  small  to  be  detected.  In  sweeping  through  the 
 zone  of  asteroids,  we  are  like  a  ship  threading  her 
 way  through  innumerable  icebergs,  large  and  small. 
 
A   JOURNEY  THROUGH  SPACE.      15 
 
 Like  icebergs,  they  cross  one  another's  path,  and 
 probably  sometimes  unite,  so  as  to  form  a  more  con- 
 spicuous object — thus  accounting  for  the  fact,  that 
 asteroids  have  been  discovered  in  localities  which 
 were  scrutinised  with  the  utmost  care  a  little  before, 
 and  were  found  not  to  exist.  It  is  easy  to  understand 
 how  two  bodies,  invisible  from  their  smallness,  should 
 become  a  notable  object  when  united.  Let  us  step 
 on  one  of  these  miniature  worlds,  no  larger  than  an 
 English  county.  With  our  present  muscular  strength, 
 we  could  easily  clear  the  broadest  rivers  and  the 
 loftiest  spires — our  bodies  being  literally  lighter  than 
 a  feather.  We  could  readily  keep  up  with  the  rota- 
 tion of  the  asteroid,  and  prevent  the  sun  from  setting. 
 We  could  have  all  climates  at  command.  We  could 
 withdraw  to  the  polar  regions  during  the  heat  of  the 
 day,  and  return  to  the  torrid  zone  to  spend  the  even- 
 ing. Cyclopean  structures  might  be  raised,  com- 
 pared to  which,  the  pyramids  of  Egypt  would  be  but 
 mole-hills.  The  very  globe  itself  might  be  tunnelled 
 and  split  up,  so  that  contending  parties  might  have 
 little  worlds  of  their  own  to  live  in.  The  imagina- 
 tion can  thus  easily  revel  in  the  wildest  fancies,  if  we 
 exchange  the  normal  conditions  of  life  for  extreme  phy- 
 sical suppositions.  This  zone  of  asteroids  serves  as 
 the  boundary  between  the  two  distinct  groups  of 
 planets.  The  planets  which  we  have  already  visited 
 have  all  distinctive  characters,  and  a  family  likeness. 
 They  are  characterised  by  their  greater  size  and  their 
 
i6     A   JOURNEY  THROUGH  SPACE. 
 
 remarkable  lightness.  The  outer  planets  may  Le 
 compared  to  wood,  ^Yhile  those  within  the  zone  of 
 asteroids  are  more  allied  to  metals  in  density. 
 
 But  our  fiery  chariot  is  now,  on  account  of  its 
 proximity  to  the  sun,  experiencing  strange  internal 
 commotions.  The  globular  mass  is  now  elongated 
 towards  the  sun,  the  nucleus  being  situated  near  the 
 foremost  end,  and  as  we  approach  still  nearer,  the 
 nucleus  is  thrown  into  a  state  of  wild  excitement. 
 A  jet  of  bright  luminous  matter  rises  from  it,  shnilar 
 in  shape  to  a  bat-wing  gas-burner;  and,  in  other  re- 
 spects, this  fan  of  light  is  not  unlike  a  jet  of  gas.  It 
 is  sometimes  seen  to  dance  like  a  gas-burner  when 
 there  is  water  in  the  pipe.  The  whole  comet  seems 
 for  a  moment  or  two  to  be  extinguished,  and  then 
 suddenly  flashes  out  with  its  former  brilliancy.  This 
 excited  action  increases  in  intensity,  till  the  comet 
 reaches  its  nearest  point  to  the  sun,  and  it  is  only 
 after  the  comet  has  emerged  from  the  rays  of  the  sun, 
 that  it  has  attained  its  maximum  brilliancy.  The 
 motion  of  the  comet,  and  the  increase  of  brilliancy,  is 
 sometimes  so  rapid,  that  it  appears  to  burst  all  at 
 once,  as  in  the  case  of  the  recent  comet  (1861),  upon 
 an  astonished  world. 
 
 As  our  vehicle  now  advances  with  such  rapidity, 
 and  as  the  stations  are  now  very  close  to  one  another, 
 we  shall  take  but  a  cursory  glance  at  each  body  as 
 we  advance.  The  first  of  the  heavy  planets  is  Mars, 
 and  on  his  surface  we  can  readily  descry  the  circle  of 
 
A  JO  URNE  Y  THR  0  UGH  SPA  CE.      1 7 
 
 snow  at  the  poles,  and  the  general  outlines  of  his  con- 
 tinents. The  Earth  next  appears  with  its  surround- 
 ing blue  atmosphere.  Her  continents  and  oceans  are 
 seen  dimly  down  through  the  openings  in  the  clouds 
 that  float  in  her  atmosphere.  Belts  more  or  less  dis- 
 tinct, corresponding  to  the  trade-winds,  will  also  be 
 detected.  We  pass,  in  rapid  succession,  Venus,  Mer- 
 cury, and  Vulcan ;  and  we  probably  find  that  Vul- 
 can is  only  one  of  innumerable  asteroids  that  form  a 
 zone  between  Mercury  and  the  sun.  At  last  we  reach 
 the  goal,  and  find  ourselves  in  close  proximity  to  the 
 sun.  Conceive  of  our  sun  expanding,  so  as  nearly  to 
 fill  the  whole  concave  of  the  sky,  and  we  shall  have 
 some  conception  of  a  comet's  approach  to  it ;  and,  in 
 their  daring  course,  comets  sometimes  almost  graze 
 its  surface.  Here  the  diamond  would  flash  into 
 flame  like  gunpowder,  and  the  hardest  metals  would, 
 in  an  instant,  be  volatilized,  so  intense  must  be  the 
 heat.  Here,  too,  we  may  closely  survey  those  mys- 
 terious rose-coloured  flames,  seen  in  total  eclipses, 
 that  have  so  puzzled  observers.  Through  the  lumin- 
 ous envelope  we  see  down  into  these  perforations, 
 which  appear  as  dark  spots  from  the  earth.  These 
 minute  specks  are  now  seen  to  be  gulfs,  down  which 
 the  earth  could  be  projected  with  the  greatest  ease ; 
 and  so  capacious  is  the  sun,  that  it  could  engulf  all 
 the  planets  of  the  system,  and  yet  shew  no  appreci- 
 able difl'erence  in  size.  Millions  of  meteorolites  and 
 comets  have    probably  been   cd  gulfed  already,   and 
 
 B 
 
1 8     A  JOURNEY  THROUGH  SPACE. 
 
 yet  millions  more  would  not  visibly  enlarge  the  fur- 
 nace. 
 
 To  understand  the  relative  position  of  the  stations 
 at  which  we  have  stopped  in  our  excursion,  it  is  neces- 
 sary to  assign  a  scale.  If,  then,  we  call  the  distance 
 of  the  earth  to  the  sun  one  mile,  the  distance  of  Nep- 
 tune will  be  thirty  miles  ;  and  our  nearest  neighbour, 
 the  moon,  will  only  be  four  yards  from  us.  To  ex- 
 pand this  scale  to  represent  the  reality,  we  have  only 
 to  keep  in  mind  that  a  railway  train,  going  at  the 
 rate  of  thirty  miles  an  hour,  and  travelling  day  and 
 night,  would  take  twenty  thousand  years  to  go 
 straight  across  the  whole  breadth  of  the  solar  system. 
 
 But,  after  all,  this  journey  is  nothing  more  than  a 
 morning  drive  to  the  houses  of  a  few  friends  in  the 
 neighbouring  streets.  We  have  still  an  expedition 
 before  us,  which  may  be  compared  to  the  crossing  of 
 the  Atlantic,  or  a  voyage  to  China.  We  have  not  yet 
 really  left  home,  and  now  that  we  propose  going 
 p.broad,  what  vehicle  shall  we  take  to  aid  us  in  our 
 flight  to  other  systems  ?  The  comet  is  all  too  slow 
 for  our  purpose.  We  must  have  something  still  more 
 subtle  and  swift.  The  only  physical  agency  that  can 
 serve  our  purpose  is  a  ray  of  light.  On  a  ray  of  light 
 we  may  reach  the  moon  in  a  single  second,  and  the 
 sun  in  eight  minutes.  Instead  of  taking  twenty  thou- 
 sand years,  like  the  railway  train,  to  cross  the  solar 
 system,  it  would  require  only  eight  hours.  Let  us 
 suppose,  then,  that,  with  the  ethereal  vehicle  of  light 
 
A   JOURNEY  THROUGH  SPACE.      ig 
 
 we  are  to  start  upon  a  journey  far  beyond  the  solar 
 system,  where  shall  be  our  first  resting-place  ?  Alpha 
 Centauri  is  the  nearest  of  the  stars  whose  distance  has 
 been  well  determined ;  but  with  all  the  spiritual 
 swiftness  of  light,  we  can  reach  it  only  in  three  years 
 and  a  quarter.  We  are  separated  from  the  planets  by 
 an  interval  that  may  be  compared  to  the  breadth  of 
 a  river ;  but  an  expanse  like  the  Atlantic  Ocean, 
 separates  us  from  the  nearest  of  the  fixed  stars.  The 
 smallest  stars  visible  to  the  naked  eye  can  probably 
 be  reached  by  a  ray  of  light  only  in  about  fourteen 
 years ;  and  the  smallest  stars,  visible  in  the  largest 
 reflectors,  would  probably  require  a  journey  of  four 
 thousand  years. 
 
 Let  us  now  start  from  the  star  on  which  we  have 
 gained  a  footing,  for  a  position  from  which  we  may 
 look  down  upon  the  group  of  fixed  stars  to  which  our 
 sun  belongs.  Having  gained  this  position,  we  find 
 that  the  sun  is  part  of  the  Milky  Way,  which  lies 
 like  a  bright  ring  before  us,  with  perhaps  a  tendency 
 to  the  spiral  structure ;  the  cleft  in  the  galaxy  cor- 
 responding to  a  coil  of  the  spiral.  To  expand  this 
 ring  to  its  true  dimensions,  we  must  remember  that  a 
 ray  of  light  would  probably  take  a  thousand  years  to 
 speed  across  its  whole  breadth.  But  from  our  posi- 
 tion we  find  that  the  Milky  Way,  with  its  millions  of 
 stars  is  not  the  only  luminous  disc.  The  whole 
 heavens  are  studded  over  with  similar  patches  of  light 
 or  nebulse  which,  on  closer  inspection,  are  found  to  be 
 
20     A   JOURNEY  THROUGH  SPACE. 
 
 firmaments,  consisting,  like  the  Galaxy,  of  innumer- 
 able stars.  They  may  appear  as  single,  hazy  stars,., 
 but  they  are  the  combined  light  of  countless  hosts.. 
 These  groups  are  separated  by  gulfs  which  it  would 
 require  millions  of  years  for  a  ray  of  light  to  traverse. 
 
 As  we  in  thought  travel  from  firmament  to  firma- 
 ment, we  see  new  forms  constantly  presented  to  our 
 view.  Each  firmament  has  some  bond  of  unity,  and, 
 generally,  a  symmetrical  structure.  However  much 
 they  differ,  a  tendency  to  the  spiral  structure  may  be 
 discovered.  One  cannot  look  at  the  figures  of  the 
 spiral  nebulse  without  having  suggested  the  idea  of 
 vast  vortices,  in  which  streams  of  stars  are  hastening 
 on  to  some  grand  consummation.  There  is  nothing 
 fixed  or  final  in  the  heavens ;  all  things  are  passing 
 through  cycles  of  decay  or  revivification.  As  thero 
 are  silent  molecular  changes  going  on  in  the  most 
 solid  masses  on  the  earth's  surface,  so  these  suns, 
 which  to  a  mind  of  superior  grasp  may  appear  as 
 only  single  particles  of  which  the  nebula  is  the  mass, 
 are  in  constant  motion  in  the  galaxy  to  which  they 
 belong. 
 
 But  where  are  we  to  stop  ?  Are  we  to  assume  that 
 the  firmament  or  resolvable  nebula  is  the  last  step  ? 
 or,  are  we  to  look  for  some  higher  unity,  under  which 
 these  groups  may  be  subsumed  ?  Speculations  con- 
 nected with  the  indestructibility  of  force,  have  led  to 
 the  idea  that  all  the  worlds  and  system  which  as- 
 tronomy has  revealed,  are  included  within  one  vast 
 
A   JOURNEY  THROUGH  SPACE.      21 
 
 sphere  of  definite  dimensions,  and  consisting  of  the 
 ethereal  medium  through  which  light,  heat,  electricity, 
 and  gravity  are  propagated.  But  are  we  to  accept 
 this  definite  sphere  as  the  sum  of  the  physical  uni- 
 verse? Overwhelmingly  vast  it  may  appear  to  us, 
 but  shall  we  limit  the  creative  power  of  the  Infinite 
 to  a  sphere  which,  compared  to  the  infinitude  of  space, 
 is  as  a  mote  in  the  sunbeam  ?  But  then  the  meta- 
 physical question  arises — and  the  ultimate  problems 
 of  physics  always  merge  in  metaphysical  questions — 
 What  is  space?  Is  it  an  objective  reality,  or  a  sub- 
 jective condition  of  thought?  We  cannot  enter  on 
 this  mare  magnum  of  controversy,  but  we  must  advert 
 to  the  curious  correlations  of  time  and  space  brought 
 out  by  the  laws  of  light. 
 
 From  the  simple  law,  that  light  requires  time  to 
 travel  from  one  point  to  another,  it  follows,  that  we 
 see  everything  in  the  past.  In  the  case  of  very  dis- 
 tant objects,  this  leads  to  startling  results.  For  every 
 event  in  the  past  history  of  the  world,  there  is  a  cor- 
 responding point  in  space,  and  if  we  were  situated  on 
 a  star  at  that  point,  we  would,  on  looking  down  upon 
 the  earth,  see  the  corresponding  event  transacted. 
 For  example,  if  we  took  up  our  position  in  a  star,  to 
 which  light  would  take  six  thousand  years  to  travel 
 from  this  globe,  we  would  witness  the  scenes  of  para- 
 dise, and  the  roll  of  the  world's  history  would  unfold 
 itself  to  our  eyes.  If  the  course  of  events  appeared 
 too  slow,  we  could  hasten  it,  in  any  degree,  by  glid- 
 
22     A  JOURNEY  THROUGH  SPACE. 
 
 ing  swiftly  towards  the  earth,  along  the  course  of  the 
 rays.  If  we  could  accomplish  the  journey  in  an  hour, 
 the  history  of  six  thousand  years  would  be  condensed 
 into  that  period.  The  schoolmen  defined  eternity  as 
 punctum  stansj  and  the  propagation  of  light  gives  a 
 startling  illustration  of  their  meaning.  We  can  arrest 
 the  flow  of  time  by  continued  motion.  Suppose  our 
 world  is  the  illuminated  dial  of  a  clock,  that  the  hand 
 is  at  twelve  o'clock,  and  that  the  machinery  is  faith- 
 fully doing  its  duty;  we  have  only  to  take  up  our 
 position  in  a  star  that  moves  from  the  earth  as  rapidly 
 as  the  rays  from  the  dial,  in  order  to  arrest  the  hand 
 for  ever  at  that  hour.  To  one  who  is  stationary,  the 
 hand  makes  its  ordinary  revolution ;  but  one  who 
 moves  away  with  the  rapidity  of  light,  sees  it  per- 
 fectly fixed.  Nay,  it  is  possible  to  turn  back  the 
 hand,  as  in  the  case  of  the  dial  of  Ahaz.  In  a  star 
 moving  away  from  the  earth  more  rapidly  than  the 
 light,  a  person  would  see  the  hands  gradually  move 
 in  the  reverse  order,  from  twelve  to  eleven  o'clock, 
 and  so  on.  By  moving  in  the  direction  opposite  to 
 that  of  the  light,  centuries  might  be  concentrated  into 
 hours,  and  hours  into  seconds.  Had  we  unlimited 
 powers  of  locomotion,  we  would  not  be  under  the  ne- 
 cessity of  reading  unintelligible  and  prosaic  accounts 
 of  campaigns  and  battles  in  the  past  history  of  our 
 country ;  it  would  only  be  necessary  to  wing  our  way 
 to  some  star  where  the  light  from  the  seat  of  war  is 
 
A   JO  URNE  V  THR  0  UGH  SPA  CE.     2  3 
 
 just  arriving,  and  leisurely  watch  tlie  actual  progress 
 of  events. 
 
 These  curious  relations  of  space  and  time,  as  linked 
 together  by  the  laws  of  light,  sufficiently  show  how 
 the  properties  of  matter  may  aid  the  spirit,  in  a  future 
 state  of  being,  in  obtaining  a  wide  and  comprehensive 
 view  of  the  works  and  the  providence  of  God.  Matter 
 and  force,  as  far  as  we  know,  are  indestructible,  and 
 time  itself,  the  most  perishable,  in  one  sense,  of  all 
 things,  is,  in  another,  indestructible  too.  It  can  be 
 recalled,  as  we  have  seen,  and  forced  again  to  do  duty, 
 by  repeating  the  events  of  the  past. 
 
 When  we  step  from  planet  to  sun,  from  sun  to 
 system,  and  from  system  to  firmament,  we  are  ascend- 
 ing the  rounds  of  the  ladder  that  leads  up  to  the  In- 
 finite ;  and  this  is  the  great  end  of  the  book  of  God 
 in  the  heavens.  But  a  hard-featured  philosophy 
 comes,  and  tells  us  that  we  cannot  know  the  Infinite, 
 that  the  notion  we  form  is  merely  a-  synthesis  of 
 finites,  that  no  number  of  finites  can  ever  make  an 
 infinite ;  and  that  this  arises  from  the  very  limits  of 
 thought.  This  is  true,  if  it  means  merely  that  we 
 cannot  construe  to  our  minds  the  image  of  an  infinite 
 ladder,  by  indefinitely  increasing  the  rounds  of  it ; 
 but  surely  we  can  know  a  thing,  though  we  cannot 
 draw  a  definite  picture  of  it  to  the  eye  or  the  imagina- 
 tion. We  can,  in  like  manner,  know  the  Infinite 
 and  the  Eternal,  though  we  cannot  construe  to  our 
 
24     A  JO  URNE  V  THR  O  UGH  SPA  CE. 
 
 minds  either  infinite  duration  or  infinite  space.  The 
 African  on  the  banks  of  the  Niger  may  be  altogether 
 ignorant  of  its  source  and  termination ;  but  would  it 
 be  right,  on  that  account,  to  deny  that  he  has  any 
 knowledge  of  the  river  ?  It  would  be  equally  wrong 
 to  deny  that  we  can  know  God,  merely  on  the  ground 
 that  we  do  not  and  cannot  grasp  His  Infinite  attri- 
 butes. 
 
Gaa3C5;i<lI. 
 
 n. 
 
 THE  MOON— IS  IT  INHABITED? 
 
 In  the  more  detailed  survey  which  we  mean  to  take 
 of  the  heavensj  as  illustrative  of  God's  glory,  we- 
 shall  first  direct  our  attention  to  the  moon,  our  nearest 
 neighbour.  The  moon  will  form  the  first  step  in 
 the  ladder,  by  which  we  shall  attempt  to  scale  those 
 heights,  commanding  the  widest  range  of  the  marvel- 
 lous works  of  the  Almighty.  Although  we  can- 
 not by  searching  find  out  God  —  although  bafiled 
 
26     THE  MOON— IS  IT  INHABITED? 
 
 in  our  attempts  to  comprehend  tlie  Absolute,  still, 
 there  are  successive  elevations  in  space  which  enable 
 us  to  enlarge  our  view,  and  form  a  juster  conception 
 of  the  Infinite  and  Eternal.  From  the  satellite,  we 
 step  to  the  primary  planet;  from  the  planet,  to  the 
 centre  of  the  system;  from  system,  to  firmament; 
 and,  while  new  firmaments  stretch  out  before  us  in 
 marvellous  form  and  grouping,  we  feel  that  we  are 
 yet  far  from  the  throne  of  the  Eternal. 
 
 The  dream  of  the  poet  has  placed  the  special  resi- 
 dence of  the  Godhead  in  some  vast  central  body, 
 round  which  all  worlds,  and  systems,  and  firmaments 
 circulate  in  lowly  homage.  The  graver  thoughts  of 
 science  have,  in  connexion  with  speculations  about 
 light  and  heat,  imagined  a  limit  within  which  all  the 
 play  of  material  action  is  confined — a  vast  globe  of 
 ethereal  matter,  within  which  all  material  bodies  are 
 embraced,  and  without  which  the  activities  of  light, 
 heat,  electricity,  magnetism,  and  gravitation,  could 
 not  exist.  These,  however,  arc  but  the  feeble  aspira- 
 tions of  humanity  to  grasp  the  incomprehensible. 
 But  why  should  we  repine  at  our  limited  knowledge  ? 
 •would  not  knowledge  cease  to  have  charms,  if  we 
 knew  all  ?  What  is  it  that  gives  to  profound  study  its 
 fascinations  ?  Is  it  not,  that  it  brings  us  face  to  face 
 with  the  unknown  ?  If  there  was  not,  still,  a  beyond, 
 our  spirits  would  shrink  within  us,  and  we  would  feel 
 as  if  our  destiny  were  unfulfilled.  The  oft-quoted 
 saying  of  Newton,  that  he  felt  he  was  only  a  child 
 
THE  MOON— IS  IT  INHABITED?    27 
 
 picking  up  pebbles  on  the  margin  of  the  ocean,  is 
 usually  taken  as  merely  illustrative  of  the  modesty  of 
 genius ;  but,  at  the  same  time,  no  one  can  occupy  a 
 more  enviable  position  than  that,  which  gives  him  an 
 unobstructed  view  of  the  great  ocean  of  the  unknown. 
 Few  get  down  to  its  brink  at  all:  the  many  are 
 satisfied  with  the  little  they  can  understand,  and  rather 
 shrink  from  what  reveals  their  ignorance  or  conceit. 
 
 In  most  other  sciences,  the  mind  is  frequently  so 
 lost  in  details,  that  it  is  difficult  to  find  a  standpoint, 
 where  you  may  gaze  freely  out  upon  the  unknown. 
 In  astronomy,  however,  you  are  brought,  almost  at 
 once,  to  stand  face  to  face  with  the  Infinite.  No  doubt, 
 you  come  at  last  to  the  unfathomable,  when  dealing 
 with  the  molecular  forces  of  matter — and  the  mind 
 can  be  as  much  lost  in  aioms,  as  in  suns  and  systems ; 
 still,  the  popular  intellect  can,  more  readily,  deal 
 with  the  infinitely  great  than  the  infinitely  little ;  and 
 the  foot  stands  more  firmly  on  systems  of  worlds  than 
 groups  of  molecules.  The  fact  that  the  material  uni- 
 verse presents  no  boundary-wall  to  limit  inquiry,  so 
 far  from  being  a  g?*ound  for  turning  from  astronomical 
 inquiry,  accounts  for  the  charm  which  has  ever  sur- 
 rounded this  study. 
 
 The  moon  is,  by  far,  our  nearest  neighbour.  While 
 Neptune  is  a  mile  distant,  the  moon  is,  on  the  same 
 scale,  only  about  six  inches.  And  man,  even  when 
 he  could  form  no  idea  of  the  real  distance,  ever  looked 
 to  the  moon  with  a  familiarity,  which  he  could  feel 
 
28     THE  MOON— IS  IT  INHABITED  ? 
 
 towards  no  other  heavenly  body.  While  bowing  to 
 the  lordly  sun  in  devout  adoration,  he  endowed  the 
 moon  with  the  feminine  attributes  of  gentleness,  love, 
 and  weakness.  This  idea  of  tenderness  and  famili- 
 arity, is  well  expressed  in  the  lines  of  Wordsworth : — 
 
 "  Wanderer,  that  stoop'st  so  low  and  comest  so  near 
 To  human  life's  unsettled  atmosphere ; 
 Wko  lovest  with  night  and  silence  to  partake, 
 So  might  it  seem,  the  cares  of  them  that  wake. 
 
 The  most  rude, 
 Cut  off  from  home  and  country,  may  have  stood, 
 3ven  till  long  gazing  hath  bedimm'd  his  eye, 
 Or  the  mute  rapture  ended  in  a  sigh. 
 With  some  internal  lights  to  memory  dear, 
 Or  fancies  stealing  forth  to  soothe  the  breast. 
 Tired  with  its  daily  share  of  earth's  unrest ; 
 Gentle  awakenings,  visitations  meek, 
 A  kindly  influence  whereof  few  will  speak, 
 Though  it  can  wet  with  tears  the  hardest  cheek." 
 
 The  charm  of  the  moon  over  the  infant  mind,  is  de- 
 scribed, by  the  same  author,  in  the  following  lines  : — 
 
 "  Oh,  still  beloved,  (for  thine,  meek  power,  are  charms 
 That  fascinate  the  very  babe  in  arms. 
 While  he,  uplifted  towards  thee,  laughs  outright, 
 Spreading  his  palms  in  his  glad  mother's  sight.) 
 Oh,  still  beloved,  once  worshipp'd." 
 
 The  aspect  of  the  moon,  to  the  unaided  eye,  pre- 
 sents a  most  tantalising  appearance.  We  just  see 
 enough  to  assure  us,  that  there  is  something  more  to 
 be  seen.  In  the  other  heavenly  bodies,  we  see  only 
 a  uniform  blaze  of  light,  and  there  is  little  to  tempt 
 our  curiosity.      It  is  not  so  with  the  moon  :    there 
 
Pi  A[t    II 
 
 RUGGED     EDGE    OF  THE    MOON. 
 
THE  MOON— IS  IT  INHABITED?     29 
 
 are  diversities  of  shade,  which  allure  us  to  form  con- 
 jectures about  their  significance ;  and,  in  the  crescent 
 moon,  we  can  readily  discover  that  the  concave  side 
 presents  a  rugged  edge.  It  can  hardly  be  surprising, 
 then,  that  the  instincts  of  genius  should  in  this,  as  in 
 other  departments,  anticipate  the  discoveries  of  science. 
 Democritus  propounded  the  idea  of  the  spots  on  the 
 moon  being  diversities  of  surface,  consisting  of  moun- 
 tains and  valleys,  seas  and  rivers.  The  Orphic  Hymns 
 wxnt  further,  by  ascribing  cities  with  a  teeming  popu- 
 lation. The  power  of  the  telescope  was,  however,  re- 
 quired to  bring  out  in  relief  the  diversities  of  surface, 
 which  make  the  moon  the  counterpart  of  our  own 
 globe. 
 
 To  those  who  have  not  had  the  opportunity  of 
 examining  the  moon  through  a  telescope,  the  stereo- 
 scopic pictures  of  Mr  Warren  De  la  Rue  form  an 
 admirable  substitute.  Indeed,  to  the  unscientific  eye, 
 the  stereoscopic  picture  gives  a  much  truer  idea  of  the 
 configuration  of  the  body.  The  reason  is  simple.  We 
 have  not,  in  looking  through  the  telescope,  the  aids 
 of  perspective,  which  we  possess,  when  looking  at  any 
 terrestrial  object ;  and,  consequently,  there  is  difficulty 
 in  bringing  out  in  relief  the  mountain  ranges,  peaks, 
 and  rims  of  craters.  Sometimes,  the  moon,  to  the  un- 
 practised eye,  appears  a  uniform  level ;  at  others,  the 
 relief  is  reversed,  the  mountain  sinking  into  a  cavity, 
 and  the  sharp  peak  into  a  perforation.  The  stereo- 
 scopic views  of  the  moon,  however,  remedy  all  this : 
 
30     THE  MOON— IS  IT  INHABITED? 
 
 the  moon  is  seen  with  all  its  natural  roundness^  and 
 every  mountain  projects  as  in  a  model,  placed  onlj  a 
 few  inches  from  the  eye.  But  how  is  it  that  a  stereo- 
 scopic picture  of  the  moon  can  be  obtained  ?  This, 
 at  first  sight,  appears  impossible,  as  she  always  turns 
 the  same  side  to  us.  When  a  stereoscopic  portrait 
 is  taken,  two  views  of  the  party  must  be  obtained, 
 and  this  may  be  done  in  two  ways.  When  one 
 picture  is  taken,  the  camera  is  moved  a  little  to  one 
 side  and  a  second  taken,  the  party  sitting  immovable 
 all  the  time ;  or  the  camera  may  be  fixed,  and  the 
 party  may  turn  his  body  a  little  round  for  the  second 
 picture.  It  is  in  this  latter  way,  a  stereoscopic  picture 
 of  the  moon  is  obtained.  The  camera,  of  course,  can- 
 not be  moved  sufficiently  aside  to  take  a  picture  from 
 a  difierent  point  of  view,  and  it  is  therefore  stationary. 
 The  moon,  however,  effects  the  object  required  by 
 turning  her  face  a  very  little  round,  so  that  a  some- 
 what different  perspective  is  obtained.  This  small 
 movement  is  called  her  libration,  and,  though  small, 
 is  quite  sufficient  to  give  the  required  stereoscopic 
 effect.  The  moon  always  presents  tne  same  face  to 
 us,  as  she  rotates  on  her  axis  in  the  sam.e  time  that 
 she  revolves  round  the  earth  ;  but  these  two  motions 
 are  not  perfectly  coincident  during  a  revolution,  and 
 we  are,  therefore,  permitted  to  see,  a  small  way,  round 
 her  globe.  It  is  from  this  slight  oscillation  that  the 
 stereoscope  gives  us  so  perfect  a  representation  of  the 
 lunar  surface.    If  the  student's  first  acquaintance  with 
 
THE  MOON— IS  IT  INHABITED?    31 
 
 the  moon  be  made  in  this  way,  he  will  be  able  to 
 understand,  much  more  readily,  the  revelations  of  the 
 telescope. 
 
 As  soon  as  we  get  a  glimpse  of  the  mountain  ranges, 
 volcanic  craters,  and  vast  plains  of  our  satellite,  the  na- 
 tural inquiry  is — lailinhabited  ?  There  is  a  sufficient 
 general  resemblance,  at  the  first  glance,  to  prompt  the 
 inquiry  ;  but — Does  minuter  inspection  countenance 
 the  hypothesis  ?  We  have  not  the  more  obvious  proofs 
 of  habitableness.  We  do  not  find  cities  with  ramify- 
 ing streets,  or  such  diversities  of  colour  as  would  in- 
 dicate cultivated  districts,  though  we  have  telescopic 
 power  to  discover  such  traces  if  they  existed.  If 
 peopled  with  beings  like  ourselves,  we  might  naturally 
 expect  single  buildings,  which  would  be  quite  dis- 
 cernible by  the  telescope ;  for,  in  the  moon,  blocks  of 
 stone  could  be  raised  by  one  man,  that  would  require, 
 in  this  globe,  the  united  energies  of  six.  Here,  struc- 
 tures are  very  limited  in  magnitude  by  the  tendency 
 of  the  weight  to  crush  the  stone ;  but,  there,  from  the 
 lightness  of  the  materials,  the  range  would  be  much 
 wider.  No  such  buildings,  however,  no  trace  of  cities, 
 no  proofs  that  the  soil  has  been  disturbed  by  the 
 plough,  or  that  yellow  harvests  alternate  with  green 
 fields,  have  been  discovered. 
 
 There  is  no  necessity,  however,  that  the  inhabitants 
 should  be  after  the  type  of  man's  bodily  constitution; 
 we  can  conceive  intellect  united  to  a  very  difierent 
 corporeal  organisation  ;  and  we  know  that  there  is  a 
 
32     THE  MOON— IS  IT  INHABITED? 
 
 very  wide  range,  even  in  this  globe,  in  the  conditions 
 necessary  to  sustain  life.  Still,  we  must  start  from 
 some  essential  conditions  of  life  in  this  globe,  if  we 
 are  to  make  our  argument  one  of  analogy.  No  doubt, 
 it  may  be  said  that  God  could,  in  the  case  of  the 
 planetary  bodies,  make  life  dependent  on  totally  dif- 
 ferent conditions.  This  is  true,  but  it  is  a  totally  dif- 
 ferent question  from  that  of  analogy.  The  question 
 is  one,  not  of  ^possibility^  but  of  p^ohohility^  and  the 
 probability  is  to  be  derived  from  the  existence  of  con- 
 ditions in  the  moon,  similar  to  those  in  the  earth. 
 While  ignorant  of  the  absence  of  air  and  water  in  the 
 moon,  the  many  other  points  of  similarity  would 
 afford  some  presumption  that  the  moon  is  inhabited. 
 But  these  points  of  similarity  militate  against  the 
 presumption,  now  that  the  essential  conditions  of  life 
 on  our  globe  are  found  to  be  wanting.  If  it  be  held 
 that  life  may  be  sustained  by  totally  different  means, 
 then  the  hypothesis  is  best  sustained  by  finding  points 
 of  difference  instead  of  similarity. 
 
 Let  us  take  one  of  the  most  essential  conditions 
 of  life  on  our  globe,  the  existence  of  air  :  air  is  less 
 essential  to  some  creatures  than  to  others,  but  we  have 
 no  reason  to  believe  that,  under  a  total  deprivation  of 
 it,  any  creature  can  exist  on  our  globe.  It  may  be 
 argued,  that  God  could  create  beings  capable  of  exist- 
 ing without  air,  and  that  life  may  exist  in  the  moon, 
 even  though  no  atmosphere  should  be  discovered.  The 
 question  is,  however^  not,  What  is  within  the  com- 
 
THE  MOON— IS  IT  INHABITED  f    33 
 
 pass  of  God's  power  ?  but,  What  has  likely  been  the 
 exercise  of  His  power  in  the  moon,  from  our  know- 
 ledge of  His  power  in  our  globe  ?  And,  to  have  any- 
 ground  of  probability  to  stand  upon,  the  astronomical 
 argument  must  prove,  that  the  conditions  essential  to 
 life  here  are  also  found  in  the  moon  j  or,  at  least,  that 
 the  existence  of  such  conditions  is  probable. 
 
 Every  possible  test  has  been  applied,  but  no  trace 
 whatever  of  air  has  been  found  in  the  moon.  Eclipses 
 and  occultations  have  been  watched  with  the  utmost 
 care,  but  all  in  vain ;  some  of  the  tests  are  so  delicate, 
 that  if  there  was  an  atmosphere  capable  of  raising  the 
 mercury  one-sixtieth  of  an  inch  in  the  barometer,  it 
 would  have  been  detected.  If  there  is  an  atmosphere 
 after  all,  how  evanescent  it  must  be  compared  with 
 ours,  which  raises  the  mercury  to  about  thirty  inches. 
 Could  we  conceive  living  creatures  to  exist  in  the 
 moon  without  air,  how  strange  must  be  the  conditions 
 of  life !  Let  us  only  imagine  that  life  moves  on  very 
 much  as  it  does  here,  with  the  only  difference,  that 
 there  is  no  air,  and  we  shall  at  once  see  how  won- 
 drously  our  nature  is  adapted  to  the  physical  condi- 
 tions in  which  we  are  placed.  Most  people  probably 
 think  little  of  the  functions  of  the  atmosphere,  except 
 when  it  is  pressed  on  their  attention  by  the  danger  of 
 suffocation,  or  by  witnessing  the  terrible  mechanical 
 effects  of  the  storm.  But  think  how  strange  life  must 
 be  in  the  moon  without  an  atmospheric  medium. 
 Eternal  silence  must  reign  there.     A  huge  rock  may 
 
 c 
 
34     THE  MOON— IS  IT  INHABITED  ? 
 
 be  precipitated  from  the  lofty  lunar  cliffs,  but  no  sound 
 is  heard — it  falls  noiselessly  as  a  flock  of  wool.  The 
 inhabitants  can  converse  only  by  signs.  The  musi- 
 cian in  vain  attempts  to  elicit  sweet  music  from  his 
 stringed  instrument;  no  note  ever  reaches  the  ear. 
 Armies  in  battle  array  do  not  hear  the  boom  of  the 
 cannon,  though  rifled  arms,  from  the  low  trajectory  of 
 the  ball,  must  acquire  a  fatal  precision  and  range.  No 
 moving  thing  can  live  aloft ;  the  eagle  flaps  its  wings 
 against  the  rocks,  and  in  vain  attempts  to  rise.  The 
 balloon,  instead  of  raising  the  car,  crushes  it  with  the 
 weight  of  its  imprisoned  gas. 
 
 Again,  the  inhabitants,  having  no  atmosphere  to 
 shelter  them  from  the  sun  and  store  up  its  heat,  must 
 recoil  with  terror  from  its  fierce  rays.  During  the 
 long  lunar  day,  the  ground  must  become  as  burning 
 marl,  from  which  the  scorched  feet  shrink  with  pain ; 
 during  the  equally  long  night,  it  must  be  colder  than 
 frozen  mercury.  No  fuel  will  burn  to  mitigate  the 
 rigour  of  the  cold,  and  none  but  the  electric  light 
 can  avail  to  dispel  the  darkness. 
 
 Then  as  to  light,  how  strange  are  the  conditions ! 
 At  noon-day  the  sky  is  as  black  as  pitch,  except  in 
 the  region  of  the  sun ;  and  the  stars  shine  out  as  at 
 midnight.  When  the  sun  disappears  in  the  horizon, 
 darkness  is  as  sudden  as  the  darkness  of  an  eclipse, 
 or  the  extinguishing  of  a  candle  in  a  room.  The  in- 
 habitants, on  the  shady  side  of  a  range  of  mountains, 
 must  be  in  almost  total  darkness,  though  the  sun  is 
 
THE  MOON— IS  IT  INHABITED?     33 
 
 above  the  horizon ;  and  a  room,  lighted  by  windows 
 in  the  roof,  must  be  in  the  same  predicament,  except 
 when  the  sun  shines  directly  down.  No  clouds  float 
 overhead ;  and  the  murky  atmosphere,  and  the  dense 
 clouds  of  smoke  hanging  over  our  manufacturing 
 towns,  must  be  incomprehensible  to  the  Lunarians,  as 
 they  watch  our  globe  rapidly  rotating  on  its  axis,  but 
 immovably  fixed  in  the  heavens.  These  are  a  few  of 
 the  consequences  involved  in  the  want  of  an  atmo- 
 sphere, apart  altogether  from  the  incompatibility  of 
 such  want  with  life.  We  are,  every  moment,  bathed 
 in  this  fluid,  which  ministers  to  our  wants  in  a  thou- 
 sand ways  5  and,  yet,  how  little  are  we  conscious  of 
 its  benefits !  How  seldom  do  we  think  of  Him  who 
 has  so  wondrously  adapted  the  medium,  in  which  we 
 move,  to  the  necessities  of  our  nature ! 
 
 It  will  be  then  said,  that  the  moon  must  be  aban- 
 doned as  an  argument  for  the  plurality  of  worlds,  see- 
 ing that  it  fails  to  exhibit  the  prime  condition  of  life. 
 The  advocates  of  this  doctrine,  after  fruitless  endea- 
 vour to  educe  an  argument,  gave  it  up  in  despair.  A 
 recent  discovery  has,  however,  entirely  changed  the 
 aspect  of  things ;  and  the  moon  may  now  be  appealed 
 to,  as  furnishing  a  theatre  for  the  display  of  all  the 
 activities  of  animated  and  intelligent  beings.  This 
 discovery,  while  curious  in  reference  to  its  bearing  on 
 this  question,  also  presents  one  of  the  most  brilliant 
 achievements  of  science  in  modern  times. 
 
riato. 
 
 in. 
 
 THE  MOON'S  INVISIBLE  SIDE. 
 
 An  artistic  eye  can  readily  discover,  amidst  much 
 diversity,  the  pervading  style  of  a  great  master.  The 
 architect  may  display  his  skill  in  very  varied  forms. 
 The  private  dwelling,  the  public  sanctuary,  and  the 
 monumental  pile  may  all  reveal  the  genius  of  one 
 presiding  mind.  There  may  be  the  utmost  diversity 
 of  purpose,  combined  with  a  perfect  unity  of  style. 
 In  the  universe  of  worlds,  it  is   not  necessary  to 
 
THE  MOON'S  INVISIBLE  SIDE.     ^ 
 
 detect  a  sameness  of  purpose,  in  order  to  recognise 
 the  hand  of  the  one  great  Architect.  We  do  not 
 require  to  prove  that  the  moon  is  inhabited,  in  order 
 to  shew  that  it  was  formed  by  the  same  hand  that 
 constructed  our  world,  teeming  with  living  beings. 
 Standing  on  the  summit  of  a  lunar  mountain,  and 
 surveying  the  lifeless  waste  around,  we  can  have  no 
 difficulty  in  tracing  the  same  Divine  wisdom  that  so 
 marvellously  moulded  this  world  of  ours,  as  a  fit 
 abode  for  all  the  activities  of  life.  We  find  the  same 
 great  laws  that  have  sway  upon  our  globe.  Gravita- 
 tion reigns  there,  as  well  as  here.  The  forces  that 
 upheaved  the  crust  of  the  moon,  and  moulded  it  into 
 such  strange  forms,  obeyed  similar  laws. 
 
 The  configuration  of  the  lunar  surface  bears  a  strik- 
 ing resemblance  to  the  diversities  on  that  of  the  earth. 
 There  are  differences,  but  differences  that  consist  with 
 the  same  type.  The  solitary  peaks,  the  mountain 
 ranges,  the  circular  craters  have  their  own  distinctive 
 characters, — just  as  the  scenery  of  one  part  of  the 
 earth's  surface  differs  from  that  of  another;  still,  there 
 is  one  general  plan  assimilating  them  to  the  analogous 
 terrestrial  forms.  It  is  this  that  gives  so  great  a  charm 
 to  the  contemplation  of  the  lunar  surface.  The  plea- 
 sure of  travel  in  foreign  countries  consists,  very  much, 
 in  the  discovery  of  likeness  to  our  manners  and  cus- 
 toms, arts  and  institutions,  underlying  much  apparent 
 and  often  startling  dissimilarity ;  and  when  we  travel 
 beyond  the  limits  of  our  own  orb,  and  alight  upon 
 
38      THE  MOON'S  INVISIBLE  SIDE. 
 
 this  strange  island  floating  in  space,  we  are  startled 
 to  find  it  so  strange,  and  yet  so  like  the  world  that 
 we  left  behind. 
 
 This  pleasing  similarity  may  be  felt,  and  the  hand 
 of  the  one  omnipotent  Architect  may  be  recognised, 
 although  we  do  not  find  the  moon  provided  with 
 inhabitants.  Still  it  would,  no  doubt,  lend  an  ad- 
 ditional charm,  if  we  had  any  plausible  ground  for 
 entertaining  such  a  belief.  As  soon  as  the  telescope 
 unveiled  a  world  so  like  our  own,  in  its  general 
 aspect,  the  popular  imagination  peopled  it  with  living 
 forms,  and  astronomers  strove  with  one  another  to 
 gratify  the  popular  wish.  On  the  dark  surface,  active 
 volcanoes  were  discovered.  The  flames  were  seen 
 to  burst  forth  with  great  fierceness,  and  then  slowly 
 expire,  shewing  that  there  was  air  to  sustain  the  com- 
 bustion. Planets  and  fixed  stars  were  seen  to  linger 
 on  the  moon's  edge,  before  they  passed  behind  its  disc, 
 just  as  they  ought  to  do,  if  there  was  an  atmosphere. 
 All  these  observations  are  now  discredited ;  and  the 
 inexorable  decision  of  scientific  research  is,  that  there 
 is  no  valid  argument  for  the  existence  of  an  atmo- 
 sphere. Not  long  ago,  an  admirable  test  was  afforded 
 by  the  occultation  of  Jupiter,  and  every  astronomer 
 was  on  the  alert  to  discover  the  result.  The  figure 
 of  the  planet  ought  to  be  distorted  by  the  atmosphere, 
 if  there  was  really  one,  and  many  eyes  were  strained 
 to  detect  the  distortion.  The  result  was  a  strange 
 one.     Many  saw  the  exact  appearance  that  ought  to 
 
THE  MOON'S  INVISIBLE  SIDE.     39 
 
 be  presented ;  the  disc  of  Jupiter  was  changed  just 
 as  theory  required.  Others  again  saw  no  distortion ; 
 the  disc  presented  its  natural  form,  and  gave  no  in- 
 dication of  a  refracting  medium.  What  deduction 
 are  we  to  draw  from  such  conflicting  testimony? 
 Where  does  the  truth  lie  ?  The  observers  were  all 
 equally  veracious,  and  they  all  appealed  to  the  testi- 
 mony of  the  senses.  Which  testimony  are  we  to 
 receive  ?  Or  must  we  hold  that  the  evidence  of  the 
 one  side  neutralises  that  of  the  other  ?  The  objective 
 facts  were  undoubtedly  the  same  to  all ;  but  a  curious 
 subjective  law  of  our  nature  extricates  us  from  the 
 dilemma.  The  law  is  that  of  expectant  attention, 
 which  explains  so  many  of  the  facts  of  mesmerism. 
 When  the  mind  is  possessed  of  some  dominant  idea, 
 and  when,  in  accordance  with  it,  we  have  a  strong 
 expectation  of  some  event,  the  senses,  in  these  cir- 
 cumstances, become  to  a  certain  extent  the  sport  of 
 our  subjective  feelings.  Taking  this  fact  in  our 
 nature  into  account,  and  also  the  known  character 
 of  the  observers,  the  conclusion  is,  that  the  distor- 
 tion of  the  disc  of  Jupiter  was  not  real, — that  it  re- 
 sulted merely  from  the  excited  state  of  the  observers' 
 feelings  at  the  moment.  Their  foregone  conclusion 
 overpowered  the  legitimate  testimony  of  sense.  The 
 testimony  of  the  most  competent  observers  was  all 
 against  the  existence  of  an  atmosphere. 
 
 The  advocates  of  a  plurality  of  worlds  have  either 
 abandoned  the  case  of  the  moon  as  not  one  in  point, 
 
40      THE  MOON'S  INVISIBLE  SIDE. 
 
 being  only  a  satellite,  or  resorted  to  strained  hypo- 
 theses ;  such  as,  that  there  may  be  an  atmosphere  at 
 the  bottom  of  the  valleys,  or  that  she  must  neces- 
 sarily have  appropriated,  by  her  attraction,  the  matter 
 of  the  tails  of  comets,  and  of  the  zodiacal  light.  A 
 recent  discovery,  has,  however,  been  made,  which 
 entirely  changes  the  aspect  of  the  question.  In  all 
 previous  speculations,  astronomers  proceeded  on  the 
 supposition  that  w^hat  held  in  reference  to  one  side  of 
 the  moon,  would  equally  hold  in  reference  to  the  other. 
 The  profound  research  of  a  continental  astronomer 
 has  now  shewn,  that  this  is  by  no  means  a  legitimate 
 supposition,  and  that  the  non-existence  of  an  atmo- 
 sphere in  the  visible  side,  does  not,  at  all,  imply  that 
 the  other  is  equally  destitute. 
 
 The  moon  constantly  turns  the  saine  side  to  us. 
 She  does,  indeed,  as  if  to  tantalise  us,  shew  a  small 
 portion  of  the  other  side.  She  turns  round  at  one  time 
 the  western  edge,  so  as  to  shew  us  a  few  more  mountains 
 and  craters,  and  then,  at  another,  the  eastern  ;  there  is 
 a  similar  oscillation  at  the  poles,  but  it  is  only  a  very 
 limited  region  that  she  thus  reveals.  It  is  by  this 
 libration,  as  we  have  seen,  that  we  are  able  to  take 
 stereoscopic  pictures  of  her  disc.  She  turns  constantly 
 the  same  side  to  us,  for  the  simple  reason,  that  she 
 rotates  once  upon  her  axis,  in  the  same  time  that  she 
 performs  a  revolution  round  the  earth.  It,  at  first 
 sight,  appears  like  a  contradiction,  to  say  that  she  turns 
 round  upon  her  axis,  and  yet,  that  she  never  shews  us 
 
THE  MOON'S  INVISIBLE  SIDE.     41 
 
 but  one  hemisphere.  Does  not  rotation  consist  in 
 turning  round  to  us  all  sides  in  succession  ?  This  has 
 always  been  a  puzzle  in  astronomy,  though  only  very 
 elementary  knowledge  is  sufficient  to  solve  it.  Even 
 the  acute  metaphysician  Hegel  could  not  understand 
 how  she  should  rotate,  and  he  proves,  from  the 
 fundamental  principles  of  his  philosophy,  that  she 
 cannot.  The  perplexity  arises  from  the  position  we 
 occupy.  If  we  were  without,  instead  of  within  the 
 circle  she  describes  in  the  heavens,  there  could  be  no 
 misconception.  The  inhabitants  of  the  other  planets 
 see,  in  succession,  all  parts  of  her  circumference.  In 
 the  course  of  twenty-eight  days  they  can  scrutinise 
 every  part  of  her  surface.  For  the  same  reason,  a 
 person,  in  the  centre  of  a  circus,  sees  only  one  side  of 
 the  horse  galloping  round  the  circumference,  while  the 
 spectators  beyond  see  both  sides  in  succession. 
 
 Until  lately,  no  conjecture  could  be  formed  of  the 
 state  of  things  on  the  other  side  of  the  moon.  It  was 
 regarded  as  one  of  those  inscrutable  mysteries  which 
 it  would  be  folly  to  attempt  to  unveil.  Human  genius 
 has  triumphed  over  the  difficulty,  and  has  thrown  a 
 curious  light  on  that  which  has  hitherto  been  in- 
 volved in  deepest  darkness.  And,  in  such  cases,  one 
 feels  at  a  loss  which  to  admire  most — the  wonders 
 of  God's  works,  or  the  genius  with  which  He  has 
 endowed  man  to  explore  these  works.  It  is  to  M. 
 Hansen  that  the  credit  of  the  discovery  is  due.  Mr 
 Airy,  the  Astronomer-Royal,  supplied  him,  no  doubt, 
 
V 
 
 42      THE  MOON'S  INVISIBLE  SIDE. 
 
 with  the  data,  but  the  merit  of  the  solution  is  all  his 
 own.  The  Astronomer-Eojal  has,  as  it  were,  dug  up 
 from  some  Assyrian  mound,  a  tablet  with  mystic 
 cuneiform  characters,  and  M.  Hansen  has  supplied  the 
 key  to  the  interpretation.  The  moon  is  so  eagerly 
 scrutinised  at  Greenwich,  that  any  deviation  from  the 
 prescribed  path  is  soon  detected.  M.  Hansen  had 
 already,  on  more  than  one  occasion,  vindicated  the 
 law  of  gravitation,  by  reducing  unexplained  lunar  ir- 
 regularities to  its  dominion.  When  again  applied  to, 
 he  set  to  work  to  discover  the  cause  of  the  irregularity. 
 The  deviation  was  slight,  but  if  the  moon  does  not 
 keep  time  to  a  very  second,  some  explanation  is  re- 
 quired ;  and,  on  this,  as  on  all  former  occasions,  M. 
 Hansen  was  triumphant.  He  has  given  a  most  mar- 
 vellous solution,  but  one  in  which  all  astronomers 
 have  acquiesced. 
 
 The  scientific  statement  of  the  solution  is,  that 
 the  moon's  centre  of  gravity  and  her  centre  of  figure 
 are  not  coincident,  the  one  being  distant  about  37 
 miles  from  the  other.  Most  momentous  results  flow 
 from  this.  The  one  hemisphere  must  be  lighter 
 than  the  other.  This,  indeed,  is  but  another  way  of 
 stating  the  discovery.  The  sphere  of  the  moon  may 
 be  regarded  as  made  up  of  a  light  half  and  a  heavy 
 one — the  lighter  being  always  turned  towards  the 
 earth. 
 
 But  how  could  such  a  strange  discovery  be  made  ? 
 It  would  not  be  easy  to  give  a  popular  explanation  of 
 
THE  MOON'S  INVISIBLE  SIDE.     43 
 
 the  mathematical  process  by  which  M.  Hansen  arrived 
 at  this  result,  but  there  is  no  difficulty  in  understand- 
 ing the  general  principles  on  which  it  is  founded.  In 
 discharging  a  ball  from  a  gun,  calculation  can  predict 
 che  trajectory  it  will  describe.  But  if  the  ball  is  not 
 equally  dense  on  opposite  sides,  it  will  not  pursue  the 
 same  path  it  would  do  if  homogeneous.  Let  us 
 suppose,  that  while  the  ball  is  perfectly  spherical,  one 
 half  is  iron  and  the  other  cork,  the  curve  described 
 will  be  different,  both  in  range  and  form,  from  that 
 which  would  be  described  by  a  ball  equally  dense 
 throughout.  Balls  have  been,  indeed,  purposely 
 so  cast,  to  increase  the  range  —  the  sphere  being 
 hollow,  but  having  one  side  thicker  than  the 
 other.  Given  the  difference  of  density,  the  curve  can 
 be  laid  down,  and  given  the  curve,  the  difference  of 
 density  can  be  determined.  This  last  case  is  that  of 
 the  moon.  It  differs  in  no  respect  from  a  ball  dis- 
 charged from  a  gun,  and,  in  examining  the  curve  it 
 describes,  the  conclusion  is,  that  while  she  is  quite  or 
 nearly  splierical,  the  hemisphere,  tiurned  towards  us, 
 is  lighter  than  the  opposite  one. 
 
 But  how  does  this  tell  on  the  question  of  inhabit- 
 ants? The  application  is  very  direct  and  startling. 
 Supposing  the  sphere  of  the  moon  originally  covered 
 with  water,  and  enveloped  in  an  atmosphere,  both 
 water  and  air  would  flow  to  the  heavier  side,  and  leave 
 i;  the  lighter  side  destitute  of  both,  just  as  water  and  air 
 leave  the  summits  of  our  mountains,  and  gravitate 
 
44      THE  MOON'S  INVISIBLE  SIDE. 
 
 towards  the  valleys.  They  seek  the  lowest  level,  or, 
 in  other  words,  the  point  least  distant  from  the  centre 
 of  gravity. 
 
 In  the  case  of  the  moon,  the  side  turned  to  us  is 
 virtually  one  enormous  mountain,  and  the  opposite 
 side  the  corresponding  valley.  We  could  not  expect 
 to  find  traces  of  air  on  the  summit  of  a  terrestrial 
 mountain  134  miles  high.  The  conclusion,  therefore, 
 is,  that  though  the  near  hemisphere  is  a  lifeless  desert, 
 having  neither  water  nor  air  to  sustain  life,  the  hidden 
 hemisphere  may  have  a  teeming  population,  rejoicing 
 in  all  the  comforts  and  amenities  of  life.  The  imagina- 
 tion is  set  free  to  picture  broad  oceans,  bearing  on 
 their  bosom  the  commerce  of  this  new  world,  rivers 
 fertilising  the  valleys  through  which  they  flow,  a 
 luxuriant  vegetation,  and  buildings  of  colossal  size. 
 
 This,  however,  only  increases  the  mystery,  and  the 
 longing  to  see  farther  round  the  limb  of  the  moon. 
 If  there  was  mystery  before,  when  life  was  not  dreamt 
 of,  how  much  is  that  mystery  increased,  when  we 
 now  know  that  there  may  be  life — that  there  may  be 
 another  world  the  counterpart  of  our  own!  Every- 
 thing on  this  side  of  the  moon,  is  fixed  in  the  rigidity 
 of  death.  No  movement,  indicating  life  or  action,  is 
 observed.  How  different  would  be  the  other  side, 
 were  we  only  permitted  to  obtain  a  glimpse!  Its 
 ever-changing  atmosphere  would  be  a  source  of 
 continual  interest.  We  could  study  its  weather,  as 
 easily  as  our  own ;  and,  if  the  atmosphere  was  not 
 
THE  MOON'S  INVISIBLE  SIDE.     45 
 
 too  dense,  we  could  watch  tlie  progress  of  agri- 
 culture, and  the  growth  of  cities.  If  it  is  a  world  of 
 strife,  we  could  distinguish,  on  the  battle-field,  the 
 colour  of  the  uniforms  of  the  opposing  masses.  All 
 this  could  be  accomplished  by  our  present  optical 
 means;  and,  as  our  powers  of  vision  increased,  we 
 could  descend  to  the  minuter  details  of  life.  We 
 could  readily  conceive  a  code  of  signals  by  which 
 telegraphic  communication  might  be  carried  on  be- 
 tween us  and  our  lunar  neighbours.  The  moon, 
 however,  sternly  withholds  from  us  her  great  secret, 
 and  for  ever  turns  from  us  her  hidden  hemisphere. 
 
 Granting  that  the  other  side  of  the  moon  is  peo- 
 pled, can  our  world  be  ever  known  to  the  inhabitants, 
 seeing  that  only  the  lighter  side  is  turned  toward 
 us?     It  is  plain  that  the  inhabitants,  if  they  keep 
 to  their  own  side,  can  never  get  a  glimpse  of  the 
 earth.      If  there  is  an   atmosphere,  it   is   probable 
 that  it  may  extend  a  small  way  within  the  visible 
 side,  though  in  a  rarefied  form.     We  can  then  con- 
 ceive the  intrepid  lunar  inhabitants  venturing,  as  far 
 as  they  can  breathe,  within  the  barren  hemisphere; 
 just  like  adventurous  travellers  on  our  globe,  scaling 
 lofty  mountains,  to  obtain  an  extended  view  of  the 
 landscape.      What   an    astonishing   spectacle  must 
 burst  upon  the  view  of  the  lunar  tourist,  as  soon  as  he 
 fairly  gets  within  the  new  hemisphere!     The  tra- 
 veller, who  has  spent  the  night  on  the  summit  of  the 
 Rigi,  to  watch  the  rising  of  the  sun  over  the  snow- 
 
46      THE  MOON'S  INVISIBLE  SIDE. 
 
 clad  ranges  of  the  Oberland  Alps,  feels  rewarded  for 
 all  his  toil  by  the  glorious  spectacle.  The  explorer  of 
 the  southern  hemisphere,  when  he  first  beholds  the 
 southern  cross  and  the  Magellanic  clouds,  experiences 
 no  ordinary  delight  at  having  ushered  into  view  a  new 
 portion  of  God's  universe.  But  these  illustrations 
 can,  but  imperfectly,  enable  us  to  realise  the  case  of 
 the  lunar  traveller,  when  he  first  beholds  the  earth. 
 He  will  see  an  immense  blue  orb  hung  up,  immovably 
 fixed,  in  the  heavens.  It  will  appear  to  him  fourteen 
 times  larger  than  the  moon  appears  to  us.  The  sun 
 will  be  seen,  as  in  the  other  lunar  hemisphere,  to  rise 
 in  one  horizon,  and  in  fourteen  days  set,  in  the  op- 
 posite ;  but  the  earth  never  moves.  The  stars  at  mid- 
 day, as  well  as  at  midnight,  will  appear  to  pass 
 behind  its  disc,  while  it  maintains  the  same  position. 
 But  though  immovably  fixed  in  the  heavens,  won- 
 drous activities  will  be  discovered.  It  will  exhibit 
 in  twenty-eight  days  all  the  phases  of  the  moon — 
 now  a  thin  crescent,  then  a  full  orb.  Its  rapid 
 rotation  will,  also,  be  a  most  notable  object,  for,  in  so 
 large  an  orb,  the  twenty-four-hours'  period  will  be 
 most  marked.  And  then  the  blue  atmosphere  will 
 be  undergoing  incessant  changes.  Belts,  corre- 
 sponding to  the  trade-winds,  will  be  seen,  and  through- 
 out the  whole  extent,  the  varying  clim^ates  of  the 
 world  will  be  observable.  Though  objects  on  the 
 surface  of  the  earth  will  be  but  dimly  descried,  still 
 our  seas,  continents,  and  mountain-ranges  may  be 
 
THE  MOON'S  INVISIBLE  SIDE.     47 
 
 distinguished.  What  a  tale  of  wonder  will  the 
 traveller  have  to  tell^  when,  after  his  perilous  ad- 
 ventures, he  returns  to  the  bosom  of  his  family ! 
 
 It  is  obvious,  that  the  results  of  M.  Hansen  furnish 
 no  positive  evidence  for  the  existence  of  lunar  in- 
 habitants. It  is  valuable  to  the  advocate  of  a  plu- 
 rality of  worlds,  only  in  as  far  as  it  enables  him  to 
 rebut  the  argument  of  his  antagonist,  when  he  points 
 to  the  moon  as  a  proof  that  his  speculations  are  only 
 a  dream.  He  can  now  maintain,  that  if  we  knew 
 all,  we  would  find  that  the  moon  is  not  destitute  of 
 life. 
 
 While  we  write  (1860),  tidings  are  brought  of  the 
 discovery  of  a  new  planet,  and  a  new  difficulty  for  the 
 advocate  of  planetary  inhabitants.  Strange,  that  with 
 so  many  professional  eyes  gazing  day  after  day  at  the 
 spots  on  the  sun,  it  should  be  left  to  a  provincial  doctor 
 in  France,  with  the  rudest  instruments,  to  make  the 
 discovery  of  the  little  black  pellet-like  spot,  which,  by 
 its  form  and  rapid  motion,  indicated  the  transit  of  a 
 new  planet  within  the  orbit  of  Mercury.  The  honour, 
 after  all,  does  not  fall  to  the  man  of  keen  eyes,  who 
 detected  this  spot  accidentally,  but  to  the  master-mind, 
 who,  by  a  finer  sense,  detected  its  existence,  months 
 before  the  results  of  observation  were  made  known. 
 Leverrier,  in  this  case,  as  in  that  of  the  planet  Neptune, 
 was  the  intellectual  seer. 
 
Eratosthenes. 
 
 IV. 
 
 LUNAR  LANDSCAPE. 
 
 Paley  holds  that  astronomy  does  not  afford  such 
 striking  proofs  of  a  Divine  intelligence,  as  the  won- 
 derful adaptation  of  means  to  ends  presented  every- 
 where in  the  animal  and  vegetable  kingdoms ;  but 
 that,  a  Divine  intelligence  being  granted,  no  field 
 presents  such  impressive  views  of  the  grandeur  and 
 power  of  God.  Every  one  must  feel  the  force  of  this 
 observation  when,  in  thought,  he  wanders  over  the 
 
LUNAR  LANDSCAPE,  49 
 
 barren  surface  of  the  moon,  and  fails  to  discover  such 
 proofs  of  design  as  are  abundantly  strewn  over  the 
 surface  of  our  glohe. 
 
 It  is  the  fact  of  life  that  furnishes  those  innumer- 
 able adaptations,  which  irresistibly  impress  the  mind 
 with  a  superintending  intelligence,  and  raise  the 
 devout  heart  to  the  contemplation  of  Him  who  made 
 and  ruleth  over  all.  Did  we  find  life  in  the  moon, 
 we  would,  at  the  same  time,  find  inexhaustible  and 
 novel  illustrations  of  a  designing  mind.  On  our 
 globe  everything  is  delicately  adjusted  to  the  cosmi- 
 cal  laws  that  have  sway  over  it  as  a  member  of  the 
 solar  system.  The  very  curve  of  the  snowdrop,  as 
 it  bends  its  head,  is  regulated  by  the  attractive  power 
 of  the  globe.  The  flower  could  not  thrive  in  a  world 
 which  attracted  more  or  less.  A  slight  change  in  the 
 constitution  of  the  atmosphere,  or  in  the  alternation 
 of  night  and  day,  would  be  fatal  to  many  forms  of 
 life.  Did  a  comet  come  into  collision  with  our  earth, 
 so  as  to  change  its  axis,  new  conditions,  wholly  de- 
 structive to  a  wide  range  of  animal  and  vegetable  life, 
 would  be  introduced.  If  life  exists  in  the  moon, 
 there  must  be  special  adaptations  corresponding  to  its 
 physical  constitution.  The  fact  that  bodies  are  nearly 
 six  times  lighter  in  the  moon  than  on  the  earth,  would 
 admit  of  their  being  on  a  much  more  colossal  scale. 
 Trees,  for  example,  on  our  globe,  throw  out  their 
 branches  timidly,  lest  they  break  with  their  own 
 weight.      They  carefully  keep  within  the  breaking 
 
50  LUNAR  LANDSCAPE, 
 
 point,  and  so  nicely  is  this  adjusted,  that  when,  from 
 any  extraneous  cause,  they  become  overloaded,  they  ^ 
 are  apt  to  come  away  with  a  crash ;  as  in  the  case  of 
 the  ancient  forest  in  Italy,  which,  recently,  had  every 
 tree  stripped  of  its  branches  by  the  ice  with  which 
 they  were  weighted.    A  slight  wind  was  all  that  was 
 necessary  to  convert  into  bare  poles  the  stately  trees 
 of  a  forest,  that  claimed  a  classic  antiquity.    A  strik- 
 ing illustration  of  the  same  thing,  is  seen  at  the  Falls 
 of  Niagara.     The  spray  incrusts  with  ice  the  branches 
 of  the  trees  in  the  neighbourhood,  so  that  if  they 
 extend  beyond  a  certain  point,  they  are  broken  off. 
 This  accounts  for  their  bare  and  stunted  appearance. 
 In  the  moon,  however,  trees  could  safely  throw  out 
 their  branches  to  a  much  greater  extent,  simply  for 
 the  reason  that  they  are  so  much  lighter.     It  is  a 
 great  feat  in  architecture,  to  construct  a  spire  or  fac- 
 tory chimney  a  few  hundred  feet  high  ;  and  when  such 
 structures  exceed  a  certain  height,  there  is  danger 
 of  their  toppling  over,  or  of  being  crushed  by  their 
 own  weight.     But  in  the  moon,  the  colossal  chimneys 
 of   our    manufacturing  towns,  would    be   altogether 
 dwarfed,  standing,  side  by  side,  with  the  chimneys  of 
 the  lunar  factories.     Then,  as  to  the  alternation  of 
 day  and  night,  how  singularly  constituted  must  the 
 forms  of  life  be,   to  bear  a  fortnight  of  unmitigated 
 sunshine,  and  then  a  long  dreary  night  of  similar 
 length.     Scorching  is  avoided,  on  our  globe,  by  our 
 turning  away  from  the  central  fire  after  twelve  hours' 
 
LUNAR  LANDSCAPE.  51 
 
 exposure.  During  the  night  we  are  agreeably  cooled, 
 and  prepared  once  more  to  hail  the  genial  light  and 
 heat  of  the  sun.  But  were  our  summer  days  doubled 
 in  length,  the  heat  would  be  intolerable,  and  all 
 things  would  languish  and  die.  How  widely  different 
 must  animal  and  vegetable  life  be  in  the  moon,  to 
 bear  the  long  scorching  of  a  day,  equal  to  fourteen  of 
 the  earth's  days.  Did  we  discover  living  creatures 
 adapted  to  these  and  the  other  strange  conditions 
 existing  in  the  moon,  we,  no  doubt,  would  be  filled 
 with  adoring  wonder  at  such  manifestations  of  God's 
 wisdom  and  goodness. 
 
 But  is  the  survey  of  the  moon's  surface  devoid  of 
 interest,  and  does  it  fail  to  point  to  a  Divine  intelli- 
 gence, because  we  can  discover  none  of  these  special 
 adaptations  that  so  abound  on  the  surface  of  our  globe? 
 Paley  would  answer  that  it  is  barren  in  theological 
 results,  and  that,  unless  we  can  establish  a  use^  we 
 cannot  turn  that  strangely-diversified  surface  to  any 
 account,  as  proving  a  Divine  intelligence.  Natural 
 theology  has  made  an  advance  since  Paley' s  time, 
 inasmuch  as  it  more  fully  recognises  as  proofs  of  intel- 
 ligence, order,  symmetry,  arrangement,  type,  as  well 
 as  the  adaptation  of  means  to  special  ends.  It  is  not 
 necessary  to  prove  a  use  in  order  to  recognise  intelli- 
 gence. It  is  very  much  the  fashion,  at  the  present 
 day,  to  disparage  the  argument  of  Paley,  and  to  re- 
 solve all  into  mere  order.  But  it  is  by  no  means 
 necessary  to  do  this,  so  that  we  may  be  able  to  recog- 
 
52  LUNAR  LANDSCAPE. 
 
 nise  mere  order  as  a  proof  of  intelligence.  Paley'a 
 argument,  as  to  special  ends,  will  ever  retain  its  dis- 
 tinct, substantive  character,  while  it,  in  no  degree, 
 interferes  with  the  argument  from  mere  order  or 
 arrangement. 
 
 The  necessity  of  extending  the  argument  beyond 
 that  of  mere  use  was  seen,  when  there  were  found,  in 
 the  animal  structure,  parts  which  appeared  to  serve  no 
 purpose,  but  were  there  merely  as  indicating  a  general 
 pattern,  after  which  the  class  was  constructed.  In 
 vertebrate  animals,  there  is  discoverable  a  general  type, 
 amidst  the  infinite  diversity  of  form.  There  are  un- 
 developed limbs  which  are  of  no  use  to  the  particular 
 animal  in  which  they  are  found,  but  which  point  to  a 
 Divine  intelligence  by  indicating  the  fact,  that  all 
 vertebrate  animals  were  constructed  after  the  same 
 general  pattern.  Owen  imagines  that  we  have  not, 
 in  this  globe,  all  the  diversities  of  which  this  general 
 pattern  or  archetype  is  susceptible,  and  that  limbs, 
 which  are  found  only  in  an  undeveloped  state  in  this 
 world,  may  be  fully  developed  in  the  other  planetary 
 bodies. 
 
 We  have  not  been  able  to  discover  any  living 
 forms  in  the  moon,  and  we  cannot,  therefore,  say 
 whether  the  pattern  that  prevails  here  is  also  the 
 lunar  model.  We  can,  however,  detect  on  the  sur- 
 face of  the  moon  a  configuration  that  conforms  to  the 
 plan  on  which  the  earth's  surface  is  modelled.  We 
 have  undeveloped  forms  on  our  earth,  which  we  find 
 
LUNAR  LANDSCAPE.  53 
 
 fully  developed  in  the  moon.  There  are  terrestrial 
 configurations,  the  meaning  of  which  we  could  not 
 understand,  without  studying  the  lunar  analogues. 
 
 It  is  to  German  thought  that  we  owe  very  much 
 of  those  generalisations,  which  have  resulted  in  the 
 recognition  of  typical  forms  in  nature.  It  appears 
 very  marvellous  that  men,  possessed  of  very  limited 
 acquaintance  with  science,  and  often  grossly  ignorant 
 of  its  simplest  truths,  should,  as  if  by  inspiration, 
 obtain  glimpses  of  general  laws,  which  have  escaped 
 the  scrutiny  of  the  most  diligent  collectors  of  facts. 
 Oken  records  the  very  hour  when,  reclining  on  a 
 green  sloping  bank,  and  gazing  on  the  bleached 
 skull  of  a  deer,  the  truth  suddenly  flashed  upon  him, 
 that  the  bones  of  the  cranium  were  only  the  repetition 
 of  the  vertebrae ;  and  this  momentary  inspiration  revo- 
 lutionised the  science  of  anatomy.  But  there  is  another 
 remarkable  anticipation  of  the  same  philosopher,  for 
 which,  as  far  as  we  know,  he  has  not  yet  got  credit. 
 He  declared  that  the  planets  and  the  sun  were  mutu- 
 ally polar,  and  that  this  held  also  in  the  case  of  satel- 
 lites and  their  primaries.  He  gives  no  intelligible 
 reasons  for  holding  that  the  sun  and  moon  are  mag- 
 nets ;  but  quite  recent  investigations  have  proved  the 
 correctness  of  the  oracular  dictum  of  this  German 
 dreamer.  He  died  long  before  this  verification ;  but, 
 probably,  such  testimony  would  have  moved  him  little, 
 as  his  own  transcendental  grounds  of  belief  were  far 
 more  satisfactory  to  his  mind,  than  the  empirical  in- 
 
54  LUNAR  LANDSCAPE. 
 
 ductions  of  science.  It  was  also  a  favourite  idea  of 
 Oken,  that  the  earth  is  a  great  crystal,  and  that  the 
 moon  also  partakes  of  this  character.  Science  has,  as 
 yet,  thrown  no  light  on  Oken's  meaning.  Possibly 
 all  that  he  means  by  a  crystal  is,  that  it  is  the  symbol 
 of  form,  apart  from  organic  structm-e.  The  notion  of 
 a  crystal  has  been  adopted  by  most  of  the  German 
 cultivators  of  science  from  the  ideal  side.  Thus 
 Hegel  holds  that  the  moon  is  a  "  material  crystallisa- 
 tion, without  atmosphere,  and  without  formative  pro- 
 cesses." He  defines  a  crystal  to  be  a  "mute  life." 
 Again,  speaking  of  crystalline  form,  he  says,  "It  is 
 the  silent  geometer  in  the  interior  of  the  body,  which, 
 independently  of  external  impulse,  organises  it  within 
 and  without."  By  the  "  silent  geometer,"  the  Chris- 
 tian means  the  Divine  intelligence  which  shapes  it 
 into  symmetry  and  beauty.  And,  though  we  can 
 discover  no  organic  forms  in  the  moon,  yet  the  foot- 
 steps of  the  Creator  can  be  detected.  Viewing  the 
 moon  as  an  individual  crystal,  we  can  detect  sym- 
 metry, and  as  one  of  a  group,  we  can  recognise  type. 
 But,  leaving  these  abstract  views,  let  us  now  deal 
 with  the  reality. 
 
 When  you  first  view  the  moon  through  a  telescope, 
 even  though  it  be  an  excellent  one,  you  can  hardly 
 fail  to  be  disappointed.  No  doubt,  the  surface  of  the 
 moon  will  excite  surprise  by  its  curious  and  novel 
 aspect,  but  it  will  fail  to  give  you  any  idea  of  magni- 
 tude.    You  may  tell  the  beholder  that  the  little  specks 
 
LUNAR  LANDSCAPE.  55 
 
 of  light  he  sees  at  the  edge,  are  mountains  higher  than 
 Mont  Blanc,  hut  he  has  no  feeling  of  the  reality. 
 And  many  a  one  who  looks  through  a  telescope, 
 comes  away  as  incredulous  as  ever.  The  objects 
 descried  through  the  telescope  are  not  seen  to  be 
 mountains.  It  is  only  by  a  process  of  thought,  that 
 the  mind  is  convinced  that  they  are  mountains.  The 
 maps  in  relief,  hung  up  in  the  hotels  in  Switzerland, 
 though  faithful  models  of  the  Alps,  do  not  convey  the 
 impression  of  magnitude.  Even  the  gigantic  model 
 in  the  library  of  Zurich,  with  its  glass  lakes,  fails  to 
 give  you  this  impression.  But  look  through  the 
 library  windows  at  the  actual  mountains  before  you, 
 and  you  fully  realise  the  magnitude,  even  though  the 
 picture  on  the  retina  is  larger,  in  the  case  of  the  model, 
 than  in  that  of  the  actual  mountains.  Now,  the  per- 
 spective we  have  of  the  moon  is  such  that  it  produces 
 only  the  effect  of  a  model,  and,  when  looking  through 
 a  telescope,  we  have  the  same  difficulty  in  transmut- 
 ing the  stucco-like  prominences  into  mountains,  as  we 
 would  have  in  converting  the  hotel  model  into  a  real 
 Alpine  range. 
 
 We  must  call  in  the  aid  of  imagination,  before  the 
 landscape  of  the  moon  can  stand  out  before  us  with 
 the  reality  of  a  terrestrial  scene.  Let  the  reader  join 
 us  in  a  lunar  excursion,  and  we  shall  endeavour  to 
 trace  out  the  points  of  resemblance  and  contrast  in 
 the  scenery  of  the  earth  and  moon.  Let  us  wing  our 
 flight  from  this  globe  and  mark  the  changes  in  the 
 
56  LUNAR  LANDSCAPE. 
 
 aspect  of  the  moon  as  we  gradually  approacli.  We 
 are  soon  able  to  discover  a  diversity  of  colour.  From 
 the  earth's  surface,  the  blaze  of  light  obliterates  the 
 differences  of  colour,  so  that  only  variety  of  shade  can 
 be  discerned ;  but  as  we  approach,  things  assume  the 
 aspect  of  real  mountains,  valleys,  and  plains.  We 
 soon  discover  that  the  dark  parts  in  the  moon,  which 
 fancy  shapes  into  the  eyes,  nose,  and  mouth  of  the 
 face-in-the-moon,  are  vast  plains.  They  are  not, 
 now,  imiformly  dark,  for  one  region  assumes  the  as- 
 pect of  ploughed  fields,  another  that  of  a  vast  savannah. 
 The  district  known  as  the  Sea  of  Serenity,  and  cor- 
 responding to  the  left  eye  of  the  face,  has  a  rich  green, 
 as  if  clothed  with  luxuriant  grass,  or  covered  with 
 vast  forests  of  pine.  We  shall  not  alight  upon  the 
 forest,  but  shall  choose  rather  the  Sea  of  Showers — 
 the  darkest  part  of  the  moon's  surface,  and  corre- 
 sponding to  the  right  eye.  We  find  here  good  foot- 
 ing, for  it  is  neither  a  forest  nor  a  sea.  For  hundreds 
 of  miles  on  all  sides  there  is  a  dead  flat.  Here  and 
 there,  solitary  peaks,  like  that  of  Teneriffe,  start  from 
 the  plain,  unconnected  with  any  mountain-range. 
 They  rise  from  the  vast  prairie,  as  abruptly  as  the 
 pyramids  do  from  the  sands  of  Egypt. 
 
 But  as  we  travel  on,  we  descry  mountain-ranges 
 rising  in  the  horizon.  Before  alighting  on  the  moon, 
 we  could  distinctly  note  the  contour  of  these  ranges. 
 While  some  stretched  for  hundreds  of  miles  in  nearly 
 straight  lines,  there  were  others,  and  these  the  most 
 
LUNAR  LANDSCAPE.  57 
 
 numerouSj  that  formed  a  vast  circle.  We  shall  make 
 for  one  of  the  most  regular  of  this  last  class,  viz., 
 Eratosthenes.  But,  before  reaching  the  foot  of  this 
 range,  we  must  pass  over  bright  rays,  radiating  from 
 the  circular  mountain,  Copernicus.  These  rays  are 
 one  of  the  most  marked  features  of  the  moon,  as  seen 
 through  a  telescope.  Oken  speaks  of  mountains  as 
 the  organs  of  a  planet,  and,  certainly,  these  mountains 
 may  not  inaptly  be  represented  by  a  star-fish  with  its 
 diverging  rays.  But  now  we  can  examine  the  mystery, 
 and  we  find  that  the  rays  are  trap-dykes,  rising  little, 
 if  at  all,  above  the  level  of  the  general  surface.  They 
 appear  as  bright  rays  through  the  telescope,  merely 
 because  they  reflect  the  light  better  than  the  rest  of 
 the  plain.  No  mould  or  verdure  has  covered  them 
 up,  as  the  lava  of  Vesuvius  has  been  by  the  vine-clad 
 slopes.  Not  even  does  the  lichen  grow  upon  them, 
 and  hence  they  are  clearly  discernible  from  the  earth. 
 We  can  even  discover  where  one  dyke  cuts  another, 
 and  tell  which  is  the  older  of  the  two.  We  can  thus 
 draw  up  a  chronological  scale  for  the  convulsions  of 
 the  moon.  Some  of  the  rays  are  evidently  superfi- 
 cial streams  of  lava. 
 
 But  let  us  pursue  our  journey  onwards  to  our 
 destination,  Eratosthenes.  This  circular  mountain, 
 or  rather  range  of  mountains,  is  thirty-seven  miles  in 
 diameter ;  and  we  know  its  dimensions  m  ore  accurately 
 than  those  of  the  mountains  of  our  globe.  The  ascent 
 is  by  a  comparatively  easy  slope.     We  do  not  feel 
 
58  LUNAR  LANDSCAPE. 
 
 the  want  of  mules,  for  we  combine  the  strength  of  a 
 man  with  the  weight  of  a  child.  We  can  bound  from 
 rock  to  rock  more  lightly  than  the  chamois,  and  can 
 leap  across  chasms  six  times  broader,  than  any  we 
 could  venture  to  take  on  the  surface  of  the  earth. 
 Were  it  not  for  this  convenient  lightness,  the  task 
 would  be  impracticable.  The  rocks  have  all  their 
 natural  angularity.  There  has  been  no  weathering 
 to  mitigate  the  roughness;  and  chasms  and  sharp 
 peaks  face  us  at  every  turn.  We  at  last  gain  the 
 summit,  7500  feet  above  the  plain  outside.  An 
 astounding  spectacle  presents  itself,  when  we  view  the 
 interior  of  this  vast  volcanic  crater.  The  rise  on  the 
 outside  of  the  rim  is  gradual,  but  in  the  inside  it  is 
 almost  perpendicular.  As  we  cautiously  creep  to  the 
 edge,  we  see  plumb  down  15,800  feet,  which  is  about 
 the  height  of  Mont  Blanc  above  the  sea.  Let  us  take 
 a  stone — a  large  block  can  easily  be  lifted — and  drop 
 it  over.  How  long  it  hovers  in  the  air !  It  descends 
 so  slowly — six  times  slower  than  upon  the  earth — 
 and  it  has  so  far  to  descend.  Did  we  listen  ever  sc 
 long,  we  would  hear  no  reverberation  from  that  pro- 
 found depth.  In  many  places  around  this  circular 
 mountain  wall,  there  are  traces  of  terraces.  In  fact, 
 the  whole  is  a  vast  amphitheatre  seated  with  terraces. 
 In  the  centre  of  this  crater  a  mountain  rises  many 
 thousand  feet  in  height.  Let  us  transport  ourselves 
 to  the  summit;  and,  as  you  look  around,  you  find 
 yourself  imprisoned   within    a   perpendicular   wall, 
 
1 
 
 / 
 
 •% 
 
LUNAR  LANDSCAPE.  59. 
 
 15,800  feet  in  height,  and  eighteen  miles  distant  on 
 all  sides,  with  no  possibility  of  egress.  There  is  no 
 gap  in  the  wall,  no  outlet  by  which  you  may  escape. 
 On  the  summit  of  the  central  cone  on  which  you 
 stand,  there  is  a  lesser  cavity,  through  which  the  ashes 
 and  lava,  of  which  the  cone  consists,  were  ejected. 
 But  all  activity  is  past,  and  eternal  silence  reigns. 
 You  stand  on  volcanic  ashes,  but  you  do  not  suffer 
 the  inconvenience  of  ascending  the  cone  of  Vesuvius. 
 Thanks  to  the  weak  attraction  of  the  moon,  you  can 
 tread  on  the  treacherous  slope  without  sinking. 
 
 Now  this  singular  formation  is  not  singular  in  the 
 moon.  It  is  the  grand  feature  of  the  lunar  surface. 
 That  surface  is  divided  into  the  dark  plains  and  the 
 "bright  alpine  regions,  and,  in  the  latter,  the  grand 
 characteristic  is  the  circular  form  with  the  central 
 cone.  These  craters  are  of  various  dimensions.  Some 
 are  fifty  or  sixty  miles  across,  others  are  only  a  few 
 hundred  yards.  Now,  do  we  find  anything  corre- 
 sponding to  this  on  the  earth  ?  It  is  plain  that  our  ac- 
 tive volcanoes  only  feebly  represent  the  lunar  craters. 
 The  volcanic  apertures  on  the  earth  are  only  small 
 craters  at  the  top  of  volcanic  mountains  of  no  great 
 dimensions,  such  as  Vesuvius.  The  terrestrial  approxi- 
 mations to  the  typical  form  are  only  like  the  unde- 
 veloped limbs  of  animals,  pointing  to  the  more  per- 
 fect. Among  the  older  formations,  however,  we  find 
 indications  of  the  lunar  circularity.  In  Auvergne, 
 for  example,  there  are  some  illustrations,  and  probably, 
 
60  LUNAR  LANDSCAPE. 
 
 at  one  time,  they  might  have  been  very  numerous. 
 Successive  upheavals,  however,  and  various  denuding 
 influences  have  obliterated  the  distinctive  features, 
 and  it  is  only,  in  a  few  cases,  that  we  can  trace  the 
 typical  form.  Monte  Yenere,  at  Eome,  presents  a 
 very  fair  specimen,  being  the  central  cone  of  a  large 
 crater. 
 
 As  in  the  morphology  of  plants,  we  detect,  amidst 
 diversity,  the  same  typical  form  of  the  leaf,  so  Tve  find 
 in  the  moon  endless  repetitions  of  the  typical  crater 
 with  the  central  cone.  There  are,  for  example,  walled 
 plains  of  vast  extent,  some  of  them  being  as  much  as 
 150  miles  in  diameter.  They  differ  from  the  typical 
 crater  only  in  this,  that  the  enclosed  part  is  a  plain^ 
 instead  of  a  concavity,  and  that  there  is  no  central 
 peak.  Again,  extensive  ranges  of  mountains  assume 
 a  semicircular  form,  and  when  the  vast  dark  plains 
 were  regarded  as  seas,  these  semicircular  forms  were 
 called  bays  or  gulfs.  But  this  semicircular  form 
 evidently  points  to  the  circular  typical  form.  Again, 
 some  of  the  craters  are  without  any  walls  or  rims, 
 and,  in  others,  the  floor  of  the  crater  is  convex,  though, 
 in  all  cases,  it  is  sunk  below  the  level  of  the  surround- 
 ing country.  But  it  is  not  merely  the  more  prominent 
 features  that  conform  to  the  crater  type.  On  minute 
 inspection,  we  find  that  the  whole  surface  has  a  crateri- 
 form  structure.  When  you  take  a  large  crystal  of 
 calc  spar,  and  break  it  into  numerous  pieces,  you  find 
 that  the  large  rhomboid  is  made  up  of  innumerable 
 
LUNAR  LANDSCAPE.  6i 
 
 small  ones.  So,  in  the  case  of  tlie  lunar  craters,  you 
 find  the  large  ones  studded  over  with  small  ones,  and 
 these,  againj  have  craters  of  a  third  order  of  smallness. 
 If  you  throw  successive  handfuls  of  pebbles  into  a 
 pond,  you  will  see,  at  the  same  time,  circles  inter- 
 lacing with  one  another,  and  smaller  ones  diversifying, 
 in  every  imaginable  way,  the  larger  ones.  Precisely 
 such  a  spectacle  is  presented  by  the  structure  of  the 
 moon.  Theories  of  volcanic  action  have  been  pro- 
 posed to  explain  all  this ;  but  we  cannot  linger  longer 
 on  the  summit  of  the  central  peak,  and  as  there  is  no 
 other  mode  of  egress,  we  shall  take  an  imaginary 
 flight  over  the  encircling  wall,  and  again  alight  on 
 the  vast  savannah  from  which  we  ascended. 
 
 We  studiously  avoided  making  any  remarks  upon 
 the  nature  of  this  surface  when  we  previously  passed 
 over  it,  as  we  could  really  offer  no  plausible  account 
 of  it.  But  so  rapid  is  the  advance  of  science,  even  in 
 the  department  of  astronomy,  that,  in  the  interval 
 between  the  ascent  and  descent  we  have  learned  that 
 Father  Secchi,  of  the  observatory  at  Rome,  has  made 
 a  curious  discovery  on  the  subject.  Surfaces  reveal 
 their  nature,  to  a  certain  extent,  by  reflecting  certain 
 colours  in  perference  to  others,  but  they  also  give  a 
 clue  to  their  character  by  the  various  ways  in  which 
 they  polarise  light.  Now,  Secchi  has  found  equally 
 polarised  light  in  the  wdiole  smooth,  dark  plains  of 
 the  moon,  whatever  be  the  inclination  of  the  incident 
 and  reflected  rays.      The   only   substance  we   are 
 
62  LUNAR  LANDSCAPE. 
 
 acquainted  witH  that  gives  practically  the  same  re- 
 sultj  is  glass  paper,  used  in  the  arts  for  polishing,  and 
 he  thinks  that  this  may  he  made  to  explain  the  corona 
 encircling  the  moon  in  total  eclipses.  This,  after  all, 
 does  not  give  a  very  definite  notion  of  the  nature  of 
 the  surface,  but  it  dissipates  the  idea  that  Arago  had 
 lately  revived,  that  these  dark  plains  were  really  seas, 
 so  shallow  that  the  unevenness  of  the  bottom  might 
 be  detected  through  the  transparent  water. 
 
 More  recently  Mr  Warren  De  la  Eue  has  been  led 
 to  suspect  that  the  dark  regions  owe  their  darkness 
 to  vegetation.  These  regions  are  much  darker  in  the 
 photograph  than  in  the  moon  itself,  and  he  thinks 
 this  feebleness  of  actinic  action  can  only  be  due  to 
 tlie  foliage,  with  which  the  plains  may  be  clothed.  In 
 the  absence  of  any  other  indications  of  an  atmosphere, 
 this  view  must  be  received  with  caution. 
 
 Let  us  direct  our  steps  to  the  lunar  Alps,  a  very 
 lofty  range  of  mountains  skirting  the  Mare  Imbrium. 
 In  passing  along  the  plain,  we  come  to  interruptions 
 like  the  crevasses  in  a  glacier,  only  they  are  much 
 wider,  m.ore  regularly  formed,  and  of  unfathomable 
 depth.  They  present  exactly  the  appearance  a  trap- 
 dyke  would  do,  if  quarried  out.  These  rents,  or  rills^ 
 as  they  are  termed,  cross  each  other  in  such  a  way  as 
 to  produce  fantastic  forms.  The  first  observers 
 imagined  that  they  were  roads  or  canals.  The  most 
 probable  explanation  is,  that  they  are  rents  in  the 
 moon's  surface;  which  have  never  been  filled  np  with 
 
LUNAR  LANDSCAPE.  63 
 
 lava.  They  correspond  to  the  white  radiating  streams 
 which  we  have  ah'eady  noticed,  and  which  are  univer- 
 sally held  to  be  lava  pushed  up  through  the  rents. 
 We  can  readily  conceive  the  cracking  of  the  surface 
 v/ithout  a  subsequent  filling  up.  The  trap-dykes  in 
 the  crust  of  the  earth,  in  many  cases,  plainly  indicate 
 that  the  lava,  with  which  they  are  filled  up,  was  not 
 the  disruptive  power  by  which  the  rents  were  caused. 
 Besides  the  figures  formed  by  the  rills,  there  are  others 
 of  a  very  striking  character.  These  regular  forma- 
 tions, in  some  instances,  assume  the  shape  of  the  letters 
 of  the  alphabet.  The  letters  Z  and  H  can  readily  be 
 distinguished.  But  the  forms  are  not  restricted  to  the 
 Eoman  character;  the  Chinese  alphabet  furnishes  a 
 pattern  for  some  of  these  strange  figures.  It  does 
 not  require  a  very  vivid  imagination  to  construe  such 
 lusus  naturcB  into  attempts,  on  the  part  of  the  lunar 
 inhabitants,  to  hold  intercourse  with  our  world. 
 Weaker  arguments  have  been  employed  to  prove  the 
 existence  of  intelligence  in  the  moon. 
 
 With  our  newly-acquired  buoyancy,  we  may 
 attempt  to  clear  the  rill,  as  it  is  a  small  one;  and, 
 now  that  we  are  on  the  other  side,  we  pursue  our 
 journey  to  the  base  of  the  Alps,  and  the  first  thing 
 that  strikes  us  is,  that  the  cliffs,  fronting  the  plain, 
 rise,  almost  perpendicularly,  from  the  base.  When, 
 however,  we  go  round,  and  take  them  in  the  rear,  we 
 find  that  the  ascent  is  comparatively  easy.  This  leads 
 us  at  once  to  a  remarkable  analogy.     On  the  surface 
 
64  .  LUNAR  LANDSCAPE. 
 
 of  the  earth,  we  find  that  the  precipitous  sides  of  all 
 great  mountain-ranges  face  the  sea.  The  terrestrial 
 Alps,  for  example,  have  their  steep  side  towards  the 
 Mediterranean.  Those  who  have  crossed  the  Alps 
 by  the  pass  of  the  St  Gothard,  will  remember  the 
 long,  gradual  ascent  from  Fluelen,  through  the  Canton 
 of  Uri,  and  the  sudden  descent  and  terrific  zig-zags 
 down  the  Val  Tremola  to  the  plains  of  Italy.  All 
 the  ranges  in  the  moon  have  their  steep  sides,  in  like 
 manner,  towards  the  so-called  seas.  If  we  cannot 
 admit  that  they  are  seas  now,  is  it  not  probable  that 
 they  may  have  once  been  seas  ?  If  all  our  seas  and 
 oceans  were  drained,  the  surface  of  the  earth  would 
 present  precisely  the  same  spectacle  that  the  moon 
 does.  But  do  we  know  of  any  draining  cause  ?  We 
 have  seen  that  science  has  clearly  established  the  fact, 
 that  if  any  water  existed  on  the  nearest  side  of  the 
 moon,  it  would  necessarily  flow  to  the  other  side. 
 Let  us  only  suppose  that  the  centres  of  figure  and 
 gravity  were  at  one  time  coincident,  that  it  was  in- 
 ternal convulsions,  of  which  we  have  such  numerous 
 proofs,  that,  at  a  subsequent  epoch,  changed  the  centre 
 of  gravity,  and  we  have  at  once  a  cause  adequate  to 
 tlie  effect. 
 
 Short  as  our  survey  has  been,  we  have  seen  enough 
 to  reveal  the  "  silent  Geometer  within  " — the  supreme 
 Intelligence,  who  manifests  His  presence  in  symmetry 
 and  type,  as  well  as  in  the  special  adaptation  of  means 
 to  ends. 
 
Moon  in  Quarter. 
 
 V. 
 
 THE  USES  OF  THE  MOON. 
 
 M.  COMTE,  while  forced  to  admit  that  we  do  derive 
 some  benefit  from  the  moon,  scouts  the  idea  that 
 there  was  any  anterior  design  to  make  it  useful  to  us. 
 His  views  on  the  religious  aspect  are  given  in  the  fol- 
 lowing passage : — "  To  those  who  are  strangers  to  the 
 study  of  the  heavenly  bodies,  although  frequently 
 masters  of  the  other  parts  of  natural  philosophy, 
 astronomy  has  still  the  reputation  of  being  an  emi- 
 
 E 
 
66  THE  USES  OF  THE  MOON. 
 
 nently  religions  science,  as  if  the  famous  verse,  ^  The 
 heavens  declare  the  glory  of  God/  still  preserved  all 
 its  value.  To  minds  early  familiarised  with  true 
 philosophical  astronomy,  the  heavens  declare  no  other 
 glory  than  that  of  Hipparchus,  of  Kepler,  of  New- 
 ton, and  of  all  those  who  have  aided  in  establishing 
 their  laws.  It  is,  however,  certain,  as  I  have  shewn, 
 that  all  real  science  is  in  radical  and  necessary  op- 
 position to  all  theology,  and  this  characteristic  is 
 more  decided  in  astronomy  than  anywhere  else,  just 
 because  astronomy  is,  so  to  speak,  more  a  science 
 than  any  other.  No  other  has  given  more  terrible 
 shocks  to  the  doctrine  of  final  causes,  generally  re- 
 garded by  the  moderns  as  the  indispensable  basis  of 
 every  religious  system,  although,  in  reality,  it  has 
 been  the  consequence  of  them.  The  simple  know- 
 ledge of  the  movement  of  the  earth  must  have 
 destroyed  the  prime  and  real  foundation  of  this  doc- 
 trine— the  idea  of  the  universe  subordinated  to  the 
 earth,  and  consequently  to  man.  Besides,  the  accu- 
 rate exploration  of  our  system  could  not  but  dispel 
 that  blind  and  unlimited  wonder  which  the  general 
 order  of  nature  inspired,  by  shewing,  in  the  most 
 sensible  manner,  and  in  various  respects,  that  the 
 elements  of  this  system  are  certainly  not  d-isjjosed  in 
 the  most  advantageous  manner ^  and  science  permits  us 
 easily  to  conceive  a  Jiappier  arrangement^ 
 
 We  shall  not  stop  to  notice  the  tone  of  arrogant 
 assumption  in  the  statement  that  every  philosophic 
 
THE  USES  OF  THE  MOON.  67 
 
 astronomer  must  be  an  atheist.  We  mean  only  to 
 advert  to  the  argument  here  employed  to  banish  a 
 Divine  Intelligence  from  the  universe.  It  amounts  to 
 this — that,  as  we  can  conceive  a  better  arrangement, 
 there  could  have  been  no  intelligence  in  the  original 
 adjusting  of  the  arrangement.  Let  us  take  the  moon 
 for  illustration.  Laplace  fancied  he  could  improve 
 on  the  solar  system  by  placing  the  moon  differently. 
 He  endeavours  to  shew  that  if  the  purpose  of  the 
 moon  was  to  give  light  to  the  earth,  this  could  be 
 .accomplished  far  more  effectually  if  the  moon  was  so 
 situated  that  it  revolved  round  the  earth  in  the  same 
 time  that  the  earth  revolved  round  the  sun.  In  that 
 case,  she  would  be  always  full,  and  her  light  would 
 be  enjoyed  every  night,  instead  of  only  occasionally. 
 The  conclusion  is,  that  she  was  not  ordained  to  rule 
 the  night,  seeing  that,  by  a  different  arrangement, 
 this  could  be  more  effectually  accomplished.  But 
 with  all  his  skill  in  celestial  mechanics,  Laplace 
 would  not,  by  the  suggested  arrangement,  improve 
 matters.  If  the  moon' s  orbit  were  situated  where  he 
 proposed,  her  light  would  be  sixteen  times  less  than 
 at  present,  and,  what  is  more,  the  arrangement  would 
 not  be  a  stable  one.  The  moon  would  not  only  be 
 at  first  a  very  dim  lamp,  but  it  would  be  in  danger 
 of  going  out  altogether. 
 
 Sir  David  Brewster,  in  maintaining  the  habitable- 
 ness  of  the  moon,  questions  the  doctrine  that  her  use 
 is  to  give  light  to  the  earth  j  and  he  does  this  on  the 
 
68  THE  USES  OF  THE  MOON. 
 
 ground  that  she  would  give  a  much  better  light  if  her 
 surface  was  all  of  a  chalky  whiteness,  and  not  studded 
 over,  as  it  is,  with  dark  spots.  Now,  granting  that 
 there  might  be  a  happier  arrangement,  if  the  use  of 
 the  moon  was  to  give  light — granting  that  it  would 
 be  better  to  have  a  wider  orbit,  and  a  more  uniform 
 disc,  are  we  to  conclude  that  a  use  cannot  be  proved, 
 unless  we  can  shew  that  it  is  the  best  possible  con-  ■ 
 trivance  for  the  use  intended  ?  Let  us  take  the  case 
 of  Paley's  watch  on  the  heath.  Would  the  inference 
 of  design  be  legitimate  only  on  the  supposition  that 
 the  watch  had  the  most  faultless  scapement,  and  the 
 most  artistic  finish?  Would  not  some  rude,  old  crown- 
 and-verge  movement,  dropped  by  some  boor  as  he 
 crossed  the  common,  quite  as  irresistibly  lead  to  the 
 inference  of  design?  And  in  dealing  with  the 
 mechanism  of  the  heavens,  the  real  question  at  issue, 
 is  not  —  Is  the  intelligent  contriver  perfect?  but. 
 Is  there  a  contriver  at  all  ?  No  doubt,  the  ultimate 
 aim  of  the  theist  is  to  prove  a  perfect  intelligence, 
 but  the  first  is  to  prove  that  there  is  an  intelligence 
 — that  the  use  necessarily  implies  a  designing  mind, 
 lie  knows  that  the  atheist  must  be  forced  to  surren- 
 der all,  if  he  admits  that  mind,  in  any  form,  is 
 necessary  to  account  for  material  laws  and  arrange- 
 ments. When  it  is  therefore  held  that  the  design  of 
 the  moon  is  to  give  light,  or  the  eye  to  see,  it  is  not 
 necessary  at  all  to  prove  that  the  moon  is  the  best 
 possible  lamp,  or  the  eye  the  best  possible  lens. 
 
THE  USES  OF  THE  MOON.  69 
 
 But  is  the  atheist  to  be  permitted  to  maintain  his 
 position  that  any  given  arrangement  is  imperfect? 
 Are  we  to  concede  to  Laplace  that  he  can  improve 
 the  mechanism  of  the  solar  system  ?  By  no  means. 
 We  may  not  be  able  to  prove  the  absolute  perfection 
 of  the  arrangement,  but  we  can  shew  the  probability 
 that  the  caviller  is  far  more  likely  to  be  at  fault, 
 than  that  there  should  be  a  defect  in  the  machine. 
 A  skilful  mechanician  may,  on  examining  the  works 
 of  a  watch,  say,  without  presumption,  that  the 
 scapement  is  imperfect,  and  that  he  could  suggest  an 
 improvement ;  and  the  reason  simply  is,  that  the  tools 
 formed  by  man  for  useful  purposes  have  their  object 
 clearly  defined.  It  is  easy  to  see  what  the  one  re- 
 quirement of  a  good  scapement,  for  example,  is,  and 
 there  is  no  presumption  in  suggesting  how  this  one 
 well-defined  object  is  to  be  attained  in  a  more  satis- 
 factory manner.  But  the  instruments  of  nature  are 
 not  like  human  tools.  The  extent  of  their  uses  can- 
 not be  defined.  All  nature  is  one  great  whole  ;  and  it 
 would  require  omniscience  itself  to  say  whether  any 
 given  arrangement  is  the  best  possible  for  the  in- 
 numerable uses  it  may  subserve.  To  give  light  is 
 one  use  of  the  moon,  but  we  know  not  the  many 
 other  uses  it  may  serve.  It  is  not,  however,  neces- 
 sary to  discover  all  these  uses  in  order  to  maintain 
 the  position  that  it  is  ordained  to  give  light,  and  we 
 are  not  entitled  to  criticise  its  efficiency  till  we  know 
 all  its  functions. 
 
 I 
 
70  THE  USES  OF  THE  MOON. 
 
 Although  we  cannot  prove  the  absolute  perfection 
 of  any  contrivance,  yet,  when  increased  research  in- 
 variably discovers  new  points  of  excellence,  we  are 
 warranted  to  conclude  that,  did  we  know  all,  we 
 would  be  forced  to  acknowledge  that  all  is  perfect. 
 We  see  only  a  few  of  the  spokes  of  a  revolving  wheel, 
 and  it  accords  more  with  the  modesty  of  true  science, 
 to  ascribe  the  apparent  imperfection  to  our  point  of 
 view,  than  to  conclude  that  the  circle  is  defective. 
 The  more  we  enlarge  our  view  the  more  complete  does 
 the  circle  become;  and  it  is  but  the  doctrine  of  inductive 
 philosophy  to  conclude,  that  if  our  vision  were  entirely 
 unobstructed,  the  machinery  would  appear  in  all  its 
 perfection.  But  Laplace  and  M.  Comte  would  project 
 their  own  imperfection  on  the  perfect  works  of  God. 
 
 To  appreciate  the  usefulness  of  the  moon  as  a  source 
 of  light,  we  must  view  man  in  his  least  civilised  state. 
 The  refinements  of  civilisation  have,  to  a  great  degree, 
 contracted  the  usefulness  of  the  moon  in  this  respect. 
 City  life,  too,  is  not  favourable  to  a  grateful  spirit  for 
 the  service  of  the  moon.  In  towns  lighted  by  gas, 
 little  depends  on  the  state  of  the  moon ;  .but  in  the 
 country,  the  moon  is  consulted  in  the  fixing  of  all 
 social  and  religious  meetings,  and  country  people  in 
 general  are  able  to  inform  you  as  to  the  quarter  in  which 
 the  moon  is.  This  mixing  up  of  the  moon  with  the  daily 
 thoughts  of  the  people  in  rural  scenes,  shews  that  her 
 usefulness  is  fully  appreciated. 
 
 In  savage  life,  especially  in  high  latitudes,  the  moon 
 
THE  USES  OF  THE  MOON.  71 
 
 is  an  ever-present  power.  When  the  Eed  Indian 
 speaks  of  moons,  as  measures  of  time,  he  speaks  in 
 the  tone  of  affection  and  reverence  for  the  benign 
 luminary  that  guides  his  steps  through  the  trackless 
 forest.  The  Oriental  bows  to  the  sun,  but  the  Eed 
 Indian  nurtures  his  grand  and  impassive  nature  in 
 the  mild  beams  of  the  moon.  In  hunting  and  trap- 
 ping, the  moon  is  his  ever- faithful  ally,  and  he  would 
 as  soon  think  of  doubting  its  use,  as  he  would  the  use 
 of  his  spear  or  his  traps. 
 
 But  the  use  of  the  moon  is  not  confined  to  light- 
 giving.  As  a  mechanical  power,  the  moon  is  of, 
 much  service.  The  sun  is  the  grand  source  of  power 
 on  the  face  of  the  earth,  but  still,  some  little  work 
 is  left  to  the  moon.  To  her  chiefly  is  assigned 
 the  task  of  raising  the  tides  of  the  ocean.  The 
 tides  are  of  incalculable  benefit  to  man.  In  a  sani- 
 tary point  of  view,  the  moon  may  be  regarded  as 
 the  great  scavenger  of  our  globe.  Twice  every  day 
 she  flushes,  with  sea  water  in  abundance,  the  rivers 
 on  which  our  towns  are  situated,  and  keeps  them 
 comparatively  pure.  Again,  by  her  mechanical  power, 
 she  bears  ships  on  the  crest  of  the  tidal  wave,  deep 
 into  the  heart  of  the  country,  where  the  centres  of 
 commerce  are  often  found.  Insignificant  streams  are 
 thus  rendered  navigable,  and  cities  brought  into 
 immediate  connexion  with  the  ocean — the  highway 
 of  commerce.  By  the  convenience  afforded  by 
 the  moon,  London  is,  at  the  same  time,  connected 
 
72  THE  USES  OF  THE  MOON. 
 
 with  the  ocean,  and  in  the  heart  of  the  country, 
 where  it  can  be  best  protected  from  any  invasion.  In 
 an  island  of  such  limited  extent  as  Great  Britain,  the 
 rivers  must  necessarily  be  small,  but  the  tidal  wave 
 compensates  for  the  defect,  and  gives  us  the  advan- 
 tages of  river  navigation.  The  mechanical  power  of 
 the  tide  is  made  available  by  means  of  the  tide  mill. 
 The  rise  and  fall  of  the  tide  can  be  utilised  as  well 
 as  the  fall  of  a  river.  This  source  of  power  has  not 
 been  very  generally  turned  to  account,  though  there 
 is  no  mechanical  difficulty  in  applying  it. 
 
 One  of  the  most  useful  purposes  served  by  the 
 moon  is  that  of  a  time-ball.  When  the  time-ball 
 falls  at  Greenwich,  all  within  range  of  seeing,  have 
 the  opportunity  of  knowing  that  it  is  precisely  one 
 o'clock  at  Greenwich.  But  its  utility  would  be 
 vastly  increased,  if  the  mariner  far  out  at  sea,  could 
 also  see  the  signal,  for  it  would  at  once  give  him  his 
 longitude.  He  has  the  means  on  shipboard,  of  ascer- 
 taining the  local  time,  and  at  sea  the  clock  in  the  saloon 
 is  put  right  every  day  at  noon.  If  the  ship  is  sailing 
 westwards,  the  hands  must  be  put  back  in  propor- 
 tion to  the  speed  of  the  ship.  The  longitude  of  a  ship 
 is  simply  the  difference  between  her  own  clock  and  a 
 clock  at  Greenwich.  If,  for  example,  the  ship's  clock 
 shews  twelve  o'clock  at  the  moment  the  time-ball  falls 
 at  one  o'clock  at  Greenwich,  her  longitude  is  one  hour 
 west.  The  great  object,  then,  is  to  see  the  time-ball 
 at  Greenwich,  or  something  equivalent  to  it.     The 
 
THE  USES  OF  THE  MOON.  73 
 
 moon  admirably  serves  the  purpose.  Suppose  it  is  pre- 
 viously ascertained,  by  calculationjthat  the  moment  the 
 ball  falls,  the  moon,  in  its  progress  through  the  sky, 
 will  touch  or  occult  a  certain  star  ,*  then,  though  the 
 mariner  cannot  see  the  ball,  it  is  enough  if  he  can 
 watch  the  moment  when  the  moon  comes  in  contact 
 with  the  star.  The  nautical  almanac  tells  when  he 
 may  expect  the  contact,  and  if  he  succeeds  in  ob- 
 serving it,  it  is  as  serviceable  to  him  as  if  he  had  the 
 time-signal  itself.  It  is  not  necessary,  however,  that 
 the  moon  should  actually  come  in  contact  with  some 
 star.  It  may  happen  that  the  moon  is  still  some 
 little  distance  from  the  star  at  the  moment  the  ball 
 falls,  but  this  serves  the  purpose  equally.  If  it  is 
 known  from  the  almanac,  that  the  moon  will  be  so 
 many  degrees  from  the  star  when  the  ball  falls,  it  is 
 only  necessary  to  watch  the  instant  when  the  moon 
 comes  within  the  precise  distance,  in  order  to  know 
 when  it  is  one  o'clock  at  Greenwich.  But  there  is 
 no  need  to  limit  the  signal  to  one  o'clock.  It  is  only 
 necessary  to  know  from  the  almanac  the  time  by  the 
 Greenwich  clock  when  the  moon  will  arrive  at  any 
 point  i'n  her  track  across  the  heavens,  in  order  to 
 ascertain  what  the  time  at  Greenwich  is.  To  people 
 living  along  a  line  of  railway,  the  trains  are  so  many 
 time-signals.  The  time-table  shews  the  Greenwich 
 time  when  the  trains  should  arrive  at  each  station, 
 and  if  they  be  regular,  they  serve  the  purpose  of  a 
 clock.     If  a  person  wishes  to  know  the  longitude  of 
 
74  THE  USES  OF  THE  MOON. 
 
 the  station,  lie  has  only  to  ascertain  the  local  time 
 from  a  sun-dial,  and  the  difference  between  this  and 
 the  railway  time  gives  the  longitude.  What  the 
 railway  train  is  to  the  landsman,  the  moon  is  to 
 the  mariner,  and  while  the  landsman  uses  a  dial 
 to  ascertain  the  local  time,  the  sailor  uses  a  sex- 
 tant. The  sailor  may  adopt  the  obvious  plan  of 
 carrying  a  chronometer  set  to  Greenwich  time,  and 
 which,  by  comparison  with  the  local  time,  at  once 
 gives  him  the  longitude;  but  no  chronometer  can 
 equal  the  moon  as  an  indicator  of  time.  The  cap- 
 tain may  forget  to  wind  up  the  chronometer,  some 
 parts  of  the  works  may  give  way,  the  rate  of  going 
 may  change,  and  many  other  accidents  may  occur  to 
 render  the  chronometer  useless ;  but  the  moon  can 
 ever  be  relied  on.  No  winding  up  is  needed,  no 
 danger  of  the  mainspring  of  gravitation  breaking. 
 She  no  doubt  changes  her  rate  of  motion,  but  the 
 rate  of  change  can  be  calculated  so  that  her  precise 
 position  at  any  moment  can  be  predicted  with  ab- 
 solute accuracy. 
 
 The  moon  would  be  useful  to  man  for  the  division 
 of  time,  though  it  was  only  monthly  periods  that  she 
 marked  off,  and  though  she  only  met  the  necessities 
 of  savage  life ;  but  the  usefulness  becomes  more  ap- 
 parent when  she  serves  to  give  the  minutest  divisions 
 of  time  to  meet  the  increasing  necessities  of  man  as 
 he  advances  in  civilisation.  It  is  this  development 
 of  adaptation,  running  parallel  with  the  development 
 
THE  USES  OF  THE  MOON.  75 
 
 of  the  human  intellect  and  the  social  advance  of  the 
 human  race,  that  most  clearly  indicates  the  exercise 
 of  divine  intelligence.  No  doubt  the  illustrations  of 
 direct  adaptation  of  the  material  world  to  man's 
 physical  constitution  are  striking  enough,  and  it  is 
 these  that  are  usually  appealed  to  in  support  of  a 
 divine  intelligence ;  but  the  secondary  adaptations  to 
 man  as  a  moral,  intellectual,  and  social  being,  are 
 still  more  striking  and  convincing.  These  adapta- 
 tions, being  progressive,  also  recognise  the  progressive 
 nature  of  man  and  his  higher  destiny. 
 
 It  may  appear  straining  the  argument  too  much 
 to  speak  of  the  usefulness  of  the  moon  in  developing 
 poetical  sentiment,  but  we  have  an  gesthetic  element 
 in  our  nature  which  requires  suitable  appliances,  as 
 much  as  the  functions  of  digestion  and  respiration. 
 The  material  universe,  in  the  midst  of  which  we  are 
 placed,  is  not  adapted  merely  to  gross  utilitarian  pur- 
 poses. It  is  equally  fitted  to  cherish  refined  and 
 lofty  sentiment,  and  when  a  want  of  our  nature  is 
 supplied  we  have  a  use.  And  how  useful  in  this  re- 
 spect is  the  moon!  Volumes  might  be  filled  with 
 the  poetry  of  the  moon ;  and  yet  the  theme  is  ever 
 fresh.  The  poet  and  the  painter  find  the  subject  to 
 be  inexhaustible.  The  aspect  of  nature  in  moon- 
 light is  so  different,  that  we  have,  by  the  gift  of  the 
 lesser  light,  virtually  two  worlds  for  our  abode. 
 The  gorgeous  sunlit  scene  gives  way,  like  a  dissolving- 
 view,  to  the  milder  radiance  of  the  moon,  and,  as  by 
 
ye  THE  USES  OF  THE  MOON. 
 
 a  magic  spell,  a  new  scene,  with  its  own  characteristic 
 beauty,  starts  out  from  nature's  canvas.  The  pictur- 
 esque effects  of  moonlight  are  infinitely  varied ;  but 
 how  many  are  lost  simply  because  we  do  not  look 
 for  them  with  aesthetic  fondness.  In  crossing  the 
 Atlantic,  we  had  once  the  opportunity  of  witnessing 
 the  effect  produced  by  a  moon  picture  which  was  new 
 to  the  whole  ship's  company,  and  to  which  we  do 
 not  remember  any  allusion  in  the  pages  of  the  poet 
 or  the  savant.  The  attention  of  the  captain  was 
 called  to  a  dark  pillar  rising  from  the  horizon  and 
 terminating  in  the  full  moon,  which  was  about  thirty 
 degrees  above  the  horizon.  It  assumed  the  form  of 
 an  elongated  pyramid,  the  moon  being  at  the  apex. 
 He  had,  no  doubt,  seen  this  hundreds  of  times  before, 
 but  he  had  never  really  observed  it.  But  now  that  his 
 attention  was  called  to  it,  he  was  filled  with  wonder 
 at  the  magnificence  of  the  phenomenon,  and  the  dis- 
 tinct manner  in  which  the  pillar  stood  out  in  relief 
 from  the  sky.  The  officers  gathered  round  the  cap- 
 tain, and  it  was  also  new  to  them,  as  they  gazed  in 
 admiration.  The  passengers,  who  lingered  on  the 
 deck,  swelled  the  crowd  of  admirers,  and  to  all  the 
 spectacle  was  perfectly  novel.  After  all  were  filled 
 with  the  beauty  of  the  spectacle,  the  spirit  of  philo- 
 sophy arose,  and  the  captain  was  appealed  to  for  an 
 explanation.  His  solution  was  one  characteristic  of 
 the  sailor — it  was  a  sign  of  bad  weather.  This  ten-, 
 tative  effort  at  a  theory  was  negatived  by  simply  shad- 
 
THE  USES  OF  THE  MOON.  yy 
 
 iiig  the  eye  from  the  bright  wake  of  the  moon  in  the 
 sea.  The  instant  this  was  done,  the  majestic  pillar 
 vanished,  shewing  that  it  was  the  counterpart  of  the 
 wake,  and  merely  the  effect  of  contrast.  This  simple 
 solution  did  not  divest  the  object  of  its  beauty,  and 
 during  successive  nights  the  same  effect  was  watched 
 with  increased  interest,  and  all  tacitly  acknowledged 
 that  the  moon  had  a  use  in  thus  giving  a  new  charm 
 to  the  ocean  scenery,  and  helping  to  while  away  the 
 hours  of  the  long  voyage. 
 
 The  moon  has  a  use,  too,  in  reference  to  the  religious 
 element  in  man's  nature,  not  merely  by  furnishing 
 an  argument  for  design  but  by  directly  cherishing 
 the  religious  spirit.  Its  adaptation  to  this  purpose  is 
 shewn  in  the  almost  universal  adoration  paid  to  this 
 luminary.  The  idolatry  of  the  heathen  is  only  the 
 perversion  of  a  native  instinct  of  the  human  heart, 
 and  is  a  testimony  to  the  fact  that  the  object  of  ador- 
 ation has  a  natural  tendency,  in  the  pure  and  en- 
 lightened spirit,  to  lift  the  heart  up  to  God.  When 
 the  Psalmist  considered  the  heavens,  and  contem- 
 plated the  luminaries  in  detail,  the  moon  had  the  first 
 place,  as  declaring  the  glory  and  goodness  of  God. 
 The  moon  is  the  most  familiar  symbol  of  God's  provi- 
 dence; we  feel  that  she  is  nearer  to  us  than  any  other 
 heavenly  body,  and  that  her  special  duty  is  to  wait 
 upon  us.  She  accompanies  us  like  a  guardian  angel, 
 bearing  a  lamp  before  us,  in  the  darkness  of  the  night. 
 She  circles  round  us  like  the  parent  bird  round  the 
 
78  THE  USES  OF  THE  MOON. 
 
 nest  of  her  helpless  young.  She  is  the  j&rst  round  in 
 the  ladder  that  leads  up  to  the  throne  of  God — 
 the  first  link  in  the  chain  that  binds  us  to  the  uni- 
 verse of  worlds.  The  moon  is  thus  specially  fitted  to 
 be  useful  in  bringing  home  to  us  the  presence  and  the 
 providence  of  God. 
 
 It  was  undoubtedly  the  feeling  that  the  moon  was 
 our  nearest  neighbour,  that  led  man  to  ascribe  fanciful 
 functions  to  the  moon.  While  the  sun  was  supposed 
 to  preside  over  the  heart,  the  moon  was  believed  to 
 have  supreme  power  in  controlling  the  brain — the 
 characteristic  part  of  man's  organisation.  Hence,  any 
 crisis  in  mental  phenomena  was  always  connected 
 with  the  phases  of  the  moon,  and  paroxysms  of  insan- 
 ity were  long  believed  to  be  regulated  by  the  maxima 
 and  minima  of  the  moon's  illuminated  disc.  It  is 
 strange  that  such  a  delusion  should  have  so  long 
 clung  to  the  human  mind  although  contradicted  by 
 innumerable  facts.  This  is  explained  by  the  principle 
 of  an  anterior  bias,  and  the  love  of  coincidences.  The 
 passion  of  tracing  coincidence  has  its  use  in  prompting 
 to  scientific  inquiry,  but  we  often  find  it  indulged  in 
 for  its  own  sake.  How  many  examine  their  barometer 
 daily  to  see  whether  it  is  rising  or  falling,  simply  for 
 the  pleasure  of  marking  the  coincidence  between  the 
 weather  and  the  indications  of  the  barometer.  They 
 may  be  neither  mariners  nor  sailors,  and  have  no 
 immediate  interests  at  stake.  They  may  have  nc 
 pretensions  to  scientific  inquiry.     And  whether  theii 
 
THE  USES  OF  THE  MOON.         79 
 
 theory  is  that  the  barometer  influences  the  weather, 
 or  the  weather  the  barometer,  the  pleasure  is  still 
 great  of  tracing  a  coincidence.  So,  in  regard  to  the 
 moon,  the  human  mind  has  derived  great  pleasure  in 
 tracing  the  coincidence  between  the  moon's  phases 
 and  the  mental  and  physical  phenomena  on  the  sur- 
 face of  the  globe.  From  the  bias  of  this  love  of 
 coincidence,  the  many  adverse  facts  were  overlooked, 
 and  the  few  favourable  ones  were  allowed  to  have 
 more  than  their  due  weight.  The  influence  of  the 
 moon  in  insanity  is  now  entirely  discredited,  but  many 
 cling  to  its  influence  on  the  weather.  Many  who 
 have  a  half  conviction  that  their  belief  is  a  mere 
 superstition,  still  have  a  pleasure  in  speaking  of  a 
 change  of  weather  at  the  new  or  full  moon.  And 
 there  ^re  always  a  sufficient  number  of  coincidences 
 to  give  colour  to  their  belief.  Almost  every  different 
 country  has  its  own  rules  for  prognosticating  the 
 weather  from  the  phases  of  the  moon,  but  however 
 difl'erent  they  may  be,  they  all  serve  equally  well  to 
 cherish  the  conviction  that  there  is  some  real  influ- 
 ence. Many  scientific  researches  have  been  made  to 
 settle  the  point,  but  no  decisive  result  has  been  arrived 
 at.  Sometimes  a  preponderating  efl'ect  has  been 
 ascribed  to  particular  phases,  but  it  has  been  as  often 
 against  the  popular  belief  as  in  favour  of  it. 
 
 There  is  no  a  priori  reason  why  the  moon  should 
 not  influence  the  weather.  It  is  simply  a  question 
 of  fact,  and  as  yet  no  appreciable  effect  has   been 
 
8o  THE   USES  OF  THE  MOON. 
 
 detected.  Perhaps  the  only  effect  for  which  there  is 
 tolerable  probability,  is  the  influence  of  the  full  moon 
 in  dispelling  light  fleecy  clouds.  This  is  effected'  by 
 the  heat  of  the  moon  which  is  expended  in  the  higher 
 strata  of  the  air — the  heat  being  employed  in  con- 
 verting the  clouds  into  invisible  vapour. 
 
 While  science  is  lessening  the  influence  of  the 
 moon  in  one  direction,  it  is  extending  it  in  another. 
 The  moon  is  now  found  to  be  a  magnet,  and  to  exer- 
 cise an  influence  on  the  magnetic  elements  of  our 
 globe.  The  oscillations  of  the  barometer  are  found 
 to  be  slightly  affected  by  the  phases  of  the  moon. 
 The  rays  of  the  moon  are  found  to  have  a  chemical 
 influence  like  those  of  the  sun,  and  its  heat,  though 
 insignificant,  has  at  last  been  measured.  These 
 physical  effects  render  it  not  improbable  that  the 
 moon  may  influence  the  weather  and  the  human  con- 
 stitution, but  the  precise  effects  are  yet  to  be  discerned. 
 The  effects  hitherto  ascribed  to  the  moon  have  been 
 shewn  to  be  either  fanciful,  or,  when  real,  produced 
 by  other  causes.  But  admitting  all  this,  there  is  a 
 wide  enough  margin  for  the  undoubted  uses  of  the 
 moon. 
 
Herscliel's  Great  Telescope. 
 
 TI. 
 
 DISCOYEEY  OF  THE  NEW  PLANET 
 VULCAN. 
 
 A  RECENT  French  philosoplier  impiouslj  main- 
 tained, that  the  heavens  declare  not  the  glory  of 
 God,  but  that  of  Newton  and  Laplace;  that  the 
 laws  wdiich  govern  the  heavenly  bodies  are  only 
 the  necessary  conditions  of  matter,  the  result  of 
 a  blind  necessity;  and  that  the  only  glory  is  that 
 of   the    human    intellect,   which    has   educed    these 
 
82  DISCOVERY  OF  THE 
 
 laws  from  the  midst  of  a  bewildering  complexity. 
 We  would  only  meet  this  by  the  comiter  assertion, 
 that  both  the  structure  of  the  heavens  and  that  of 
 man's  intellect  combine  in  declaring  God's  glory. 
 The  heavens  have  their  glory — man's  intellect  has 
 its  glory;  but,  like  the  divided  beams  of  a  doubly- 
 refracting  crystal,  they  both  can  be  traced  to  the 
 same  source.  They  meet  in  the  all-wise  Creator,  who 
 so  wondrously  adjusted  the  objective  universe  to  the 
 subjective  faculties  of  man.  The  vital  germ  in  the 
 seed  requires,  for  its  development,  certain  conditions 
 of  light,  heat,  and  moisture ;  without  these,  it  cannot 
 expand  and  fulfil  its  destiny.  So,  for  the  education 
 of  man's  powers,  it  was  necessary  that  he  should  be 
 placed  in  a  world  which  would  present  to  him  fit 
 problems  for  solution,  and  lofty  enough  themes  to 
 reflect  the  glory  of  his  Creator.  The  child  at  school 
 must  work  his  way  upwards  from  the  hornbook  to  the 
 subtleties  of  profound  scholarship,  and  so  the  material 
 universe  presents  a  system  of  graduated  lessons  for 
 the  training  of  the  human  intellect.  The  various 
 branches  of  natural  history,  form  an  easy  hornbook  for 
 the  beginner,  and  the  problems  of  physical  astronomy 
 try  the  full  compass  of  the  human  intellect.  It  is  to 
 the  heavens  we  must  point  for  the  most  wondrous 
 trophies  of  man's  intellectual  powers.  God's  glory  is 
 seen,  not  by  looking  at  the  heavens  alone,  nor  at  man's 
 intellect  alone,  but  to  the  exquisite  adjustment  of  the 
 one  to  the  other.     We  could  readily  conceive  of  in- 
 
NE  W  PL  A  NE  T  VUL  CA  N.  Zi 
 
 tellectual  powers  without  a  universe  so  wondrousljr 
 adapted  to  test  tlieir  grasp.  As  tlie  doublj-refraeting 
 crystal  transmits  two  distinct  images  of  the  sun,  so 
 God  has,  in  creation,  impressed  one  image  of  Himself 
 on  the  material  universe,  and  one  on  man's  mental 
 constitution.  M.  Comte  would  admit  only  the  latter 
 — man  being  his  own  God — and  ignore  altogether 
 the  common  source.  But  logic  and  philosophy  de- 
 mand the  recognition  of  the  two  distinct  images,  and 
 of  their  synthesis  in  the  Divine  glory. 
 
 The  glory  of  God  is  declared,  not  merely  in  the 
 adaptation  of  man's  intellect  to  the  unravelling  of  the 
 mysteries  of  the  universe,  but  also  in  the  manner  by 
 which,  in  His  providence,  discoveries  are  so  timed  as 
 to  tell  most  powerfully,  not  only  on  the  progress  of 
 science,  but  on  the  moral  and  religious  welfare  of  man. 
 Isolated  discoveries,  born  out  of  date,  would  fall  dead 
 upon  the  world.  How  strikingly  have  the  discoveries 
 of  science,  bearing  on  the  means  of  international  in- 
 tercourse; been  timed  so  as  to  meet  the  rising  mission- 
 ary spirit  of  our  age !  No  sooner  did  the  Church  of 
 Christ  fully  awaken  to  the  great  duty  of  preaching 
 the  gospel  to  every  creature,  than  God  put  into  her 
 hands  the  material  agencies  necessary  to  carry  out 
 the  projects  of  missionary  enterprise. 
 
 Seldom  has  an  astronomical  discovery  been  so  well- 
 timed  as  that  of  the  planet  Vulcan,  due  to  an  obscure 
 village-doctor  in  France.  At  any  previous  time,  the 
 passage  of  the  little,  round,  dark  spot  across  the  disc 
 
84  DISCO  VER  Y  OF  THE 
 
 of  the  sun  would  not  have  the  same  significance.    Two 
 men,  unknown  to  one  another,  were  at  work  on  the 
 same   subject,  and   though  pursuing   very  different 
 methods,  arrived  at  results,  the  coincidence  of  which 
 forms  one  of  the  most  interesting  romances  of  science. 
 The  village-doctor  humbly  inquired  of  nature  what  is. 
 The  high  priest  of  science  had  oracularly  declared 
 what  must  he.       The  former  had  no  pretensions  to 
 science  ;  he  loved  to  gaze  upon  God's  handiwork,  and 
 was  happy  that  nature  should  reveal  spontaneously 
 some  new  wonder.     The  other  occupied  a  loftier  posi- 
 tion.    He  surveyed  the  celestial  structure  as  already 
 known,  and,  with  the  sharp  eye  of  an  architect,  he 
 declared  that  there  was  something  wanting  to  com- 
 plete the  symmetry.     His  conclusion  was,  that  there 
 must  be  a  planet  between  Mercury  and  the  sun.    The 
 motion  of  Mercury  could  not  otherwise  be  accounted 
 for.     There  must  be  a  perturbing  body  to  explain  the 
 apparent  irregularities  of  its  path.     He  declared  his 
 conviction  to  the  Academy  of  Science,  and  the  fact 
 was  accepted  by  that  learned  body  as  one  of  the  estab- 
 lished facts  of  science,  though  no  eye  had  ever  been 
 reported  to  have  seen  it.    But,  all  the  time,  the  village* 
 doctor  knew  the  planet  as  a  fact  of  observation,  yet 
 hesitated  to  proclaim  the  discovery,  lest  it  was  too 
 good  a  thing  to  be  true.     The  interest  of  the  story 
 lies  in  the  manner  in  which  Leverrier  fully  estab- 
 lished  the  reality  of  the  discovery  by  M.  Lescar- 
 bault,  doctor  at  Orgbres. 
 
NEW  PLANET  VULCAN.  85 
 
 It  isj  however,  necessary,  in  tlie  first  place,  clearly 
 to  understand  the  difference  between  the  discovery  of 
 Vulcan,  and  that  of  the  small  planets,  which  are  now 
 so  numerous  that  the  announcement  of  a  new  one  has 
 ceased  to  be  a  matter  of  interest.  The  discovery  of 
 Vulcan  ranks  with  that  of  ISTeptune.  It  is  not,  how- 
 ever, likely  to  excite  such  popular  interest,  as  there 
 are  no  contending  national  claims.  There  is  no 
 Adams  in  this  case  to  dispute  the  claim  with  Lever- 
 rier.  It  has,  therefore,  simply  the  interest  of  one  of 
 the  greatest  triumphs  of  the  human  intellect.  In  the 
 case  of  the  asteroids,  the  discovery  implies  no  pro- 
 phetic vision.  Let  a  man,  with  proper  instruments 
 and  charts,  explore  a  certain  region  of  the  heavens, 
 and  there  is  a  probability,  almost  amounting  to  cer- 
 tainty, that  he  will,  within  a  few  months,  discover  a 
 new  one,  though  he  have  few  or  no  scientific  accom- 
 plishments. From  experience,  it  has  been  found  that, 
 in  a  certain  zone,  these  asteroids  abound,  and,  from 
 the  rate  of  discovery  in  the  past,  we  naturally  infer 
 the  rate  of  the  future.  This  case  is  wholly  difi'erent 
 from  that  of  Neptune  and  Vulcan,  where  the  existence 
 of  the  planets  w^as  predicted  on  a-^riori  grounds.  The 
 matter  may  be  illustrated  by  the  discovery  of  gold  in 
 Australia.  The  digger  buys  a  claim  on  the  banks 
 of  a  river,  sinks  a  shaft,  and  is  fortunate  enough  to 
 discover  some  nuggets.  But  there  is  no  scientific 
 merit  in  this.  He  was  only  led  by  an  instinct,  which 
 is  as  strong  in  the  inferior  anim.als  as  in  man.     He 
 
S6  DISCO  VER  Y  OF  THE 
 
 merely  expected  that  what  had  happened  before,  would 
 happen  again  in  similar  circmnstances.  The  case  is, 
 however,  different  in  regard  to  the  prediction  of  Sir 
 E-oderick  Mm-chison,  who  foretold,  simply  from  his 
 knowledge  of  the  laws  of  the  distribution  of  gold  on 
 the  earth's  surface,  that  gold  would  be  found  in 
 Australia.  The  discovery  of  new  asteroids,  is  like  the 
 discovery  of  nuggets  by  the  gold-digger.  The  star- 
 finder,  in  such  a  case,  claims  none  of  the  prophetic 
 genius  of  Leverrier  and  Adams. 
 
 In  September  1859,  Leverrier,  now  director  of  the 
 Observatory  of  Paris,  laid  before  the  Academy  of 
 Science  the  proofs  which  had  led  him  to  the  conclusion, 
 that  there  must  be  a  planet  within  the  orbit  of  Mer- 
 cury. He  shewed,  in  his  paper,  that  the  existence  of 
 such  a  planet  would  fully  explain  the  apparent  ano- 
 malies in  the  motion  both  of  Mercury  and  the  earth. 
 He,  at  the  same  time,  warned  all  observers  to  keep  a 
 sharp  look-out  upon  the  sun's  disc,  as  the  only  hope 
 of  discovering  it,  was  by  detecting  its  transit.  Being 
 always  in  the  immediate  vicinity  of  the  sun,  and 
 quenched  by  its  rays,  it  could  manifest  its  existence 
 only  by  appearing  as  a  black  spot  on  the  bright  back- 
 ground of  the  sun.  In  December  1859,  Leverrier 
 received  a  letter,  dated  from  the  small  town  of  Orgbres, 
 in  the  department  of  Eure-et-Loire.  This  was  from 
 M.  Lescarbault,  announcing  that  he  had,  on  the  26th 
 of  March  preceding,  observed  a  small  planet  cross  the 
 disc  of  the  sun.     Leverrier  lost  no  time  in  sifting  the 
 
NEW  PLANET  VULCAN.  Zj 
 
 matter.  Lescarbault  had  kept  the  secret  to  himself 
 for  several  months,  hoping  that  he  might  again  see 
 the  planet,  for  he  feared  lest  he  might  have  deceived 
 himself.  But  the  results  of  Leverrier,  reaching  his 
 ears,  gave  him  courage  to  divulge  it,  though  with 
 some  trepidation.  Leverrier  started  for  Orgeres  with 
 similar  feelings,  hope  being  mingled  with  fear.  He 
 was  sustained  by  the  hope  that  he  might,  a  second 
 time,  wear  the  proudest  laurels  that  can  encircle 
 mortal  brows;  but  he  had  the  secret  fear  that  he 
 might  be  the  victim  of  a  delusion  or  a  hoax. 
 
 It  is  rarely  that  science  is  associated  with  incidents 
 of  so  dramatic  a  character.  Our  demonstrative  neigh- 
 bours have  been  charmed  by  the  romantic  interest  of 
 the  story,  and  have  given  expression  to  their  feelings 
 in  their  own  characteristic  manner.  The  academic 
 halls  and  the  gay  salons  of  Paris  resounded  for  weeks 
 with  the  name  of  the  village-doctor.  Leverrier,  after 
 detailing  the  incidents  of  his  visit  to  Orgeres  to  his 
 brother  savans  in  the  Academy  of  Science,  was  called 
 to  repeat  the  story  in  less  learned,  but  more  fashion- 
 able parties.  Others  still  more  eloquent  took  up  the 
 story ;  and,  embellished  with  additional  incidents,  it 
 was  repeated  over  and  over  again  to  eager  audiences. 
 We  shall  follow  the  version  of  the  Abbe  Moigno,  who 
 heard  Leverrier  detail  the  incidents  to  a  brilliant 
 throng  in  the  salon  of  his  father-in-law,  M.  Choquet. 
 
 It  was  on  the  30th  of  September,  that  Leverrier 
 started  from  Paris  for  the  village  of  Orgeres.      He 
 
88  .DISCOVERY  OF  THE 
 
 must  have  had  a  secret  conviction  that  the  story  of 
 the  discovery  might  be  true;  but,  to  guard  himself 
 against  the  laugh  of  Paris,  he  went  ostensibly  for  the 
 purpose  of  punishing  the  impudent  attempt  to  hoax 
 so  high  an  official  as  the  Director  of  the  Imperial 
 Observatory.  It  was  not  probable  that  the  discovery 
 could  be  made  by  a  man  who  was  never  heard  of  in 
 science,  and  about  whom  no  one  knew  anything.  Be- 
 sides, it  was  unlikely  that  a  Frenchman  would,  for  so 
 many  months,  keep  the  secret  to  himself.  If  true  to 
 his  national  instinct,  he  would  at  once  have  pro- 
 claimed the  discovery,  and  reaped  the  glory.  These 
 reasons  weighed  much ;  still  the  story  might  be  true, 
 and  on  this  possibility  he  acted.  To  preserve  his 
 dignity,  and  to  be  a  check  on  any  bias  he  might  feel, 
 he  took  with  him  a  M.  Vallee,  a  civil  engineer,  who 
 might  witness  the  severity  with  which  he  would  treat 
 the  culprit. 
 
 They  started  by  railway ;  but  the  station  at  which 
 they  stopped,  was  about  twelve  miles  from  Orgbres. 
 They  had  to  trudge  along  this  weary  distance  over  a 
 most  miserable  road.  Foot-sore,  and  in  no  pleasant 
 mood,  Leverrier  reached  the  village,  and  at  once  went 
 up  and  knocked  at  the  doctor's  door.  The  door  was 
 opened  by  M.  Lescarbault  himself.  The  great  man 
 at  once  gave  his  name  and  titles,  with  an  air  that  was 
 meant  to  be  very  imposing.  But  we  must  now  em- 
 ploy the  very  words  of  the  Abbe  Moigno.  "One 
 would  require  to  have  seen  M.  Lescarbault,  so  simple. 
 
NEW  PLANET  VULCAN.  89 
 
 so  modest,  so  timidj  to  compreliend  the  agitation  with 
 which  he  was  seized,  when  the  interrogator,  drawing 
 himself  up  to  his  full  height,  and  with  that  brusque 
 intonation,  which  he  can  assume  when  he  pleases, 
 said  to  him,  with  severe  look,  'Is  it  you,  sir,  who 
 pretend  to  have  discovered  the  intra-Mercurial  planet, 
 and  who  have  committed  the  grave  offence  of  keeping 
 your  observation  secret  for  nine  months  ?  I  have  to 
 tell  you,  that  I  come  with  the  intention  of  expos- 
 ing your  pretensions,  and  of  demonstrating  your  great 
 delusion,  if  not  your  dishonesty.  Tell  me,  at  once, 
 categorically,  what  you  have  seen?'  The  lamb 
 trembled  all  over  at  this  rude  summons  of  the  lion ; 
 he  tried  to  speak,  but  he  only  stammered  out  the 
 following  reply: — 'At  four  o'clock,  on  the  26th  of 
 March  last,  faithful  to  my  constant  habit,  I  looked 
 through  my  telescope,  and  observed  the  disc  of  the 
 sun,  when,  all  at  once,  I  detected,  near  the  eastern 
 edge,  a  small  black  point,  perfectly  round,  and  sharply 
 defined,  passing  across  the  disc,  with  a  very  sensible 
 motion.  It  gradually,  though  quite  perceptibly,  in- 
 creased its  distance  from  the  edge,  but'" 
 
 Let  us  leave  the  Abbe  Moigno's  account  to  pause 
 on  this  hut.  How  awkwardly  and  fatally  are  huts 
 often  interjected  in  the  smooth  current  of  life !  How 
 often,  too,  is  the  dignity  of  science  offended,  and  its 
 success  marred  by  contre-femjjs  so  ludicrous,  or  so 
 little,  that  a  man  would  not  do  well  to  be  angry  at 
 them.      A   whisk  of  Diamond's   tail,  in  Newton's 
 
90  DISCO  VER  Y  OF  THE 
 
 studj,  set  his  papers  on  fire^  and  destroyed  the 
 labours  of  many  years.  The  great  philosopher 
 shewed  an  equanimity  worthy  of  his  fame,  when  his 
 only  remark  on  the  catastrophe  was,  '^  0  Diamond, 
 Diamond,  thou  little  knowest  the  mischief  thou  hast 
 done ! "  M.  Lescarhault's  hut  was  nearly  as  fatal  to 
 the  discovery  he  was  on  the  brink  of  making-.  At 
 the  most  interesting  moment  of  the  observation,  a 
 knock  was  heard  on  the  counter  of  the  laboratory 
 below.  He  listened  for  a  moment  without  moving. 
 The  knocking  became  more  emphatic  ;  it  was  a  patient 
 demanding  medical  relief.  He  would  fain  look  on, 
 and  follow  the  dark  spot  rapidly  travelling  across  the 
 sun's  disk.  But  it  may  not  be.  The  call  of  duty 
 must  be  obeyed  ,*  and  no  villager  could  say  that  the 
 good  doctor  ever  forgot  his  patients  in  his  devotion 
 to  the  stars.  Fortunately,  it  was  not  a  call  to  go 
 abroad.  A  soothing  draught  was  all  that  was  needed. 
 He  scrupulously  measured  out  the  ingredients,  corked 
 and  labelled  the  bottle ;  and  not  till  then  did  the  con- 
 scientious doctor  feel  at  liberty  to  rush  up  to  his  little 
 observatory,  and  eagerly  apply  his  eye  to  the  tele- 
 scope. It  is  not  too  late ;  the  strange  planet  is  still 
 upon  the  disc. 
 
 He  marked  precisely  the  time  when  he  saw  it  near 
 the  eastern  edge.  He  must  now  carefully  watch  the 
 moment  when  it  leaves  the  disc.  Having  noted 
 these  times,  and  measured  the  size  and  position  of 
 the  segment  of  the  sun's  disc  cut  off  by  the  path  of 
 
NEW  PLANET  VULCAN.  91 
 
 the  planet,  he  has  branded  the  object,  so  that  it 
 can  ever  afterwards  be  identified.  Had  he  been 
 only  able  to  report  that  he  had  seen  a  black  point, 
 his  observation  would  have  been  of  little  value,  and 
 no  one  would  know  where  to  look  for  it  again. 
 B7  simply  ascertaining  how  long  it  took  to  cross 
 an  ascertained  portion  of  the  sun's  disc,  its  dis- 
 tance from  the  sun  and  its  period  of  revolution  could 
 at  once  be  deduced,  and  thus  the  chief  elements  of 
 identity  would  be  determined.  These  essential  points 
 were  not  observed  when  the  knock  was  heard,  and 
 we  can  well  conceive  the  painful  suspense  of  the 
 observer,  till  his  eye  was  once  more  applied  to  the 
 tube. 
 
 This  reminds  one  of  the  interruptions  of  Sir  Wil- 
 liam Herschel,  when  pursuing  his  musical  avocations 
 in  the  pump-room  at  Bath.  He  had  a  small  work- 
 shop close  at  hand,  and  when  the  exacting  loungers 
 in  the  pump-room  admitted  of  a  pause  in  the  music, 
 he  slipped  off  to  complete  the  polishing  of  a  specu- 
 lum, or  the  grinding  of  a  lens.  But  he  was  always 
 ready,  when  he  heard  the  signal,  to  snatch  up  his 
 instrument,  and  be  the  first  in  the  orchestra.  He  did 
 not  permit  his  astronomical  tastes  to  interfere  with 
 the  duties  of  his  calling.  He  was  allowed  to  be  one 
 of  the  best  drummers  in  the  Hanoverian  army,  and 
 few  in  Bath  could  match  him  on  the  fiddle,  the  flute, 
 or  the  cornet-a-piston.  While  his  fellow-musicians 
 spent   their  pauses  in    drinking   and   gossiping,  he 
 
92  DISCO  VER  V  OF  THE 
 
 gathered  up  the  fragments  of  time,  and  it  was  these 
 fragments  that  made  him  the  friend  of  monarchs,  and 
 the  first  of  astronomers. 
 
 Let  us  now  return  to  the  cross-questioning  of  the 
 Imperial  astronomer.  In  order  to  be  convinced  that 
 the  story  is  not  a  fabrication,  he  must  have  proof 
 that  the  observer  had  proper  instrumental  means  for 
 making  the  observation.  The  astronomer  must  be 
 so  exact  in  his  observation,  that  seconds  and  fractions 
 of  seconds  must  be  taken  into  account.  He  must  be 
 able,  for  example,  to  tell  the  precise  second  when 
 Vulcan,  in  his  progress  across  the  sun's  disc,  touches 
 the  border.  He  listens  to  the  beats  of  a  pendulum, 
 counting  them  all  the  time,  and  he  must  be  able 
 to  note  the  second  that  ~  coincides  with  the  instant 
 of  contact;  nay,  more,  it  may  happen  that  the  con- 
 tact takes  place  between  two  successive  beats  ; 
 and,  in  that  case,  he  must  be  able  to  estimate  to 
 the  tenth  of  a  second.  Leverrier  interrogates,  still 
 maintaining  the  grand  attitude  of  the  lion,  "  Where 
 is  your  chronometer,  sir?"  ^^  My  chronometer !  I 
 have  only  this  minute  watch,  the  faithful  companion 
 of  all  my  professional  visits."  ^'What!  with  that 
 old  watch,  marking  only  minutes,  do  you  dare  to 
 speak  of  estimating  seconds?  I  fear  my  suspi- 
 cions are  too  well  founded."  The  doctor  shewed  to 
 his  satisfaction  how  he  accomplished  the  object. 
 With  the  aid  of  a  ball  hung  by  a  silk  thread,  and 
 swinging  seconds,  combined  with  the  counting  of  his 
 
NEW  PLANET  VULCAN.  93 
 
 pulse  while  observing,  he  attained  the  requisite  ac- 
 curacy. It  is  the  mark  of  genius  to  obtain  valuable 
 results  by  imperfect  instruments.  We  know  what 
 good  service  has  been  rendered  to  chemical  science 
 by  blacking  pots  in  the  hands  of  a  Priestly. 
 
 The  next  point  was  the  telescope.  Was  it  good 
 enough  to  see  the  small  black  point?  Here  Lescar- 
 bault  spoke  with  more  confidence.  He  had,  after 
 great  privation  and  suffering,  saved  enough  to  buy  a 
 lens.  The  optician,  seeing  his  enthusiasm  and  poverty, 
 gave  it  cheap.  He  made  the  tube  himself,  and  all  the 
 fittings  necessary  to  mount  it  properly.  He,  then, 
 went  into  some  technical  details,  to  explain  how, 
 by  means  of  threads  stretched  across  the  focus  of  the 
 telescope,  he  was  able  to  measure  distances  on  the 
 sun's  disc. 
 
 Leverrier  being  thoroughly  satisfied  as  to  the  means 
 of  making  the  observation,  next  turned  to  the  obser- 
 vation itself.  It  might  be,  after  all,  a  fabrication, 
 such  things  being  known  in  the  history  of  astronomy. 
 He,  therefore,  demanded  the  original  jotting  of  the 
 observation,  to  see  if  it  tallied  with  the  deduced  state- 
 ment. Lescarbault  now  got  somewhat  alarmed,  as  he 
 was  in  the  habit  of  burning  the  scraps  of  paper  on 
 which  he  had  jotted  down  his  observations,  after  he 
 had  fairly  entered  them.  He,  however,  rummaged 
 every  corner,  and  at  last  found  the  scrap  in  his 
 nautical  almanac,  serving  as  a  book-mark.  Leverrier 
 seized  it  eagerly.     It  was   a  square  powder-paper, 
 
94  DISCO  VER  Y  OF  THE 
 
 which  had  seen  some  service  in  the  shop,  being 
 spotted  with  grease  and  laudanum.  An  apparent  dis- 
 crepancy was  at  once  detected.  The  figures  did  not 
 quite  coincide  with  the  deduced  observation  which 
 had  been  transmitted  to  him.  Lescarbault  met  this 
 difficulty  with  ease,  as  he  shewed  that,  in  the  reduced 
 observation,  there  was  an  allowance  made  for  the 
 clock  error. 
 
 He  was  next  asked,  if  he  had  made  any  attempt  to 
 calculate  the  distance  of  the  planet  from  the  sun.  His 
 answer  was  that  he  was  no  mathematician,  that  he 
 had  been  long  trying  to  come  to  a  definite  result, 
 and  that  one  motive  in  delaying  his  discovery,  was 
 his  wish  to  be  able  to  announce  the  distance  and 
 the  period  of  revolution,  at  the  same  time  that  he 
 announced  the  discovery.  "  You  must  send  me  the 
 rough  draught  of  these  calculations."  ^'  My  rough 
 draught!  Your  request  embarrasses  me  much. 
 Paper  is  a  scarce  article  with  me.  I  am  somewhat 
 of  a  carpenter  as  well  as  astronomer,  and  I  make  all 
 my  calculations  in  my  workshop.  I  write  with  chalk 
 upon  the  boards  which  I  am  using,  and  I  have  to 
 plane  the  boards  over  again,  when  I  wish  to  use  the 
 surface  for  new  calculations.  I  fear  that.  I  have 
 obliterated  the  calculations  in  question  ;  but  come 
 and  see."  They  descended  to  the  ground-floor,  and, 
 happily,  the  calculations  were  still  traceable.  The 
 carpenter's  board  formed  the  climax  of  the  investiga- 
 tion.    Leverrier  could  no  longer  resist  the  evidence. 
 
NE IV  PLANE T  VUL CAN.  95 
 
 "The  time  had  now  come,"  says  the  Abh^  MoigHD, 
 "  for  the  lion  to  soften  down,  and  to  give  heart  to  the 
 trembling  lamb.  Leverrier  did  this  with  perfect 
 grace — with  a  dignity  full  of  kindness.  M.  Lescar- 
 bault  felt  the  blood  rushing  to  his  heart ;  he  breathed 
 with  difficulty  when  the  Director  of  the  Imperial 
 Observatory  expressed  his  perfect  satisfaction,  and 
 gave  him  the  most  cordial  congratulations."  Le- 
 verrier, as  he  meditated  something  generous,  was 
 anxious  to  obtain  some  information  about  the  general 
 character  of  the  discoverer.  He  therefore  called  on 
 the  village  authorities,  who  all  united  in  describing 
 him  as  a  skilful  and  laborious  practitioner,  and  a 
 most  benevolent  and  pious  man.  He  lost  no  time  in 
 publishing  the  discovery  to  the  world,  and  represent- 
 ing his  claims  to  the  Emperor.  The  result  is,  that 
 the  village-doctor  is  now  decorated  with  the  order  of 
 the  Legion  of  Honour. 
 
 From  the  observations  of  Lescarbault,  it  follows 
 that  the  distance  of  Vulcan  from  the  sun  is  about 
 half  that  of  Mercury.  The  time  of  revolution  is  19 
 days  17  hours,  which  is  about  four  times  less  than 
 Mercury's  period  of  revolution.  M.  Lescarbault  saw 
 Mercury  pass  across  the  disc  of  the  sun  in  1845,  and, 
 from  his  recollection,  he  would  estimate  the  apparent' 
 diameter  of  Vulcan  as  four  times  less  than  that  of 
 Mercury.  This  would  make  Mercury  seventeen  times 
 larger  than  Vulcan.  A  planet  of  this  size,  unless  the 
 density  is  excessive,  does  not  account  forjlifr-Js^itdk-iif,^^ 
 
96  DISCO  VER  V  OF  THE 
 
 the  observed  perturbation,  so  that  it  is  likely  other 
 planets  will  yet  be  discovered  on  the  sun's  disc. 
 
 The  black  spot,  produced  by  a  planet  coming  be- 
 tween us  and  the  sun,  can  readily  be  distinguished 
 from  the  dark  spots  on  the  sun  itself,  which  can 
 often  be  seen  by  the  naked  eye.  The  planet's 
 motion  is  much  more  rapid.  Vulcan's  time  of  pas- 
 sage was  only  1  hour  17  minutes.  As  the  sun  takes 
 twenty-five  days  to  rotate  on  his  axis,  the  solar 
 spots  are  seen  usually  for  days  together  before  they 
 disappear.  The  planetary  spot  is  perfectly  round  and 
 sharp;  the  solar,  is  usually  of  an  irregular  form, 
 and  shaded.  The  planetary  spot  does  not  change  its 
 form  in  passing  across  the  disc  ,*  it  is  otherwise  with 
 the  solar  spots.  In  the  case  of  the  latter,  the  black 
 central  spot  is  the  bottom  of  a  deep  pit,  and  the 
 shaded  parts  are  the  shelving  sides.  When  the  spot 
 is  in  the  centre  of  the  disc,  you  are  looking  straight 
 down,  and  if  it  is  circular  you  see  it  perfectly  round ; 
 but  when  it  moves  to  the  side,  the  circle,  from  the 
 change  of  perspective,  becomes  an  oval.  Solar  spots 
 are  usually  near  the  equator  of  the  sun ;  planets  may 
 be  seen  at  any  distance  from  it.  Besides  these,  there 
 are  other  points  of  difference  which  render  it  impossi- 
 ble to  mistake  a  solar  spot  for  a  planet. 
 
 The  last  news  from  Paris,  is  that  the  medical  prac- 
 titioners, there,  have  been  attempting  to  spoil  their 
 unassuming  brother,  who  has  been  thus  suddenly 
 raised  to  distinction.     They  invited  him  to  a  grand 
 
NEW  PLANET  VULCAN.  97 
 
 banqnet  in  the  Hotel  du  Louvre.  His  reply  shews 
 that  he  is  a  man  of  great  good  sense,  as  well  as  an 
 enthusiastic  astronomer  : — "  I  beg  to  express  my  most 
 grateful  acknowledgment  for  the  flattering  invitation 
 which  you  have  sent  to  me.  I  am  far  from  being- 
 worthy  of  such  a  testimony.  I  am  not  a  savant,  as 
 you  appear  to  believe.  The  honourable  offer  of  a 
 banquet,  which  you  have  made  me,  does  not  accord 
 with  the  habits  of  my  simple  and  retired  life;  besides, 
 I  have  received  similar  offers  from  our  brethren  of 
 Chartres  and  Blois,  which  I  have  declined.  The 
 duties  of  our  profession  do  not  admit  of  such  frequent 
 absences;  and  I  have  not  the  facilities  which  you 
 enjoy  of  securing  a  substitute  to  wait  on  my  dear 
 patients.  I  earnestly  hope  that  you  may  take  no 
 offence  by  my  thus  declining  the  invitation." 
 
Solar  Sputa. 
 
 YIL 
 
 TOTAL  ECLIPSE  OF  THE  SUN. 
 
 When  the  alarm  of  an  eclipse  is  given  in  a  Hindu 
 village,  the  whole  population  turn  out  to  avert  the 
 impending  calamity.  The  black  disc  of  the  moon, 
 encroaching  upon  the  bright  surface  of  the  sun,  is 
 believed  to  be  the  jaws  of  a  monster  gradually  eat- 
 ing up  the  latter.  Tomtoms  are  violently  sounded, 
 the  air  is  rent  with  screams  of  terror  and  shouts  of 
 vengeance;    and   all  ihis  uproar    is  made  with  the 
 
TOTAL  ECLIPSE  OF  THE  SUN.      99 
 
 hope  of  scaring  away  the  dragon  from  his  dreaded 
 purpose.  For  a  time  their  efforts  are  in  vain.  The 
 glorious  sun  disappears  gradually  in  the  mouth  of 
 the  voracious  monster ;  but  at  last  increasing  din 
 seems  to  effect  its  purpose.  The  monster  appears 
 to  pause,  and,  like  a  fish  that  has  nearly  swallowed 
 the  bait,  but,  on  second  thought,  rejects  it,  gradu- 
 ally disgorges  the  burning  morsel.  When  the  sun 
 is  quite  clear  of  the  jaws,  a  shout  of  joy  is  raised, 
 and  the  villagers  disperse  with  the  pleasing  satis- 
 faction that  they  have  done  the  luminary  a  good  ser- 
 vice. This  is  but  a  type  of  the  human  mind  in  its 
 untutored  state,  when  it  is  unable  to  rise  to  the  con- 
 ception of  a  God  whose  glory  lies  in  the  orderly  and 
 regular  evolution  of  His  works  of  providence. 
 
 The  power  of  predicting  the  time  of  eclipses,  has 
 divested  such  phenomena  of  their  terror.  The  most 
 ignorant  Hindu  could  hardly  but  be  ashamed  of 
 his  superstition,  and  have  his  faith  in  his  tomtom 
 shaken,  if  the  astronomer  told  him,  beforehand,  the 
 precise  moment  when  the  monster  would  come  and 
 depart.  Eclipses,  more  than  anything  else,  demon- 
 strate the  perfect  regularity  of  the  motions  of  the 
 heavenly  bodies,  and  of  the  wisdom  of  Him  who 
 so  exquisitely  adjusted  to  one  another,  all  the  parts  of 
 the  celestial  machine.  No  doubt,  the  whole  nautical 
 almanac,  with  its  mass  of  figures,  is  full  of  predictions, 
 which  manifest  an  order  equal  to  that  indicated  by 
 eclipses.      Still,  an  eclipse,  with  its  imposing  phe- 
 
100     TOTAL  ECLIPSE  OF  THE  SUN. 
 
 nomena,  proclaims,  in  the  most  emphatic  mannerj 
 the  marvellous  order  of  the  heavenly  host.  An  idea 
 of  the  extreme  accuracy  with  which  the  moon's  posi- 
 tion, at  any  moment,  can  be  predicted,  may  be  formed 
 from  the  keen  dispute  at  present  (1860)  going  on  in 
 the  Academy  of  Sciences  between  Leverrier  and  M. 
 Delauny,  in  reference  to  the  lunar  theory  of  the  latter, 
 as  compared  with  that  of  M.  Hansen,  the  Danish 
 astronomer,  to  whom  is  due  the  merit  of  discovering 
 the  difference  of  density  between  the  nearer  and  more 
 distant  hemispheres  of  the  moon.  The  controversy 
 turns  on  the  value  of  a  constant  entering  into  the 
 calculation,  and  the  difference  between  the  two  views 
 is  only  a  space,  represented  by  the  one  three-hun- 
 dredth part  of  the  moon's  apparent  diameter.  Yet  on 
 these  few  seconds  of  space,  depends  the  result  of  an 
 important  question,  on  opposite  sides  of  which  the 
 chief  astronomers  of  our  day  are  ranged.  The  Astro- 
 nomical Society  of  London  have  virtually  given  their 
 decision  in  favour  of  Hansen,  by  crowning  him  with 
 their  highest  award  of  the  gold  medal.  They  have 
 recognised  his  lunar  tables  as  the  complete  solution  of 
 the  grand  nautical  problem  of  finding  the  longitude 
 at  sea.  The  problem  consisted  in  merely  assigning, 
 with  absolute  accuracy,  the  place  of  the  moon  in  the 
 heavens  at  any  given  time.  Hitherto  this  was  not 
 done,  as  the  perplexing  and  complicated  irregularities 
 of  the  moon's  motion,  baffled  all  attempts  to  calculate 
 her  position  with  the  requisite  accuracy.     There  are, 
 
TOTAL  ECLIPSE  OF  THE  SUN,     loi 
 
 even  still,  some  outstanding  errors  which  are  to  be 
 accounted  for,  but  they  are  so  small,  that  any  further 
 approximation  would  practically  be  of  no  service  to 
 the  mariner. 
 
 Every  time  the  sailor  takes  a  lunar  with  his  sex- 
 tant, he  has  a  practical  illustration  of  the  triumphs  of 
 astronomy,  in  assigning  the  exact  place  of  the  moon 
 at  any  moment  in  the  heavens.  Still,  every  mind 
 must  feel  the  more  startling  effect  produced,  when,  in 
 an  eclipse  of  the  sun,  the  first  impact  of  the  moon 
 coincides  with  the  very  beat  of  the  clock  predicted 
 by  the  astronomer  j  and  predicted,  too,  not  as  an  em- 
 pirical deduction  from  previously  observed  regularity 
 but  as  the  result  of  the  all-pervading  force  of  gravita- 
 tion, which  not  only  produces  the  most  bewildering 
 inequalities,  but  furnishes,  by  its  simple  law,  a  key 
 by  which  they  may  be  all  reduced  to  the  most  won- 
 derful symmetry  and  order. 
 
 We  have,  however,  on  the  present  occasion,  taken 
 up  the  subject  of  eclipses,  not  so  much  with  the  view 
 of  illustrating  the  accuracy  of  astronomical  calcula- 
 tions, as  of  turning  the  attention  of  our  readers  to  tlie 
 physical  aspects  of  the  total  eclipse  on  the  18th  of 
 July  1860.  No  total  eclipse  has  been  witnessed  in 
 these  islands  for  several  generations.  The  last  ob- 
 served at  Greenwich,  was  in  1715 ;  and  there  was  an 
 interval  of  375  years  between  this  and  the  previous 
 one.  The  chance  of  a  person  ever  witnessing  in  his 
 lifetime  a  total  eclipse  in  any  given  spot  of  the  earth's 
 
102     TOTAL  ECLIPSE  OF  THE  SUN. 
 
 surface,  is  exceedingly  small.  The  shadow  forms 
 only  a  narrow  band  on  the  earth's  surface,  and  though 
 that  strip  of  darkness  will  cross  Europe  six  times 
 during  the  remainder  of  the  present  century,  yet  com- 
 paratively few  places  will  enjoy  the  spectacle.  It  is 
 certain  that  none  of  the  present  inhabitants  of  the 
 British  Isles  will  ever  see  a  total  eclipse,  if  they  do 
 not  move  beyond  their  own  shores.  But  if  the 'shadow 
 does  not  come  to  us,  we  have  the  alternative  of  going 
 to  the  shadow. 
 
 It  may,  however,  be  asked.  Is  it  worth  while  to  go 
 much  out  of  one's  way  to  enjoy  the  spectacle?  We 
 have  seen  eclipses  very  nearly  total,  and  we  can 
 readily  conceive  one  that  is  absolutely  so.  Would 
 it,  then,  really  reward  one  to  travel  far  to  behold  a 
 sight  which  may  differ  so  little  from  what  we  have 
 already  seen  ?  We  can  give  a  very  decided  answer 
 to  this  question.  No  approach  to  totality  can  give 
 the  slightest  conception  of  the  effect  produced,  the 
 instant  that  the  last  thread  of  light  is  extinguished. 
 The  light  of  the  sun  is  so  intense,  that  while  the 
 slightest  part  of  the  disc  is  visible,  the  darkness  is  by 
 no  means  alarming.  The  eclipse  of  1857,  which  was 
 nearly  total,  gave  great  disappointment  to  many  who 
 were  led  to  expect  something  very  appalling.  Ac- 
 counts of  total  eclipses  were  previously  given,  and  it 
 was  a  natural  and  popular  expectation,  that  one  so 
 nearly  total  would  produce  effects  very  similar.     But 
 
TOTAL  ECLIPSE  OF  THE  SUN.     103 
 
 such  was  not  the  case.  The  darkness  was  no  greater 
 than  that  often  produced  by  a  passing  cloud,  and,  in 
 the  case  of  many,  the  eclipse  occurred  without  being 
 in  the  least  noticed.  Partial  and  annular  eclipses  are 
 now  regarded  as  matters  of  mere  curiosity,  and  a 
 momentary  glance  upwards  is  regarded  as  all  that  is 
 demanded  in  the  way  of  attention.  It  is  far  other- 
 wise with  the  total  eclipse.  The  gradual  creeping  of 
 the  moon  over  the  disc  of  the  sun,  gives  no  prepara- 
 tion for  the  grand  final  effect  when  the  last  ray  is 
 quenched.  It  is  felt  not  to  be  a  matter  of  gradation, 
 so  frightfully  sudden  is  the  darkness.  There  is  no 
 comparison  between  a  man  nearly  drowned  and 
 drowned  altogether,  or  between  a  man  half  over  a 
 precipice  and  over  altogether ;  so  there  is  no  compa- 
 rison between  a  nearly  total  eclipse  and  one  abso- 
 lutely total.  As  it  is  the  last  straw  that  breaks  the 
 back  of  the  camel,  so  it  is  the  extinction  of  the  last 
 line  of  light  that  produces  the  darkness  that  may  be 
 felt;  and  the  "feeling  of  the  darkness"  is  hardly  a 
 metaphor,  as  the  borders  of  the  terrible  pall  thrown 
 over  the  earth  can  be  actually  seen  swiftly  floating 
 past  in  the  air. 
 
 In  these  days,  when  the  passion  for  travel  is  so 
 strongly  developed,  people  are  ready  to  go  any  dis- 
 tance to  experience  a  new  and  strong  sensation.  They 
 do  not  scruple  to  traverse  the  Atlantic,  that  they  may 
 gaze  on  the  Falls  of  Niagara,  or  shoot  the  rapids  of 
 
104     TOTAL  ECLIPSE   OF  THE  SUN. 
 
 the  St  Lawrence ;  but  such  sights  are  not  to  be  com- 
 pared to  a  total  eclipse,  if  measured  by  the  power  of 
 stirring  strong  emotion.  In  an  eclipse,  all  things 
 combine  to  deepen  the  effect ;  there  is  nothing  out  of 
 keeping  with  the  grandeur  and  awfulness  of  the 
 spectacle.  In  viewing  the  Falls  of  Niagara,  there  is 
 much  to  tone  down  the  feelings  of  awe  and  wonder. 
 Familiarity  has  destroyed  man's  reverence ;  merry, 
 laughing,  picnic  parties  dispel  the  charm.  Blondin 
 exhibits  his  tight-rope  feats  in  their  presence.  The 
 very  birds  despise  their  terrors,  and  dash  heedlessly 
 into  the  spray,  to  catch  the  stupefied  fish  as  they 
 come  tumbling  down  the  liquid  arch.  The  descent 
 of  the  rapids  of  the  St  Lawrence,  however  daring  the 
 exploit  may  at  first  seem,  fails,  from  the  requisite 
 accessaries,  to  produce  a  very  powerful  sensation. 
 When  shooting  the  Long  Sault,  or  even  the  Lachine, 
 or  the  Cedars,  there  is  no  overpowering  feeling.  The 
 Indian  at  the  wheel,  with  his  imperturbable  matter- 
 of-fact  every-day  expression  ;  the  old  traveller,  not 
 caring  to  rise  from  the  breakfast-table  to  look  out  on 
 the  tumultuous  rush  of  waters;  the  air  of  security 
 around,  all  combine  to  break  the  spell  of  that  wonder- 
 ful feat.  It  is  quite  different  in  the  case  of  the  total 
 eclipse.  All  nature  sympathises  with,  and  enhances 
 your  feelings  of  awe  and  mysterious  apprehension. 
 The  earth,  seas,  and  sky  assume  a  lurid,  unnatural  hue. 
 An  unearthly  silence  is  felt  at  the  moment  of  totality. 
 Every  living  thing  catches  the  influence,  and  cowers 
 
TOTAL  ECLIPSE  OF  THE  SUN.     105 
 
 under  the  great  blank  in  the  heavens.  Beasts  of 
 burden  lie  down  with  their  loads  on  the  road,  and 
 refuse  to  move  on.  Swallows,  in  their  bewilderment, 
 dash  against  the  walls  of  houses,  and  fall  down  dead. 
 The  dog  drops  its  bone  from  its  mouth,  and  does  not 
 venture  to  seize  it  again  till  the  light  returns.  Chickens 
 seek  the  shelter  of  the  parent  wing ;  and  even  ants 
 halt  in  their  tracks  with  their  loads,  and  remain  im- 
 movable till  the  shadow  is  past. 
 
 With  such  accessaries  as  the  above,  it  cannot  be 
 wondered  at  that,  in  the  case  of  man,  however  im- 
 passive his  nature  may  be,  a  total  eclipse  never  fails 
 to  produce  feelings  of  mysterious  awe.  The  most 
 learned  savant,  as  well  as  the  most  unsophisticated 
 peasant,  confesses  to  such  feelings.  It  is,  however, 
 when  men  are  massed  together,  that  the  finest  oppor- 
 tunity is  afforded  for  watching  the  psychical  effects  of 
 an  eclipse.  Such  an  opportunity  was  enjoyed  by  the 
 French  astronomers,  when  observing  the  total  eclipse 
 of  1842  at  Perpignan.  The  observers  were  stationed 
 on  the  ramparts  with  their  instruments  ;  the  soldiers 
 were  drawn  up  in  a  square  on  one  hand,  and,  on  the 
 other,  the  inhabitants  were  grouped  on  the  glacis,  so 
 that  the  station  commanded  the  full  view  of  twenty 
 thousand  upturned  faces.  The  astronomers  did  not 
 fail  to  watch  the  phases  of  feeling  in  the  crowd,  as 
 well  as  those  of  the  eclipse.  The  moment  that  the 
 people,  with  smoked  glasses  to  their  eyes,  marked  the 
 first  indentation  in  the  sun's  disc,  they  raised  a  deaf- 
 
io6     TOTAL  ECLIPSE  OF  THE  SUN, 
 
 ening  shout  of  applause,  much  in  the  way  in  which 
 they  would  salute  a  military  hero,  or  a  popular  actor. 
 The  moon  gradually  crept  over  the  sun,  and,  for  a 
 considerable  time,  there  was  nothing  observable  but 
 the  ordinary  loquacity  of  a  French  crowd.  As  the 
 eclipse  drew  towards  totality,  the  murmur  of  twenty 
 thousand  voices  rapidly  increased — each  telling  his 
 neighbour  of  the  strange  feelings  coming  over  him. 
 Suddenly,  the  last  filament  of  the  sun's  disc  was 
 covered,  and,  at  that  moment,  a  deep  prolonged  moan, 
 as  from  one  man,  arose  from  that  vast  crowd.  It  was 
 like  the  stifled  groan  of  the  multitude  witnessing  a 
 public  execution,  at  the  moment  that  the  axe  or  the 
 drop  falls.  The  moan,  however,  did  not  mark  the 
 climax  of  high-strained  feeling.  The  dead  silence 
 that  ensued  was  the  culminating  point.  Not  a  whisper 
 was  heard,  not  an  attitude  was  changed,  as  with  the 
 rigidity  of  a  statue  each  man  stood  and  gazed  upwards. 
 So  unearthly  was  the  silence,  that  the  beat  of  the 
 chronometers  was  heard  with  painful  distinctness. 
 The  heart  of  the  universe  seemed  to  cease  its  throb- 
 bings.  Nature  had  fallen  into  a  state  of  syncope. 
 For  two  and  a  half  minutes  this  dreadful  pause  con- 
 tinued. At  the  end  of  this  period  a  thread  of  light 
 burst  forth ;  the  tension  was  at  once  relieved,  and  one 
 loud  burst  of  joy  rent  the  heavens.  The  people  could 
 not  restrain  their  transports  of  happiness,  now  that  the 
 dread,  undefinable  woe  had  passed  over.  They  did 
 not  care  now  to  look  at  the  final  phase  of  the  eclipse, 
 
TOTAL  ECLIPSE  OF  THE  SUN.     107 
 
 as  the  darkness  wore  off;  they  had  beheld  the  crown- 
 ing spectacle ;  they  would  not  weaken  the  impression 
 by  looking  at  the  partial  obscuration,  and,  soon,  the 
 whole  crowd  melted  away — leaving  the  astronomers 
 to  continue  their  observations  alone. 
 
 We  have  seen  how  the  eclipse  told  upon  a  French 
 crowd,  noted  for  its  impressible  and  demonstrative 
 character.  But  there  were  also  numerous  illustrations 
 of  its  power  over  individuals.  Take  one  as  a  speci- 
 men : — A  young  boy,  on  the  same  occasion,  was  herd- 
 ing a  few  sheep  in  a  lonely  heath,  under  a  cloudless 
 sky ;  he  felt  a  strange  darkness  coming  over  the  face 
 of  nature,  and  at  the  moment  of  totality,  he  fled  to- 
 wards home,  sobbing  piteously.  Before  he  reached 
 the  door,  the  sun  burst  forth,  and  in  the  transport  of 
 his  joy,  he  clapped  his  hands,  exclaiming,  "  Beautiful 
 sun !  beautiful  sun  ! " 
 
 We  have  viewed  the  total  eclipse  merely  as  a  spec- 
 tacle of  surpassing  grandeur ;  but  it  is  one,  too,  of  the 
 greatest  scientific  interest,  as  throwing  unexpected 
 light  on  the  physical  constitution  of  the  sun — 
 
 "  Who  could  have  thought  such  darkness  lay  conceal'd 
 Within  thy  beams,  0  sun  !  or  who  could  find. 
 Whilst  fly,  and  leaf,  and  insect  stood  reveal'd, 
 
 That  to  such  countless  orbs  thou  mad'st  us  blind  ! 
 Why  should  we  then  shun  death  with  anxious  strife  ? 
 If  light  can  thus  deceive,  wherefore  not  life  ? " 
 
 If  night  can  give  us  a  surprise  by  revealing  countless 
 worlds,  the  eclipse  can  also  surprise  by  revealing  a 
 new  glory  of  the  sun.    When  the  totality  is  complete, 
 
io8     TOTAL  ECLIPSE  OF  THE  SUN. 
 
 a  corona  bursts  out  around  the  black  circle,  like  the 
 glory  that  surrounds  the  heads  of  saints  in  the  pic- 
 tures of  the  old  masters.  This  corona  has  usually 
 been  observed  to  consist  of  two  zones  or  concentric 
 strata.  The  innermost  is  the  brighter  of  the  two, 
 and  the  light  is  nearly  uniform.  The  outer  and 
 fainter  zone  is  diversified  with  radiating  beams.  In 
 consequence  of  the  light  of  the  corona,  the  dark- 
 ness is  by  no  means  so  great  as  that  of  night. 
 The  degree  of  obscuration  is  best  measured  by  the 
 number  of  stars  visible.  In  all  the  authentic  accounts 
 of  total  eclipses,  none  but  the  brighter  stars  have 
 been  seen. 
 
 The  most  remarkable  and  baffling  phenomenon,  is 
 the  rose-coloured  prominences  seen  in  the  innermost 
 and  brighter  zone.  They  affect  curious  shapes ;  one, 
 seen  in  the  eclipse  of  1851,  has  been  designated  the 
 boomerang,  another,  the  balloon.  Some  have  been 
 compared  to  the  teeth  of  circular  saws,  others  to  the 
 flames  issuing  from  the  top  of  a  burning  house,  and 
 driven  aside  by  the  wind. 
 
 The  most  important  inquiry  that  suggests  itself 
 is,  '•'-  Does  this  corona  belong  to  the  sun,  the  moon, 
 or  the  earth  ? "  This  point  has  been  keenly  dis- 
 puted ;  but  the  general  belief  is  that  it  is  an  appen- 
 dage of  the  sun.  Father  Secchi,  to  whose  discoveries 
 in  regard  to  the  nature  of  the  moon's  surface  allu- 
 sion has  been  made  above,  is  disposed  still  to  refer 
 the  phenomenon  to  the  moon,  and  to  explain  it  by 
 means  of  his  discoveries.     It  is  a  much  more  pro- 
 
Plate  I! 
 
 TOTAL    ECLIPSE   OF  THE   SUN 
 
TOTAL  ECLIPSE  OF  THE  SUN.     109 
 
 bable  supposition  that  the  corona  is  the  atmosphere 
 of  the  sun  extending  beyond  its  luminous  disc,  and 
 that  the  red  flames  are  substances  floating  in  that 
 atmosphere.  In  ordinary  circumstances,  the  photo- 
 sphere of  the  sun,  or  luminous  envelope,  is  so  over- 
 powering, that  the  corona  and  the  prominences  are 
 invisible.  When,  however,  the  eye  is  protected  by 
 the  moon  covering  the  luminous  disc,  they  are  at 
 once  revealed.  No  plausible  theory  has  yet  been 
 given  to  explain  the  nature  of  the  red  flames.  Some 
 have  attempted  to  trace  a  coincidence  between  the 
 position  of  the  flames  and  that  of  the  dark  spots  of 
 the  sun ;  and  it  has  been  conjectured  from  this,  that 
 these  dark  spots  are  funnels  in  the  luminous  envelope, 
 through  which  inflammable  gases  rise,  and  are  burned 
 in  the  region  of  the  corona  or  atmosphere,  where  they 
 appear  as  red  flames.  Others  hold  that  the  promi- 
 nences are  only  the  crests  of  the  waves,  or  faculse 
 of  the  photosphere.  The  truth  is,  that  we  have  al- 
 most no  ground  whatever,  as  yet,  on  which  to  base  a 
 theory.  It  was  thought  that  during  the  last  eclipse 
 of  1851  several  points  would  be  set  at  rest ;  but  the 
 evidence  was  very  conflicting,  arising  very  much  from 
 the  flurried  state  of  feeling  caused  by  the  startling 
 character  of  the  phenomena,  and  their  very  brief  du- 
 ration. European  astronomers  are  looking  forward  to 
 the  eclipse  of  the  present  year  (1860)  with  eagerness, 
 as  it  is  confidently  expected  that  it  will  be  conclusively 
 settled  whether  the  corona  and  red  prominences  really 
 belong  to  the  sun  or  the  moon ;  and,  for  this  purpose, 
 
no     TOTAL  ECLIPSE  OF  THE  SUN. 
 
 attention  will  be  directed  to  two  points  in  the  pheno- 
 mena— first,  whether  the  corona  retains  its  symmetry, 
 or  continues  concentric  with  the  black  circle  of  the 
 moon  during  the  totality  j  and,  secondly,  whether, 
 during  the  same  period,  the  red  flames  change  their 
 position  on  the  circumference  of  the  moon.  If  there 
 be  a  want  of  symmetry,  and  if  the  flames  change 
 their  place,  the  evidence  is  conclusive  that  the  appen- 
 dage belongs  to  the  sun. 
 
 Another  point  of  interest  will  be  the  search  for  the 
 newly-discovered  planet  Vulcan.  It  is  expected  that 
 it  will  be  readily  found,  from  our  knowlege  of  its 
 approximate  place. 
 
 To  make  amends  for  the  imperfection  of  the  testi- 
 mony of  the  human  eye  in  such  unusual  circum- 
 stances, it  is  intended  to  employ  an  artificial  sub- 
 stitute, which  wall  record  the  impression  with  due 
 calmness  and  fidelity.  This  is  to  be  done  by  apply- 
 ing a  sensitive  photographic  surface  to  the  telescope, 
 instead  of  the  human  retina.  In  other  words,  photo- 
 graphic pictures  of  the  eclipse  are  to  be  taken,  and 
 under  Mr  De  La  Kue's  superintendence,  we  may 
 expect  all  that  skill  and  experience  can  effect 
 
 We  are  persuaded  that  many,  beside  professed 
 astronomers,  will  seize  this  opportunity  of  beholding 
 the  grandest  spectacle  in  nature.  And  why  should 
 they  not  ?  It  is  not  a  matter  specially  belonging  to 
 the  astronomer.  It  involves  no  profound  calcula- 
 tions, nor  demands  any  delicate  astronomical  methods. 
 
TOTAL  ECLIPSE  OF  THE  SUN.     iii 
 
 It  is  simply  a  physical  phenomenon^  which  any  in- 
 telligent observer  can  appreciate  as  much  as  the  astro- 
 nomer. Indeed,  the  astronomer  with  all  his  imposing 
 instruments,  has,  as  yet,  contributed  little  more  than 
 any  one  might  have  done  with  the  use  of  his  naked 
 eye.  Any  one  who  goes  merely  for  the  enjoyment  of 
 the  spectacle,  should  discard  all  scientific  pretensions, 
 and  abjure  the  use  of  instruments.  The  time  of  obser- 
 vation is  so  brief,  that  the  attention  would  be  dis- 
 tracted and  the  enjoyment  destroyed  by  attempting  to 
 employ  any  optical  appliances. 
 
 The  most  accessible  part  of  the  eclipse's  track  is 
 in  the  north-west  of  Spain.  The  centre  of  the  shadow 
 first  touches  the  coast  about  Santander,  and  crosses 
 the  peninsula  nearly  along  the  valley  of  the  Ebro. 
 The  French  astronomers  have  selected  the  lofty 
 mountain  of  Moncayo,  as  being  in  the  very  centre  of 
 the  shadow,  and  enjoying  a  climate  that  precludes  all 
 fear  of  disappointment.  There  is,  however,  no  need 
 to  climb  a  mountain  to  enjoy  the  spectacle  to  advan- 
 tage. The  mere  amateur  will  have  much  more  scope 
 for  observation  in  the  neighbourhood  of  a  populous 
 town.  Perhaps  the  best  for  this  purpose  is  Vittoria. 
 The  traveller  reaches  Bayonne  from  Paris  by  rail- 
 way the  whole  distance,  and  the  distance  from 
 Bayonne  to  Vittoria  across  the  Cantabrian  Pyrenees  is 
 only  about  twenty-five  miles,  the  journey  being  per- 
 formed by  diligence.  The  eclipse  is  also  total  at 
 Pampeluna,  Burgos,  Santander,  Bilbao,  Eeynosa,  all 
 
112     TOTAL  ECLIPSE  OF  THE  SUN. 
 
 in  the  same  region.  The  Spanish  Government  have 
 promised  every  facility  to  travellers,  and,  notwith- 
 standing the  Carlist  insurrection  in  the  district,  there 
 is  little  fear  of  political  discomfort.  Mr  Brassey 
 with  his  army  of  navvies  is  busy  as  the  pioneers  of 
 civilisation,  in  the  valley  of  the  Ebro.  He  and  Mr 
 Vignoles,  the  engineer  of  the  railway  in  progress, 
 have  generously  offered  any  aid  in  their  power  to 
 travellers.  It  is  understood  that  the  Admiralty  are 
 ready  to  put  a  steamship  at  the  disposal  of  such' 
 observers  as  wish  to  go  by  sea,  and  to  land  at  San- 
 tander.  The  rare  opportunity  is  thus  afforded  of 
 combining  a  visit  to  one  of  the  most  interesting 
 regions  of  the  earth's  surface,  with  the  sight  of  the 
 gi-andest  spectacle  the  heavens  can  present. 
 
Section  of  the  Sun. 
 
 VIIL 
 
 THE  SUN :  ITS  WOEK  AND  STEUCTUEE. 
 
 John  Kitto,  Lefore  leaving  for  Cannstadt  to  lay  his 
 ashes  in  its  quiet  churchyard,  was  persuaded  to  have 
 his  likeness  taken  by  the  photographic  process.  Not- 
 withstanding the  sadness  that  weighed  on  his  heart, 
 he  could  not  restrain  the  humour  which  so  often 
 served  to  buoy  up  his  sinking  spirits.  He  remarked 
 to  his  daughter,  while  the  photographer  was  adjust- 
 ing the  apparatus,  that  "  the  sun  had  hitherto  lived 
 
114  THE  SUN: 
 
 like  a  gentleman,  but  that  now  lie  was  obliged  to 
 work  for  his  living."  But  he  was  mistaken  in  think- 
 ing that  the  sun  had  ever  the  life  of  a  gentleman. 
 He  has  always  worked  as  a  slave,  nay,  he  has  been 
 always  the  slave  of  slaves.  He  has  really  done  all 
 the  work,  while  men  and  their  machines  have  taken 
 all  the  credit  to  themselves.  They  have  only  directed 
 the  work,  while  all  the  power  has  been  supplied  by 
 the  sun.  AVe  speak  of  the  marvellous  power  of  the 
 steam-engine;  but  to  what  does  it  owe  its  power? 
 The  answer  is,  the  elasticity  of  steam.  But  how  is 
 this  elasticity  accounted  for?  The  answer  is  equally 
 ready,  that  the  heat  of  the  furnace  has  produced  it. 
 But  the  circle  of  causation  is  not  yet  complete.  From 
 what  source  has  the  coal  derived  its  heat  ?  Till  lately 
 the  answer  would  be  held  satisfactory,  that  the  coal 
 is  fossil  wood,  and  therefore  it  produces  heat  by  burn- 
 ing. But  we  must  now  wring  from  nature  the  secret 
 of  this  possession  of  heat  and  power  by  coal.  The 
 answer  of  science  is,  that  the  coal  is  merely  a  recep- 
 tacle for  the  heat  and  light  of  the  sun.  The  sun's 
 energy  is  bottled  up,  as  it  were,  in  the  coal,  and  the 
 burning  of  it  is  the  uncorking  of  the  bottle.  It  may 
 be  said  that  this  is  only  a  play  upon  words,  as  it  is 
 a  mere  truism  to  hold  that  a  tree  could  not  grow 
 without  the  influence  of  the  sun,  and  that  there 
 could  be  no  coal  without  trees;  but  that  this  does  not 
 imply  that  the  heat  of  the  coal  is  the  very  heat  of 
 the  sun.     Now,  what  we  ^vish  to  impress  is,  that  the 
 
ITS   WORK  AND  STRUCTURE.      115 
 
 identity  is  complete,  and  this  results  from  the  grand 
 generalisation  of  recent  times,  that  force,  and  heat  is 
 but  a  form  of  force,  is  indestructible,  just  as  matter  is 
 indestructible.  God  has  created  a  certain  amount  of 
 force,  as  well  as  of  matter,  in  the  universe,  and  it  is 
 inconceivable  that  either  should  ever  bo  lessened  in 
 amount,  except  by  a  miraculous  act  of  annihilation. 
 This  generalisation  now  looks  like  a  truism  j  but  how 
 strano-e  is  it,  that  the  human  mind  should  arrive  at  it 
 only  in  very  recent  times.  But  so  it  is  in  the  whole 
 history  of  human  thought.  The  inscrutable  mystery 
 of  one  period  is  the  self-evident  axiom  of  another. 
 
 Another  source  of  power  of  which  we  avail  our- 
 selves is  the  fall  of  water.  We  plant  our  mills  on 
 the  banks  of  a  stream,  and  the  descent  of  the  water 
 turns  the  wheel.  We  do  not  readily  think  of  the 
 impalpable  rays  of  the  sun  turning  the  spokes  of  the 
 wheel ;  and  yet  the  connexion  is  easily  traced.  The 
 rays  elevate  the  water  in  the  form  of  vapour  from  one 
 level  to  a  higher ;  the  vapour  is  deposited  in  the  form 
 of  rain ;  the  rain  accumulates  in  the  river ;  the  river 
 fills  the  buckets  of  the  wheel,  and  through  the  opera- 
 tion of  the  wheel,  the  heat  of  the  sun  is  converted 
 into  useful,  industrial  work ;  and  this  is  done  as  really 
 as  if  the  rays  turned  round  directly  the  spokes  of  the 
 wheel. 
 
 It  may  be  said  that  there  is  one  kind  of  power  at 
 least  which  cannot  possibly  be  traced  to  the  sun — 
 viz.,  animal  power.     The  horse  in  harness,  or  the 
 
ii6  THE  SUN: 
 
 labourer  with  his  spade,  surely  exercises  a  power  that 
 has  no  relation  to  the  sun.  Is  not  volition  a  power 
 altogether  distinct  from  material  force?  Does  not 
 the  will  create  force?  Science,  however,  clearly 
 shews  that  this  is  no  exception  to  the  general  rule. 
 The  body  is  to  man  what  the  coals  are  to  the  steam- 
 engine.  The  mind  may  direct,  but  it  cannot  create. 
 And  every  time  that  a  man  strikes  a  blow  with  a  j 
 hammer,  he  as  surely  wastes  a  certain  amoui  t  of 
 physical  force  stored  up  in  his  body  as  every  stroke 
 of  the  piston  in  a  steam-engine  wastes  a  certain 
 amount  of  coals  in  the  furnace.  The  waste  of  tissues 
 in  the  body  corresponds  to  the  combustion  of  coals 
 in  the  furnace.  But  whence  the  power  stored  up 
 in  these  tissues  ?  The  answer  is,  from  the  sun.  All 
 animal  structures  can  be  ultimately  traced  to  vege- 
 table food ;  and  the  vegetable  world  is  only  the 
 storehouse  of  the  force  emanating  from  the  sun. 
 The  only  force  existing  on  the  face  of  the  earth  not 
 traceable  directly  to  the  sun  is  that  of  the  tides.  The 
 tides  would  exist  if  the  fluidity  of  the  ocean  could  be 
 maintained,  even  though  the  heat  of  the  sun  was  ex- 
 tinguished. The  trade  winds  are  also  in  part  inde- 
 pendent of  the  sun,  the  direction  being  due  to  the 
 rotation  of  the  earth.  These,  however,  form  but  in- 
 significant exceptions  to  the  general  rule,  that  the 
 power  available  for  the  purposes  of  man  can  be  traced 
 to  the  sun  as  the  great  source. 
 
 The  sun^  then,  is  the  great  worker,  and  the  slave 
 
ITS   WORK  AND  STRUCTURE.      117 
 
 of  man.  He  works  every  spinning-jenny  in  our 
 manufacturing  towns,  forges  every  shaft,  propels 
 every  ship,  turns  every  water-wheel,  and  moves  the 
 limbs  of  every  man  and  animal.  Man,  with  the 
 power  of  intellect,  merely  stands  over  him  with  the 
 rod  of  dominion,  and  directs  his  giant  strength  to 
 suitable  tasks.  In  one  point  of  view,  we  may  well 
 exclaim,  ^'  What  is  man,  that  thou  art  mindful  of 
 him  ?  or  the  son  of  man,  that  thou  shouldst  visit 
 him?"  But  the  above  views  give  new  force  to  the 
 declaration,  ^^  Thou  hast  crowned  him  with  glory 
 and  honour ;  thou  madest  him  to  have  dominion 
 over  the  works  of  thy  hands  :  thou  hast  put  all 
 thin2:s  under  his  feet." 
 
 The  triumphs  of  mechanical  genius  are  the  boast 
 of  our  age,  as  well  as  the  foundation  of  much  of  our 
 national  wealth  j  but  how  rude  are  the  inventions  of 
 men  compared  to  the  adjustments  of  the  Divine  Me- 
 chanician in  the  solar  system !  We  place  a  furnace 
 on  the  ground,  and  by  means  of  a  system  of  boilers, 
 cylinder,  piston,  levers,  shafts,  and  wheels,  are  en- 
 abled, in  the  topmost  storey  of  a  factory,  to  spin 
 thread  of  gossamer  fineness ;  and  no  intelligent  per- 
 son has  ever  witnessed  the  sight  without  being  im- 
 pressed with  the  marvellous  dominion  of  man  over 
 the  material  world.  But  how  puny,  after  all,  is  this 
 effort  compared  to  that  which  the  working  power  of 
 the  sun  exhibits  I  Here  the  furnace  is  not  placed  a 
 few  yards  distant,  but  95  millions  of  miles^  and  on 
 
ii8  THE  SUN: 
 
 what  a  stupendous  scale  I  This  world,  compared  to 
 the  sun,  is  no  larger  than  a  single  stone  of  St  Paul's 
 compared  to  the  whole  fabric.  It  is  one  of  the  most 
 difficult  problems  in  practical  mechanics  to  transmit 
 power  to  a  distance,  and  we  have  to  employ  the  rude 
 device  of  long  shafts,  as  in  factories ;  rope  and  drum, 
 as  in  the  case  of  railway  inclines;  or  air-pumps,  as  in 
 the  case  of  atmospheric  railways ;  and,  after  all,  we 
 can  only  act  at  a  very  limited  distance.  But  the  sun 
 transmits  its  power  many  millions  of  miles  without 
 the  aid  of  mechanical  contrivances,  and  so  smoothly 
 and  silently  that  we  are  almost  unconscious  of  its 
 working.  It  is  by  the  impalpable  lever  of  the  sun- 
 beam that  the  central  power  acts  on  our  distant  globe. 
 And  mark  how  conveniently  concentrated  the  sun- 
 beams are  for  our  daily  use.  Were  we  under  the 
 necessity  of  relying  upon  the  diffused  heat  of  the  sun, 
 it  would  be  very  difficult  to  apply  its  power.  We 
 might,  no  doubt,  employ  glasses  to  condense  the  rays 
 of  the  sun  upon  steam-boilers,  but  the  result  would 
 be  more  curious  than  useful.  We  have,  in  nature,  a 
 far  more  useful  condensation,  viz.,  fuel,  which  is  just 
 a  vehicle  for  the  sun's  power.  The  water-fall  is 
 another  convenient  form  of  condensed  power  supplied 
 to  oar  hand.  The  sun's  rays  are  imprisoned  by  the 
 very  act  of  raising  the  water  to  a  higher  level  ]  or,  in 
 other  words,  they  are  transformed  and  condensed  into 
 mechanical  power. 
 
 This  wondrous  mechanism,  by  which  the  power  of 
 
ITS   WORK  AND  STRUCTURE.      119 
 
 tlie  sun  is  transmitted  to  our  globe,  and  conveniently- 
 stored  up  for  man's  use,  is  to  us  a  far  more  striking 
 illustration  of  divine  intelligence,  than  the  mechan- 
 ism of  the  solar  system  by  which  its  stability  is 
 maintained.  The  attention  of  theologians  has  been 
 almost  exclusively  turned,  since  the  days  of  Newton, 
 towards  this  one  point,  as  the  grand  proof  of  a  pre- 
 siding intelligence.  But  it  may  be  questioned 
 whether  a  divine  intelligence  might  not  as  well  be 
 proved  from  the  order  of  a  system,  one  element  of 
 which  was,  that  the  present  arrangement  was  not  per- 
 manent, but  only  a  cycle  in  some  grander  evolution. 
 Were  it  proved,  as  some  astronomers  hold,  that  the 
 solar  system  and  the  system  of  Saturn's  rings  are 
 hastening  to  a  dissolution,  or  rather  fulfilling  their 
 role  as  parts  of  a  grander  scheme,  would  we  be  forced 
 to  abandon  the  whole  as  proving  a  divine  intelli- 
 gence? There  may  be  as  much  beauty  and  order 
 in  a  mutable  as  in  a  permanent  system,  and  where 
 these  elements  are  found,  we  have  proof  of  intelli- 
 gence. The  argument  for  intelligence  rises  to  a 
 higher  species  of  proof,  when  we  consider  not  merely 
 the  beautiful  adaptation  of  one  part  of  the  material 
 machine  to  another,  but  also  the  correlation  of  the 
 machine  to  life  and  intellect  Now,  the  most  mar- 
 vellous of  such  correlations  are  those  which  are  fur- 
 nished by  the  sun,  as  the  grand  moving  power  on 
 the  face  of  our  globe,  and  a  moving  power  in  virtue 
 of  its  light  and  heat.     Gravitation  is  not  properly  a 
 
120  THE  SUN: 
 
 moving  power.  It  is  only  a  condition,  not  a  source 
 of  power  to  man.  No  doubt,  if  wx  raise  a  stone  it 
 will  fall  by  gravity  to  the  earth,  w-hen  we  drop  it 
 from  our  hand;  but  the  great  w^ant  of  man  is  a 
 power  to  raise  ^the  weight,  and  w^hat  we  mean  by  a 
 moving  power  is  just  one  that  can  raise  a  weight. 
 Now,  the  sun,  as  the  great  central  furnace  of  the 
 machine,  is  the  prime  moving  power  of  the  world — 
 the  lifter  of  every  weight.  He  drives  the  great  shaft 
 of  the  machine,  and  all  that  man  does  is  merely  to 
 put  on  a  belt  upon  the  drum  when  he  wishes  to 
 utilise  the  powxr. 
 
 Man's  body  may,  no  doubt,  be  regarded  as  a 
 working  machine,  its  power  being  derived,  as  that 
 of  all  other  machines,  from  the  sun  ;  bijt  its  chief 
 function  is,  as  the  vehicle  of  intellect,  to  direct  the 
 illimitable  power  at  his  command.  ]Man,  valued 
 simply  as  a  source  of  mechanical  power,  is  worth 
 only  three  tons  of  coals.  Let  a  man  labour  all  the 
 days  of  his  life,  and  his  labour  will  not  exceed  the 
 mechanical  power  stored  up  in  a  single  truck  of  fuel. 
 Nothing  can  illustrate  more  strikingly  the  superiority 
 of  intellect,  and  afford  a  more  convincing  proof  that 
 the  differentia  of  man  is  mind,  and  that  his  body  is 
 but  an  accident.  It  was  needful,  however,  that  his 
 body  should,  to  some  extent,  be  a  source  of  power 
 to  open  the  sluices  of  energy  stored  up  in  the  material 
 world  around  him.  The  engine-driver  needs  bodily 
 strength  to  work  the  valves,  and  so  direct  the  giant 
 
ITS   WORK  AND  STRUCTURE.      121 
 
 power  that  is  to  propel  a  floating  palace  across  the 
 ocean  with  the  swiftness  of  a  race-horse.  Intellect 
 thus  enables  man  to  multiply  indefinitely  the  strength 
 of  his  body. 
 
 Let  us  now  turn  to  the  structure  of  the  vast  fur- 
 nace which  supplies  us  with  all  our  moving  power. 
 It  is  strange  how  little  attention  has  been  paid  till 
 recently  to  this  function  of  the  sun.  The  human 
 mind  seemed  to  be  quite  satisfied  with  the  grand 
 discovery  of  Newton,  that  the  sun  is  the  centre  of 
 gravitation  in  the  solar  system ;  and  can  we  wonder 
 that  it  should,  for  a  time,  be  entranced  with  the  dis- 
 covery, so  that  still  more  interesting  relations  of  the 
 sun  to  man  should  be  overlooked  ?  The  attention  of 
 physicists  has  now  been  fairly  arrested  by  this  sub- 
 ject, and  much  light  has  already  been  thrown  on  the 
 constitution  and  structure  of  the  sun. 
 
 Much  of  our  ignorance  of  the  constitution  of  the 
 sun  may  be  ascribed  to  the  awe  and  mystery  with 
 which  it  has  always  been  regarded.  The  oriental 
 worshipper  of  the  luminary  would  shrink  from  the 
 idea  of  unravelling  the  mystery  of  the  universe  by 
 too  curious  a  scrutiny,  and  a  similar  feeling  appears 
 to  have  restrained  the  prying  eye  of  the  astronomer. 
 The  spell  of  mystery  is  now  broken,  and  the  sun 
 must  submit  to  examination  like  any  of  his  subject 
 planets. 
 
 It  is  almost  incredible  that  there  is  no  authentic 
 account  of  observations  of  the  spots  on  the  sun  till  a 
 
122  THE  SUN: 
 
 very  recent  period.     Millions  of  worshippers  for  age3 
 hailed  the  rising  sun,  or  bowed  their  faces  at   his 
 setting  ;  and  yet  these  spots  seem  never  to  have  been 
 observed,  though  quite  noticeable  often  by  the  naked 
 eye.     One  would  almost  be  inclined  to  conclude  that 
 they  are  a  modern  feature  of  the  sun,  were  it  not  that 
 we  have  many  parallel  cases,  where  obvious  facts  have 
 been  overlooked  for  successive  generations.     The  ex- 
 perience of  most  people  will  corroborate  this  fact  from 
 their  own  experience.     How  few  have  actually  seen 
 a  spot  on  the  sun,  though  every  person  must  have 
 had  many  opportunities  of  observing  them  !     There 
 is  no  town  so  favourably  circumstanced  for  the  ob- 
 servation of  the  spots  as  Glasgow.     The  cloud  of 
 smoke  that  usually  hangs  over  it,  mingled  with  the 
 fog   of  the   river,   affords    an    admirable    darkening 
 medium  for  viewing  them  with  comfort.     Yet  how 
 few  of  the  inhabitants  have  seen  them,  though  there 
 are  few  days  in  winter  which  do  not  present  favour- 
 able opportunities  for  noticing  objects  often  so  con- 
 spicuous to  the  naked  eye. 
 
 It  was  probably  the  advantages  of  the  murky  at- 
 mosphere of  Glasgow  that  led  Dr  Wilson,  the  dis- 
 coverer of  the  nature  of  the  spots,  to  direct  his  atten- 
 tion to  the  subject.  His  theory  is  now  almost  univer- 
 sally adopted,  though  the  recent  results  of  spectrum 
 analysis  will  probably  lead  to  some  modification. 
 The  spots  are  perforations  in  the  luminous  envelope 
 of  the  sun,  through  which  we  see  its  dark  body. 
 This  envelope  or  photosphere  may  be  conceived  as 
 
ITS  WORK  AND  STRUCTURE.      123 
 
 a  stratum  of  luminous  cloud,  floating  in  a  trans- 
 parent atmosphere.  But  when  we  look  down  through 
 the  perforation,  we  see  the  edges  of  other  strata,  ap- 
 parently non-luminous.  Two  of  these  have  been 
 detected,  and  there  may  be  many  more.  The  sun 
 may  then  be  conceived  of  as  composed  of  a  dark 
 central  body,  encompassed  by  successive  envelopes 
 or  shells,  suspended  at  different  heights  in  the  at- 
 mosphere— the  uppermost  being  the  one  which  forms 
 the  luminous  disc  of  the  sun.  A  Chinese  ivory  ball, 
 composed  of  carved  concentric  shells,  represents  very 
 well  the  structure  of  the  sun  and  the  nature  of  the 
 spots.  In  looking  down  the  large  holes  in  the  ivory 
 ball,  we  see  the  successive  edges  of  the  concentric 
 shells,  and  in  like  manner  do  we  see  the  successive 
 edges  of  the  concentric  strata  of  the  sun.  The  visible 
 portion  of  the  middle  stratum  forms  the  penumbra 
 or  shading  round  the  black  centre,  which  is  merely 
 the  dark  body  of  the  sun  seen  down  through  the 
 perforation  or  funnel.  But  recently  another  grada- 
 tion of  shade  has  been  discovered,  indicating  another 
 stratum.  The  figure  at  the  head  of  this  article 
 illustrates  this.  The  outermost  unshaded  ring  re- 
 presents the  luminous  stratum,  and  the  other  two 
 interior  rings  are  the  non-luminous  strata,  which  may 
 so  shade  the  body  of  the  sun  as  to  fit  it  for  the  abode 
 of  living  beings. 
 
 The  late  solar  eclipse  was  looked  forward  to  with 
 intense  interest,  as  likely  to  throw  new  light  on  the 
 constitution  of  the  sun,  and  it  has  not  disappointed 
 
124  THE  SUN: 
 
 expectation.  The  two  grand  points  to  be  determined 
 were,  the  nature  of  the  red  flames,  and  that  of  the 
 corona  seen  dm-ing  the  time  of  totality.  In  regard 
 to  the  red  flames,  the  observations  of  Leverrier,  who 
 conducted  the  expedition,  are  quite  conclusive.  He 
 has  established  beyond  all  doubt  that  they  belong 
 to  the  sun.  But  not  only  so,  he  has  shewm  that 
 the  flames  are  only  prominences  in  a  red  stratum, 
 enveloping  the  whole  luminous  disc  of  the  sun. 
 Another  concentric  shell  has  thus  been  added  to  the 
 sun.  The  light  of  this  stratum  is  so  comparatively 
 faint,  that  it  is  quite  invisible,  except  when  the  moon, 
 in  a  total  eclipse,  intercepts  the  overpowering  light 
 of  the  white  disc.  When  we  look  at  the  disc  of  the 
 sun,  we  are  looking  through  this  rose-coloured  stra- 
 tum, but  its  colour  is  quite  obliterated  by  the  light 
 of  the  stratum  beneath.  It  has  been  supposed  that 
 the  prominent  flames  correspond  with  the  spots  in 
 the  sun,  as  if  they  were  caused  by  a  gas  rising  up 
 through  the  spots,  as  through  a  chimney  from  below. 
 When  we  view  the  disc  of  the  sun  with  a  telescope, 
 we  find  that  it  is  strangely  mottled  with  bright  w^avy 
 lines,  called  faculai^  and  minute  dark  points  through- 
 out its  wdiole  structure.  The  appearance  is  very 
 much  that  of  a  sponge.  The  corrugation  of  the 
 surface  of  the  sponge  represents  the  wavy  appear- 
 ance of  the  disc,  and  its  numerous  pores,  the  dark 
 points  in  question.  The  large  spots,  or  maculse, 
 may  be  represented  by  the  rugged  perforations 
 through  the  mass  of  the  spoage.     The  rose-coloured 
 
ITS   WORK  AND  STRUCTURE.      125 
 
 stratum  may  be  supposed  to  be  produced  by  some 
 gaseous  substance  pressing  up  through  the  structural 
 pores  of  the  photosphere,  and  the  prominences  rising 
 above  the  general  level  have  been  regarded  as  the 
 same  gaseous  product  issuing  in  greater  volume  from 
 the  spots  or  perforations.  The  stratum  of  smoke 
 hanging  over  a  large  manufacturing  town  presents 
 an  appearance  similar  to  that  of  the  rose-coloured 
 stratum  of  the  sun.  The  smoke  issuing  from  the 
 innumerable  chimneys  of  private  houses  corresponds 
 to  the  red  substance  issuing  from  the  pores  of  the 
 photosphere^  and  a  uniform  stratum  is  in  this  way 
 produced.  Above  the  general  level  are  the  tall 
 chimneys  of  factories,  vomiting  forth  their  volumes 
 of  smoke,  which  is  carried  away  by  the  wind,  parallel 
 to  the  murky  stratum  beneath.  The  shapes,  how- 
 ever, of  the  red  prominences  give  us  rather  the  idea 
 of  tongues  of  flame  than  of  volumes  of  smoke,  and  the 
 red  stratum  looks  like  a  sea  of  flame  violently  agitated 
 by  the  wind.  The  section  of  the  red  stratum,  seen  in 
 the  total  eclipse,  and  represented  in  our  illustrative 
 flgure,  suggests  the  idea  of  the  line  of  fire  presented 
 by  a  burning  forest  in  Canada,  or  a  pine  barren  in 
 Florida.  As  the  tide  of  fire  sweeps  along,  there  is  a 
 general  level,  but  the  flame  is  broken  up  into  distinct 
 tongues  and  waves ;  and  when  it  meets  with  some 
 ancient  and  lofty  clump  of  trees,  it  rushes  up  to  the 
 topmost  point,  and  this  burning  spire  towers  far 
 above  the  sea  of  fire  beneath.  In  some  places  there 
 may  be  a  calm,  and  the  tongues  shoot  straight  up  j 
 
126  THE  SUN: 
 
 at  other  places,  the  flames  are  agitated  by  a  fierce 
 tempest,  and  they  are  bent  at  right  angles  to  their 
 original  direction.  In  other  cases  still,  the  gas  does 
 not  take  fire  till  it  has  attained  a  considerable  height, 
 and  then  the  flame  appears  quite  detached  from  the 
 general  surface.  It  will  help  us  to  conceive  the 
 scale  of  the  conflagration  if  we  keep  in  view  that 
 some  of  the  single  tongues  of  flame  were,  in  the  late 
 eclipse,  more  than  300  times  larger  than  the  earth. 
 The  observations  in  connexion  with  the  recent  eclipse 
 do  not,  however,  confirm  the  supposition  that  the  red 
 prominences  coincide  with  the  spots  of  the  sun. 
 Leverrier  has  called  in  question  the  generally  re- 
 ceived theory  of  the  spots  of  the  sun.  He  reverts  to 
 the  old  hypothesis,  that  they  are  not  perforations 
 in  the  photosphere,  but  clouds  floating  in  the  atmo- 
 sphere. This  is,  however,  quite  inconsistent  with 
 the  facts  of  the  case.  The  spectrum  observations  of 
 Professors  Bunsen  and  Kirchhoff  rather  countenance 
 the  idea  that  the  photosphere  is  not  a  gaseous 
 envelope,  but  the  solid  body  of  the  sun  itself, — the 
 atmosphere  in  which  the  metals  are  found  being 
 supposed  to  be  exterior  to  the  photosphere.  The 
 phenomena  of  the  spots  are  irreconcilable  with  this 
 theory.  The  supposition  that  the  faculiB  are  due  to 
 waves  in  the  red  stratum  is  more  plausible. 
 
 Foucault  was  intrusted  with  the  observations  on 
 the  corona,  or  broad  zone  of  light,  extending  far 
 beyond  the  red  stratum,  and  presenting  very  mucli 
 the  appearance  of  the  glory  around  a  saint's  head. 
 
ITS   WORK  AND  STRUCTURE.      127 
 
 He  has  satisfied  himself  that  the  corona  is  not  the 
 atmosphere  of  either  the  sun  or  moon.  He  holds 
 that  it  is  not  an  objective  substance  at  all,  but  merely 
 an  affection  of  light,  due  to  tlie  edge  of  the  moon. 
 When  light  passes  the  edge  of  opaque  bodies,  it  is 
 diffracted  and  bent  into  the  shadow.  Foucault  holds 
 that  the  corona  is  merely  the  diffracted  light  of  the 
 sun.  The  radial  beams  of  light  seen  in  the  corona, 
 he  ascribes  to  prominences  in  the  contour  of  the 
 moon.  This  conclusion  cannot  be  admitted.  There 
 is,  on  other  grounds,  every  probability  that  there  is 
 an  atmosphere  in  winch  the  various  solar  strata  float, 
 and  we  would  have  reason  to  expect  that  this  atmo- 
 sphere would  be  rendered  visible  in  a  total  eclipse. 
 Father  Secchi  declares,  that  he  saw  the  corona  for 
 a  few  seconds  after  the  disc  of  the  sun  appeared; 
 and  such  a  phenomenon  is  incompatible  with  the 
 theory  of  diffraction.  None  of  the  observations  have 
 given  any  countenance  to  the  idea,  that  the  corona 
 is  the  atmosphere  of  the  moon.  Mr  Airey  holds 
 that  the  phenomenon  would  receive  a  satisfactory 
 explanation  dn  the  supposition  that  the  earth's  atmo- 
 sphere extended  to  the  moon.  The  corona,  in  that 
 case,  would  be  only  a  portion  of  the  earth's  atmo- 
 sphere illuminated  by  the  sun.  The  result  of  the 
 observations  of  the  late  eclipse  amounts  to  this,  that 
 the  red  prominences  have  been  proved,  beyond  all 
 doubt,  to  belong  to  the  sun,  and  that  they  are  mere 
 elevations  of  a  stratum  of  the  same  matter  enveloping 
 the  whole  solar  sphere.     The  photographic  observa- 
 
128  THE  SUN: 
 
 tions  of  Mr  Warren  de  la  Eue  are  very  conclusive. 
 He  took  several  views,  with  short  intervals  between, 
 which  clearly  exhibit  the  progress  of  the  moon  across 
 the  red  prominences.  While  those  on  the  one  side 
 were  gradually  elongated,  those  on  the  opposite  side 
 were  shortened.  This  clearly  proves  that  they  belong 
 to  the  sun,  and  not  to  the  moon,  the  probability  being 
 that  they  are  only  the  facul^e  seen  in  profile.  Vulcan 
 was  anxiously  looked  for,  but  it  was  not  detected. 
 
 When  we  look  with  curious  eye  into  the  glowing 
 furnace  of  a  steam-engine,  we  have  to  shade  our  face 
 from  the  fierce  glare,  and  survey  the  bars  and  boiler- 
 tubes  in  detail.  When  we  look  into  the  great  central 
 furnace  of  the  solar  system,  we  need  a  screen  too, 
 and  the  moon  admirably  serves  the  purpose.  It 
 most  effectually  intercepts  the  light  and  heat  of  the 
 central  parts,  so  that  we  may  descry  the  fainter 
 objects  round  the  circumference.  Night  reveals  to 
 us  a  new  glory  of  the  heavens,  by  unveiling  its  in- 
 numerable hosts,  and  the  darkness  of  the  eclipse  has 
 revealed  to  us  a  new  glory  of  the  sun.  This  strange 
 structure  is  not  an  isolated  case ;  it  has  a  typical 
 significance.  It  reveals  to  us  the  unity  of  plan  of 
 the  great  Architect.  This  concentricity  of  structure 
 is  probably  the  grand  archetypal  element  of  suns 
 and  planets.  Saturn  presents  a  curious  modification 
 — the  concentric  shells  being  reduced  to  concentric 
 rings ;  and  it  is  singular  enough,  that  the  red  shell 
 or  firmament  should  be  added  to  the  sun,  almost 
 
ITS   WORK  AND  STRUCTURE.      129 
 
 simultaneously  with  a  dark  ring  to  Saturn.  We 
 might  have  little  difficulty  in  tracing  indications  of 
 this  concentric  structure  in  the  other  planets,  but  we 
 may  not  linger  on  this  tempting  field  of  speculation. 
 
 Having  inspected  the  furnace,  which  is  the  grand 
 source  of  power  on  the  surface  of  the  earth,  the  inquiry 
 naturally  suggests  itself :  How  is  this  power  sustained? 
 How  is  the  furnace  kept  burning?  Formerly,  there 
 was  a  vague  idea  that  the  sun  could  dispense  heat 
 for  evermore  without  ever  wasting;  but  the  law  of  the 
 correlation  of  physical  forces  tells  us,  that  while  the 
 sum  of  force  in  the  universe  is  ever  the  same,  any 
 special  form  of  force  must  waste  by  exercise  unless 
 it  is  replenished.  The  sun  cannot  give  forth  force 
 without  loss,  unless  it  receives  in  turn.  The  favourite 
 theory  at  the  present  moment  is,  that  the  sun  is  sur- 
 rounded with  a  zone  of  fuel  in  the  form  of  meteorites, 
 and  that  it  is  supplied  from  this  source  as  the  furnace 
 of  a  locomotive  is  fed  from  the  tender  which  follows 
 it.  But  whence  comes  this  zone  ?  How  is  the  circle 
 of  correlation  to  be  completed  ?  Here  we  have  reached 
 the  boundaries  of  knowledge,  and  even  speculation  is 
 silent.  We  can  trace  only  a  few  links  of  the  chain 
 of  causation  depending  from  the  throne  of  the  Eternal; 
 the  last  link  is  hid  in  impenetrable  mystery.  ^^  Lo, 
 these  are  parts  of  his  ways,  but  how  little  a  portion  is 
 heard  of  him !  but  the  thunder  of  his  power  who  can 
 understand?" 
 
ABC  P  f- 
 
 ,  mifiii^^ 
 
 hm 
 
 iiin 
 
 'iiigiffiiiiiii'^^^^^"""""" ""'''I 
 
 ROY 
 
 1.  Lines  of  Solar  Srectrum.       2.   Colours  of  SfJar  Spectrum. 
 3.  Spectrum  of  Sodium.      4.  Spectrum  of  Lithium. 
 
 IX. 
 
 THE  CHEMISTRY  OF  THE  SUN. 
 
 Reference  has  already  been  made  to  the  results  of 
 spectrum  observations  by  Professors  Kirchhoff  and 
 Bunsen  of  Heidelberg.  The  method  of  research  is, 
 however,  so  important  as  to  demand  a  separate  notice. 
 A  new  era,  both  in  chemistry  and  astronomy,  has  been 
 inaugurated  by  the  discovery  of  this  method.  Suffi- 
 cient time  has  not  yet  elapsed  for  the  accumulation 
 
THE  CHEMISTRY  OF  THE  SUN.     131 
 
 of  results,  but  no  douLt  exists  as  to  the  incalculable 
 value  of  tlie  new  analysis. 
 
 When  a  ray  of  white  light  is  passed  through  a 
 prism,  it  is  separated  into  the  various  colours  of  the 
 spectrum,  viz.,  red,  orange,  yellow,  green,  blue, 
 indigo,  and  violet.  It  is  thus  shewn,  that  the  white 
 ray  is  compound — and  that  the  prism  decomposes 
 this  ray  into  the  variously-coloured  constituent  rays. 
 If  we  compare  the  white  ray  to  a  closed  fan,  the 
 opening  of  the  fan  will  represent  the  effect  of  the 
 prism,  in  spreading  out  and  representing  separately 
 the  constituent  rays.  We  shall  suppose  the  fan  to 
 consist  of  seven  ribs  or  sectors,  representing  the 
 seven  primitive  colours ;  when  the  fan  is  shut,  these 
 colours  are  not  visible,  but  when  it  is  opened  it  repre- 
 sents the  spectrum  of  white  light.  A  ray  of  white 
 light  may,  also,  be  compared  to  a  rope,  made  up  of 
 strands  of  the  various  colours  of  the  spectrum,  and  the 
 prism  serves,  by  refraction,  to  open  up  the  rope  and 
 present  the  strands  separately.  Perhaps  a  still  better 
 illustration  is  to  compare  the  white  ray  to  a  quantity 
 of  sand,  composed  of  seven  differently-coloured  kinds. 
 In  this  case,  the  prism  separates  the  different  kinds  of 
 sand,  and  assorts  them  in  distinct  coloured  layers — 
 there  being  always  a  regular  gradation  from  the  red 
 to  the  violet.  The  position  of  the  various  colours  in 
 the  spectrum  is  perfectly  fixed.  The  fan  may  be 
 opened  more  or  less,  but  the  relative  positions  of  the 
 ribs  are, always  the  same.    In  the  case  of  other  colours 
 
132     THE  CHEMISTRY  OF  THE  SUN. 
 
 than  white,  the  spectrum  of  course  gives  only  the 
 primitive  colours  necessary  to  make  up  the  given 
 colour.  If,  for  example,  yellow  is  wanting,  the  spec- 
 trum will  give  a  black  band  instead  of  a  yellow  one. 
 If,  on  the  other  hand,  the  colour  transmitted  through 
 the  prism  be  an  elementary  colour,  there  will  be  only 
 one  band,  as  in  the  case  of  the  yellow  flame  produced 
 by  sodium ;  all  the  other  colours  are  wanting,  and 
 only  one  yellow  band  is  given.  The  flame  in  which 
 lithium  is  difl'used,  gives  only  two  bands,  yellow  and 
 red. 
 
 The  value  of  the  discovery  of  the  researches  of 
 the  Heidelberg  professors  lies  in  this,  that  these 
 bands  are  proved  to  be  perfectly  characteristic  of  the 
 substances  which  produce  them ;  that  is,  each  sub- 
 stance has  its  own  distinctive  bands,  so  that  they 
 cannot  be  confounded  with  the  bands  of  any  other. 
 The  distinctive  marks  are — their  number,  breadth, 
 tone,  and  grouping  in  the  spectrum.  The  charac- 
 teristic lines  are  as  invariable  as  the  circles  of  longi- 
 tude and  latitude;  and  just  as  these  circles  fix  with 
 certainty  the  locality  of  any  city,  so  the  bands  in  the 
 spectrum  determine  the  nature  of  the  substance 
 emitting  the  colour  thus  decomposed. 
 
 The  delicacy  of  the  prism  in  detecting  minute 
 quantities,  far  surpasses  the  reagents  of  the  labora- 
 tory. One  hundred-millionth  of  a  grain  can  thus  be 
 detected.  A  very  minute  quantity  of  sodium  difl'used 
 in  a  room,  can  at  once  be  revealed  by  its  effect  on  the 
 
THE  CHEMISTRY  OF  THE  SUN.     133 
 
 flame  of  a  burner.  The  light  of  the  burner  has  only 
 to  be  transmitted  through  the  prism  in  order  that 
 it  may  yield  the  secret. 
 
 The  grand  discovery,  in  reference  to  solar  chemis- 
 try,  is  the  meaning  of  the  dark  lines  in  the  solar 
 spectrum.  Besides  the  bands  of  the  seven  primitive 
 colours,  there  are  innumerable  black  lines  which  cross 
 the  spectrum,  and  divide  the  colours  into  very  narrow 
 stripes.  In  the  cut,  the  diagram  of  lines  must  be  con- 
 ceived as  superimposed  on  that  of  the  colours.  These 
 lines  are  seen  when  the  sun's  rays  are  passed  through 
 a  narrow  slit  before  falling  on  the  prism.  If  a  large 
 beam  be  taken  instead,  they  cannot  be  detected,  as, 
 in  this  case,  the  spectrum  is  composed  of  several 
 spectra,  overlapping  one  another  and  confusing  the 
 details.  These  dark  markings  are  called  Frauen- 
 hofer's  lines.  The  principal  ones  are  designated  by 
 the  letters  B,  C,  D,  E,  F,  G,  H,  and  occupy  precisely- 
 defined  positions  in  the  spectrum.  But  besides  these, 
 there  are  thousands  more;  every  new  refinement  in 
 observation  detects  additional  ones.  These  dark 
 lines  have  long  formed  an  enigma  to  physicists.  It 
 was  plain,  that  they  indicated,  that  some  of  the  rays 
 were  somehow  absorbed  or  obstructed.  If  we  lay  a 
 comb  on  a  piece  of  coloured  paper,  the  teeth  will 
 obstruct  the  view  of  the  paper  under  them,  so  that 
 we  can  see  the  colour  of  the  ground  only  in  the 
 spaces  between  the  teeth.  This  is  precisely  what 
 is  seen  in  the  spectrum ;  the  whole  coloured  spaces 
 
134     ^-^^^  CHEMISTRY  OF  THE  SUN. 
 
 have  minute  dark  parallel  lines  laid  ujDon  them, 
 -similar  to  the  teeth  of  the  comb.  The  chief  merit 
 of  Kirchhoff  and  Bunsen  lies  in  furnishing  a  com- 
 plete explanation  of  the  lines,  and,  at  the  same  time, 
 putting  within  our  reach  a  new  and  universal  ana- 
 lysis, applicable  alike  to  celestial  and  terrestrial 
 objects.  A  few  grains  of  a  gaseous  substance  can 
 be  detected  in  the  remotest  orb,  as  well  as  in  the 
 lamp  upon  our  table. 
 
 If  a  solid  body,  such  as  platinum  or  charcoal,  be 
 raised  to  a  white  heat,  the  spectrum  given  by  the 
 prism  will  be  complete,  and  perfectly  continuous, — 
 that  is,  all  the  colours  will  be  found  following  one 
 another  in  regular  order ;  but  they  will  not  be  cut  up 
 or  striated  by  dark  lines.  This  arises  from  the  soli- 
 dity of  the  body.  If  we  saw  only  the  naked  incan- 
 descent ball  of  the  sun,  there  would  be  no  dark  lines 
 in  the  spectrum.  How,  then,  are  we  to  account  for 
 these  lines? — simply  by  supposing  that  the  sun  is 
 surrounded  wdth  a  gaseous  envelope,  in  which  the 
 incandescent  particles  of  various  substances  are  dif- 
 fused. These  substances  intercept  the  rays  of  the 
 incandescent  body  of  the  sun,  and  they  intercept  in 
 such  a  way  as  to  betray  their  nature.  The  climax 
 of  the  discovery  is,  that  the  dark  lines  are  the 
 negative  spectra  of  the  gaseous  substances  in  the 
 sun's  atmosphere.  What  is  meant  by  negative-  is, 
 that  the  bright  bands  in  the  spectrum  of  any  sub- 
 stance, when  diffused  in  the  flame  of  a  lamp,  become 
 
THE  CHEMISTRY  OF  THE  SUN.     135 
 
 black  in  the  solar  spectrum.  Suppose  that,  when 
 viewmg  the  solar  spectrum,  the  light  of  the  solid 
 or  liquid  photosphere  of  the  sun  were  suddenly  extin- 
 guished, the  gaseous  atmosphere  still  glowing,  the 
 colours  which  we  at  present  see  would  be  at  once 
 extinguished,  and  all  the  dark  lines  would  become 
 bright  bands  with  their  appropriate  colours.  We 
 would  now  be  viewing  a  gaseous  incandescent  atmo- 
 sphere, and  we  would  have  the  spectra  of  all  the 
 bodies  in  this  atmosphere  represented  by  these  bands. 
 The  next  total  eclipse  will  present  an  opportunity  of 
 applying  this  test.  The  perfect  conversion  of  the 
 positive  into  the  negative  spectrum  is  that  which 
 gives  its  validity  to  this  new  analysis.  We  can  read 
 these  lines  and  interpret  their  meaning,  as  distinctly 
 as  we  read  the  symbols  and  formulae  of  the  chemist. 
 We  have  only  to  ascertain  what  is  the  positive  symbol 
 of  any  substance  by  diffusing  it  in  the  flame  of  a 
 Bunsen's  lamp,  and  then  look  to  the  sun  for  a  similar 
 symbol;  the  only  difference  is,  that,  in  the  former 
 case,  the  letters  are  written  in  coloured  inks,  whereas, 
 in  the  latter,  they  are  all  black ;  but  the  form,  group- 
 ing, and  position  are  such  that  their  meaning  cannot 
 be  mistaken. 
 
 But  how  is  it  that  the  spectrum  of  a  substance  is 
 colom*ed  in  terrestrial  flame,  and  black  in  the  gaseous 
 ^hvelope  of  the  sun  ? — simply  from  the  circumstance, 
 that  behind  the  incandescent  atmosphere  of  the  sun 
 
136      THE  CHEMISTRY  OF  THE  SUN. 
 
 there  is  the  brighter  incandescent  solid  or  liquid  photo- 
 sphere of  the  sun.  It  is  this  brighter  background  that 
 makes  the  lines  black,  just  as  the  bars  of  a  window 
 appear  dark  when  viewed  against  the  sky,  though 
 painted  white.  A  truer  idea  is  afforded  by  the  illustra- 
 tion of  the  comb.  Let  us  take,  for  example,  the  spec- 
 trum of  sodium.  Here  there  is  only  one  tooth,  all  the 
 other  primitive  colours  being  wanting.  This  single 
 tooth  is  yellow,  and  we  shall  suppose  made  of  glass.  If 
 you  look  through  this  yellow  glass  at  another  yellow 
 but  much  brighter  object,  such  as  the  yellow  portion 
 of  the  sun's  spectrum,  it  becomes  a  dark  line.  The 
 yellow  tooth,  or  bar  of  sodium,  when  thus  seen 
 against  the  yellow  portion  of  the  sun's  spectrum, 
 becomes  a  black  line,  and  we  know  that  it  is  the 
 same,  from  its  position  in  the  spectrum.  Finding 
 that  the  dark  line,  called  D,  in  the  solar  spectrum, 
 corresponds  with  the  bright  yellow  band  of  sodium, 
 we  conclude  that  sodium  is  part  of  the  gaseous 
 solar  atmosphere  interposed  between  us  and  the  sun. 
 Other  substances  have  more  bands  or  teeth ;  and  as 
 there  are  many  substances  in  the  sun's  atmosphere, 
 the  lines  are  like  so  many  combs  laid  the  one  over 
 the  other,  each  having  its  own  character,  number, 
 and  disposition  of  teeth,  so  that,  though  they  appear 
 confused,  it  is  possible  to  single  out  the  more  marked 
 with  great  ease.  The  sailor  can  easily  detect,  through 
 the  forest  of  masts  in  a  harbour,  the  rig  of  his  own 
 
THE  CHEMISTRY  OF  THE  SUN.       137 
 
 ship  ;  and  the  chemist  can  easily  discover,  amidst  the 
 crowd  of  lines  in  the  solar  spectrum,  the  pattern 
 corresponding  to  the  various  substances.  In  this  way, 
 iron,  magnesium,  chromium,  sodium,  and  nickel,  have 
 been  found  in  the  sun's  atmosphere.  On  the  other 
 hand,  no  trace  has  been  found  of  silver,  copper,  zinc, 
 aluminium,  cobalt,  and  mercury,  though  they  have 
 very  characteristic  spectra. 
 
 It  may  be  objected,  that  it  is  a  mere  assumption, 
 that  the  brighter  opaque  photosphere  of  the  sun  is 
 shining  through  a  gaseous  atmosphere.  This,  how- 
 ever, is  not  the  case.  These  precise  conditions  can  be 
 represented  artificially,  and  the  same  results  obtained. 
 The  charcoal  points  in  the  electric  light,  represent 
 the  opaque  incandescent  photosphere  of  the  sun.  A 
 Bunsen's  lamp,  which  gives  a  great  heat  without 
 much  light,  represents,  with  substances  diffused  in 
 its  flame,  the  gaseous  envelope  of  the  sun.  When 
 the  flame  of  the  lamp  is  viewed  with  the  brighter 
 electric  light  as  a  background,  phenomena  precisely 
 similar  to  those  of  the  solar  spectra  are  observed. 
 The  only  difference  is,  that  in  the  lamp  we  can 
 diffuse  any  one  substance  at  a  time  and  get  its 
 spectrum  isolated,  while,  in  the  sun's  atmosphere, 
 numerous  substances  are  diffused,  and  we  have  thus 
 various  spectra  mixed  up  together. 
 
 But  this  spectrum  analysis  is  not  confined  to  the 
 sun.     We  can  now  analyse  the  remotest  stars  that 
 
138       THE  CHEMISTRY  OF  THE  SUN. 
 
 bum  in  space.  As  far  as  observations  have  already 
 gone,  each  star  lias  its  own  individuality  as  to  chemical 
 composition.  The  line  D,  characteristic  of  sodium, 
 has  been  detected  in  the  spectra  of  Pollux,  Capella, 
 Beltigeux,  and  Procyon ;  and  it  is  probable  that  the 
 colour  of  yellow  stars  is  due  to  this  widely- diffused 
 element.  It  is  probable  that  there  are  systems  where 
 metals  chiefly  prevail,  and  others  where  the  charac- 
 teristic elements  are  alkalies. 
 
 This  new  instrument  of  research  is  by  far  the  most 
 comprehensive  that  has  yet  been  put  into  man's  hand. 
 It  is  destined  alike  to  deal  with  worlds  and  with  atoms. 
 It  can  decompose  the  distant  star,  and  the  invisible 
 molecule.  All  science  tends  to  bind,  under  the  same 
 mechanical  laws,  the  motions  of  orbs  and  atoms. 
 Light  and  heat  are  regarded  merely  as  modes  of 
 motion.  The  elementary  atoms  are  in  a  constant 
 state  of  vibration  ;  that  vibration  produces  a  vibration 
 in  the  ether,  and  the  vibration  of  the  ether,  in  reaching 
 us,  is  light  or  heat — a  light  vibration  being  merely  a 
 heat  vibration,  with  the  rate  so  intensified  that  it 
 becomes  luminous.  It  is  exceedingly  probable  that 
 the  complexity  of  the  spectrum  of  any  elementary 
 body  is  related  to  the  complexity  of  the  atom  itself. 
 If,  for  example,  the  spectrum  of  an  atom,  hitherto 
 supposed  to  be  elementary,  give  several  colours,  it 
 is  probable  that  there  are  several  component  atoms 
 vibrating  at  different  rates — corresponding  to  the  dif- 
 
THE  CHEMISTRY  OE  THE  SUN.       139 
 
 ferent  colours — each  atom  having  its  own  chemical 
 characteristics.  How  simple  the  means  by  which 
 results  so  momentous  are  achieved !  Strange  that  an 
 angular  bit  of  glass,  turning  aside  a  ray  of  light, 
 should  be  the  means  of  revealing  to  us  the  secrets 
 of  the  two  extremes  of  the  material  universe — worlds 
 and  atoms!  The  unity  of  the  Creator  is  shewn, 
 not  merely  in  the  unity  of  plan  pervading  the  uni- 
 verse, but  in  the  existence  of  instruments  by  which 
 the  discovery  of  that  unity  might  be  made  known. 
 We  might  conceive  intellectual  beings  so  circum- 
 stanced, that  they  would  have  no  means  of  discover- 
 ing the  unity  of  plan.  They  might  dwell  in  a  world 
 of  marvellous  order,  unity,  and  beauty,  while  they 
 might  be  shut  out  for  ever,  on  account  of  the  want 
 of  proper  instruments,  from  the  discovery  of  these 
 elements  of  God's  glory.  When,  then,  we  have 
 the  means  of  discovery  so  marvellously  provided, 
 the  existence  of  one  Creator  and  Governor  is  more 
 forcibly  impressed  on  our  minds. 
 
 The  new  light  thrown  upon  the  constitution  of  the 
 sun  will  greatly  unhinge  former  speculations  on  this 
 subject.  The  body  of  the  sun,  if  it  is  to  be  taken  as 
 the  source  of  light,  can  no  longer  be  regarded  as  an 
 abode  cool  enough  for  inhabitants.  It  is  now  to  be 
 held  as  hotter  and  brighter  far  than  the  gaseous 
 envelope.  But  how,  on  this  supposition,  are  we  to 
 explain  the  dark  body  of  the  sun  seen  down  through 
 
140     THE  CHEMISTRY  OF  THE  SUN. 
 
 the  perforations  of  the  outer  envelopes  ?  Or  may  we 
 still  regard  the  body  as  comparatively  dark,  while 
 the  photosphere  underlying  the  red  stratum  is  to  be 
 regarded  as  an  opaque,  liquid  substance,  comporting 
 itself,  as  to  radiation,  like  a  solid  body  ?  Is  the  red 
 stratum,  with  its  rose-coloured  prominences,  or  the 
 corona  above  it,  the  region  of  the  gaseous  atmosphere 
 in  which  the  various  substances  are  diffused?  The 
 luminous  envelope  can  no  longer  be  regarded  as  a 
 gaseous  body,  but  then  the  phenomena  which  it  pre- 
 sents are  altogether  inconsistent  with  the  supposition 
 that  it  is  solid.  Neither  does  the  idea  of  continuous 
 liquidity  furnish  a  satisfactory  solution.  But  does 
 not  the  analogy  of  other  parts  of  the  solar  system 
 furnish  a  clue  ?  If  we  suppose  it  to  consist  of  dis- 
 crete meteoric  matter,  as  in  the  case  of  Saturn's  rings, 
 the  principal  phenomena  will  receive  an  adequate 
 explanation.  The  condition  of  solidity  is  satisfied, 
 and  the  porous  structure  is  accounted  for.  The 
 zones  of  meteoric  matter  round  the  sun,  the  limits  of 
 the  mass  of  which  have  been  determined  by  Levenier, 
 indicate  the  sources  from  which  it  is  fed.  The  visi- 
 ble envelope  of  Saturn  has  probably  a  similar  consti- 
 tution, and  if  incandescent,  as  it  probably  once  was, 
 would,  with  his  rings,  present  a  complete  analogue 
 to  the  photosphere  of  the  sun  and  his  encircling  zones. 
 These  unsettled  questions  shew,  that  our  theories 
 regarding  the   constitution  of  the   sun   have    been 
 
THE  CHEMISTRY  OF  THE  SUN.     141 
 
 merely  provisional.  We  have  now,  however,  got 
 our  foot  on  solid  ground,  and  there  is  every  proba- 
 bility that  the  great  outstanding  questions  will  soon 
 be,  to  a  large  extent,  settled,  though  the  scaling  of 
 every  new  mountain  top  will  only  bring  into  view 
 other  loftier  and  more  distant  summits. 
 
Head  of  Donati's  Comet. 
 
 X. 
 
 THE  STRUCTURE  OF  COMETS. 
 
 The  comet  of  Donati,  which  presented  so  imposing 
 a  spectacle  in  our  northern  hemisphere  in  1858, 
 strongly  revived  the  popular  interest  in  such  phe- 
 nomena. Few  of  the  present  generation  had  an  op- 
 portunity of  gazing  on  any  comet  of  remarkable 
 splendour  and  magnitude.  Our  fathers  told  us  of 
 the  wonderful  comet  of  1811,  spanning  half  the  cir- 
 cuit of  the  heavens  with  its  tail,  and  hanging  over 
 
THE  STRUCTURE  OF  COMETS.     143 
 
 the  earth  for  weeks  together  like  a  drawn  sword; 
 we  listened,  however,  as  to  a  legend  of  the  olden 
 time,  and  despaired  of  seeing  such  sights  in  our  day. 
 The  comet  of  1858  burst  upon  our  view,  and  pro- 
 claimed that  there  were  still  wonders  in  nature,  sur- 
 passing any  that  the  eye  of  man  had  yet  seen.  Not- 
 withstanding the  tendency  of  the  old  to  exaggerate 
 the  wonders  of  their  youth,  the  privileged  few  who 
 remembered  the  comet  of  1811,  confessed  that  Donati's 
 comet  was  altogether  a  finer  object,  though  it  did  not 
 stretch  so  far  across  the  heavens. 
 
 Though  comets  served  no  other  object  than  to 
 awaken  fresh  interest  in  celestial  phenomena,  their 
 visits  to  our  regions  of  space  would  not  be  in  vain. 
 Such  startling  phenomena  serve  to  dispel  the  indif- 
 ference with  which  we  are  prone  to  gaze  upon  the 
 unvarying  page  of  the  "  Book  of  God,"  presented  to 
 us  by  the  ordinary  aspect  of  the  heavens.  It  was  a 
 bright  star  in  the  sixteenth  century,  suddenly  burst- 
 ing forth,  and  as  suddenly  dying  out,  that  gave  to 
 the  world  the  great  astronomer  Tycho  Bralie.  This 
 imposing  object  determined  his  tastes  and  fixed  his 
 future  career.  Mr  Bond,  the  distinguished  American 
 astronomer,  who  has  just  been  gathered  to  his  fathers, 
 dates  his  astronomical  career  from  the  total  eclipse 
 of  1806.  This  sublime  and  awe-inspiring  spectacle 
 took  possession  of  his  mind  to  such  a  degree,  that  he 
 gazed  with  ceaseless  and  inquiring  wonder  on  the  face 
 of  the  heavens  ;  this  eager  prying  into  the  depths  of 
 
144     I^H^  STRUCTURE  OF  COMETS. 
 
 space  gave  him,  while  yet  a  boy,  almost  supernatural 
 power  of  vision  with  the  naked  eye.     As  a  watch- 
 maker's apprentice,  he  could  not  command  the  aid  of 
 instruments,  but,  with  the  faith  of  genius,  he  believed 
 that  he  would  not  be  denied  a  sight  of  nature's  secrets, 
 if  he  made  good  use  of  the  advantages  within  his 
 reach.     He  employed  various  arts  to   increase  the 
 sensitiveness  of  his  retina,  such  as  looking  into  dark 
 wells,    so   that   his  eye  acquired   such  keenness  of 
 vision,  that  he  was  the  first  on  the  American  conti- 
 nent to  discover  the  great  comet  of  1811.     Little  did 
 the  young  apprentice  think  that  he  was,  in  this  way, 
 most  effectually  qualifying  himself  for  the  manage- 
 ment, as  head  of  an  observatory,  of  some  of  the  finest 
 instruments  in  the  world.     His  finely  trained  eye 
 enabled  him,  in  after-life,  to  make  the  independent 
 discovery  of  the  dark  ring  of  Saturn,  and  of  a  new 
 satellite  belonging  to  the  same  system.     His  early 
 mechanical  training  enabled  him  to  devise  and  per- 
 fect one  of  the  greatest  improvements  in  observation 
 in  modern  times — viz.,  the  substitution,  by  means  of 
 electricity,  of  touch,  instead  of  hearing,  to  mark  the 
 instant  of  any  astronomical  event.     To  him,  also,  arc 
 we  chiefly  indebted  for  the  art  of  celestial  photo- 
 graphy, which  promises  to  revolutionise  the  system  of 
 astronomical  observations.     May  we  not  hope  that 
 Donati's    comet,  in   like    manner,   has  aroused   the 
 dormant  powers  of  many  a  young  astronomer  who 
 
THE  STRUCTURE  OF  COMETS.     145 
 
 may  live  to  extort  from  nature  her  deepest  and  most 
 wonderful  secrets  ? 
 
 One  great  charm  of  the  comet,  both  in  a  popular 
 and  scientific  view,  is  the  illustration  it  affords  of 
 formative  processes  visibly  going  on  in  the  grandest 
 scale.  What  would  not  the  geologist  give  to  see 
 illustrated,  in  a  conveniently  brief  space,  the  molten 
 globe,  and  the  subsequent  induration ;  and  the  vari- 
 ous upheavals  and  submergences,  which  his  theories 
 require?  But  the  comet  reveals  corresponding  or- 
 ganic changes  in  the  course  of  a  few  days  or  weeks, 
 and  on  a  scale  vastly  greater  than  what  our  earth 
 could  exhibit.  What  is  it  that  renders  the  sight  of 
 the  moon's  surface  so  disappointing  ?  Is  it  not  tliat 
 all  is  motionless  ?  There  are  no  moving  clouds,  no 
 fluctuating  seas,  no  fleeting  snow-covering,  no  active 
 volcanoes;  all  is  motionless  and  deathlike.  Why 
 does  the  surface  of  the  sun  attract  such  deep  interest 
 at  this  moment?  Because  we  discover  agencies 
 working  with  intense  activity.  There  are  elements 
 of  change  detected,  and  these  are  watched  with  the 
 most  anxious  interest.  In  the  moon  we  see  a  frozen 
 torrent ;  in  the  sun  we  see  the  stream  dashing  on 
 with  impetuous  speed. 
 
 Measured  by  this  source  of  interest,  the  comet  ar- 
 rests our  attention  much  more  powerfully  than  even 
 the  sun,  the  changes  being  much  more  rapid  and 
 comprehensive.     We  see  the  whole  orb  transformed 
 
 K 
 
146     THE  STRUCTURE  OF  COMETS. 
 
 before  our  eyes.  We  are  apt  to  tliink  that  tlic  full- 
 sized  comet  is  merely  the  same  as  the  cloudy  speck 
 which  we  descried  some  weeks  before,  and  that  the 
 whole  difference  of  aspect  is  due  to  difference  of  dis- 
 tance; just  as  the  white  speck  on  the  distant  horizon 
 differs  from  the  frigate  entering  the  harbour  with  all 
 her  sails  set.  This,  however,  is  far  from  being  the 
 case  :  no  doubt,  increasing  proximity  magnifies  the 
 object;  but  apart  from  this,  there  is  a  wonderfully 
 rapid  expansion  and  change  of  form.  The  comet  at 
 a  distance  is  the  flower  in  bud ;  in  the  proximity  of 
 the  sun,  it  is  the  flower  in  full  blossom.  In  the  latter 
 position,  there  is  an  astonishing  development  in  size 
 and  shape.  Perhaps  a  more  apt  comparison  would  be 
 to  the  sea  anemone,  in  which  we  have,  with  the  same 
 substance,  an  alteration  of  bulk  and  form.  The  comet 
 in  its  remote  position  is  the  shrunken  anemone ;  with 
 its  bright  nucleus  and  flaming  tail,  it  is  the  anemone 
 with  its  tentacles  expanded,  and  its  brilliant  colours 
 displayed. 
 
 With  the  naked  eye,  we  can  only  see  the  bright 
 petals  of  the  flower  coming  forth  from  the  calyx ;  we 
 do  not  detect  the  formative  processes  going  on  within 
 the  germ.  But  just  as  with  the  microscope  we  can. 
 dissect  a  flower,  and  detect  the  most  secret  proce.'sses 
 of  nature  in  the  germ,  so  can  we,  with  the  telescope, 
 penetrate  the  nucleus  of  the  comet,  and  discover  the 
 plan  of  evolution  by  which  the  tail  oi^  the  comet 
 springs  from  this  centre.     As  we  watch  with  interest 
 
Pl/\te   IV 
 
 TYPICAL    STRUCT.U-RE  OF  COMETS 
 
THE  STRUCTURE  OF  COMETS.    147 
 
 the  potter  fashioning  an  artistic  vase  from  a  mass  of 
 clay,  so  do  we  witness  with  a  higher  interest  the 
 comet,  with  all  its  symmetry  and  beauty,  emerging 
 from  a  mass  of  cloud,  fashioned  by  great  laws  which 
 are  only  the  hands  of  the  Divine  Artist,  by  which  it 
 is  moulded  into  the  requisite  form. 
 
 The  plate  illustrating  the  structure  of  the  comet's 
 head,  is  intended  to  have  only  a  typical  significance. 
 In  drawing  it  we  have  been  indebted  to  the  views,  by 
 Mr  Cooper,  of  Donati's  comet,  as  seen  by  him  through 
 his  great  refractor  at  Markree  Observatory.  We 
 have  combined  with  these  the  observations  of  M. 
 Chacornac,  of  the  Observatory  at  Paris,  in  order  to 
 illustrate  the  stratified  appearance  presented  by  the 
 successive  envelopes. 
 
 The  particles  of  which  the  comet  is  composed  are 
 never  motionless ;  they  are  in  a  ceaseless  flow,  im- 
 pelled by  forces  which  communicate  to  them  an  in- 
 conceivable rapidity  of  motion.  The  deepest  mystery 
 hangs  over  the  nature  of  these  forces,  but  the  pheno- 
 mena, as  witnessed  with  the  aid  of  the  telescope,  are 
 easily  described.  When  a  comet  is  first  descried  in 
 the  heavens,  it  appears  as  a  faint  star,  with  a  haze 
 around  it.  It  is  often  impossible  to  tell  by  its  mere 
 physical  aspect  whether  it  is  really  a  comet.  To 
 solve  the  doubt,  the  observer  must  wait  a  little  and 
 see  whether  it  is  in  motion.  This  assures  him  that  it 
 is  not  a  mere  nebula,  and  he  concludes  that  it  must 
 be  a  comet.      He  traces,  for  a  short  way,  the  curve 
 
148    THE  STRUCTURE  OF  COMETS. 
 
 described,  and  having  got  a  sample,  he  readily  de- 
 duces the  shape,  dimensions,  and  position  of  the 
 whole  orbit.  He  proceeds  just  as  one  would  do  in 
 cutting  out  figures  in  the  sward  of  a  garden.  When 
 a  portion  of  a  regular  figure  is  given,  it  is  easy  to 
 cut  out  the  whole  figure.  In  this  way  the  astro- 
 nomer can  readily  tell  how  near  it  will  approach  the 
 sun,  and  at  w^hat  time.  As  the  comet  approaches 
 the  sun,  internal  changes  can  be  detected.  The 
 globular  mass  is  drawn  out,  the  nucleus  or  brightest 
 point  being  at  the  end  nearest  the  sun.  The  other 
 end  soon  assumes  the  appearance  of  a  tail. 
 
 The  forms  of  most  large  comets  conform  to  one 
 general  type.  The  tail  is  slightly  convex  on  one 
 side,  and  has  very  much  the  appearance  of  a  scimi- 
 tar, the  nucleus  representing  the  hand  with  which 
 it  is  grasped.  The  Chinese  call  comets  "  broom- 
 stars;"  and  the  appearance  of  many  is  very  much 
 that  of  a  broom,  bent  and  worn  with  much  use.  The 
 outline  of  the  convex,  is  generally  better  defined  than 
 that  of  the  concave  side.  A  comparatively  dark  band 
 runs  lengthways  through  the  middle  of  the  comet,  so 
 that  it  has  often  the  appearance  of  two  tails  ;  the  two 
 bright  streaks  on  each  side  of  the  tail  being  taken 
 for  two  distinct  tails. 
 
 This  is  the  appearance  to  the  naked  eye.  When 
 the  nucleus  is  watched  with  the  telescope,  very 
 remarkable  changes  are  witnessed.  The  luminous 
 matter  of  the  comet  rushes  forth  from  the  nucleus^ 
 
THE  STRUCTURE  OF  COMETS.    149 
 
 as  the  stream  of  fiery  particles  issues  from  a  rocket. 
 They  rush  out  towards  the  sun  with  great  velocity, 
 but  soon  they  reach  a  certain  point,  when  they  are 
 driven  back  to  form  the  tail.  The  appearance  is  not 
 unlike  that  of  a  lighted  torch  held  against  the  wind. 
 The  tendency  of  the  flame  to  rise  is  counteracted 
 by  the  action  of  the  wind,  which  drives  it  back.  The 
 most  perfect  illustration  we  have  seen  of  the  internal 
 form  and  movement  of  the  comet,  was  the  playing  of 
 the  fountain  in  the  garden  of  the  Tuileries,  close  to 
 the  Place  de  la  Concorde.  The  water  rose  to  a  con- 
 siderable height,  and  fell  back  in  an  umbrella  form. 
 There  was  a  slight  wind,  and  the  jet  was  slightly 
 curved  along  its  length,  as  in  the  case  of  the  comet. 
 The  windward  side  was  also  best  defined,  the  loose 
 spray  being  all  thrown  to  the  leeward  side.  The  de- 
 scending canopy  being  hollow,  the  outline  of  both 
 sides  was  more  condensed  than  the  central  part,  the 
 eye  having  to  look  through  a  greater  mass  of  water. 
 The  luminous  particles  shoot  forth  from  the  nucleus, 
 just  as  the  water  spouts  forth  from  the  jet,  and  are 
 thrown  back  to  form  a  hollow  envelope.  The  curva- 
 ture of  the  comet,  and  the  sharper  definition  of  the  con- 
 vex side,  are  usually  explained  on  the  supposition  that 
 the  comet  is  moving  through  a  resisting  medium,  so 
 that  an  effect  similar  to  the  influence  of  the  wind  on 
 2i>  jet-cf  eau  is  produced. 
 
 In  the  case  of  Donati's   comet,  the  telescope  de- 
 tected the  formation  of  numerous  envelopes,  so  that 
 
150    THE  STRUCTURE  OF  COMETS. 
 
 the  head  presented  the  appearance  of  distinct  stra- 
 tification. The  forces  brought  into  action,  seemed 
 to  be  intermittent,  and  this  intermission  is  marked 
 by  the  bomidaries  of  the  strata.  There  is  no  con- 
 tinuous flow  in  nature,  and  the  play  of  a  fountain 
 gives  a  very  good  illustration  of  this.  However 
 steady  the  pressure  of  the  water  may  be,  the  foun- 
 tain plays  by  jerks,  and  not  by  a  steady  continuous 
 stream  ;  and  the  development  of  the  comet  illustrates 
 this  on  a  grand  scale,  the  different  envelopes  being 
 the  result.  What  is  the  structure  that  results  from 
 this  view  of  the  comet's  formation  ?  It  may  be  re- 
 presented by  a  series  of  hollow  cones  packed  the  one 
 within  the  other.  The  grocer's  paper  cones  may  serve 
 as  a  familiar  illustration,  or  a  nest  of  flower-pots,  thfe 
 smallest  being  in  the  centre,  and  the  others  forming 
 concentric  envelopes  of  increasing  size.  This  will 
 give  a  striated  appearance  to  the  tail,  and  when  there 
 is  a  space  between  the  envelopes,  the  successive  in- 
 tervals will  appear  comparatively  dark,  so  that  the 
 comet  may  seem  to  have  many  tails.  Almost  all  the 
 perplexing  shapes  comets  assume,  may  be  explained 
 on  this  assumption  of  hollow  concentric  cones. 
 
 There  were  three  distinct  stages  in  the  develop- 
 ment of  Donati's  comet.  The  first  was  that,  imme- 
 diately previous  to  its  perihelion  passage,  on  the  30th 
 of  September ;  the  second  at  its  nearest  approach  to 
 the  earth ;  and  the  third,  at  its  nearest  approach  to 
 Venus.     It  was  ten  days  before  the  perihelion  pas- 
 
THE  STRUCTURE  OF  COMETS.    151 
 
 sage,  when  the  first  streams  of  light  were  seen  to 
 shoot  out  from  the  nucleus  towards  the  sun.  The 
 two  streams  diverged  from  one  another,  like  hair 
 parted  on  the  forehead.  Six  days  afterwards  the  ap- 
 pearance of  a  fan-like  bright  sector  was  presented. 
 This  was  surrounded  by  a  darkish  arc,  and  next  by 
 a  brighter  semicircle  of  nebulous  light.  At  the  peri- 
 helion, the  fan  still  continued — its  axis  making  with 
 the  axis  of  the  tail  an  angle  of  25''.  The  dark 
 division  of  the  latter  was  very  black  towards  the 
 nucleus.  Immediately  after  the  perihelion,  the  second 
 stage  commenced,  and  a  totally  new  class  of  pheno- 
 mena was  presented  in  the  shape  of  luminous  en- 
 velopes. Three  envelopes  were  discovered,  with  the 
 nucleus  in  the  centre.  These  did  not  quite  encircle 
 the  nucleus— a  sector,  of  about  90°  in  the  direction 
 of  the  tail,  being  cut  out  of  each  of  them.  The 
 comet  was  now  approaching  the  earth,  and,  three 
 days  before  the  minimum  distance,  great  distortions 
 were  observed  in  the  form  of  the  outer  envelope.  It 
 appeared  like  the  ragged  ends  of  heavy  rain-clouds 
 during  a  violent  shower.  Two  days  before  the  nearest 
 approach,  a  new  fan  was  formed,  and  the  streams 
 from  the  nucleus  shewed  a  tendency  to  return  into 
 the  tail — thus  restoring  to  the  comet  the  form  it  had 
 before  the  developing  process  began.  According  to 
 Father  Secchi's  theory,  these  disturbances  were  caused 
 by  the  action  of  the  earth.  At  the  nearest  approach 
 on  the  11th  of  October,  the  comet  was  half  the  dis- 
 
152     THE  STRUCTURE  OF  COMETS. 
 
 tance  between  the  earth  and  the  sun.  The  last  stage 
 of  development  was  when  the  comet  approached  Venus. 
 The  nearest  approach  to  this  planet  w^as  on  the  17th 
 October,  when  the  distance  was  only  one-ninth  the 
 distance  between  the  earth  and  the  sun.  Two  days  ' 
 before  this,  a  new  set  of  phenomena  presented  them- 
 selves, in  the  form  of  comma-like  curved  appendages 
 to  the  nucleus,  as  if  formed  of  bright  burning  matter, 
 w^hich  had  been  projected  from  the  nucleus,  and  then 
 twisted  back  again. 
 
 The  next  inquiry  is,  How  is  this  extraordinary  de- 
 velopment produced?  What  are  the  forces  brought 
 into  play?  The  jet  of  luminous  matter  from  the 
 centre,  is  naturally  explained  by  the  action  of  the 
 sun's  heat,  for  the  action  is  energetic  in  proportion  to 
 the  nearness  of  the  comet  to  the  sun.  The  grand 
 difficulty  is  the  throwing  back  of  the  matter  into  the 
 tail.  Father  Secchi  thinks  that  it  can  be  explained 
 by  the  unequal  action  of  gravitation  on  different 
 parts  of  the  comet,  and  holds  that  the  distortions 
 produced  on  the  approach  to  the  earth  and  Venus 
 corroborate  this  view.  It  is  evident  that  there  is 
 some  repelling  power,  and  a  power  capable  of  com- 
 municating an  inconceivable  velocity  to  the  repelled 
 particles.  The  usual  method  is  to  ascribe  it  to  electric 
 or  magnetic  action.  It  is  ascertained  that  the  sun 
 and  the  moon,  as  w^ell  as  the  earth,  are  magnets ;  and 
 the  great  probability  is,  that  all  the  heavenly  bodies 
 are  magnetic.     This  seems  to  afford  a  plausible  ex- 
 
THE  STRUCTURE  OF  COMETS,    153 
 
 planation  of  the  apparently  polar  forces  at  play  in 
 the  evolution  of  the  comet.  Bessel's  theory  is,  that 
 at  a  great  distance  all  the  particles  have  a  polarity  op- 
 posite to  that  of  the  sun,  but  that  on  a  near  approach 
 the  comet  itself,  as  a  distinc  unit,  is  polarised,  so  as 
 to  emit  streams  of  luminous  matter.  The  repelling 
 of  the  luminous  matter  is  not  satisfactorily  accounted 
 for.  Another  theory  has  recently  been  started,  which 
 has,  for  the  tim'e,  put  all  others  in  abeyance,  and  is 
 in  process  of  being  tested  by  the  French  savans. 
 We  allude  to  the  hypothesis  of  M.  Faye,  which  is, 
 that  there  is  a  repelling  force  radiated  from  the  sun, 
 as  well  as  the  attractive  force  of  gravitation,  and 
 that  this  is  only  a  single  case  of  a  universal  law 
 of  matter.  He  maintains  that  every  incandescent 
 body  exercises  this  repulsion,  but  that  it  is  so  feeble, 
 that  it  can  be  detected  only  in  the  case  of  matter  of 
 such  extreme  tenuity  as  that  of  comets.  He  sup- 
 poses that  the  force  emanates  only  from  the  surface  of 
 the  sun,  and  not,  like  gravitation,  from  its  mass. 
 With  this  simple  assumption,  he  endeavours  to  ex- 
 plain the  formation  and  all  the  phenomena  of  comets. 
 The  envelopes  are  produced  by  the  expansive  power 
 of  the  sun's  heat,  balanced  by  this  special  repelling 
 power.  The  shortening  of  the  period  of  the  comet  of 
 Encke,  is  also  explained  by  the  same  means.  He  has 
 agreed  to  submit  the  law  to  the  test  of  experiment. 
 It  was  objected,  that  if  the  incandescent  surface  of 
 the  sun  repelled  the  rarefied  matter  of  comets,  the 
 
154    THE  STRUCTURE  OF  COMETS. 
 
 same  thing  should  happen  in  the  case  of  incandes- 
 cent bodies  on  the  surface  of  the  earth.  He  at  once 
 accepted  the  inference,  and  agreed  to  subject  his 
 theory  to  this  test,  if  matter  rare  enough  could  be 
 found  and  made  visible.  The  extremely  rarefied  air 
 left  in  the  vacuum  of  an  air-pump,  was  taken  as  the 
 test ;  and  a  heated  plate  was  employed  to  repel  this 
 matter.  The  difficulty  was  to  make  the  repulsion 
 visible.  This  was  effected  by  passing  an  electric  dis- 
 charge through  the  exhausted  receiver.  The  air  was 
 made  palpable  by  means  of  the  stratified  light  pro- 
 duced by  a  powerful  coil.  Several  distinguished 
 physicists  hold  the  point  demonstrated,  though,  as 
 yet,  most  withhold  their  assent. 
 
 If  this  new  law  be  established,  it  will  be  the  most 
 important  advance  since  the  time  of  Newton.  It  will, 
 indeed,  dethrone  gravitation  from  the  sole  sway  which 
 it  has  hitherto  exercised.  Newton's  law  has  been  re- 
 peatedly put  to  the  test,  and  more  than  once,  astrono- 
 mers trembled  lest  the  whole  Newtonian  structure 
 should  totter  and  fall ;  but  gravitation,  with  its  simple 
 ratio,  has  come  forth  triumphant  from  the  severest 
 ordeals.  One  trial  more  awaits  it,  and  all  the  astro- 
 nomers of  European  fame  are  ranged  on  one  side  or 
 other  of  the  question.  The  two  principal  parties  are 
 M.  Hansen  of  Altona,  and  M.  Delauny,  and  with  one 
 or  other  of  these  the  various  combatants  side.  The 
 controversy  raged  for  some  time  in  the  Academy  of 
 
THE  STRUCTURE  OF  COMETS.    155 
 
 Sciences  between  Leverrier  and  Delauny,  but,  gradu- 
 ally, all  the  great  astronomers  of  the  day  have  been 
 caught  in  the  vortex.  Adams  is  almost  the  only 
 astronomer  of  note  that  stands  by  Delauny ;  Ponte- 
 coulant  and  Plana  are  leagued  with  Leverrier  in 
 support  of  the  results  of  Hansen.  Delauny  has 
 elaborated  a  theory,  by  which  he  shews  that  the 
 moon's  actual  motion  does  not  accord  with  the  law 
 of  gravitation.  Hansen,  on  the  other  hand,  asserts 
 that  his  theory  is  correct,  as  his  tables,  adopted  by 
 the  British  Government,  accord  completely  with  ob- 
 servation. The  precise  point  is,  what  is  termed,  the 
 acceleration  of  the  moon's  mean  motion,  one  result  of 
 which  is,  that  the  moon,  in  the  course  of  the  year, 
 nears  the  earth  by  about  an  inch.  Yet  on  this  inch 
 depends  the  issue  of  the  controversy.  Adams  and  his 
 French  associate,  hold  that  these  results  point  clearly 
 to  some  other  cause  than  the  law  of  gravitation,  and 
 M.  Faye  indicates  his  new  law  of  repulsion  as  the 
 true  cause  to  explain  the  residual  phenomenon. 
 Though  the  controversy  has  not  assumed  a  national 
 aspect,  the  temper  displayed  on  both  sides  ill  befits 
 the  dignity  of  science.  The  comet  in  the  hand  of 
 Newton  broke  through  and  shivered  the  crystal 
 spheres  of  antiquity,  and  annihilated  the  vortices  of 
 Descartes.  Strange  if  it  be  destined  also  to  shake 
 the  foundations  of  even  his  own  system.  But,  after 
 all,  Newton  himself  did  not  regard  the  law  of  gravi- 
 
156    THE  STRUCTURE  OF  COMETS. 
 
 tation  as  final  and  exclusive.  He  conceived  it  as 
 merging  in  some  higher  law,  or  being  modified  by 
 other  forces. 
 
 When  Newton  failed  to  shew  how  his  law  could 
 prevent  the  perturbations  of  the  planets  introducing 
 confusion  into  the  system,  he  suggested  that  the  direct 
 interference  of  the  Almighty  might  be  employed,  oc- 
 casionally, to  rectify  matters.    He  and  the  theologians 
 of  his  day  seemed  to  think,  that  there  must  be  a 
 defect  in  the  celestial  machine,  unless  it  was  proved 
 to  be  capable  of  lasting  for  ever,  and  great  was  the 
 rejoicing  when  the  stability  of  the  system  was  estab- 
 lished.   But  suppose  that  there  is  a  resisting  medium, 
 accounting  for  the  destructive  course  of  Encke's  comet 
 towards  the  sun,  or  that  the  law  of  gravitation  re- 
 quires to  be  modified  by  some  new  law,  which  may 
 compromise  the  present  order  of  things  by  introduc- 
 ing an  element  of  decay,  are  we  to  conclude  that 
 there  is  a  defect  of  wisdom  in  the  constitution  of  the 
 celestial  machine?     We  might  as  reasonably  deny 
 the  traces  of  wisdom  in  the  structure  of  our  bodies, 
 because  they  have  not  the  stamp  of  eternity.     Theo- 
 logians have  been  too  much  led  away  with  the  idea 
 of  the  solar  system  being  a  rigid  machine,  with  un- 
 varying adjustments,  instead  of  a  single  phase  of  the 
 mighty  evolutions  of  the  material  universe.     There 
 is  nothing  fixed  and  rigid  in  the  material  world  ex- 
 cept the  laws  by  which  the  all-wise  Kuler  governs  it. 
 Every  star  in  the  heavens,  and  every  molecule  on  the 
 
THE  STRUCTURE  OF  COMETS,    1^7 
 
 earth,  is  in  incessant  movement.  There  is  a  constant 
 flow,  and  the  wisdom  of  the  Creator  is  seen,  rather  in 
 the  exquisite  rhythm  of  movement,  than  in  the  rigid 
 collocation  of  the  material  world.  We  see  only  a  few 
 spokes  of  the  great  wheel  of  the  universe ;  and  what 
 appears  to  be  a  destructive  breach  of  continuity,  may 
 be  only  the  completed  part  of  a  mighty  cycle. 
 
 As  to  the  purpose  served  by  comets,  the  odd  fancy 
 of  Newton,  that  they  are  intended  to  serve  as  fuel  to 
 the  sun,  is  again  revived,  and  revived  by  our  ablest 
 philosophers.  It  is  held,  in  connexion  with  the  dyna- 
 mical theory  of  heat,  that  the  sun's  heat  and  light 
 must  be  exhausted,  unless  supplied  with  fuel,  and 
 comets  are  held  as  part  of  the  fuel  destined  to  keep 
 the  central  fire  burning.  It  is  supposed  that  there 
 are  zones  of  meteoric  matter  round  the  sun,  of  which 
 the  zodiacal  light  may  be  one,  which  supply  the 
 sun  with  the  needful  fuel.  And  some  careful  ob- 
 servers state,  that  they  have  actually  seen  large 
 bodies  plunge  into  the  luminous  atmosphere,  just  as 
 a  large  block  of  coal  is  thrown  into  the  furnace  by 
 the  stoker.  These  bodies  are  not  supposed  to  act 
 precisely  as  fuel,  though  they  keep  up  the  heat.  In 
 the  practice  of  the  Armstrong  guns,  it  was  found 
 when  a  bolt  was  lodged  in  the  sides  of  the  gun- 
 boat serving  as  target,  that  it  could  not  be  touched 
 with  the  hand  on  account  of  the  great  heat  —  the 
 arrested  motion  being  converted  into  heat.  So  the 
 meteorites   and  comets    are  supposed  to    communi- 
 
158    THE  STRUCTURE  OF  COMETS. 
 
 cate  the  requisite  heat,  bv  having  their  prodigious 
 velocity  arrested  and  converted  into  this  other  form 
 of  force.  This  is,  however,  a  point  of  so  much  in- 
 terest, and  sheds  so  much  Hght  on  the  wise  balancing 
 of  forces  throughout  the  material  world,  that  we  re- 
 serve it  for  special  discussion. 
 
 Some  advocates  for  the  doctrine  of  a  plurality  of 
 worlds  do  not  hesitate  to  maintain,  that  the  purpose 
 of  comets  is  to  be  inhabited.  They  start  on  the  prin- 
 ciple, that  it  is  not  necessary  to  prove  any  probable 
 conditions  of  life,  in  order  to  hold  that  any  body  of 
 the  system  is  inhabited  5  and,  consequently,  they  can 
 assign  no  limits  to  their  theory.  They  do  not  scruple 
 to  hold,  although  the  heat  is  so  great  as  to  burn  up 
 diamonds  like  tinder,  and  although  the  substance  of  I 
 the  comet  is  rarer  than  the  most  perfect  vacuum  of 
 the  air-pump,  that  there  may  be  living  beings  on 
 every  particle  of  its  matter.  The  argument  em- 
 ployed to  support  this  view,  is,  that  it  is  quite  pos- 
 sible for  God  to  make  beings  capable  of  existing  in 
 such  conditions.  But,  is  it  right  to  make  our  notions 
 of  2^ossihiUty  the  basis  of  a  theory  of  God's  provi- 
 dence ?  The  question  is  one  of  ^^rohability ^  not  of 
 loossihiUty.  And  if  we  are  to  proceed  reverentially, 
 we  must  argue  from  the  known  to  the  unknown,  from 
 our  experience  on  this  globe  to  what  is  probably  the 
 Divine  procedure  in  worlds  the  physical  conditions  of 
 which  are  only  partially  revealed  to  us. 
 
Head  of  Comet  ol  ISll. 
 
 XI. 
 
 THE  HISTORY  OF  COMETS. 
 
 We  are  induced  to  return  to  the  subject  of  comets, 
 chiefly  on  account  of  the  sudden  appearance  (1860) 
 of  one  of  these  bodies  in  the  northern  horizon,  which 
 is  suspected  by  some  to  be  one  of  much  historical 
 -interest,  and  whose  return  has  been  long  expected. 
 At  the  date  of  our  writing,  nothing  is  positively 
 known  about  it  except  its  physical  aspect.      Suffi- 
 
i6o        THE  HISTORY  OF  COMETS. 
 
 cient  time  has  not  elapsed  to  determine  its  orbit,  and 
 establish  its  identity  with  one  of  a  previous  epoch. 
 
 The  manner  of  its  discovery  has  been  a  little  tan- 
 talising to  professional  observers.  No  observatory 
 claims  the  honour ;  no  amateur,  even,  has  been  the 
 first  favoured  discoverer  of  it.  There  are  many  whose 
 sole  occupation  is  to  dredge  the  depths  of  space  for 
 comets.  In  astronomical  language,  they  "  sweep"  the 
 heavens  with  their  comet-seeker,  and  perseverance  is 
 almost  always  rewarded  with  success.  In  sweeping 
 for  asteroids,  there  is  a  zone  of  the  heavens  to  which 
 observations  are  limited ;  and  the  astronomer  selects 
 this  lucky  region,  just  as  the  fisherman  lets  down  his 
 net  over  some  bank  which  he  knows,  by  experience, 
 is  likely  to  reward  his  toil.  The  dredger  for  comets 
 must,  however,  cast  his  net  at  random,  for  these  erra- 
 tic bodies  affect  no  special  locality.  They  come,  as 
 moths,  from  out  the  darkness,  and  are  visible  only 
 when  they  circle  round  the  sun,  as  moths  flutter  about 
 the  lamp ;  but  they  come  in  all  directions,  and  the 
 telescope  must  sweep  over  the  whole  heavens  to  detect 
 the  next  comer. 
 
 The  discovery  of  the  comet  is  tantalising,  as  it  was 
 made  by  one  who  was  not  at  all  in  search  of  it.  M. 
 le  Baron  de  Marguerit,  while  attending  to  his  mili- 
 tary duties  in  the  camp  at  Chalons,  was  the  fortunate 
 man.  In  his  letter  to  the  Abbe  Moigno,  announcing>» 
 the  discovery,  he  tells  with  great  naivete  the  manner 
 in  which  it  was  made.     Disgusted  with  the  slow  life 
 
THE  HISTORY  OF  COMETS.        i6i 
 
 of  tlie  camp,  and  the  desolate  plains  of  Champagne, 
 he  turned  his  eyes  in  dreamy  mood  towards  the 
 heavens.  He  thought  he  saw  something  unusual, 
 and  on  taking  up  his  opera-glass,  he  found  it  was  a 
 comet  with  a  well-marked  tail,  the  full  extent  of 
 which  could  not  be  detected,  on  account  of  the  strong 
 twilight  in  the  northern  horizon.  It  has  been  seen 
 by  many  since  as  a  brilliant  object  to  the  naked  eye. 
 The  stronger  twilight,  in  the  higher  latitudes  of  Scot- 
 land, has  as  yet  deprived  us  of  this  interesting  spec- 
 tacle. The  shape  is  much  like  that  of  the  comet  of 
 1858,  but  its  lustre  is  much  greater  than  that  of  the 
 latter,  when  it  first  became  visible  to  the  naked  eye. 
 Leverrier  apologises  for  the  nodding  of  his  staff  of  o'b- 
 eervers,  by  pleading  the  badness  of  the  weather.  The 
 comet  was  allowed  to  approach,  and  gather  brilliancy 
 behind  the  murky  atmosphere,  and  when,  at  last,  the 
 clouds  broke  up,  the  unaided  eye,  on  account  of  the 
 brilliancy  of  the  object,  had  as  good  a  chance  as  the 
 most  powerful  telescope. 
 
 It  is  difficult  to  understand  the  rationale  on  which 
 science  distributes  her  honours.  If  a  man,  innocent 
 of  all  scientific  knowledge,  only  happen  to  catch  the 
 first  glimpse  of  a  comet,  or  pick  up  some  new  fossil, 
 he  receives  the  award  of  immortality,  by  having  his 
 name  associated  with  the  discovery.  The  comet  or 
 the  fossil  is  called  after  him  for  all  future  time.  When, 
 however,  the  discovery  is  of  real  merit,  such  as  that 
 of  a  planet,  all  attempts  to  affix  to  them  the  names  of 
 
1 62        THE  HISTORY  OF  COMETS. 
 
 mortals  are  in  vain.  It  was  attempted  to  give  the 
 name  of  Leverrier  to  the  planet  Neptune ;  but  the 
 scientific  world  would  not  recognise  the  designation. 
 Galileo,  as  a  compliment  to  the  family  of  the  Medici, 
 named  the  satellites  of  Jupiter  after  them,  but  the 
 name  is  now  obsolete.  Uranus,  for  a  time,  bore  the 
 name  of  the  discoverer,  and  then  of  his  royal  patron, 
 but  it  is  now  never  known  by  the  planet  of  Herschel, 
 or  the  Georgium  Sidus.  How  differently  are  comet- 
 ary  honours  meted  out,  when  the  new  comet  will,  in 
 future,  be  known  as  that  of  the  Baron  de  Marguerit, 
 his  sole  merit  consisting  in  looking  up  to  the  sky  as 
 he  sauntered  forth  in  the  evening  to  while  away  the 
 time. 
 
 Discoverers  are  losing  their  hold  even  of  comets,  as 
 they  are  more  frequently  designated  by  the  year  of 
 the  discovery  and  the  numerical  order  in  which  they 
 have  been  discovered  dm'ing  the  year.  At  present 
 an  attempt  is  made  by  Leverrier  to  abandon  the  pre- 
 sent system  of  naming  the  asteroids  after  heathen 
 deities,  and  to  adopt,  instead,  the  name  of  the  dis- 
 coverer, with  the  number  of  the  asteroid  in  the  order 
 of  discovery.  This  innovation  is  strongly  resisted  by 
 most  astronomers,  and,  at  present,  there  is  one.  No. 
 59,  without  a  name,  simply  because  the  discoverer, 
 M.  Chacornac,  thinks  with  Leverrier,  and  persists  in 
 refusing  to  give  it  a  name. 
 
 The  appearance  of  the  present  comet  naturally  sug- 
 gests the  inquiry,  Is  it  the  great  comet  of  1556,  the 
 
THE  HISTORY  OF  COMETS.        163 
 
 return  of  which  has  been  confidently  expected  about 
 this  time  ?  After  various  approximations,  Mr  Hind 
 has  finally  fixed  the  limits  of  1857  and  1861  within 
 which  we  may  reasonably  expect  this  return.  In 
 establishing  the  identity  of  a  comet,  little  reliance  can 
 be  placed  on  the  physical  aspect.  Comets  that,  at  one 
 period,  shone  with  great  splendour,  have,  at  another, 
 come  back  again,  shorn  of  all  their  glory.  They  have 
 not  the  stable  constitution  of  the  planets,  which  pos- 
 sess an  identity  altogether  independent  of  their  orbit. 
 They  may  be  more  fitly  compared  to  a  cloud  floating 
 in  the  atmosphere.  At  sunset  we  see,  in  the  western 
 horizon,  well-defined  clouds  gleaming  with  golden 
 glory,  and  when  we  look  again,  the  glory  is  gone, 
 and  we  fail  to  recognise  the  object,  its  shape  being 
 now^  entirely  altered.  A  comet  fluctuates  in  like 
 manner — its  substance  being  of  a  much  rarer  consis- 
 tency, and  subject  to  influences  which  are  constantly 
 inducing  changes  in  shape  and  lustre.  The  comet 
 differs  from  a  cloud  in  this,  that  it  has  a  well-defined 
 path  by  which  its  identity  is  established.  The  peri- 
 odic revolution  of  comets  cannot  in  general,  however, 
 be  fixed  with  such  accuracy  as  that  of  the  planets. 
 We  can  observe  only  one  end  of  the  long  ovals  in 
 which  comets  move,  but  the  ends  of  difierent  ovals 
 may  be  very  much  alike,  and  yet  they  may  difier 
 very  much  in  length;  consequently,  an  error  made 
 in  determining  the  shape  of  the  ellipse  may  entail  a 
 great  error  in  its  length,  and  the  comet's  period  of 
 
1 64        THE  HISTORY  OF  COMETS. 
 
 revolution.  Besides,  comets  move  across  the  orbits 
 of  the  planets,  and  are  jostled  about  as  a  man  moving 
 through  a  crowd.  One  planet  pulls  this  way  and 
 another  that,  so  that  the  comet's  real  course  may 
 differ  much  from  the  undisturbed  orbit.  In  predict- 
 ing the  return  of  the  great  comet  of  1556,  another 
 formidable  source  of  error  lies  in  the  circumstance, 
 that  the  observation  of  its  appearance  in  1264  was 
 very  imperfectly  recorded.  The  most  reliable  ac- 
 counts are  those  of  the  Chinese,  who  were  at  that 
 period  far  in  advance  of  European  astronomers ;  still, 
 tbey  are  not  given  with  sufficient  accuracy  to  enable 
 us  to  predict  the  return  within  a  single  year.  Assum- 
 ing that  the  above  dates  are  correct,  the  period  is  292 
 years,  and  the  comet,  if  it  moved  in  an  undisturbed 
 orbit,  should  return  in  1848.  But  allowing  for  the 
 disturbance  of  planets,  the  probable  period  is  about 
 ten  years  longer.  As  we  are  now  approaching  the 
 latest  limit  assigned  by  competent  astronomers,  it  is 
 natural  that  the  first  inquiry  should  be,  on  the  dis- 
 covery of  a  new  comet,  Is  it  the  expected  great 
 comet?  The  comet  of  1556  is  named  after  Charles 
 v.,  from  the  circumstance  that  its  dreaded  aspect  is 
 said  to  have  led  that  monarch  to  cede  the  imperial 
 crown  to  his  son  Ferdinand. 
 
 We  are  saved  the  necessity  of  any  further  specula- 
 tion as  to  whether  the  comet  Marguerit  is  the  comet 
 of  Charles  V.,  by  learning,  while  we  write,  that  Lever- 
 rier  has  authoritatively  decided  the  matter.     He  has 
 
THE  HISTORY  OF  COMETS.        165 
 
 made  observations  on  three  different  days,  and  has 
 thus  been  able  to  determine  all  the  elements  of  the 
 orbit  of  the  former.  The  result  is,  that  it  is  not  the 
 expected  comet.  A  year  of  grace  is  still  given,  and 
 astronomers  have  yet  a  short  period  of  anxiety  and 
 suspense  before  them.  But  even  though  the  great 
 comet  should  not  appear  in  1861,  it  is  not  to  be  in- 
 ferred that  astronomical  observations  are  fallacious.  It 
 may  return,  but  it  may  be  so  dimmed  in  its  lustre,  or 
 so  overpowered  by  the  sun's  rays,  that  it  may  escape 
 detection.  The  return  would  certainly  establish  the 
 identity,  but  the  non-appearance  would  not  necessi- 
 tate the  conclusion  that  astronomy  has  been  at  fault. 
 
 For  about  a  week,  it  was  doubtful  whether  Mar- 
 guerit  was  to  retain  his  laurels,  as  it  was  maintained 
 by  some  observers,  that  his  comet  was  merely  one 
 that  had  been  discovered  on  the  17th  of  April  by 
 M.  Eumker  of  the  Observatory  at  Hamburgh.  The 
 observations  at  the  Paris  Observatory  have  conclu- 
 sively settled  the  matter,  by  shewing  that  the  orbits 
 are  quite  different.  The  new  comet  will  therefore 
 stand  in  the  history  of  astronomy,  as  the  comet  of 
 Marguerit,  or  Comet  III.  of  the  year  1860. 
 
 It  may  at  first  appear  singular  that  comets  should 
 so  long  retain  their  prophetic  character,  seeing  that 
 the  event  must  have  so  often  falsified  the  prediction. 
 But  in  this,  as  in  many  other  cases,  the  belief  of  the 
 prophecy  often  brought  about  the  event.  It  was  so 
 in  the  case  of  Charles  Y.,  whose  resignation  of  his 
 
i66        THE  HISTORY  OF  COMETS. 
 
 royal  honours  was  due  to  his  belief,  that  this  was  the 
 true  interpretation  of  the  celestial  prodigy.  There 
 are,  however,  fulfilments  that  cannot  be  explained  so 
 readily.  A  man,  for  example,  believes  that  the 
 appearance  of  a  comet,  or  some  other  sign  which  he 
 considers  supernatural,  announces  his  death  on  a  par- 
 ticular day,  and  he  dies  accordingly  on  the  very  day. 
 Numerous  cases  of  this  nature  might  be  cited,  which 
 cannot  be  accounted  for  merely  by  accident.  The 
 explanation  is  a  psychological  one.  The  strong  belief 
 itself  produces  the  physical  effect.  The  phenomena 
 of  mesmerism,  or,  as  it  has  been  called,  biology,  suffi- 
 ciently illustrate  this.  The  operator  works  upon  the 
 mind  of  a  weak  or  susceptible  subject,  and  impresses 
 strongly  the  belief,  that  some  effect  such  as  catalepsy 
 must  ensue,  and,  accordingly,  the  subject  becomes 
 cataleptic.  Cases  too  are  on  record,  where,  by  con- 
 cert, some  credulous  person  is  made  to  believe,  on  the 
 testimony  of  various  parties,  that  he  is  labouring 
 under  a  disease  w^hich  must  necessarily  be  fatal,  and 
 death  has  actually  ensued.  The  belief  in  the  pro- 
 phetic character  of  comets,  however,  has  chiefly  been 
 sustained  by  the  fallacy  of  human  judgment,  which 
 consists  in  giving  more  weight  to  a  few  coincidences 
 than  to  many  failures.  The  moon  is  a  familiar  in- 
 stance. Even  at  the  present  day,  there  is  a  very 
 general  belief  among  intelligent  people  that  its  various 
 phases  influence  the  weather ;  and  men  of  sound 
 judgment  in  other  matters,  will  speak  of  the  change 
 
THE  HISTORY  OF  COMETS.        167 
 
 of  the  moon,  and  its  virtue,  as  beyond  dispute,  though 
 accurate  observation  has  shewn  that  these  changes 
 influence  the  weather  as  little  as  the  comet  does  the 
 fate  of  nations  or  individuals. 
 
 It  is  curious  to  mark,  how  the  superstitions  of  a 
 dark  age,  when  banished  by  the  progress  of  science, 
 take  refuge  under  the  wing  of  science  itself.  The 
 incantation,  magic,  and  witchcraft  of  other  days  have 
 reappeared  in  our  day  under  the  forms  of  clairvoy- 
 ance and  spirit-rapping,  and,  with  the  sanction  of  the 
 quasi  science  of  mesmerism,  intelligent  people  be- 
 lieve in  and  practise  them.  When  science  banished 
 cometary  superstitions,  it  still  afforded  a  refuge  for 
 the  love  of  the  marvellous  and  dreadful.  Halley  and 
 other  astronomers,  wdio  were  the  first  to  indicate  the 
 true  nature  of  comets,  loved  to  describe  the  terrible 
 consequences  that  might  ensue  from  a  collision  with 
 the  earth.  The  comet  played  a  most  important  part, 
 too,  in  the  rude  geological  theories  of  those  days. 
 Comets  are  in  much  disrepute  among  geologists  at 
 the  present  day,  as  accounting  for  the  various  con- 
 vulsions and  cataclysms  indicated  by  the  earth's 
 crust.  They  find  it  more  convenient  to  draw  their 
 hypothetical  forces  from  the  unknown  interior  of  the 
 earth.  In  the  days,  of  Whiston,  however,  the  tails 
 of  comets  were  all-important,  as  they  could  tilt  up  the 
 axis  of  the  earth,  and  produce  deluges  at  will,  to  ac- 
 count for  the  various  geological  phenomena.  By  this 
 means,  the  popular  dread  of  comets  was  kept  up  long 
 
1 68        THE  HISTORY  OF  COMETS. 
 
 after  superstition  had  departed.  At  various  periods, 
 great  alarm  has  been  created  in  the  popular  mind. 
 To  soothe  this  alarm,  mathematicians  have  calculated 
 the  chances  of  a  collision,  and  have  shewn  the  impro- 
 bability of  such  a  catastrophe.  Still,  they  have  not 
 been  able  to  shew  the  impossihility ;  and  the  popular 
 mind  is  sometimes  as  much  alarmed  at  the  possible  as 
 at  the  probable.  Astronomers  may  give  an  assurance 
 that  a  comet  will  come  in  collision  with  the  earth 
 only  once  in  280,000,000  of  years,  but  then  they  can 
 give  no  positive  assurance  that  that  one  time  may  not 
 be  in  our  day,  and  this  possibility  is,  to  many  minds, 
 a  sufficient  ground  of  alarm.  Our  great  security  is, 
 that  the  comets  are  not  confined  to  one  plane,  as  the 
 planets  are.  If  they  were,  they  would,  in  crossing 
 our  path,  subject  us  constantly  to  the  danger  of  col- 
 lision. There  is,  however,  one  known  comet,  Biela's, 
 thus  awkwardly  circumstanced.  Its  orbit  may  be 
 compared  to  a  level-crossing  over  a  railway.  The 
 danger  of  such  crossings  is  well  known,  and  hence 
 the  stringency  of  the  law  in  requiring,  generally,  that 
 the  public  road  should  pass  above  or  under  the  line, 
 and  not  on  the  same  level.  All  other  comets,  as  far 
 as  is  known,  either  pass  above  or  under  the  path  of 
 the  earth,  but  this  one  passes  so  nearly  on  a  level, 
 that  it  is  always  a  question  of  time  every  seven  years 
 whether  we  are  to  come  into  collision.  Much  appre- 
 hension was  created  in  1832,  when  it  was  thought 
 the  case  of  our  earth  was  very  critical.     We,  how- 
 
THE  HISTORY  OF  COMETS.        169 
 
 ever,  succeeded  in  giving  a  wide  berth  to  our  danger- 
 ous neighbour,  there  being  the  margin  of  a  whole 
 month.  In  1805,  we  had  a  much  narrower  escape  ; 
 we  then  saved  our  distance  by  only  three  days.  For- 
 tunately the  danger  was  not  known  till  it  was  over. 
 It  was  not,  till  afterwards,  that  the  comet  was  known 
 to  be  a  periodic  one.  It  can,  however,  be  shewn 
 from  our  knowledge  of  its  orbit,  that,  in  this  genera- 
 tion at  least,  there  is  not  only  no  probability,  but  no 
 possibility  of  a  collision. 
 
 Some  astronomers,  on  the  subject  of  comets,  treat 
 the  popular  mind  as  they  would  a  spoiled  child,  by 
 administering  soothing  and  comforting  assurances  of 
 all  kinds.  One  of  these  is,  that  though  we  did  go 
 right  through  a  comet,  we  would  be  none  the  worse 
 of  it.  Judging  from  their  tone,  they  would  rather 
 like  the  thing  as  a  pleasant  experiment.  We  would, 
 however,  require  to  know  something  about  our  sus- 
 picious neighbours,  before  venturing  on  such  an  expe- 
 riment with  anything  like  confidence.  There  would 
 be  little  comfort  in  the  assurance,  that  the  tenuity  of 
 the  substance  is  such  that  it  would  do  neither  good 
 nor  harm.  We  know  that  the  most  deadly  miasmata 
 are  so  subtle,  that  it  is  impossible  to  detect  them  by 
 any  chemical  test,  and  a  very  homoeopathic  dose  of  a 
 comet,  in  addition  to  the  elements  of  our  atmosphere, 
 might  produce  the  most  fatal  effects. 
 
 It  is  hardly  possible,  at  the  present  time,  to  com- 
 prehend the  terror  which  a  great  comet  usually  in- 
 
170        THE  HISTORY  OF  COMETS. 
 
 spired  in  former  days.  Astrology  had  worked  up 
 the  cometary  terrors  into  a  regular  system.  Comets 
 were  divided  into  seven  species,  according  to  the 
 number  and  nature  of  the  seven  planets.  The  co- 
 lour served  as  the  chief  discriminating  mark.  Each 
 species  had  its  own  special  prognostication ;  but 
 not  only  so,  the  house  or  constellation  in  which  the 
 comet  was  visible,  had  a  modifying  influence,  and 
 the  complexity  was  so  great,  that  the  astrologer  was 
 never  baffled  in  making  the  event  coincide  with  the 
 prediction.  The  Church  of  the  middle  ages,  profit- 
 ing by  the  superstitions  of  the  times,  reaped  oc- 
 casional advantages  from  the  visitation  of  a  comet. 
 In  the  year  837,  a  great  comet  shone  forth  in  the 
 southern  part  of  the  heavens.  All  Europe  was  filled 
 with  consternation;  but  the  comet  took  chief  effect 
 on  the  conscience  of  Louis  I.,  King  of  France,  who, 
 to  avert  the  impending  judgment,  founded  many 
 conventual  establishments,  which  exist  at  the  pre- 
 sent day.  The  ringing  of  cathedral  bells  at  noon, 
 in  Koman  Catholic  countries,  can  be  traced  to  the 
 influence  of  a  great  comet,  viz.,  that  of  1456,  now 
 known  as  Halley's.  Pope  Calixtus  III.,  who  then 
 wore  the  triple  crown,  imagining  that  the  comet  was 
 some  demon  come  to  shake  his  throne,  ordered  all 
 the  bells  in  Christendom  to  be  rung — the  ringing  of 
 bells  being  always  considered  a  sovereign  remedy 
 against  evil  spirits.  How  strong  a  hold  must  that 
 comet  have  taken  of  the  popular  mind,  when   four 
 
THE  HISTORY  OF  COMETS.        171 
 
 centuries  have  not  rung  off  its  terrors !  The  ejacula- 
 tion, "  God  bless  you,"  when  a  person  sneezes,  can, 
 it  is  said,  be  traced  to  the  comet  of  the  year  590. 
 It  was  universally  believed  that  the  comet  caused 
 the  epidemic  of  that  year.  The  most  marked  char- 
 acter of  the  disease  was  the  fit  of  sneezing,  in  which 
 the  patient  frequently  died.  When  the  bystanders 
 heard  a  sneeze,  they  bestowed  their  benedictions 
 by  exclaiming,  "  God  bless  you."  And  through 
 the  long  centuries  following,  this  custom  has  been 
 kept  up. 
 
 The  Abbe  Zantedeschi  of  Padua  has  recently  con- 
 trived some  experiments  which  strikingly  illustrate 
 the  constitution  of  comets,  and  also,  as  he  thinks, 
 that  of  the  corona  of  solar  eclipses.  His  opinion  is, 
 and  it  is  shared  by  M.  Faye  and  Father  Secchi  of 
 Eome,  that  the  moon  has  an  atmosphere  of  consider- 
 able height,  and  that  the  corona  is  simply  this  at- 
 mosphere illuminated  by  the  sun  hid  behind  the 
 moon.  The  atmosphere  is  not  gaseous  like  ours, 
 but  is  composed  of  highly  attenuated  particles  of 
 matter  derived  from  the  surface  of  the  moon.  Such 
 an  atmosphere  would  not  refract  light,  so  as  to  be 
 detected  by  the  occultation  of  stars ;  but  it  would 
 reflect  light  in  such  a  way  as  to  be  made  visible  in 
 total  eclipses.  The  above  physicists  are  therefore 
 opposed  to  the  general  opinion  that  the  corona  be- 
 longs to  the  sun,  and  not  to  the  moon.  Zantedeschi, 
 by  using  very  fine  dust  to  represent  the  lunar  atmo- 
 
172        THE  HISTORY  OF  COMETS. 
 
 sphere,  has  produced  m  a  dark  chamber,  by  means  of 
 the  sun's  rays,  a  phenomenon  precisely  similar  to 
 the  corona.  These  experiments  are  exceedingly  in- 
 teresting when  viewed  in  connexion  with  the  total 
 solar  eclipse  of  the  18th  of  July  1860.  It  is  con- 
 fidently expected  that  this  debated  point  will  finally 
 be  settled  by  the  observations  to  be  then  made.  The 
 representation  of  comets  by  the  same  means  is  very 
 interesting  and  striking.  Observation  confirms  the 
 supposition  that  comets  are  not  composed  of  a  con- 
 tinuous substance  like  a  gas,  but  of  a  mass  of  dis- 
 crete particles,  like  a  cloud  of  dust.  This  is  known 
 by  its  not  refracting  light  like  our  gaseous  atmo- 
 sphere. Some  comets,  when  very  near  the  sun, 
 seem  to  lose  their  envelopes,  though  they  should 
 now  expand  to  their  largest  dimensions.  The  ex- 
 planation of  Herschel  is,  that  the  heat  converts  the 
 visible  discontinuous  particles  into  an  invisible  gas. 
 A  comet  would  thus  correspond  to  a  cloud  which 
 consists  of  watery  particles,  but  which  become  in- 
 visible on  the  application  of  heat — the  watery  par- 
 ticles being  converted  into  the  gaseous  form  of  in- 
 visible vapour.  So  attenuated  is  the  matter  of 
 comets,  that,  if  condensed  into  a  solid  body,  the 
 largest  might  probably  be  packed  into  a  ship's  hold. 
 This  is  deduced  from  the  fact  that  the  largest  comets 
 do  not,  in  the  slightest  degree,  afiect  the  motion  of 
 planets  or  satellites,  however  close  they  may  ap- 
 proach; and  we  have  the  case  of  one  comet  which 
 
THE  HISTORY  OF  COMETS.        173 
 
 swept  right  througli  the  system  of  Jupiter's  moons 
 without  altering  their  motion. 
 
 The  constitution  of  comets,  viewed  in  connexion 
 with  the  arrangement  of  the  solar  system,  strikingly 
 illustrates  the  wisdom  of  God.  Were  comets  not 
 composed  of  such  attenuated  matter,  the  stability  of 
 the  solar  system  would  be  destroyed,  and  life  would 
 soon  be  impossible  on  our  globe.  The  stability  de- 
 pends on  all  the  principal  bodies  being  confined 
 nearly  to  one  plane ;  but  the  comets  move  in  every 
 possible  plane,  and  hence  if  they  were  possessed  of 
 a  planetary  density,  they  would  fatally  disturb  the 
 equilibrium  of  the  system.  Were  the  comets  re- 
 stricted to  the  same  plane  in  which  the  planets  move, 
 the  danger  of  collision  would  be  very  great,  as  the 
 long  ovals  in  which  the  comets  move  would  be  con- 
 stantly crossing  the  more  circular  orbits  of  the 
 planets.  In  a  crowded  assembly,  as  long  as  the 
 throng  promenade  in  the  same  direction  round  a 
 suite  of  rooms,  there  is  no  danger  of  coming  to  a 
 lock ;  but  if  some  move  in  an  opposite  direction,  or 
 attempt  to  cross  the  stream,  the  circulation  is  in 
 danger  of  being  brought  to  a  dead  halt.  The  motion 
 of  comets  would  interfere  similarly  with  the  regular 
 motion  of  the  planets,  did  they  move  in  the  same 
 plane ;  and  when  we  consider  the  thousands  of  comets 
 that  are  constantly  sweeping  across  the  solar  system, 
 the  chance  of  collision  would  be  by  no  means  incon- 
 siderable.    This  danger  is  avoided  by  making  the 
 
174        THE  HISTORY  OF  COMETS. 
 
 comets  move  either  on  a  higher  or  lower  level,  just  as 
 travellers  are  made  to  do  at  railway  stations  when 
 they  wish  to  cross  the  rails.  One  comet,  Biela's, 
 crosses  the  orbit  of  the  earth,  as  if  to  remind  us  of 
 the  danger  we  would  run  were  the  crowd  of  comets 
 allowed  the  same  privilege. 
 
 Comets  may  be  regarded  as  the  scouts  or  pioneers 
 of  the  solar  system.  The  ancients  supposed  we  were 
 encased  in  crystal  spheres ;  but  the  comets  in  their 
 course  shivered  them  to  atoms.  Descartes  then  en- 
 circled us  with  vortices,  but  the  comets  in  the  hands 
 of  Newton  stopped  their  action  for  ever.  They  have 
 told  us  also  of  a  resisting  medium,  and  hinted  at  the 
 probable  doom  of  the  solar  system ;  and,  no  doubt, 
 there  are  other  high  functions  assigned  them.  We 
 may  regard  a  comet  as  a  plumb-line  let  down  into 
 the  depths  of  space,  to  explore  the  nature  of  the  cur- 
 rents, and  the  objects  that  may  exist  far  beyond  the 
 reach  of  vision.  The  change  in  their  constitution, 
 and  the  disturbance  of  their  orbits,  may  tell  us  of  the 
 existence  of  worlds  which  the  telescope  may  never 
 reach.  As  the  lead  of  the  mariner,  with  its  adhe- 
 sive surface,  brings  up  unmistakable  evidence  of  the 
 nature  of  the  bottom,  so  comets,  when  we  understand 
 them  better,  may  bring  interesting  news  of  regions 
 hitherto  unexplored.  Comets  rush  forth  from  the 
 starting-post  of  the  sun  with  the  speed  of  lightning, 
 but  they  soon  slacken  their  pace  as  if  to  feel  their 
 way ;  and,  by  the  time  they  reach  the  end  of  their 
 
THE  HISTORY  OF  COMETS.        17s 
 
 journey,  a  child  trundling  a  hoop  would  be  more 
 than  a  match  for  them  in  speed.  It  is  by  this  cau- 
 tious pace  they  are  best  fitted  to  gather  news  of  the 
 remote  regions  to  which  they  travel,  as  they  are  then 
 most  liable  to  have  their  path  changed  by  unknown 
 bodies.  But  going  at  this  sluggish  pace,  they  are 
 most  apt  to  be  captured  and  chained  for  ever  to  some 
 other  system.  Yet  their  very  loss  would  tell  an  in- 
 teresting tale. 
 
Broken  Appearance  of  Saturn's  Rings. 
 
 XII. 
 
 THE  STRUCTURE  OF  THE  PLANETS. 
 
 Were  a  city,  in  the  heart  of  Africa,  bombarded 
 by  an  enemy  employing  the  deadly  projectiles  of 
 modern  warfare,  it  would  be  possible  for  the  be- 
 sieged, though  they  had  never  before  seen  such  ob- 
 jects, to  discover,  when  picking  them  up,  a  unity 
 of  purpose.  The  Armstrong  bolt  and  the  Minie 
 bullet,  however  different  in  appearance,   would  be 
 
5  7R  UCTURE  OF  PLANE  TS,        i ;; 
 
 found  to  be  essentially  the  same  in  structure  and 
 design.  Both  are  alike  constructed  to  pass  through 
 the  air  with  the  least  resistance.  The  marks  of 
 the  rifling  would  tell  the  inquirer  that  this  contriv- 
 ance served  the  same  purpose  as  the  feathering  of  his 
 own  arrow — steadiness  of  flight.  Were  he  to  examine 
 the  Moorsom  and  the  Armstrong  shells,  he  would 
 find  a  corresponding  similarity,  with  the  same  object 
 to  be  served — the  bursting  of  the  shell  at  the  moment 
 of  striking.  Amidst  the  diversity  he  would  discover 
 unity  of  plan.  It  is  this  synthesis  of  diverse  elements 
 that  communicates  such  a  charm  to  the  study  of  the 
 works  both  of  God  and  man.  The  child  takes  a 
 delight  in  tracing  fanciful  resemblances ;  the  ma- 
 tured mind  finds  its  enjoyment  in  discovering  latent 
 but  real  analogies;  and  to  the  devout  mind,  these 
 analogies  are  so  many  steps  of  the  pyramid,  leading 
 to  the  apex — the  divine  unity  that  synthetises  all 
 diversity  in  nature. 
 
 We  have  already  examined  the  structure  of  the 
 sun.  We  have  pried  into  the  central  furnace,  and 
 seen  how  curiously  complicated  its  structure  is.  We 
 have  seen  its  surging  flames,  and  the  edges  of  its  con- 
 centric strata,  appearing  like  the  bars  of  a  mighty 
 furnace.  Our  object  is  now  to  shew,  that  the  sun  and 
 planets  belong  to  the  same  family,  however  diverse 
 they  appear  to  be.  We  speak  of  the  sun  as  if  sepa- 
 rated from  the  planets  by  a  wide  gulf,  and  as  if  be- 
 longing to  a  totally  distinct  class  of  bodies  j  but  we 
 
 M 
 
178  THE  STRUCTURE 
 
 shall  find  more  points  of  resemblance  than  of  difi'er- 
 ence. 
 
 The  central  position  of  the  sun  may  seem  to  claim 
 for  it  a  distinctive  character,  but  it  is  really  only  the 
 last  of  a  series.  The  link  that  terminates  a  chain  is 
 notliins:  more  than  a  link.  The  innermost  case  of  a 
 mummy  is  only  a  mummy  case,  though  painted  with 
 brighter  hieroglyphics.  The  last  of  a  nest  of  boxes 
 enclosing  a  jewel,  though  immediately  enveloping  the 
 precious  object,  is  only  one  of  the  set.  The  centre  of 
 the  solar  system  is  the  jewel,  and  the  sun  revolves 
 around  it  just  as  the  planets  do.  The  only  difference 
 is,  that  its  circle  is  the  narrowest. 
 
 It  may  be  urged  that  the  structure  and  constitu- 
 tion of  the  sun  completely  separate  it  from  the  planets, 
 but  there  is  evidence  to  shew  that  there  is  a  type  to 
 which  the  planets  and  the  sun  equally  belong.  The 
 sun,  no  doubt,  is  an  intense  furnace,  while  the  planets 
 are  in  themselves  dark  bodies,  but  the  structure  may 
 be  still  alike.  If  you  saw  only  one  furnace  in  action 
 at  an  iron-work,  you  would  not  conclude  that  the 
 others,  which  have  been  put  out,  belong  to  a  quite 
 different  class  of  buildings.  The  hot-blast  apparatus, 
 the  tuyeres,  the  furnace-bars,  the  well,  and  the  slag 
 before  the  furnace,  would  at  once  shew  the  purpose  of 
 the  erection,  and  prove  that  it  had  been  used  as  a 
 furnace.  Though  the  sun  is  now  the  only  body  of 
 the  system  in  active  operation  as  a  furnace,  there  are 
 evident  indications  that  the  planets  were  at  one  time 
 
OF  THE  PLANETS.  179 
 
 incandescent  bodies.  Geology  gives  abundant  proof 
 of  igneous  action  in  our  globe  at  a  former  period,  and 
 we  have  reason  to  believe  that  we  now  stand  on  a 
 crust  floating  on  a  molten  sea.  When  we  look  to 
 the  moon  J  we  find  innumerable  extinct  volcanoes,  like 
 so  many  furnaces  in  an  iron  district,  put  out  by  a 
 general  strike.  The  other  planets  do  not  allow  us  to 
 see  their  minuter  features,  but  analogy  fairly  leads  to 
 the  conclusion  that  they  were  all,  at  one  time,  active 
 furnaces. 
 
 The  concentric  envelopes  of  the  sun  are,  by  no 
 means,  a  distinctive  feature,  or  one  that  should  sepa- 
 rate it  from  the  family  of  planets.  The  rings  of 
 Saturn  are*  only  a  special  case  of  this  concentricity — 
 the  ring  being  merely  a  flattened  sphere.  The  enve- 
 lopes of  the  sun  are  somewhat  flattened,  and  Saturn's 
 rings  are  only  an  extreme  case.  The  spherical  mop, 
 when  twirled,  becomes  a  flat  ring,  so  that  the  mere 
 circumstance  of  motion  explains  the  difference.  The 
 sun  has,  indeed,  rings  similar  to  those  of  Saturn.  We 
 have  seen  that  the  zodiacal  light,  and  the  zones  of 
 asteroids  and  meteorites  are  analogous  to  these  rings. 
 The  earth  also  afl'ords  an  example  of  the  concentric 
 structure.  In  an  eclipse  of  the  moon,  an  inhabitant 
 of  that  body  would  behold  a  spectacle  sin^ilar  to  what 
 is  presented  in  a  solar  eclipse.  He  would  see  a  faint 
 corona,  and,  along  the  margin  of  the  earth,  he  would 
 see  a  copper-coloured  stratum,  with  prominences  like 
 the  rose-coloured  shell  of  the  sun,  this  stratum  being 
 
1 80  THE  STRUCTURE 
 
 the  lower  regions  of  tlie  air  loaded  with  moisture  and 
 clouds ;  and  were  he  to  see  down  through  the  crust 
 of  the  earth,  he  would  in  all  XDrobability  discover  a 
 concentric  aiTangement  of  the  interior. 
 
 In  the  case  of  Jupiter  and  Saturn,  it  is  obvious 
 that  we  see  only  the  outer  shell,  within  which  the 
 bodies  of  the  planets  are   concealed.     The   disc  of 
 Jupiter  presents  very  singular  phenomena.    There  are 
 indications  of  constant  commotion,  and  the  markings 
 of  the  belts  often  present  very  perplexing  forms,  of 
 which  no  account  can  be  given.     We  only  know 
 that  the  visible  disc  is  not  a  fixed  and  solid  crust. 
 It  is  like  the  visible  envelope  of  the  sun,  which  con- 
 ceals the  solid  nucleus  in  its  interior.     The  shadows 
 of  the  satellites  are  seen  as  dark  spots  when  they 
 cross  the  disc  of  the  planet,  and  the  satellites  them- 
 selves  can   also   at  the  same   time  be  detected  by 
 powerful  telescopes.     Besides  these,  there  are  other 
 spots   of  which  no   account  can  be  given.      They 
 sometimes  appear  in  clusters,  as  shewn  in  our  figure 
 of  the  planet.     They  have  a  proper  motion  like  the 
 spots  on  the  sun,  and,  probably,  are  due  to  the  same 
 general  cause — the  rotation  of  the  body   combined 
 with  the  higher  temperature  of  the  equatorial  regions. 
 They  will,  therefore,   correspond  with  the    circular 
 storms  or  cyclones  in  the  atmosphere  of  our  globe. 
 There  is  no  evidence  that  we  have  ever  as  yet  seen 
 the  kernel  within  the  outer  shell  of  Jupiter.     The 
 usual  explanation  of  the  dark  belts  of  Jupiter  is,  that 
 
P  LATf    V! 
 
 JUPITER 
 
OF  THE  PLANETS.  i8i 
 
 they  are  the  more  transparent  parts  of  Jupiter's  at- 
 mosphere, while  the  brighter  parts  are  the  region  of 
 clouds  which  reflect  the  light  more  abundantly.     In 
 this  hypothesis,  we  see  the  body  of  the  planet  down 
 through  the  transparent  region  of  dark  belts ;  but  it 
 is  more  probable  that,  in  the  dark  belts,  we  see  only 
 a  part  of  an  interior   shell,  and  that  the  real  body 
 may  He  far  beneath.     The  dark  belts  would,  in  this 
 way,  correspond  to  the  penumbra  of  the  spots  in  the 
 sun,  which  is  only  an  micovered  part  of  the  stratum 
 immediately  under  the  luminous  envelope.     Jupiter 
 is  by  far  the  largest  of  the  planets,  and  yet  it  may 
 have  only  a  small  solid  nucleus.    Though,  taken  as  a 
 whole,  Jupiter  is  not  heavier  than  a  sphere  of  water 
 of  the  same  size,  we  can  readily  suppose  the  real 
 body  of  the  planet  to  be  of  much  heavier  matter.     It 
 may  be  compared  to  a  bullet  of  lead  forming  the  core 
 of  a  sphere  of  cork.     Dr  Whe well's  argument  then  is 
 of  no  force,  when  he  holds  that  Jupiter  can  only  be 
 the  abode  of  molluscs,  and  other  lower  forms  of  life 
 suited  to  a  watery  abode.     Even  though  the  body  of 
 Jupiter  had  only  the  density  of  water,  it  would  not 
 at  all  be  necessary  to  assume  that  it  must  necessarily 
 be  fluid,  for  we  know  of  many  solid  substances  as 
 light  as  water.    But  there  is  no  necessity  for  holding 
 that  its  density  is  only  that  of  water.     The  Jovial 
 ball  may  be  as  dense  as  that  of  the  earth,  and  may 
 afford  to  the  teeming  inhabitants  as  sure  a  footing  as 
 our  roads  and  streets. 
 
i82  THE  STRUCTURE 
 
 How  astdnlshing  must  the  sight  of  Saturn  have  been 
 to  Galileo  when  he  first  descried  its  strange  form ! 
 ■  It  was,  however,  long  before  the  character  of  the  mon- 
 strosity was  understood.  A  telescopic  power  as  small 
 as  that  which  Galileo  used,  is  sufficient  to  convince 
 any  one,  at  the  present  day,  that  there  is  a  ring  round 
 the  body  of  the  planet;  yet  Galileo  did  not  see  a 
 ring.  He  called  the  parts  of  the  ring,  projecting  on 
 each  side  of  the  planet,  anscE^  as  they  appeared  like 
 tlie  two  handles  of  an  antique  vase.  We  may  see 
 nothing  more  at  the  present  day,  and  yet  every 
 schoolboy  would  at  once  know  that  they  are  only 
 parts  of  a  ring  seen  obliquely;  and  would  maintain 
 that  he  was  indebted  only  to  his  sight.  This  is  only 
 one  illustration  of  a  thousand,  that,  for  what  we  see 
 around  us,  we  are  as  much  indebted  to  the  intellect 
 as  to  the  eye.  The  organ  of  sense  gives  only  skele- 
 ton forms,  which  the  intellect  and  imagination  fill  up. 
 When  shewing  objects  through  a  microscope  to  one 
 unaccustomed  to  the  use  of  it,  you  are  sometimes 
 astonished  that  he  does  not  see  what  is  so  obvious  to 
 yourself;  but  the  mere  objective  nucleus  is  unmean- 
 ing, unless  the  previously  trained  mind  can  clothe  it 
 with  significance.  It  is  sometimes  matter  of  surprise 
 that  men,  living  amongst  the  beautiful  and  interest- 
 ing scenes  of  nature,  should  be  totally  uninfluenced 
 by  them ;  but  the  truth  is,  the  objects  that  interest 
 us,  may  not  be  really  seen  by  them.  For  thousands 
 of  years,  the  spots  on  the  sun,  and  the  zodiacal  light, 
 
OF  THE  PLANETS,  .      183 
 
 must  have  impressed  an  Image  on  tlie  human  retma, 
 and  yet  we  have  no  evidence  that  they  were  ever 
 really  observed  till  modern  times.  Another  case, 
 still  more  in  point,  is  the  obscure  and  innermost  ring 
 of  Saturn.  It  must  have  been  often  pictured  on  the 
 retina  of  observers,  and  yet  it  was  not  really  observed 
 till  a  few  years  ago.  Some,  indeed,  suppose  that  it 
 must  have  been  developed  in  recent  times,  but  the 
 ordinary  laws  of  observation  furnish  us  with  a  suffi- 
 cient explanation. 
 
 When  the  rings  of  Saturn  were  fairly  descried, 
 the  structure  of  the  planet  must  have  appeared  still 
 more  marvellous.  How  contrary  to  all  preconceived 
 notions  of  the  stars !  But  no  sooner  is  the  human 
 mind  struck  with  astonishment,  than  it  seeks  to 
 divest  the  wondrous  object  of  its  singularity.  There 
 is  an  instinct  that  makes  us  seek  for  points  of  simi- 
 larity. The  idea  of  one  presiding  intelligence  leads 
 us  to  the  conviction,  that,  however  strange  the  phe- 
 nomenon may  be,  it  must  be  in  harmony  with  the 
 other  works  of  God,  and  this,  not  merely  in  refer- 
 ence to  adaptation,  but  to  style.  Every  architect 
 must  conform  to  certain  structural  rules,  without 
 which  he  cannot  erect  any  edifice ;  and  we  find 
 design  and  adaptation  in  every  building.  But,  over 
 and  above  this,  there  is  the  undefinable  idea  of  style, 
 and  we  expect,  amidst  all  diversity,  to  detect  the 
 manner  of  the  man  of  genius.  Genius  confers  a 
 unity  on  works  of  the  most  diverse  structure,  and 
 
i84  THE  STRUCTURE 
 
 design.  We  expect  to  find  this  unity  in  tlie  style 
 of  God's  works,  apart  from  mere  adaptation.  But  is 
 it  possible  to  detect  a  unity  of  structure  in  the  solar 
 system  J  when  we  have  the  singular  and  startling 
 exception  of  Saturn?  Is  it  really  in  gear  with  the 
 other  parts  of  the  solar  system,  as  far  as  style  is  con- 
 cerned? It  is  to  this  interesting  point  we  would 
 now  address  ourselves. 
 
 Laplace  attempted  to  establish  a  unity  and  a  type 
 by  means  of  the  nebular  hypothesis.  He  conceived 
 a  mode  by  which  the  planets  were  manufactured,  as 
 the  potter  fashions  artistic  vases  from  the  shapeless 
 mass  of  clay.  But  our  design  is  not  to  imagine  a 
 unity  of  process  or  development,  but  to  detect  a  unity 
 of  result.  We  can  detect  the  predominating  style  of 
 Wren,  though  we  are  quite  ignorant  as  to  the  precise 
 mode  of  operation  adopted  by  him  in  rearing  St  Paul's 
 and  other  edifices.  So  in  the  architecture  of  the  solar 
 system,  we  can  discover  a  plan  independently  of  any 
 theory  of  evolution.  In  like  manner,  we  are  not 
 obliged  to  adopt  the  theories  of  Lamarck  and  Darwin 
 in  order  to  accept  the  fact  of  archetypes  in  natural 
 history.  Owen's  results  are  altogether  independent 
 of  such  theories. 
 
 Is  there,  then,  apart  from  all  theories  of  develop- 
 ment, a  general  style  of  architecture  in  the  solar  system, 
 to  which  the  structure  of  Saturn  conforms  ?  We  think 
 there  is,  and  that  there  is  a  traceable  gradation  of 
 distinctive  characters  through  all  the  planets.     The 
 
Plate   V 
 
 THE    GREAT    COMET    OF     185^ 
 
OF  THE  PLANETS.  185 
 
 fisli  is  the  lowest  form  of  the  vertebrate  type  of  animals, 
 and  the  scale  upwards  to  man  is  marked  by  the  differ- 
 entiation of  limbs.  They  are  undeveloped  in  the  fish, 
 and  they  rise,  through  innumerable  steps,  to  perfec- 
 tion in  the  human  species.  Comparing  the  solar  vv^ith 
 the  vertebrate  system,  the  moon,  with  its  naked  ball, 
 may  represent  the  undeveloped  form  of  the  fish,  and 
 Saturn  the  highest  form  of  vertebrate  animals.  When 
 we  speak  of  the  typical  perfection  of  a  planet,  we  do  not 
 at  all  refer  to  its  adaptation  to  life.  We  mean  merely 
 the  degree  in  which  the  distinguishing  characteristics 
 of  a  general  style  are  exhibited.  The  grand  character- 
 istic is  the  concentricity  of  structure,  which  we  before 
 traced  in  the  sun.  In  the  sun,  we  have  seen  that  there 
 are  successive  envelopes  or  shells  around  the  core. 
 Three  of  these  were  recognised  before  the  last  total 
 eclipse,  and  the  phenomena  of  the  eclipse  have  clearly 
 established,  what  was  before  surmised,  another  enve- 
 lope of  rose-coloured  matter  ;  and,  extending  beyond 
 this  stratum,  there  is  the  corona,  which  is,  most  pro- 
 bably, the  atmosphere  in  which  all  the  others  are  sus- 
 pended, like  strata  of  clouds  at  different  heights  of 
 our  atmosphere.  If  we  accept  the  hypothesis  of  the 
 Astronomer-Koyal,  that  the  corona  is  due  to  our  atmo- 
 sphere reaching  nearly  to  the  moon,  w^e  shall  be  forced 
 to  admit  that  this  atmosphere  exists  as  a  zone  or 
 ring  encircling  the  earth.  It  cannot  be  the  ordinary 
 atmosphere  of  the  earth.  Well-known  dynamical 
 conditions  forbid  this  supposition.    We  must  suppose 
 
i86  THE  STRUCTURE 
 
 it  of  a  nature  similar  to  tliat  of  the  faint  ring  of 
 Saturn.  This  idea  would  countenance  the  opinion 
 held  by  some  astronomers,  that  the  zodiacal  light  is 
 an  appendage  of  the  earth  and  not  of  the  sun.  There 
 are,  however,  inexplicable  difficulties  in  the  supposi- 
 tion that  the  zodiacal  light  is  a  nebulous  terrestrial 
 zone.  Whether  we  refer  it  to  the  earth  or  sun,  it 
 stands  as  an  element  of  concentric  structure. 
 
 We  have  reason  to  believe  that  Saturn,  as  well  as 
 Jupiter,  is  constructed  on  a  similar  concentric  plan, 
 and  that  his  belts  are  indications  of  an  internal  enve- 
 lope. But  does  the  similarity  between  the  sun  and 
 Saturn  cease  here  ?  By  no  means ;  the  grand  pecu- 
 liarity of  Saturn  has  its  analogue  in  the  sun.  Saturn 
 has  a  series  of  concentric  rings,  but  so  has  the  sun. 
 Where  are  they  ?  it  will  be  asked ;  we  have  no  hesi- 
 tation in  answering  that  the  zone  of  asteroids  between 
 Mars  and  Jupiter,  as  well  as  the  zodiacal  light,  are  fairly 
 analogous.  Take  the  bright  rings  of  Saturn,  and  let 
 us  compare  it  with  the  zone  of  asteroids.  These  rings 
 have  all  the  appearance  of  being  solid  bodies,  when 
 you  take  only  a  cursory  glance,  but  on  more  minute 
 inspection,  proofs  leading  to  an  opposite  conclusion 
 will  be  found.  There  is  only  one  large  dark  division, 
 but  a  smaller  one  at  both  ends  of  the  miscB^  dividing 
 the  outer  ring  into  two,  is  sometimes  seen.  The 
 views,  however,  are  so  capricious,  that  the  observer  is 
 naturally  led  to  the  conclusion,  that  there  are  changes 
 going  on  in  the  constitution  of  the  rings.      Again, 
 
OF  THE  PLANETS.  187 
 
 some  have  ol)served  a  structure  in  the  whole  breadth 
 of  the  rings,  similar  in  appearance  to  a  flat  coil  of 
 rope,  or  the  ribbed  texture  of  corduroy,  rendering  it 
 probable  that  the  rings  are  composed  of  small  bodies 
 closely  packed  and  arranged  like  concentric  strings 
 of  beads  laid  flat  on  a  table.  The  bodies,  on  this 
 hypothesis,  have  no  rigid  connexion,  and  move  in 
 independent  orbits.  They  are,  however,  so  closely 
 packed  together,  that  they  appear  as  one  body.  The 
 zone  of  the  asteroids  quite  corresponds  to  this. 
 Seventy-one  have  already  (1861)  been  discovered ; 
 and  it  is  probable,  from  the  rate  of  discovery,  that 
 there  are  thousands  upon  thousands  within  the  cir- 
 cumscribed zone.  To  an  eye  properly  situated,  and 
 at  a  sufficient  distance,  this  zone  would  appear  as  a 
 faint  ring.  If  more  compressed,  they  would  be  bright, 
 like  the  rings  of  Saturn.  These  asteroids  are  pro- 
 bably of  every  size.  Some  are  large  as  a  kingdom 
 or  a  county ;  others  are  miniature  worlds,  of  the  size 
 of  Arthur's  Seat;  and  some  may  dwindle  down  to 
 the  magnitude  of  a  cannon-ball.  We  may  suppose 
 them  so  arranged  as  to  leave  gaps  corresponding  to 
 the  divisions  of  Saturn's  rings. 
 
 Again,  the  obscure  ring  of  Saturn  may  be  compared 
 to  the  zodiacal  light.  It  will  be  seen  from  our  figure 
 of  the  planet,  that  the  recently  discovered  ring  is 
 transparent,  as  the  limb  of  the  disc  is  seen  through 
 it.  It  is  most  probably  composed  of  some  discrete 
 substance  like  dust,  as  it  does  not  comport  itself  like 
 
1 88  THE  STRUCTURE 
 
 a  gaseous  bodj.  This  is  probably  also  the  constitu- 
 tion of  the  zodiacal  light,  which  is  another  ring  or 
 zone  nearer  the  sun,  the  boundaries  of  which  are  not 
 well  defined.  It  is  shaped  somewhat  like  a  quoit. 
 The  sun  being  in  the  middle  of  the  central  hole,  we 
 see  only  the  edge  of  it  when  it  appears  to  rise  as  a 
 long  cone  from  the  horizon.  It  is  best  seen  in  Feb- 
 ruary and  March  above  the  part  of  the  horizon  where 
 the  sun  has  set.  The  generally  received  opinion  is, 
 that  it  is  composed  of  meteoric  bodies ;  and  some  hold 
 that  it  may  extend  beyond  the  orbit  of  the  earth,  so 
 that  we  pass  through  it  twice  a  year.  The  meteoric 
 bodies  become  incandescent  when  they  meet  our 
 atmosphere,  and  the  two  annual  periods  of  meteoric 
 showers  are  accounted  for  by  the  intersection  of  the 
 earth's  orbit  at  two  opposite  points.  To  an  eye  at  a 
 great  distance,  the  sun  would  appear  as  if  surrounded 
 by  two  faint  rings,  with  a  wide,  dark  space  between, 
 while  the  outer  ring,  or  that  of  the  asteroids,  would 
 likely  be  subdivided  by  smaller  dark  lines. 
 
 The  calculations  of  Leverrier,  and  the  discovery  of 
 Lescarbault,  render  it  very  probable  that  there  is  a 
 zone  of  planets  or  asteroids  within  the  orbit  of  Mer- 
 cury, so  as  to  form  a  third  faint  ring  encircling  the 
 sun.  Leverrier  has  also  shewn  that  the  perturbation 
 of  Mars  indicates  the  existence  of  a  zone  of  meteorites 
 whose  diameter  is  nearly  equal  to  that  of  the  orbit  of 
 the  earth.  Such  a  zone  Avould  most  naturally  explain 
 the  phenomena  of  meteorites  and  their  periodicity. 
 
OF  THE  PLANETS.  189 
 
 The  next  marked  example  of  the  concentric  struc- 
 ture is  furnished  by  comets.  We  have  ah'cady  shewn 
 that  this  is  one  of  their  most  striking  features.  In 
 this  case,  we  see  the  very  formation  of  the  strata  or 
 envelopes.  They  grow  before  our  eyes,  and  afford  a 
 type  of  the  structure  of  the  more  solid  bodies  of  the 
 solar  system. 
 
 Most  of  the  planets  are  so  remote  from  us,  or  so 
 near  the  sun,  that  we  cannot  speak  with  certainty  of 
 their  envelopes.  As  far  as  our  knowledge  extends, 
 the  moon  stands  lowest,  as  she  has  no  shell  of  any 
 kind  surrounding  the  solid  ball.  Mars  probably  comes 
 next.  We  can  at  all  times  see  the  fixed  features  of 
 his  surface,  and  nothing  like  clouds  has  been  detected, 
 though  there  is  evidence  for  an  atmosphere.  Next 
 comes  the  earth,  with  her  far-extending  atmosphere 
 and  her  stratum  of  clouds.  Jupiter  ranks  next  in 
 order ;  and  lastly,  Saturn,  the  most  complete  example 
 of  concentricity  of  structure. 
 
 In  the  case  of  the  moon,  taken  as  a  whole,  we  do 
 not  indeed  find  a  concentric  structure  ;  but  in  a  for- 
 mer chapter  we  shewed  that  almost  the  whole  surface 
 is  covered  with  volcanic  craters,  the  principal  feature 
 of  which  is  concentricity.  The  cone  in  the  centre — 
 the  encircling  cavity — the  rim,  with  its  successive 
 terraces,  all  combine  to  carry  out  the  planetary  ideal. 
 
 When  we  descend  from  the  cosmical  type  of  the 
 planetary  system  to  the  lowest  forms  of  organisation, 
 we  discover  the  same  concentric  feature.    The  section 
 
iQO  THE  STRUCTURE 
 
 of  a  tree  exliibits  the  concentric  rings  of  the  planet. 
 The  flower  with  its  pistil  in  the  centre,  and  its  encir- 
 cling anthers,  petals,  and  calyx,  shadows  forth  the 
 all -pervading  plan,  alike  stamped  on  the  orb  of  heaven 
 and  the  lily  of  the  valley. 
 
 When  we  range  beyond  the  solar  system,  and 
 extend  our  view  to  other  suns  and  systems,  we  shall 
 find  diversity,  but  nothing  to  destroy  the  unity  of 
 plan,  or  shake  our  belief  that  all  is  the  product  of  one 
 divine  idea.  When  w^e  fathom  the  depths  of  space, 
 we  discover  similar  forms.  We  behold  the  masses 
 of  stars  grouped  into  rings,  and  sometimes  exhibiting 
 traces  of  stratification.  But  there  is  a  higher  form, 
 into  which  increased  telescopic  power  is  fast  resolving 
 other  forms,  viz.,  the  spiral.  The  planetary  type  is 
 the  concentric  arrangement  of  the  section  of  a  tree. 
 The  streams  of  stars  constituting  nebulae,  are  coiled 
 up  like  the  mainspring  of  a  watch,  or  wheeling  round 
 to  the  centre  of  a  vortex.  The  spiral  is  the  archetype, 
 and  comprehends  the  concentric  circles  of  the  planet- 
 ary systems.  We  may  not  be  able  to  trace  the  tran- 
 sition, but  no  one  can  compare  the  rings  of  Saturn 
 with  the  spiral  of  a  nebula,  without  feeling  that  they 
 are  allied  forms,  though  the  link  may  not  yet  be 
 detected. 
 
 Our  dwelling-place  is  in  a  small  corner  of  a  vast 
 edifice,  and,  roam  where  we  may,  we  shall  find  proofs 
 that  the  plan  is  the  same  throughout.  The  cathedral 
 of  Cologne,  now  drawing  towards  completion,  has 
 
OF  THE  PLANETS.  191 
 
 had  many  architects  employed  upon  it,  but  there  is, 
 in  every  part,  evidence  of  one  presiding  mind.      The 
 successors  of  the  original  designer  have  only  striven 
 to  carry  out  his  ideas.     There  is  one  pervading  style 
 in  the  architecture  of  the  heavens,  and  thoudi  subor- 
 dinate  agencies  have  been  employed  to  carry  it  out, 
 they  do  not  in  the  least  prevent  us  from  recognising 
 tlie  hand  of  the  Original  Designer.     The  materialist 
 may  say  that  the  concentric  structure,  as  well  as  all 
 the  beauty  and  harmony  of  the  system,  can  be  ex- 
 plained by  certain  great  material  laws.     But,  grant- 
 ing that  these  laws  do  exhibit  the  modus  operandi^  do 
 they,  in  the  least,  supersede  the  necessity  of  a  plan- 
 ning and  presiding  mind?     The  style  of  the  solar 
 system  is  an  embodied  idea ;  and  an  idea  is  a  thing 
 of  mind,  not  of  matter.     We  do  not  get  rid  of  the 
 necessity  of  genius  by  shewing  how  the  artist  handles 
 his  brush,  and  lays  on  his  piiint.     The  paints  and  the 
 brush  are  only  the  material  vehicles  by  which  the 
 ideas  of  genius  are  transferred  to  the  canvas.     No 
 more  do  the  laws  of  matter  supersede  mind.      They 
 are  only  the  media  through  which  the  ideas  of  the 
 Divine  Mind  are  transferred  to  the  gallery  of  the 
 universe.     The  simpler  the  means  of  the  artist,  the 
 more  marvellous  are  his  achievements,  and  the  sim- 
 plicity and  generality  of  the  laws  of  matter,  only  en- 
 hance the  marvels  of  the  divine  idea  imprinted  on  the 
 heavens.     And  what,  after  all,  are  the  laws  of  matter 
 but  the  mode  in  which  the  Divine  Artist  works  ?    The 
 
192        STRUCTURE  OF  PLANETS. 
 
 mere  description  of  the  movements  of  a  brush  over 
 the  canvaSj  surely  does  not  supersede  the  hand,  and 
 the  mind  that  guides  the  hand,  of  the  artist  ?  We 
 might  as  well  suppose  the  chisel  of  itself  sculptur- 
 ing the  Apollo  Belvidere,  as  the  laws  of  matter,  of 
 themselves,  fashioning  the  hosts  of  heaven  into  such 
 wondrous  forms  of  order  and  beautj. 
 
THE  STRUCTURE  OF  SATURN'S  RINGS 
 
 Galileo  pointed  to  the  system  of  Jupiter,  as  ex- 
 hibiting the  solar  system  in  miniatm'e,  but,  had  he  had 
 adequate  optical  power,  he  could  have  pointed  more 
 triumphantly  to  that  of  Saturn.  On  the  first  dis- 
 covery of  the  rings,  they  were  regarded  as  a  breach 
 of  uniformity  in  the  solar  system,  but  all  subsequent 
 discovery  has  tended  to  fill  up  the  gap,  and  to  shew 
 that  there  is  a  sameness  of  pattern  throughout  the 
 
 N 
 
194  THE  STRUCTURE 
 
 whole  fabric.  As  in  a  Gothic  cathedral,  we  do  not 
 find  the  pervading  style  merely  in  the  spire  and 
 the  great  western  entrance,  but  in  every  niche  and 
 windoWj  however  small;  so,  in  the  architecture  of  the 
 heavens,  we  find  one  general  idea,  though  with  much 
 diversity,  in  every  part  of  the  solar  system. 
 
 Eecent  research  has  detected  a  striking  lesemblance 
 between  the  solar  and  Saturnian  systems.  The  dis- 
 covery of  the  analogy  was  a  long  time  retarded  by 
 the  notion,  that  the  rings  must  necessarily  be  solid. 
 The  idea  of  solidity  is  irresistibly  forced  upon  the  mind, 
 when  you  look  upon  the  rings,  as  sharply  defined  as 
 the  horizon  circle  round  a  school  globe.  And  if  a 
 first  impression  be  strong,  very  slender  arguments 
 are  sufficient  to  confirm  it.  For  example.  Sir  John 
 Herschel  concludes  that  they  must  be  solid  and  opaque, 
 because  they  cast  a  shadow  upon  the  ball  of  the 
 planet,  and  receive  one  in  turn.  But  it  is  quite  pos- 
 sible that  they  should  cast  a  shadow,  and,  j^i^  be 
 not  solid.  A  cloud,  for  example,  casts  and  receives  a 
 shadow,  though  it  is  not  opaque.  A  cloud,  too,  may 
 assume  such  a  solid  aspect,  that  you  cannot  distin- 
 guish it  from  some  snow-capped  mountain. 
 
 The  idea  of  solidity  so  strongly  took  possession  of 
 the  minds  of  astronomers,  that  the  most  strained 
 hypotheses  were  resorted  to  in  order  to  account  for 
 the  stability  of  the  rings.  How  was  tlie  ball  to  be 
 ke}3t  precisely  in  the  middle  of  the  solid  ring?  For, 
 though  originally  adjusted  with  the  utmost  precision, 
 
OF  SATURN'S  RINGS.  195 
 
 the  slightest  disturbance  would  bring  the  ball  in  con- 
 tact with  the  rings,  just  as  an  egg-shell  floating  in  the 
 middle  of  a  tea-cup  is  in  a  state  of  unstable  equilibrium 
 from  capillary  attraction,  so  that  the  slightest  disturb- 
 ance of  its  central  position  brings  it  in  contact  with 
 the  sides  of  the  cup.  The  satellites  exercise  such  a 
 disturbing  force,  so  that  if  the  movement  once  began, 
 it  would  necessarily  continue  till  the  contact  was 
 effected,-  and,  if  the  rings  once  touched  the  planet, 
 they  would  be  in  a  state  of  stable  equilibrium,  so  that 
 they  would  never  rise  from  it.  It  was  not  a  satisfac- 
 tory reply  that  the  rings  rotated  in  the  same  time  that 
 a  satellite,  at  the  same  distance,  would.  A  satellite, 
 making  the  appropriate  number  of  revolutions  in  a 
 given  time,  is  in  no  danger  of  falling  upon  the  primary, 
 but  the  case  is  totally  different  with  a  ring.  Sliould 
 a  comet  come  into  collision  with  a  satellite,  and  throw 
 it  a  little  out  of  its  course,  no  further  harm  would  re- 
 sult. The  disturbance  would  not  be  progressive. 
 The  orbit  might  be  altered,  but  then  it  would  con- 
 tinue permanent  in  that  altered  course.  If  a  comet, 
 on  the  other  hand,  struck  a  ring  so  as  to  bring  one  side 
 nearer  the  ball  than  the  other,  the  motion  would  be 
 progressive.  It  would  be  like  that  of  a  stone  moved 
 from  the  top  of  a  hill,  which  does  not  stop  till  it 
 reaches  the  bottom.  The  ring,  once  pushed  by  a 
 satellite,  virtually  starts  down  the  hill  till  it  reaches 
 the  body  of  the  planet,  and  it  can  no  more  rise  from 
 its  prostrate  position,  than  a  stone  can  of  itself  move 
 
196  THE  STRUCTURE 
 
 up  hill.  To  meet  this  difficulty,  Laplace  resorted  to 
 an  ingenious  hypothesis.  Let  us  suppose  that  the 
 rigid  solid  ring  is  not  of  uniform  density  or  thickness. 
 Let  uSj  for  example,  imagine  that  a  portion  of  it  ia 
 made  of  lead,  while  the  rest  is  lighter  than  cork,  and 
 its  gravitation  insignificant  in  comparison ;  it  is  plain 
 that  such  a  system  would  approximate  to  that  of 
 a  simple  satellite,  and  so  far  be  stable.  The  lead 
 would  move  as  a  satellite,  and  the  light  portion,  by 
 supposition,  is  not  sufficiently  powerful  to  alter  the 
 conditions.  If  we  attach  a  sovereign  to  a  light  ring 
 of  paper  and  throw  both  into  the  air,  the  curve  de- 
 scribed will  be  that  due  to  the  sovereign  and  not  that 
 due  to  the  paper ;  simply  because  the  gold  so  far 
 preponderates,  that  the  effect  of  the  paper  may  be  re- 
 garded as  nil.  This  is,  however,  a  wholly  gratuitous 
 supposition  of  Laplace.  Observation  does  not  con- 
 firm any  notable  difference  in  thickness  or  density. 
 No  doubt,  when  the  edge  of  the  ring  is  presented  to 
 us,  some  bright  points  remain  when  the  rest  dis- 
 appears ;  but  this  appearance,  first  ascribed  to  lofty 
 mountains,  is  not  due  to  any  fixed  features  of  the 
 ring ;  for  the  bright  points  are  stationary,  while  the 
 ring  rotates.  These  points  of  light  are  believed  to  be 
 due  to  the  reflection  of  the  inner  edges  of  the  rings 
 presented  to  the  sun.  They  do  not  appear  to  move, 
 for  the  same  reason  that  the  sun's  image  does  not 
 move  on  with  the  flowing  river  from  which  it  is 
 reflected. 
 
OF  SATURN'S  RINGS,  197 
 
 The  next  great  difficulty  in  the  rigid  theory  is, 
 that  the  rate  of  rotation  in  different  parts  of  the 
 breadth  of  the  ring  does  not  conform  to  the  condi- 
 tions of  stability.  The  inner  edge  of  the  ring  should 
 rotate  much  more  rapidly  than  the  outer — as  the 
 combined  breadth  of  the  two  bright  rings  is  28,000 
 miles.  They  should  rotate  as  satellites  would  do  at 
 corresponding  distances.  The  nearer  a  satellite  is  to 
 the  body  of  a  planet,  the  more  rapidly  must  it  revolve, 
 in  order  that  it  may  not  fall  upon  the  surface.  If  you 
 swing  a  stone  at  the  end  of  a  string  round  your  head, 
 you  must,  in  order  to  keep  it  up,  increase  the  number 
 of  revolutions  as  you  shorten  the  string  ,*  and,  for  a 
 similar  reason,  the  nearer  a  satellite  is,  the  greater 
 must  be  the  number  of  its  revolutions  in  a  given  time. 
 It  has  been  surmised,  that  there  is  a  small  satellite 
 or  large  meteoric  stone  revolving  round  the  earth  at 
 about  the  distance  of  5000  miles  from  its  surface ;  if 
 this  be  so,  it  must,  in  order  that  it  may  not  fall  to 
 the  earth,  swing  round  seven  times  a  day.  The  moon 
 is  about  twenty-six  times  further  off,  and,  to  maintain 
 its  position,  it  has  only  to  swing  round  once  in 
 twenty-eight  days.  Let  us  suppose  that  the  moon 
 and  the  little  satellite  are  yoked  together  by  being 
 made  parts  of  a  rigid  ring  whose  breadth  extends 
 from  the  one  to  the  other.  It  is  plain  that  the  ten- 
 dency will  be  to  rend  the  system  in  pieces.  The 
 one  is  a  slow  horse,  obstinately  keeping  back  the 
 vehicle  3  the  other  is  a  fiery  steed,  that  will  break 
 
198  THE  STRUCTURE 
 
 his  harness  rather  than  be  retarded.  The  pressure 
 of  the  difficulty  is  somewhat  lightened  by  the  fact, 
 that  the  bright  ring  is  divided  into  two  halves,  so  that 
 the  inner  half  can  go  at  a  more  rapid  pace  without 
 being  retarded  by  the  outer  one.  Still,  notwithstand- 
 ing this  relief,  the  difficulty  is  great;  for  the  outer 
 bright  ring  is  11,000  miles  broad,  while  the  inner  is 
 17,000.  We  must  also  keep  in  view  the  fragile  struc- 
 ture of  these  rings.  If  we  take  the  whole  system 
 of  rings,  it  may  be  represented  by  a  strip  of  tissue 
 paper,  a  foot  long,  and  an  inch  broad.  This  strip, 
 in  the  form  of  a  ring,  is  to  maintain  a  state  of  equi- 
 librium ;  and  it  is  obvious  that  its  stability  is  not 
 consistent  with  powerful  internal  forces,  tending  to 
 rend  it  asunder,  as  there  must  be,  if  the  substance  is 
 solid,  and  the  rings  broad.  We  can  conceive  that 
 mternal  rupture  would  be  avoided  by  reducing  the 
 breadth  of  the  rings ;  and  observation  has  given  in- 
 dications that  the  rings  are  very  numerous.  A 
 structure,  something  like  the  coil  of  a  mainspring 
 of  a  watch,  and  a  pretty  broad  division  in  the  outer 
 bright  ring,  have  been  detected.  This  would,  in 
 one  way,  relieve  the  difficulty  of  rigidity;  but,  in 
 another,  would  increase  it.  A  system  of  close,  nar- 
 row rings,  packed  the  one  within  the  other,  each 
 with  its  own  period  of  rotation,  would  be  subject  to 
 constant  collisions  among  its  constituent  parts.  Be- 
 sides all  this,  the  system,  as  a  whole,  would  be  in  a 
 
OF  SATURN'S  RINGS.  199 
 
 state  of  unstable  equilibrium  in  reference  to  the  body 
 of  the  planet. 
 
 These  difficulties,  along  with  new  observations,  led 
 to  the  idea  that  the  rings  were  all  fluid.  The  con- 
 centric structure  seemed  to  change ;  divisions,  seen 
 plainly  at  one  time,  were  not  seen  at  another ;  and 
 this  was  so  frequently  noticed,  that  the  inference 
 seemed  natural,  that  there  was  a  real  fluctuation  in 
 the  divisions  of  the  fluid  system.  The  idea  of  fluidity 
 was  certainly  an  advance,  as  it  allowed  each  portion 
 of  the  system  to  assume  its  appropriate  period  of 
 rotation.     A  slow  ring  was  not  yoked  to  a  fast  one. 
 
 The  idea  of  fluidity  has,  however,  given  way  to 
 one  Avhich  more  naturally  explains  the  phenomena, 
 and  brings  this  part  of  the  solar  system  into  har- 
 mony with  other  parts.  The  theory  in  question  is, 
 that  the  rings  are  composed  of  meteoric  matter,  each 
 particle  moving  as  an  independent  planet  in  its  own 
 orbit.  It  is  not  at  all  necessary  to  suppose  that  the 
 particles  are  very  minute.  There  may  be  meteorites 
 of  considerable  dimensions,  but,  at  the  distance  of  the 
 earth,  they  can  appear  only  as  a  continuous  mass.  The 
 rings  of  Saturn  would  thus  correspond  to  the  zones 
 of  meteoric  bodies  and  asteroids  encircling  the  sun. 
 
 A  remarkable  confirmation  of  tliis  theory  is  af- 
 forded by  the  history  of  the  rings.  Saturn,  above  all 
 the  other  planets,  is  full  of  interest,  in  this  respect, 
 that  it  furnishes  proof  of  great  organic  changes.     It 
 
200  THE  STRUCTURE 
 
 is  in  this  point  of  view,  also,  that  it  furnishes  a  link 
 between  the  comets  and  the  planets.  The  planet  oc- 
 cupies the  one  pole  of  permanency,  while  the  comet 
 represents  the  opposite,  of  mutability;  but  Saturn 
 occupies  a  middle  position,  exhibiting  great  organic 
 changes,  the  progress  of  which  is  slow,  compared  to 
 that  of  the  comet.  The  gradual  expansion  of  the 
 rings  towards  the  body  of  the  planet,  has  been  ob- 
 served. The  rings  may  be  regarded  as  the  iris  of 
 the  eye ;  and  as  the  iris  contracts  the  pupil,  so  the 
 rings  close  in  upon  the  planet.  This  closing  in  is 
 not  effected  by  the  contraction  of  the  outer  circum- 
 ference of  the  system  of  rings,  but  only  by  the  in- 
 crease of  the  breadth  of  the  rings.  The  strip  of 
 tissue  paper,  to  which  we  have  compared  the  system, 
 is  becoming  broader,  and  probably  thinner,  but  the 
 outer  edge  remains  of  the  same  length.  There  is  a 
 process  of  stretching-out  going  on,  but  it  is  not  the 
 same  for  the  whole  breadth  of  the  ring.  The  parts 
 nearest  the  planet  expand  more  than  those  more  re- 
 mote. This  result  is  due  to  the  researches  of  M. 
 Otto  Striive,  who  has  examined  the  measurements 
 of  the  rings  for  two  hundred  years  back,  and  by 
 comparing  them  with  those  taken  at  the  present  day, 
 he  has  been  able  to  compute  the  rate  of  growth.  He 
 .calculates  that,  in  about  one  hundred  and  twenty 
 years,  the  inner  edge  of  the  system  of  rings  will 
 reach  the  planet.  This  conclusion  has  been  ques- 
 tioned by  Mr  Main  of  the  Koyal  Observatory,  Green- 
 
OF  SATURN'S  RINGS.  20T 
 
 wich,  but  the  weiglit  of  evidenoe  is  on  the  side  of 
 the  distinguished  foreign  astronomer. 
 
 The  most  remarkable  evidence  of  growth  is  the 
 dusky,  transparent  ring,  discovered  by  Mr  Bond,  in 
 1850.  There  is  evidence,  indeed,  that  it  was  seen 
 before,  but  its  nature  was  not  suspected.  It  was 
 seen  crossing  the  ball  of  the  planet,  but  it  was  taken 
 for  a  permanent  belt  of  the  planet.  The  question 
 arises.  How  should  it  be  so  distinctly  seen  and  re- 
 cognised by  several  independent  observers  all  about 
 the  same  time  ?  Mr  Dawes  in  England,  and  Father 
 Secchi  at  Kome,  discovered  its  nature  independently, 
 and  that  with  far  inferior  telescopes  than  those  which, 
 at  a  previous  period,  could  not  detect  it.  This  leads 
 to  the  surmise,  that,  although  not  developed  for  the 
 first  time,  it  now  received  such  an  accession  of  bright- 
 ness as  no  longer  to  be  mistaken.  This  is  confirmed 
 by  the  detection  of  actual  growth  since  its  discovery ; 
 and  M.  Striive  is  quite  clear  that  it  has  widened,  and 
 crept  nearer  the  ball. 
 
 This  new  ring  confirms  the  supposition  that  the 
 system  is  composed  of  meteoric  matter.  The  matter 
 is  so  rare,  that  we  see  through  it,  as  we  would  see 
 through  a  cloud  of  dust  or  a  shower  of  hail.  The 
 meteoric  bodies  may  be  of  considerable  size,  but  they 
 are  not  so  close  as  to  intercept  the  light  of  the  planet. 
 The  phenomena  do  not  agree  with  the  hypothesis, 
 that  the  ring  is  gaseous  or  fluid.  M.  Striive  has  also 
 detected  a  division  in  the  dark  ring,  so  that  it  is  of  a 
 
202  THE  STRUCTURE 
 
 compound  character  like  the  bright  rings.  It  is  not 
 improbable  that,  with  increased  power,  or  in  conse- 
 quence of  organic  changes,  rings  still  nearer  the  planet 
 may  yet  be  discovered. 
 
 From  the  above  consideration  it  is  extremely 
 probable,  that  the  bright  rings  do  not  differ  in  nature 
 from  the  obscure  ring.  The  difference  is  likely  only 
 one  of  compression.  The  individual  bodies  in  the 
 bright  rings  may  be  so  closely  compacted,  that  we 
 cannot,  at  this  distance,  see  through  the  interstices. 
 
 Is  any  corroboration  of  this  view  furnished  by  the 
 phenomena  of  growth  ?  The  increase  of  the  breadth 
 of  the  rings  would  naturally  result  from  the  collision 
 of  the  innumerable  bodies  moving  in  a  contracted 
 zone,  and  with  orbits  crossing  each  other.  The  effect 
 of  such  collisions  would  be  to  arrest  the  motion  of  the 
 bodies  coming  in  contact,  and  the  result  of  this  arrested 
 motion  would  be  to  bring  them  nearer  the  planet. 
 The  tendency  of  the  meteoric  stones  that  fall  upon  the 
 surface  of  the  earth,  must  be  to  check  its  orbitual 
 motion,  when  they  come  in  a  contrary  direction ;  and 
 just  in  proportion  as  its  speed  is  slackened,  must  it 
 narrow  its  orbit.  The  mass  of  such  bodies  is  so 
 small,  that  no  sensible  approach  to  the  sun  can  be 
 looked  for ;  but  if  the  mass  of  the  earth  was  smaller, 
 the  effect  would  be  very  perceptible.  In  this  way 
 may  we  conceive  that  the  rings  are  drawn  out.  The 
 smaller  bodies  would  be  piecipitated  most  rapidly, 
 and   the  transparency  of  the   obscure  would  be  ac- 
 
OF  SATURN'S  RINGS.  203 
 
 counted  for,  by  supposing  it  composed  of  tlie  finer 
 particles.  The  precipitate  is,  however,  constantly  re- 
 ceiving new  accessions,  so  that  it  is  always  becoming 
 more  conspicuous,  and  its  recent  detection  may  be  due 
 to  its  increasing  density.  The  middle  portion  of  the 
 system  we  would  expect  to  be  the  most  dense ;  and 
 we  do  find  the  inner  bright  ring  to  be  the  brightest. 
 The  outermost  we  would  expect  to  be  fainter,  as  from 
 j  it  the  lower  strata  are  supplied  with  additional  matter, 
 while  it  has,  itself,  no  superior  source  from  which  to 
 draw.  We,  accordingly,  find,  that  while  the  inner 
 bright  ring  shines  like  burnished  silver,  the  outer  is 
 faint  like  tarnished  silver.  This  hypothesis  of  the 
 collision  and  union  of  meteoric  bodies,  receives  coun- 
 tenance from  the  phenomena  of  the  asteroids.  We 
 have  seen  that  some  of  the  minor  planets  have  been 
 discovered  in  regions  which  were,  shortly  before, 
 diligently  searched,  though  in  vain ;  so  that  the  sur- 
 mise is  probable,  that  they  have  become  conspicuous 
 from  the  union  of  two  bodies,  each  of  which  would 
 be  invisible  when  separate.  This  concentration  of 
 matter  would  necessarily  take  place  to  the  largest 
 extent  in  the  middle  of  the  system  of  rings,  where 
 we  actually  find  the  greatest  lustre. 
 
 The  extreme  thinness  of  the  rings  can  also  be  ac- 
 counted for  in  the  same  manner.  If,  at  one  time,  the 
 rings  were  thicker,  but  with  a  concentration  in  the 
 middle  of  the  thickness,  the  tendency  would  be  to 
 condense  still  further  the  outlying  bodies.     In  cross- 
 
204  I^HE  STRUCTURE 
 
 ing  the  stratum  of  meteoric  matter,  tliey  would  be 
 caught  in  its  meshes,  and  fixed  in  its  plane. 
 
 It  is  plain,  from  the  above  observations,  that,  in 
 one  sense,  the  system  of  Saturn  is  not  permanent,  and 
 a  natural  inquiry  is  suggested — Is  the  system  of 
 Saturn,  in  this  respect,  a  type  of  the  solar  system? 
 We  have  seen  that  the  solar  system  is  absolutely 
 stable,  but  only  on  the  supposition  that  the  planetary 
 bodies  experience  no  resistance  in  passing  through 
 space.  But  have  we  ground  for  believing  that  there 
 is  no  obstruction  ?  So  far  from  this,  there  is  the  most 
 conclusive  evidence  that  there  is  such  obstruction. 
 The  effect  upon  the  planets  has  not  been  detected,  but 
 the  comets  have  proclaimed  the  fact,  that  there  is  an 
 element  of  decay  in  the  system.  Encke's  comet  is 
 narrowing  its  circle  at  every  revolution,  and  is  going 
 down,  as  it  were,  a  spiral  staircase  to  its  ultimate 
 destiny — absorption  in  the  sun.  The  comet  is  of  a 
 consistency  so  light,  that  it  is  exceedingly  sensitive 
 to  the  retarding  influence,  just  as  the  light  balloon  at 
 once  feels  the  slightest  breath  of  air.  But  the  ques- 
 tion is  only  one  of  degree.  The  comet  has  a  rapid 
 and  gaining  spiral,  like  the  moth  circling  round  the 
 fatal  light ;  but  the  densest  planet  has  also  to  pursue 
 a  downward  course,  though  incalculable  ages  may 
 elapse  before  the  close  spn-al  shall  reach  the  central 
 furnace.  It  may  be  objected  that,  if  the  stamp  of 
 decay  is  upon  the  solar  system,  the  argument  from  its 
 stability  lalls  to  the  ground,  and  all  the  resources  of 
 
OF  SATURN'S  RINGS.  205 
 
 the  most  profound  analysis  have  been  thrown  away  in 
 proving  this  stability.  The  permanency  of  the  ad- 
 justments of  the  solar  system  has  been  appealed  to  as 
 the  most  convincing  proof  of  the  Divine  Intelligence, 
 and  are  we,  by  admitting  the  element  of  decay,  to 
 surrender  t/ie  stronghold  of  Astro-theology  ? 
 
 To  this  the  answer  is,  that  there  may  be  the  most 
 exquisite  provision  for  the  stability  of  a  system 
 which  is,  notwithstanding,  perishable.  Take,  for 
 example,  the  human  body.  How  marvellous  is  its 
 structure,  though  it  is  destined  to  endure  only  for  the 
 period  of  human  life !  The  marvel  of  the  adjustments 
 Y/ould  not  at  all  be  enhanced,  though  the  length  of 
 man's  life  was  doubled.  Threescore  and  ten  years 
 were  allotted  to  man's  spirit  on  earth,  and  a  tenement 
 is  so  adjusted  as  to  last  for  that  period.  The  Divine 
 wisdom  is  not  measured  by  the  length  of  the  period 
 of  permanence,  but  by  the  exquisite  balancing  of 
 forces,  so  that  the  system  will  endure  for  the  allotted 
 period,  whether  it  be  long  or  short.  The  ephemeron 
 that  dances  in  the  sunshine  for  its  brief  hour  of  life, 
 displays  as  much  wisdom  in  its  structure  as  the  eagle, 
 that  continues  its  gyrations  for  a  long  century.  In 
 human  mechanism,  the  mere  element  of  time  is  not 
 one  that  usually  enhances  the  skill  of  the  contrivance. 
 Time-keepers  are  sometimes  made  to  go  for  a  whole 
 year ;  yet  this  is  considered  of  so  little  consequence, 
 that  the  finest  astronomical  clocks  are  not  made  to 
 go  longer  than  eight  days.     The  whole  skill  of  the 
 
206  THE  STRUCTURE 
 
 clockmaker  is  devoted  to  the  object  of  giving  stability 
 to  the  going  of  the  clock  for  the  period,  whether  long 
 or  short,  during  which  it  is  to  go.  To  gain  this 
 object,  he  contrives  a  pendulum  by  which  the  dis- 
 turbances of  the  temperature  may  be  compensated. 
 He  cannot  prevent  the  expansion  of  metals,  but  he 
 can  so  balance,  by  the  expansion  of  different  metals, 
 the  disturbances  produced,  that  the  result  is  invariable 
 motion.  This  is  precisely  what  is  done  in  the  solar 
 system.  We  see  disturbance  so  nicely  compensated, 
 that  for  a  required  period,  the  system  may  be  regarded 
 as  absolutely  stable.  But  v/hat  is  this  period  of  sta- 
 bility in  the  case  of  the  planets  ?  If  we  regard  the 
 planets  as  destined  for  the  abode  of  living  beings, 
 then  this  stability  is  to  be  viewed  in  reference  to  the 
 period  allotted  for  their  existence.  The  stability  of 
 the  organisation  of  the  human  body,  is  calculated  for 
 the  life  of  the  individual  man.  This  globe  is  the 
 abode  of  the  human  race,  as  the  body  is  the  abode  of 
 the  individual  man  5  and  the  conditions  of  stability 
 are  related,  teleologically,  to  the  terrestrial  life  of  the 
 race.  From  the  analogy  furnished  by  geological 
 science,  the  probability  is,  that  man  has  his  allotted  : 
 period,  like  the  inferior  forms  of  life  that  have  already 
 passed  away.  The  records  of  geology  furnish  in- 
 dubitable proof,  that  the  conditions  of  life  have  varied 
 greatly  on  the  face  of  the  earth  ;  so  that  when  one  form 
 of  animal  life  has  become  extinct,  the  creative  act  of 
 God  has  called  into  existence  new  forms,  suited  to  the 
 
OF  SA  TURN'S  RINGS.  207 
 
 altered  conditions.  In  proving,  then,  the  stability  of 
 the  system,  we  have  only  to  shew,  as  far  as  the  argu- 
 ment of  design  is  concerned,  that  the  conditions  of 
 life  are  permanent  during  the  epoch  of  life  for  which 
 the  system  is  adjusted.  Man  was  called  into  exist- 
 ence by  God  when  this  abode  was  fully  prepared  for 
 his  comfort ;  and  the  fabric  is  kept  up  till  his  destiny 
 on  earth  is  fulfilled. 
 
 It  may  be  said,  that  while  this  argument  may  apply 
 to  orbs  on  which  life  exists,  it  is  inapplicable  to  sys- 
 tems like  Saturn's  rings,  where  we  may  suppose  life 
 to  be  impossible.  The  question  of  stability  is  to  be 
 dealt  with  2?er  se,  and  if  we  find  that  the  system  of  the 
 rings  is  not  stable,  must  we  not  abandon  it  as  a  proof 
 of  Divine  wisdom  ?  Formerly  we  could  point  to  these 
 arches,  nicely  poised  in  space,  as  the  most  wonderful 
 proof  of  mechanical  adjustment ;  but,  now  that  we 
 see  them  going  through  the  process  of  decay,  we  can 
 no  longer  avail  ourselves  of  this  argument.  The  an- 
 swer is,  that  we  have  still  proof  of  the  most  wonderful 
 provisions  for  permanence,  but  permanence  for  only 
 one  phase  of  a  mighty  evolution.  The  only  differ- 
 ence is,  that  in  former  views  of  the  stability  of  the 
 system,  we  considered  the  mechanism  as  a  fixed,  rigid, 
 isolated  thing,  whereas  we  are  now  forced  to  regard 
 every  part  of  the  universe  as  in  a  state  of  change  or 
 progress.  Formerly  the  heavens  were  regarded  as  a 
 frozen  river ;  but  the  light  of  science  has  shewn  that 
 there  is  an  onward  movement,  as  in  the  glacier,  though 
 
2o8  THE  STRUCTURE 
 
 it  be  almost  imperceptible.  The  material  world  is 
 passing  through  cycles  of  decay  and  restoration,  like 
 living  organisms  on  the  face  of  the  earth.  Om*  no- 
 tions of  stability  formerly  arrested  this  process,  but 
 we  now  discover  that  the  stability  is  only  during  one 
 phase  in  the  evolution.  There  is  an  organic  stability 
 in  the  seed,  the  flower,  and  the  fruit  of  a  plant,  but  it  is 
 a  stability  consistent  with  development ;  and  one  form 
 merges  into  another.  We  lose  nothing,  in  a  theolo- 
 gical point  of  view,  by  the  recognition  of  a  limit  to 
 the  stability  of  the  solar  and  other  subordinate  sys- 
 tems. The  idea  of  transition  only  points  to  a  higher 
 argument.  The  human  spirit  has  long  shrunk  from 
 the  idea  of  organic  changes  in  the  constitution  and 
 relations-  of  the  heavenly  bodies,  just  as  it  shrank 
 from  the  reception  of  the  Copernican  theory  of  the 
 solar  system ;  but  the  admission  of  the  former  will,  as 
 emphatically,  redound  to  the  glory  of  God  as  that  of 
 the  latter.  The  universe  regarded  as  a  rhythm  and 
 process,  instead  of  an  unalterable  piece  of  architecture, 
 only  declares  more  loudly  the  wisdom  of  Him  who 
 guides  and  controls  it  with  His  ever-present  power. 
 The  idea  of  Sir  Isaac  Newton,  that  the  material  uni- 
 verse may  be  regarded  as  the  sensorium  of  Deity, 
 savours  somewhat  of  Pantheism ;  but  it  was  meant 
 by  the  illustrious  philosopher  to  be  in  perfect  conson- 
 ance with  the  full  recognition  of  the  Divine  person- 
 ality ;  and  the  conception  was  designed  to  bring  us 
 closer  in  thought  to  the  living  God,  who  is  in  all  and 
 
OF  SATURN'S  RINGS.  209 
 
 through  all.  The  conception  of  the  universe  as  a 
 ceaseless  flow,  a  grand  rhythmical  evolution,  in  like 
 manner  tends  to  produce  a  livelier  and  more  direct 
 recognition  of  Him  wlio  is  ever  moving  around  us, 
 and  whose  uttered  thoughts  are  the  successive  steps 
 of  this  evolution.  Theology  has  confined  itself  too 
 much  to  the  wisdom  displayed  in  the  adjustment  and 
 proportions  of  an  unalterable  fabric  ;  but  a  still  higher 
 wisdom  is  displayed  in  the  divine  melody  of  the  grand 
 cycles  of  change.  The  music,  even  more  than  the 
 architecture  of  the  heavens,  declares  the  glory  of  God. 
 
 The  system  of  Saturn's  rings  is  transitory;  but 
 why  should  this  prevent  us  from  recognising  their 
 beauty  and  symmetry,  as  well  as  the  skill  with  which 
 they  are  poised  in  space  ?  We  do  not  refuse  to  recog- 
 nise the  beauty  and  skill  of  a  dissolving  view,  though 
 it  gradually  fades  away  upon  the  screen,  and  merges 
 into  another.  We  do  not  fail  to  acknowledge  the 
 beauty  and  symmetry  of  the  crystals  of  ice  and  arbo- 
 rescent patterns  on  the  pane  of  glass,  though  they 
 vanish  at  the  first  touch  of  the  sunbeam,  to  give  place 
 to  other  forms  of  beauty.  The  mere  transition  does 
 not  at  all  affect  the  beauty,  symmetry,  and  skill  of 
 the  fleeting  forms  that  arrest  our  notice. 
 
 The  transition  of  the  rings  of  Saturn  may  only  be 
 a  step  to  the  accomplishment  of  some  higher  form  of 
 stability.  The  individual  cell  in  the  living  organ- 
 ism dissolves,  but  only  that  the  structm-e,  of  which 
 it  is  an  element,  may  be  strengthened  and  developed. 
 
 0 
 
210  THE  STRUCTURE 
 
 It  lays  down  its  own  life  that  the  organism,  as  a 
 whole,  may  he  sustained ;  and  the  individual  organ- 
 ism, in  turn,  passes  away,  after  contrihuting  to  the 
 continuation  of  the  species.  In  like  manner,  the  dis- 
 solution of  Saturn's  rings,  and  even  that  of  the  solar 
 system,  may  be  only  steps  of  a  process  by  which  the 
 stability  of  some  higher  and  more  comprehensive 
 system  is  secured.  Although  we  cannot  trace  far  the 
 footprints  of  the  Creator,  backwards  and  onwards, 
 still  there  is  no  difficulty  in  recognising  those  that 
 mark  the  active  progression  of  the  plans  of  Divine 
 wisdom  and  power. 
 
 While  the  tendency  of  astronomical  science  is  to 
 establish  progressive  phases  in  the  evolution  of  the 
 material  world,  it  only  brings  out  in  more  prominent 
 relief  the  truth,  that  the  introduction  of  life  is  a  fact 
 in  itself  unique.  All  attempts  to  detect  a  physical 
 law  uniting  the  successive  steps  have  signally  failed.' 
 There  is,  undoubtedly,  an  order  and  system  by  which 
 successive  forms  of  life  have  been  introduced,  but  all 
 discovery  points  to  the  conclusion,  that  the  law  is  of 
 a  higher  order  than  the  physical  laws  of  nature.  It 
 is  simply  the  order  in  which  a  personal  God  exercises 
 His  creative  energy. 
 
 No  doubt,  the  order  of  the  succession  of  various 
 forms  of  life  is  correlated  to  the  successive  stages  of 
 material  adaptation,  but  the  bond  is  not  of  cause  and 
 effect.  The  successive  acts  of  the  farmer  in  plough- 
 ing, sowing,  and  reaping,  are  correlated  to  the  order 
 
OF  SA  TURN'S  RINGS.  211 
 
 in  which  the  seasons  return,  but  the  order  of  seasons 
 is  not  the  physical  cause  of  the  acts  of  the  larmer. 
 The  two  orders  of  succession,  though  correhited,  are 
 totally  different.  In  the  one  case,  a  material  law  is 
 the  bond  of  union  between  the  successive  steps ;  in  the 
 other,  volition  effects  the  synthesis.  The  like  relation 
 subsists  between  the  secondary  laws  by  which  suc- 
 cessive stages  of  adaptation  are  produced,  and  the 
 order  by  which  successive  forms  of  life  are  intro- 
 duced. All  research  has  failed  to  detect  any  physical 
 cause,  by  which  the  one  order  is  only  the  result  of 
 the  other.  Both  orders  flow  from  the  same  Divine 
 source,  but  the  lines  of  causation  are  totally  distinct. 
 
Nebulous  Rings. 
 
 XIV. 
 
 THE  NEBULAE  HYPOTHESIS. 
 
 We  have  seen  that,  apart  altogether  from  any  theory 
 of  the  formation  of  the  solar  system,  there  is  abundant 
 evidence  of  unity  of  style.  The  fact  of  types  in 
 nature,  does  not  at  all  depend  on  the  soundness  of; 
 the  theories  devised  to  account  for  their  existence;: 
 and  the  argument  for  the  necessity  of  a  divine  origin  ■ 
 for  the  typal  idea,  is  not,  in  the  least,  affected,  though 
 many  links   of  natural  causation  be  discovered  be- 
 
THE  NEBULAR  HYPOTHESIS.      213 
 
 '  tween  the  mental  conception   and  the  material  im- 
 
 1  press.     We  may  accurately  describe  the  mechanical 
 
 ;  process  by  which  the  figure  on  a  medal  is  struck 
 
 from  a  die ;  but  trace  the  process  as  minutely  as  we 
 
 may,  we  never  can  eliminate  the  mental  conception 
 
 of  which  the  figure  on  the  medal  is  a  material  em- 
 
 j  bodiment. 
 
 No  astronomical  speculation^  in  modern  times,  has 
 given  rise  to  greater  controversy  than  that  known  by 
 the  name  of  the  "nebular  hypothesis."  Considered 
 in  its  purely  scientific  aspect,  it  possesses  great  inte- 
 rest, but  its  peculiar  ciaim  lies  in  its  religious  bear- 
 ings. To  understand  these,  it  will  be  necessary 
 shortly  to  advert  to  its  physical  character. 
 
 A  slight  glance  at  the  motions  and  relations  of  the 
 bodies  of  the  planetary  system,  at  once  reveals  a 
 striking  amount  of  uniformity,  not  all  accounted  for 
 by  the  principle  of  gravitation,  01  by  any  known 
 cause.  For  example,  there  is  no  reason,  that  we 
 know  of,  why  all  the  planets  should  revolve  round 
 the  sun,  and  rotate  on  their  axes,  in  the  same  direction. 
 Laplace  devised  his  nebular  hypothesis  for  the  pur- 
 pose of  grouping  all  such  uniformities  under  one  cause 
 or  law.  The  following  are  the  phenomena  which  he 
 attempts  thus  to  account  for :  first,  the  motion  of  the 
 planets  in  the  same  direction,  and  very  nearly  in  the 
 same  plane ;  secondly,  the  motion  of  the  satellites  in 
 the  same  direction,  and  very  nearly  in  the  same  plane 
 with  the  primaries ;  thirdly,  the  motion  of  rotation  of 
 
214      THE  NEBULAR  HYPOTHESIS.  '\ 
 
 all  the  above  bodies,  and  likewise  of  the  sun,  in  the 
 same  direction  as  their  orbitual  motion,  and  in  planes 
 but  little  inclined  to  one  another  j  fourthly,  the  small 
 eccentricity  of  the  orbits  of  the  planets  and  satellites. 
 Now  the  theory  of  gravitation  throws  no  light  what- 
 ever on  this  extraordinary  amount  of  uniformity. 
 Consistently  with  the  law  of  gravitation,  there  might 
 be  a  wide  diversity,  instead  of  such  a  marked  uni- 
 formity. There  is  no  reason,  as  far  as  the  mechanical 
 action  of  gravity  is  concerned,  why  the  planets  should 
 not  move  in  opposite  directions,  and  why  their  orbits 
 should  not  have  every  possible  degree  of  inclination 
 to  one  another.  It  is  utterly  impossible,  Laplace 
 argued,  to  ascribe  this  amount  of  uniformity  to  chance, 
 and  therefore  the  human  mind  is  irresistibly  impelled 
 to  seek  some  key  to  it.  He  was  further  stimulated  to 
 seek  a  common  explanation,  from  the  circumstance 
 that  a  like  uniformity  is  not  to  be  found  in  the  mo- 
 tions of  the  comets.  These  bodies  are  regarded  as 
 not  belonging  to  our  system.  It  is  indeed  ascertained, 
 that  a  few  revolve  regularly  in  elliptic  orbits  round 
 the  sun ;  but  these  few,  out  of  the  thousands  that  un- 
 doubtedly exist,  are  regarded  as  children  of  adoption, 
 and  not  of  birth.*     Here  then  we  have  the  case  of 
 
 *  Laplace  indeed  points  out  a  uniformity  in  the  case  of  the 
 comets,  viz.,  the  great  eccentricity  of  their  orbits ;  but  this  is  em- 
 ployed as  a  confirmation  of  the  nebular  hypothesis.  He  holds  that 
 the  motions  of  the  less  eccentric  were  destroyed  by  the  resistance  of 
 the  nebulous  matter  in  the  process  of  condensation,  and  that  only 
 the  more  eccentric  were  spared  such  a  fate. 
 
THE  NEBULAR  HYPOTHESIS.      215 
 
 bodies  not  belonging  to  our  system,  exhibiting  none 
 of  that  uniformity  which  characterises  the  various 
 bodies  constituting  the  system. 
 
 Besides  the  phenomena  above  enumerated,  there 
 are  other  traces  of  uniformity  not  accounted  for  by  the 
 law  of  gravitation.  It  is  found  that  there  is  a  remark- 
 able regularity  in  the  relative  distances  of  the  planets. 
 This  disposition  is  known  as  Bode's  law  of  distances. 
 Mercury  being  regarded  as  the  point  of  departure,  the 
 distance  of  any  planet  from  this  point  is  double  the 
 distance  of  the  next  inferior  planet  from  the  same 
 point.  For  example,  the  Earth  is  twice  farther  from 
 Mercury  than  Venus  is,  Venus  being  the  next  inferior 
 planet  to  the  Earth.*  The  law  of  gravitation  requires 
 no  such  regular  progression.  It  would  hold  equally 
 well  though  no  such  regularity  could  be  discovered. 
 There  is  also  something  like  a  trace  of  law  in  the  dis- 
 position of  the  planets  in  regard  to  their  magnitude 
 and  density — the  densest  being,  generally  speaking, 
 nearest  the  sun,  and  the  largest  more  remote. 
 
 The  nebular  hypothesis  professes  to  explain,  more 
 or  less  explicitly,  the  above  cases  of  uniformity,  un- 
 accounted for  by  the  theory  of  gravitation.  Laplace 
 supposes  that  the  matter  of  which  the  sun  and  planets 
 are  formed,  consisted  originally  of  a  vast  nebula  of 
 extreme  tenuity.     He  starts  with  the  hypothesis  that 
 
 *  The  truth  of  Bode's  law  was  assumed  in  the  calculations  which 
 led  to  the  discovery  of  Neptune,  but  the  distance  of  this  planet  ia 
 found  to  be  a  fact  irreconcilable  with  this  law. 
 
2i6      THE  NEBULAR  HYPOTHESIS. 
 
 this  vapour-like  mass  assumed,  in  some  way,  a  rotatory 
 motion.  The  problem  which  he  undertook  to  solve 
 may  be  thus  stated — Given  a  nebulous  mass  in  rota- 
 tion, to  shew  how  the  various  bodies  of  our  system 
 might  be  evolved  from  it,  and  their  regularity  of 
 motion  and  disposition  accounted  for.  The  solution 
 consists  in  supposing  the  rotating  nebula  to  cool  and 
 condense,  so  that  the  central  portion  increases  its  rate 
 of  rotation,  while  an  equatorial  zone  or  ring  of  vapour 
 is  left  behind,  which  rotates  as  a  body  separate  from 
 the  central  mass.  A  conception  of  the  process  may 
 be  formed  by  supposing  the  solid  globe  of  the  earth 
 to  contract  its  dimensions  very  much.  A  correspond- 
 ing increase  in  the  rate  of  its  rotation  would  conse- 
 quently follow,  and  the  atmosphere  would  be  left  be- 
 hind, whenever  the  centrifugal  force  exactly  balanced 
 the  force  of  gravity.  The  atmosphere  thus  abandoned, 
 would  form  a  gaseous  body  revolving  round  the  earth. 
 The  successive  rings  abandoned  by  the  rotatory 
 nebula,  would  continue  to  rotate  in  the  same  direction 
 as  before.  But  it  would  be  highly  improbable  that 
 the  integrity  of  each  should  be  preserved.  From  in- 
 equalities in  the  internal  forces,  the  ring  would  most 
 probably  be  broken  up,  and  form  distinct  globular 
 masses,  all  revolving  in  the  former  plane  of  the  ring, 
 and  in  the  same  direction.  These  globes  would  most 
 likely  attract  each  other,  and  form  one  nebulous  mass, 
 the  germ  of  some  future  planet.  Now  this  mass 
 would  exhibit  the  same  phenomena  as  the  original 
 
THE  NEBULAR  HYPOTHESIS,      217 
 
 one.  It  would  condense  and  abandon  successive 
 zones,  which  would  ultimately  break  up  and  form  the 
 satellites.  It  might  be  that  the  ring  preserved  its 
 equilibrium ;  and  the  rings  of  Saturn  form  an  illus- 
 tration of  this.  It  might  happen,  on  the  other  hand, 
 that  the  globular  masses,  formed  from  the  disruption 
 of  the  ring,  preserved  their  identity;  and  we  have 
 a  case  of  this  kind  in  the  asteroids  between  Mars 
 and  Jupiter.  This  hypothesis  ingeniously  accounts 
 for  the  points  of  harmony  above  enumerated.  The 
 planets  and  satellites  revolve  nearly  in  circles  and  in 
 one  plane,  because  they  have  been  thrown  off  from 
 the  equator  of  the  rotating  mass.  The  direction  of 
 rotation  is  the  same  as  that  of  revolution,  because  the 
 outer  portion  of  the  ring,  having  a  greater  absolute 
 velocity  than  the  inner,  would  necessarily  originate 
 rotation,  and  rotation  in  the  same  direction  as  that  of 
 the  ring.  By  assuming  a  suitable  law  of  condensa- 
 tion in  the  nebulous  matter,  the  relative  distances,  den- 
 sities, and  magnitudes  may  be  accounted  for.  The 
 assumptions  of  Laplace  regarding  the  rotating  mass, 
 and  the  law  of  condensation,  are  wholly  gratuitous ; 
 but,  admitting  these,  the  results  which  he  deduced 
 from  them  flow,  as  a  necessary  consequence,  accord- 
 ing to  the  unerring  laws  of  dynamics. 
 
 It  has  been  attempted  to  support  the  nebular  hypo- 
 thesis by  what  is  known  as  "  Kirkwood's  law "  of 
 the  rotation  of  the  primary  planets.  We  have  seen, 
 that  the  direction  of  the  rotation  of  the  planets  can- 
 
2i8      THE  NEBULAR  HYPOTHESIS. 
 
 not  be  accounted  for  merely  by  the  law  of  gravitation  ; 
 but  the  period  of  rotation,  or  the  length  of  the  planet's 
 day,  is,  also,  altogether  unaccounted  for.  It  has  been, 
 therefore,  a  matter  of  interest  to  trace  such  an  analogy 
 in  these  rotations  as  might  lead  to  the  determining 
 cause.  Generally  speaking,  the  period  of  rotation  is 
 greater  in  the  planets  least  remote  from  the  sun, 
 though  there  are  particular  cases  which  contravene 
 this  rule.  No  definite  law,  then,  can  be  derived  from 
 the  mere  element  of  distance.  The  nebular  hypo- 
 thesis led  Kirkwood  to  the  surmise,  that  the  rotation 
 might  be  dependent  on  the  masses  of  the  planets, 
 and,  with  this  clue  to  guide  him,  he  was  led  to  the 
 following  law :  That  the  square  of  the  number  of 
 rotations  or  days  in  the  year  of  the  planet,  is  propor- 
 tional to  the  cube  of  the  diameter  of  the  sphere  of 
 attraction.  The  diameter  of  the  sphere  of  attraction 
 is  determined  in  this  way :  The  planet  in  question  is 
 supposed  to  be  in  conjunction  with  the  two  nearest 
 planets,  one  on  each  side  of  it, — the  three  planets  being 
 thus  in  line.  It  is  plain  that  there  are  two  neutral 
 points  on  each  side  of  the  middle  planet,  where  its 
 attraction  is  equally  balanced  by  the  attraction  of 
 either  extreme.  For  example  there  is  a  point  between 
 the  Earth  and  Venus,  where,  if  a  body  were  placed,  it 
 would  be  stationary,  being  equally  attracted  by  both. 
 A  similar  point  exists  between  the  Earth  and  Mars. 
 The  line  joining  these  two  points  is  called  the  diameter 
 of  the  sphere  of  attraction.     Now  the  law  asserts,  that 
 
 i 
 
THE  NEBULAR  HYPOTHESIS.      219 
 
 the  number  of  days  in  the  year  of  each  planet  bears  a 
 definite  proportion  to  this  line ;  and  as  this  line  de- 
 pends on  the  masses  of  the  planets,  a  definite  relation  is 
 asserted  between  the  day  of  each  planet  and  its  mass. 
 As  this  holds  through  all  the  solar  system,  it  is  main- 
 tained that  the  law  clearly  points  to  some  common 
 origin  for  the  rotation  of  the  planets,  and  that  the 
 hypothesis  of  an  original  rotating  nebulous  mass  fur- 
 nishes such  a  common  origin. 
 
 It  is  very  much  to  be  doubted,  whether  astronomers 
 will  be  disposed  to  accept  of  this  as  an  established 
 law.  The  reason  is  obvious.  The  data  on  which  the 
 law  is  founded  are  very  uncertain  in  many  cases. 
 Tlie  masses  and  periods  of  rotation  of  various  planets 
 are  merely  conjectural,  and  such  numbers  are  assumed 
 as  will  suit  the  theory ;  and  the  law,  even  in  the 
 most  favourable  cases,  does  not  pretend  to  anything 
 like  absolute  accuracy."'  The  nebular  hypothesis, 
 then,  can  only  derive  very  doubtful  support  from 
 Kirkwood's  law. 
 
 In  directing  the  eye  to  the  heavens,  it  is  at  once 
 obvious,  that  the  background  from  which  the  stars 
 appear  to  shine  is  not  uniform.  There  are  brighter 
 patches,  which  are  distinguishable  from  the  general 
 
 *  The  discordance  for  the  various  planets  is  indicated  by  the 
 following  numbers :— 928,  961,  1275,  3138,  833,  985,  3614.  If 
 the  law  held  strictly,  there  should  be  no  difference  in  these 
 numbers;  and  therefore  the  least  compared  with  the  greatest 
 indicates  the  maximum  amount  of  error,  which  is  obviously  far 
 too  great. 
 
220      THE  NEBULAR  HYPOTHESIS. 
 
 dark  background.      The  Milky  Way  appears  as  a 
 zone  of  faint  light  passing  round  the  heavens  nearly 
 in  a  great  circle.     But  besides  this  great  zone,  there 
 are  isolated  spots,  distinguishable  some  of  them  by 
 the  naked  eye,  which  appear  like  very  small  lumi- 
 nous clouds.     Now  these  isolated  cloudy  objects  are 
 denominated  nebulae,  and  the  question  arises,  What 
 is  their  constitution?     Are  they  composed,  as  they 
 appear  to  be,  of  nebulous  matter  like  comets  ?    The 
 telescope,   when   turned  to  the  Milky  Way,  which 
 presents  a  cloud-like  appearance,  at  once  resolves  it 
 into  distinct  stars.     The  unaided  eye  is  not  sensitive 
 enough  to  separate  the  individual  stars ;  so  they  ap- 
 pear to  blend  in  one  uniform  surface  of  light.     But 
 the  telescope  enables  the  eye  to  effect  the  separation, 
 and  to  reveal  its  true  character.    Are  we  to  conclude, 
 that  the  nebulse  are  of  the  same  character,  and  that 
 they  are  congeries  of  stars,  so  closely  set,  that  they 
 present  a  cloudy  appearance  without  distinct  isola- 
 tion?    Thus,  among  the  innumerable  nebulas  which 
 the  telescope  reveals,  there  are  some  which  are  at  once 
 resolved  into  stars  by  moderate  powers.     Nebulae, 
 according  to  their  resolvability,  may  be  divided  into 
 three  grades.     The  first  consists  of  those  in  which 
 the  stars  are  distinctly  separated.     The  second  con- 
 sists of  those  presenting  a  granular  appearance,  which 
 merely  indicates  the  resolvability  under  a  sufficient 
 power.     But  besides  these,  there  is  a  third  class  in 
 which  no  indication  of  resolvability  could  for  a  long 
 
THE  NEBULAR  HYPOTHESIS.      221 
 
 time  be  found.  Some  of  tliem  could  be  descried  with 
 the  naked  eye,  and,  yet,  the  highest  telescopic  power 
 that  could  be  applied  did  not  resolve  them.  It  was, 
 therefore,  concluded  that  they  differed  essentially  in 
 their  constitution  from  the  resolvable  nebula.  It 
 was  held  that  they  consisted  of  nebulous  matter,  in 
 the  process  of  condensation.  The  advocate  of  the 
 nebular  hypothesis  regarded  them  as  quite  analogous 
 to  the  nebula,  from  which  the  sun  and  planets  were 
 supposed  to  be  evolved.  Nebula3  were  pointed  out 
 in  all  the  various  stages  of  condensation,  from  the 
 diffuse  mist  to  the  perfect  star,  and  they  were  main- 
 tained to  be  demonstrative  of  actual  growth,  just  as 
 vv^e  conclude  that  there  has  been  growth  when  in  a 
 forest  we  see  all  gradations,  from  the  tender  sapling 
 to  the  full-grown  tree. 
 
 The  large  telescopes  of  Lord  Eosse  and  other  ob- 
 servers have,  however,  dissipated  such  speculations. 
 The  nebulas  which  presented  the  most  obstinate 
 character,  and  long  resisted  all  attempts  at  resolution, 
 have  at  last  yielded.  The  great  test-objects,  such  as 
 the  nebula  in  Orion  and  the  one  in  Andromeda,  which 
 are  faintly  discernible  by  the  naked  eye,  and  which 
 resisted  all  former  attempts,  have  now  been  resolved. 
 It  was  on  such  remarkable  cases,  that  the  speculation 
 chiefly  rested,  and  now  that  the  foundation  is  removed, 
 its  plausibility  is  gone.  It  is  true  that  many  nebula 
 are  still  unresolved,  but  this  we  must  expect  to  be 
 the  case,  however  great  the  telescopic  power  may  be. 
 
222      THE  NEBULAR  HYPOTHESIS. 
 
 Every  increase  of  power,  while  it  resolves  nebulge 
 hitherto  unresolved,  at  the  same  time  descries  new 
 ones  defying  resolution.      It  may  be  argued   that, 
 possibly,  some  of  these  may  consist  of  genuine  nebu- 
 lous matter ;  but  the  question  is  not  one  of  possibility 
 but  probability,  and  the  revelations  of  the  telescope 
 have  reduced  such   probability  to  its  lowest  point. 
 The  different  degrees  of  apparent  condensation,  are 
 explained  by  the  various  ways  in  which  the  stars  are 
 arranged  in  these  clusters.     Sometimes  they  appear 
 to  be  pretty  equally  distributed,  but  at  others  there  is 
 a  rapid  concentration,  so  that  at  an  unresolvable  dis- 
 tance, the  appearance  is  that  of  a  single  star  sur- 
 rounded by  a  nebulosity.     The  actual  changes  alleged 
 to  have  been  observed  in  these  nebulte,  are  ascribed  to 
 the  difference  of  appearance  presented  by  telescopes  of 
 different  optical  power;  features  being  brought  into 
 view  by  very  powerful  telescopes,  which  are  altogether 
 invisible  in  telescopes  of  inferior  power.     But  though 
 change  were  established,  it   would  only  refer  to  a 
 difference  in  the  aggregation  of  distinct  stars,  not  in 
 the  chemical  condensation  of  nebulous  matter.     The 
 existence  of  anything  like  nebulous  matter  in  space,  is 
 now  only  countenanced  by  the  constitution  of  comets, 
 the  new  ring  of  Saturn,  the  zodiacal  light,  and  the 
 zones  of  meteoric  matter.     The  existence  of  nebulae 
 in  the  process  of  condensation,    can  no   longer   be 
 used  in  support  of  the   nebular    hypothesis.      The 
 result  then  of  the  whole  is,  that  as  a  purely  mechani- 
 
THE  NEBULAR  HYPOTHESIS.      223 
 
 cal  speculation,  there  can  be  no  scientific  objection 
 to  the  nebular  hypothesis ;  for  the  data  are  assumed 
 at  will,  and  in  such  a  manner,  that  the  required 
 results  flow  as  a  necessary  sequence.  When,  how- 
 ever, it  is  attempted  to  elevate  the  hypothesis  to 
 the  rank  of  a  vera  causa  in  nature,  by  the  analogy 
 of  nebulous  condensation  in  the  remote  regions 
 of  the  universe,  the  proof  entirely  fails.  The 
 conclusion  to  which  Sir  John  Herschel  has  come, 
 after  the  light  thrown  upon  the  subject  by  recent 
 revelations,  is,  that  the  nebular  hypothesis  is  ''a 
 physical  conception  of  processes  which  may  yet,  for 
 aught  we  know,  have  formed  part  of  that  mysterious 
 chain  of  causes  and  effects  antecedent  to  the  existence 
 of  separate,  self-luminous  solid  bodies."'  He  views  it 
 not  as  an  established  theory,  but  as  an  ingenious 
 hypothesis,  still  seeking  that  confirmation  which  it 
 has  hitherto  wanted. 
 
 We  are  now  in  a  position  to  understand  the  reli- 
 gious bearings  of  the  question,  and  perhaps  no  astrono- 
 mical point,  since  the  time  of  Galileo,  has  given  rise 
 to  keener  theological  discussion.  By  the  atheistical 
 inquirer,  the  hypothesis  was  hailed  as  the  greatest 
 triumph.  He  held  that  God  might  be  dispensed 
 with  altogether,  when  the  universe  could  be  evolved 
 so  readily  from  this  nebulous  mist.  It  was  argued, 
 that  the  proofs  of  Divine  wisdom,  discerned  in  the 
 constitution  of  the  solar  system,  were  at  once  dispelled, 
 when  the  adaptation  in  question  could  be  traced  to  a 
 
224      THE  NEBULAR  HYPOTHESIS. 
 
 primordial  unintelligent  vapour.  The  nebular  hypo- 
 thesis was,  in  short,  regarded  as  a  satisfactory  substi- 
 tute for  a  God.  It  is  to  be  regretted,  that  this  cavil 
 of  the  atheist  should  have  been  sometimes  met  by 
 the  defenders  of  Christianity  in  a  manner  so  little 
 satisfactory.  Instead  of  inquiring  whether  the  hypo- 
 thesis, though  granted,  warranted  such  an  inference, 
 it  was  attempted  to  rob  the  atheist  of  the  argument 
 by  proving  the  hypothesis  to  be  altogether  unfounded. 
 This  physical  hypothesis  was  denounced  as  atheistical, 
 and  the  question  of  a  God  was  staked  upon  the  refu- 
 tation of  it.  No  line  of  argument  could  be  more 
 unfortunate,  and  more  uncalled  for.  The  principle 
 implied  in  such  a  position  is,  that  the  traces  of  a  God 
 disappear,  as  we  reduce  the  instances  of  adaptation 
 around  us  to  general  laws.  Now  the  atheist,  if  this 
 principle  were  granted,  could  afford  to  relinquish  the 
 nebular  hypothesis.  The  granting  of  this  principle 
 would  be  tantamount  to  the  admission,  that  the  con- 
 ception of  a  God  must  disappear,  as  a  spectre,  before 
 the  advancing  light  of  science — the  function  of  science 
 being  the  reduction  of  special  cases  of  adaptation  to 
 general  laws.  The  atheist  who  appeals  to  the  nebular 
 hypothesis,  can  be  met  without  making  such  a  fatal 
 admission.  Instead  of  attacking  the  scientific  theory, 
 the  proper  attitude  is  to  deny  the  theological  inference. 
 Instead  of  denouncing  the  theory  as  atheistical,  the 
 only  tenable  position  is  to  shew  that,  though  granted, 
 it  would  not  warrant  the  atheistical  deduction. 
 
Plate  X 
 
 I  (:r/\,m  n  I  bijla,  ;^  stratifi  ld  nebula 
 
THE  NEBULAR  HYPOTHESIS.      225 
 
 It  seems  almost  incredible^  that  the  mere  tracing 
 of  special  adaptations  to  general  laws,  should  ever  be 
 regarded  by  the  human  mind  as  in  the  least  degree 
 weakening  the  evidence  for  a  wise  Creator  and  Gover- 
 nor. Granting  that  the  solar  system  was  developed 
 from  a  nebulous  mist,  according  to  the  rigid  laws  of 
 mechanics,  the  question  at  once  arises  :  Who  endowed 
 the  atoms  of  this  mist  with  such  properties  and  capa- 
 bilities, as  to  form  worlds,  with  their  wondrous  adapta- 
 tions? The  j)i'ii^ioi'dial  atoms,  with  their  original 
 susceptibilities,  just  as  urgently  demand  a  wise  Intelli- 
 gence, as  the  worlds  evolved  from  them.  In  judging  of 
 human  skill,  our  estimate  is  only  enhanced,  by  finding 
 some  contrivance  of  exceeding  ingenuity  accomplished 
 by  the  simplest  means.  The  highest  achievements 
 of  art  are  those  in  which  the  simplicity  of  the  means 
 strongly  contrasts  with  the  effects  produced. 
 
 Our  conclusion,  then,  in  regard  to  the  nebular 
 hypothesis  is,  that  it  must  be  dealt  with  purely  as  a 
 question  of  science,  and  that  it  would  be  exceedingly 
 unwise  to  regard  it  as  hostile  to  religion.  Natural 
 theology  can  only  gain  by  the  discovery  of  another 
 wisely-adapted  wheel  in  the  celestial  mechanism. 
 The  hypothesis  does  not  clash  with  revealed  religion  j 
 for  the  interpretation  of  the  first  chapter  of  Genesis, 
 which  admits  of  the  long  periods  of  the  geologists, 
 also  allow^s  a  like  extension  to  the  speculations  of  the 
 astronomer.  It  is  now  almost  universally  admitted 
 by  divines,  that  the  Scriptures  indicate  no  limit,  be- 
 
 p 
 
226      THE  NEBULAR  HYPOTHESIS. 
 
 yond  which  the  history  of  the  universe  can  be  traced. 
 The  period  of  the  Mosaic  creation  is  historically  de- 
 fined in  Scripture,  but  of  the  absolute  creation  of 
 worlds,  it  is  only  asserted  that  it  was  in  time,  and 
 that  the  material  universe  is  not  self-existent. 
 
Lord  Ilosse's  Great  Telescoi^e. 
 
 XY. 
 
 STELLAR  GROUPING. 
 
 At  tlie  same  time  that  recent  observation  lias  dis- 
 pelled the  nebulous  matter,  from  which  worlds  were 
 supposed  to  be  formed,  it  has  opened  up  wondrous 
 views  of  sidereal  grouping.  The  telescope  of  Lord 
 Kosse  has  converted  the  atoms  of  nebulous  matter 
 into  suns,  and  instead  of  molecular  condensation, 
 we  must  deal  with  stellar  aggregation.  The  nebulsa 
 w^hich  were  indicated,  as  shewing  progressive  con- 
 
228  STELLAR  GROUPING. 
 
 densation,  are  still  available  for  the  same  obiect; 
 the  condensation  being  cosmical  not  atomic.  But 
 this  leads  us  to  the  wider  question  of  the  distribution 
 of  stars  throughout  space. 
 
 Stellar  distribution  may  be  compared  to  the  dis- 
 tribution of  human  habitations  on  the  face  of  the 
 earth.  These  habitations,  instead  of  being  equally 
 distributed,  are  grouped  into  towns  and  cities, 
 with  suburban  mansions  and  villas.  Again,  a  more 
 general  classification  is  afforded  by  their  distribution 
 into  different  kingdoms,  often  separated  from  one 
 another  by  great  natural  boundaries. 
 
 A  similar  grouping  is  observable  in  the  celestial 
 bodies.  The  first  step  of  aggregation  is  exemplified 
 in  the  case  of  double  stars.  It  was  found  that  the 
 number  of  twin  stars  was  much  greater  than  what 
 could  be  accounted  for  by  chance  distribution ;  and  it 
 w^as  therefore  suspected  that  there  was  some  physical 
 bond  of  connexion.  This  surmise  has  been  fully  borne 
 out  by  observation.  Many  have  been  found  to  revolve 
 round  the  same  centre,  and  several  have  completed 
 their  period  since  the  first  observations.  Systems, 
 however,  are  found  in  the  heavens  with  every  grada- 
 tion, from  twin  stars  up  to  clusters,  whose  constituent 
 elements  cannot  be  numbered.  These  clusters,  too, 
 are  often  evidently  connected  with  a  higher  grade  of 
 grouping — bearing  the  same  relation  to  the  whole 
 system,  that  a  single  square  of  a  city  bears  to  the 
 city  itself. 
 
STELLAR  GROUPING.  229 
 
 The  aggregation  of  stars  to  which  our  system  is 
 believed  to  belong,  is  that  of  the  Milky  Way — that 
 faint  zone  of  light  seen  on  a  clear  night  circling  the 
 heavens.  The  Milky  Way  or  galaxy  is  believed  to  be 
 a  stratum  of  stars  in  which  our  system  is  embedded 
 I  as  a  constituent  element — the  thickness  of  the  stratum 
 being  small  compared  to  its  other  dimensions.  If  the 
 eye  of  the  observer  be  situated  near  the  centre  of 
 the  stratum,  the  greatest  number  will  be  seen  in 
 the  direction  of  the  circumference ;  and  tliese  are  so 
 jnumerous,  that  their  intermingling  rays  produce  the 
 impression  of  a  zone  of  light.  On  looking  towards 
 either  side  of  the  stratum  comparatively  few  stars  will 
 be  seen.  A  section  of  the  Milky  Way  may  be  com- 
 pared to  a  long  narrow  belt  of  trees.  The  eye,  situ- 
 ated in  the  middle  of  such  belt,  would,  on  lookiuG: 
 along  the  length,  see  all  the  trunks  of  the  trees  blend- 
 ing in  one  mass  without  seeing  through.  On  looking, 
 however,  to  either  side,  there  would  be  few  seen,  and 
 these  quite  separated  from  one  another.  All  the  stars 
 visible  to  the  naked  eye,  as  well  as  those  constituting 
 the  galaxy,  are  believed  to  belong  to  the  same  system. 
 There  is  good  reason  for  supposing  that  the  stars  do 
 not  vary  much  from  a  certain  average  size,  conse- 
 quently those  which  appear  largest  are  nearest  us. 
 The  stratum  of  which  our  firmament  consists,  is  cleft 
 into  two  branches.  This  is  shewn  by  the  zone  of 
 light  dividing  itself,  for  a  considerable  part  of  its 
 course,  into  two  pathways  across  the  heavens.     The 
 
230  STELLAR  GROUPING. 
 
 division  of  the  galaxy  is  shewn  in  the  following  sec- 
 tion, in  which  S  is  the  position  of  the  sun.     The 
 
 Milky  Way,  when  carefully  examined,  exhibits  a 
 mottled  appearance,  shewing  an  unequal  distribution 
 of  stars.  Some  spots  appear  absolutely  black,  and 
 one  very  marked  is,  from  this  circumstance,  called 
 the  coal-sack;  some  look  like  holes  or  rather  pro-  | 
 longed  funnels,  projecting  beyond  the  general  limits 
 of  the  stratum.  An  idea  may  be  formed  of  the  crowd- 
 ing of  the  stars  in  the  Milky  Way  from  the  fact,  that 
 in  many  places  upwards  of  a  thousand  stars  have 
 been  counted  in  a  space  which  the  disc  of  the  moon 
 would  cover.  Probably  the  whole  number  amounts 
 to  more  than  twenty  millions. 
 
 But  the  Milky  Way,  with  its  outlying  stars  con- 
 stituting our  firmament,  is  only  one  of  the  many  thou- 
 sands of  the  stellar  aggregations  scattered  throughout 
 space.  These  are  the  nebulse  which,  wdien  resolved 
 by  adequate  optical  power,  yield  galaxies,  w^ondrous 
 from  their  dimensions  and  the  strangeness  of  their 
 forms.  There  are  some  nebulous  masses  quite 
 visible  to  the  naked  eye.  The  most  remarkable  of 
 these  are  the  clouds  of  Magellan  in  the  southern 
 hemisphere.     They  are  very  conspicuous,  and  occupy 
 
Plate  VI(! 
 
 CONCENTRIC    NEBUL/f 
 
I.  DUMB   BELL  NEBUL>\    2.PEKF0RATlD   NEBULA 
 
STELLAR  GROUPLNG.  231 
 
 a  considerable  apparent  space  in  the  heavens.  One 
 of  them  is  so  bright,  that  the  full  moon  does  not 
 obliterate  it.  Thej  are  very  similar  in  structure  to  our 
 galaxy ;  but  there  are  innumerable  nebulae  embedded 
 in  the  midst  of  them.  The  most  common  form  is  the 
 spherical,  but  this  shape  is  often  due  to  the  defect 
 of  optical  power.  What  appears  a  perfect  sphere 
 with  a  small  telescope,  will  often  assume  a  most  ir- 
 regular figure  under  a  larger  power — the  fainter  por- 
 tions not  being  discernible  in  the  feebler  instrument. 
 We  have,  thus,  ring  nebulae,  the  crab  nebula,  the 
 dumb-bell  nebula,  and  various  forms  of  spiral  nebulae. 
 The  revelation  of  the  spiral  structure  is  due  to  the 
 powerful  telescopes  of  LordEosse;  and  the  most  inte- 
 resting circumstance  is,  that  this  appears  to  be  a  very 
 general  character  of  the  constitution  of  nebula.  Our 
 figure  only  illustrates  the  simpler  form  of  the  spiral, 
 but,  sometimes,  eight  or  nine  originate  from  one  centre; 
 and  nebulae,  hitherto  supposed  to  be  planetary,  or 
 presenting  a  uniform  disc,  are  now  resolved  into  an 
 aggregate  of  many  spirals,  curiously  combined. 
 
 Another  curious  feature  has  been  discovered,  very 
 similar,  apparently,  to  stratification.  In  the  midst  of 
 the  nebula  long  parallel  bands  are  seen  running 
 along  the  w^hole  length;  these  bands  are  perfectly 
 black.  The  great  nebula  of  Andromeda  is  a  good 
 illustration. 
 
 The  recent  revelations  of  the  telescope  have  pre- 
 sented conditions  and  forms  of  forces  to  the  astounded 
 
232  STELLAR  GROUPING. 
 
 gaze  of  the  astronomer,  hitherto  altogether  unknown 
 in  celestial  mechanics.  It  is  impossible  to  view 
 the  strange  figures  of  the  nebulae  without  being  per- 
 suaded that  they  indicate  action,  vitality,  progress. 
 We  cannot  survey  the  many  forms  which  the  clouds 
 in  our  atmosphere  assume,  without  being  persuaded 
 that  they  are  the  result  of  forces  determining  their 
 peculiar  configuration.  The  nebulse,  in  like  manner, 
 speak  of  mighty  forces  moulding  them  into  their  par- 
 ticular form  and  constitution.  The  nebular  hypo- 
 thesis contemplates  particles  of  matter  sweeping  round 
 into  a  vortex  and  forming  a  solid  body ;  but  the  as- 
 tronomer, on  the  other  hand,  lias  now  to  contemplate 
 streams  of  bright  suns  hastening  on  along  their  spiral 
 course  to  some  unknown  destiny.  The  idea  of  efibrt 
 is  written  upon  these  strange  forms — effort  to  reach 
 some  more  perfect  ultimate  form.  Sir  John  Herschel 
 threw  out  a  conjecture  as  to  the  manner  in  which  the 
 great  condensation  observable  in  some  nebula  may 
 have  been  produced.  He  imagines  that  the  motions 
 of  the  stars  might  be  destroyed,  to  some  extent,  by 
 collisions,  which  would  have  the  effect  of  making  them 
 revolve  round  the  common  centre  of  gravity  in  a  nar- 
 rower circle  5  just  as  the  earth  would  contract  its  orbit, 
 should  part  of  its  velocity  be  destroyed  by  a  collision 
 with  a  comet.  The  effect  of  such  collision  would  be, 
 to  produce  great  apparent  condensation  in  the  group 
 of  stars.  This  great  condensation,  with  a  faint  sur- 
 rounding nebulosity,  was  one  of  the  strongholds  of 
 
STELLAR  GROUPLNG.  235 
 
 the  nebular  hypothesis,  as  it  was  thought  highly  im- 
 probable that  the  central  condensation  should  arise 
 merely  from  the  grouping  of  stars. 
 
 As  individual  stars  are  not  scattered  equally 
 throughout  space,  so  the  groups  which  they  form 
 have  far  from  a  uniform  distribution.  There  are 
 certain  regions  of  the  heavens  much  richer  in  nebula 
 than  others.  In  the  northern  hemisphere,  the  great 
 region  of  nebulse  is  near  the  pole  of  the  galactic  circle, 
 or  the  part  furthest  removed  in  every  direction  from 
 the  Milky  Way.  In  the  southern  hemisphere,  the 
 distribution  is  much  more  uniform. 
 
 We  see,  then,  the  aggregating  power  ascending  by 
 a  series  of  steps  till  an  elevation  is  attained,  which 
 makes  the  mind  giddy  to  contemplate.  The  lowest 
 term  in  this  ascending  series  is  the  revolution  of  the 
 satellite  round  the  planet.  The  next  is  the  revolution 
 of  the  planet  round  the  sun.  Then  comes  the  stellar 
 grouping,  by  which  each  sun  in  its  galaxy  revolves 
 round  the  centre  of  gravity  of  the  whole,  there  being 
 many  intermediate  steps  formed  by  double  stars  and 
 liigher  combinations.  It  had  been  attempted  by  Maed- 
 lar  to  prove  that  our  firmament  revolves  round  the 
 bright  star  Alcyone  in  the  Pleiades.  The  proof  is, 
 however,  by  no  means  satisfactory.  A  higher  step 
 still  is  presented  by  the  revolution  of  one  galaxy  round 
 another.  No  such  revolution  has  been  actually  ob- 
 served ;  but  double  nebulce  are  found  in  such  numbers, 
 that  the  same  reasonino;  holds  in  their  case  as  in  that 
 
234  STELLAR   GROUPING. 
 
 of  the  double  stars.  If  the  number  of  double  stars  war- 
 ranted the  inference  of  a  physical  connexion^  a  like 
 inference  is  equally  warrantable  in  the  case  of  the 
 nebuljfi.  It  has  been  clearly  ascertained,  that  our 
 sun  has  a  proper  motion  in  space,  carrying  all  its 
 system  of  planets  and  satellites  with  it;  and  it  has 
 even  been  attempted  to  assign  its  probable  velocity. 
 According  to  the  most  reliable  calculations,  it  advances 
 on  its  path  daily,  by  a  space  equal  to  its  own  semi- 
 diameter.  This,  combined  with  the  detected  motion 
 of  the  double  stars,  warrants  the  presumption  that 
 revolution  is  not  confined  to  the  lower  steps  of  group- 
 ing among  the  celestial  bodies.  There  is  a  strong 
 probal)ility  that  every  orb  in  the  universe  is  in 
 motion,  and  that  all  are  related  by  one  great  bond 
 of  union.  That  gravitation  is  the  great  bond  of  con- 
 nexion in  the  stellar  spaces,  as  well  as  in  the  solar 
 system,  has  been  clearly  ascertained.  This  is  settled 
 by  the  revolution  of  one  star  round  another  in  an 
 ellipse.  The  same  power  that  determines  the  shape 
 and  the  fall  of  a  rain-drop,  also  determines  the  shape 
 and  the  motions  of  the  remotest  galaxy. 
 
 The  apparent  magnitudes  of  the  nebuliB  are  very 
 various.  The  nebula  in  Andromeda,  visible  to 
 the  naked  ej^e,  has,  when  its  minutest  boundaries  are 
 brought  into  view,  a  length  equal  to  five,  and  a 
 breadth  equal  to  two  diameters  of  the  moon.  Again, 
 there  are  nebulse  so  minute,  that  a  hundred  might  be 
 packed  within  the  circumference  of  the  moon's  disc. 
 
STELLAR  GROUPING.  235 
 
 The  heavens  are  rich  in  colours ;  some  clusters  of 
 stars  glitter  like  a  rich  piece  of  jewellery^  with  gems 
 of  various  colours.  The  nebulce  shine  with  similar 
 colours.  Sir  John  Herschel  observed  some  in  the 
 southern  hemisphere  of  a  deep  blue  colour,  without 
 having  any  red  associated  with  it.  This  seems  to 
 settle  the  disputed  point,  whether  blue  stars  are  blue 
 in  virtue  of  an  inherent  colour,  or  merely  as  comple- 
 mentary to  the  red  stars,  with  which  they  are  asso- 
 ciated. It  is  now  clearly  established  that  there  may 
 be  a  whole  galaxy  of  blue  stars,  tinging  myriads  of 
 subordinate  worlds  with  their  sombre  hue. 
 
 Though  the  study  of  stellar  aggregation  does  not 
 present  such  striking  evidence  of  design  as  "we  find 
 in  the  system  with  which  we  are  now  immediately 
 connected,  still  we  cannot  contemplate  these  strange 
 forms,  in  connexion  with  the  overwhelming  magni- 
 tude of  the  scale  in  which  they  are  presented  to  us, 
 without  feeling  as  if  summoned  into  the  presence- 
 chamber  of  the  Almighty.  These  firmaments, 
 stretching  indefinitely  into  the  depths  of  space, 
 afi'ord  a  footing  on  which  the  inquiring  spirit  may 
 tread,  when  yearning  to  realise  the  ideas  of  the 
 Infinite  and  Eternal.  It  is  wrong  to  despise  such 
 views  of  God  as  are  perfectly  familiar  and  palpable. 
 Still,  it  is  good  to  be  brought  face  to  face  with  parts 
 of  God's  works  whose  design  to  us  is  unfathomable. 
 "  It  is  the  glory  of  God  to  conceal  a  thing,  but  the 
 honour  of  kings  is  to  search  out  a  matter."    The  mind 
 
236  STELLAR  GROUPING,  ^ 
 
 is  irresistibly  awed  by  the  glory  of  God  in  tbe  con- 
 cealed mystery  of  these  wondrous  stellar  groups; 
 and  though  kingly  intellects  should  unveil  much  of 
 that  mystery  in  the  future  march  of  sciencCj  still,  the 
 lifting  of  the  veil  from  one  mystery,  only  reveals 
 others  far  more  glorious  in  their  awful  concealm.ent. 
 The  philosopher  who  may  be  privileged  to  unveil 
 the  mysteries  of  these  groups  which  now  perplex  us, 
 will,  after  his  task  is  done,  feel,  even  more  strongly 
 than  Newton,  that  he  is  only  as  a  child  gathering  a 
 few  pebbles  on  the  brink  of  the  wide  ocean. 
 
 In  contemplating  the  various  grades  of  stellar 
 aggregations,  the  unity  of  plan  is  at  once  forced 
 upon  our  minds,  and,  as  a  necessary  inference,  the 
 unity  of  Him  from  whom  the  plan  proceeded.  From 
 the  fall  of  a  stone,  we  trace  the  successive  links,  up 
 to  the  revolutions  of  the  remotest  stars,  and  we  find 
 that  one  great  law  comprehends  them  all.  The 
 mighty  plan  is  one,  and  the  Architect  must  also  be 
 one.  When  we  think  of  the  Omnipotent  guiding 
 millions  of  shining  suns  in  their  spiral  course,  our 
 hearts  may  sink  within  us  as  they  speak  to  us  of  our 
 insignificance  in  the  vast  plan.  But  another  view 
 quiets  our  spirits,  at  the  same  time  chiding  us  for  our 
 unworthy  thoughts  of  God :  ^'  Are  not  two  sparrows 
 sold  for  a  farthing  ?  and  one  of  them  shall  not  fall  on 
 the  ground  without  your  Father.  But  the  very  hairs 
 of  your  head  are  all  numbered.  Fear  ye  not,  there- 
 fore." 
 
Transit  Circle  at  Cambridge  Observatory,  U.S. 
 
 XVI. 
 
 THE  OBSEEVATOEY. 
 
 We  have  endeavoured  to  give  our  readers  an  idea  of 
 the  principle,  construction,  and  function  of  the  tele- 
 scope ;  but  before  passing  from  the  subject,  we  cannot 
 but  advert  to  the  remarkable  circumstance,  that  the 
 chief  improvements  are  due  to  the  labours  of  men 
 busily  engaged  in  trades  and  professions,  which  might 
 at  first  sight  seem  incompatible  with  scientific  pur- 
 suits.    We  have  already  instanced  the  case  of  Sir 
 
238  THE  OBSER  VA  TOR  V. 
 
 William  Herscliel,  who  was  not  deterred  by  the 
 many  engagements  of  his  musical  profession  from 
 devoting  himself  to  the  grinding  of  specula.  But 
 this  is  only  one  of  many  similar  cases.  The  greatest 
 imxprovement  in  the  telescope,  since  the  date  of  its 
 invention,  is  due  to  a  Spitalfields  silk-weaver,  John 
 Dolland.  His  family  were  exiled  from  France  by 
 the  revocation  of  the  Edict  of  Nantes,  and  found  a 
 home  in  the  suburbs  of  London.  The  devotion  of 
 the  Spitalfields  weavers  to  mathematics  is  one  of  the 
 most  curious  as  well  as  the  most  gratifying  passages 
 in  the  history  of  science ;  and  John  Dolland  shone  as 
 one  of  the  most  distinguished  of  the  number.  He 
 did  not  scruple  to  break  a  lance  with  the  illustrious 
 Euler ;  and  for  his  improvements  in  the  telescope,  he 
 received  the  highest  honour  of  the  Eoyal  Society, — 
 viz.,  the  award  of  the  Copley  medal.  He  was  the 
 founder  of  the  fortunes  of  his  family,  though  it  was 
 his  son  Peter  who  amassed  the  wealth  that  flowed 
 from  the  achromatic,  arrangement.  Peter,  like  his 
 father,  plied  the  shuttle  in  his  youth,  but  he  soon 
 abandoned  it  for  the  more  promising  field  of  optics. 
 Ramsden,  who  gained  so  much  celebrity  for  his  skill 
 in  dividing  astronomical  instruments,  was  a  York- 
 shire clothier.  It  would  be  easy  to  mention  the 
 names  of  many  others,  who,  while  they  did  not  aban- 
 don the  trade  or  profession  in  which  they  were  trained, 
 yet  found  time  to  improve  the  telescope,  and  advance 
 the  cause  of  astronomy.    It  is  pleasant  to  record  such 
 
THE  OBSERVATORY.  239 
 
 cases,  in  wlilcli  the  daily  toil  of  life  has  been  liglit- 
 ened  and  dignified  by  science.  It  is  satisfactory,  too, 
 to  note,  that  science  in  those  cases  was  wooed  without 
 any  pecuniary  loss.  Their  love  of  science  seemed  to 
 make  them  only  more  prosperous  in  business.  It 
 is  frequently  very  different  when  the  mechanic  ac- 
 quires a  taste  for  light  literature.  Instead  of  strength- 
 ening his  arm,  like  science,  for  daily  toil,  it  too  often 
 enervates  him,  by  fostering  a  disrelish  for  the  stern 
 duties  of  life.  It  is  an  encouraging  fact,  viewed  in 
 connexion  with  the  elevation  of  the  labouring  classes, 
 that  in  our  large  cities,  especially  in  London,  there  is 
 a  steady  demand  amongst  this  class  for  the  higher 
 class  mathematical  works.  The  men  that  haunt  old 
 book-stalls  in  rusty  coats  or  moleskin  jackets,  are 
 not  always  bent,  as  we  are  apt  to  suppose,  on  the 
 purchase  of  the  ephemeral  literature  of  former  days ; 
 they  are  often  pondering  over  the  purchase  of  some 
 work  in  mathematics  which  formerly  was  in  repute, 
 but  which  now,  from  changes  in  educational  methods, 
 may  be  purchased  for  a  trifle.  Many  a  mechanic  is 
 working  hard  at  fluxions  in  his  garret,  ignorant  of 
 the  improved  notation  of  modern  days.  He  finds  his 
 great  reward  in  the  delight  which  the  exercise  of  his 
 intellectual  faculties  affords,  and,  with  no  thought  of 
 scientific  celebrity,  he  revels  in  the  profundities  of 
 the  higher  calculus.  Such  pure  and  disinterested 
 love  of  science  is  one  of  the  most  hopeful  features  of 
 the  labour  question.    It  proves  that  the  highest  intel- 
 
240  THE  OBSERVATORY. 
 
 lectual  labour  is  perfectly  compatible  with  daily  toil. 
 The  decay  of  mechanics'  institutes  is  usually  quoted 
 as  a  proof  that  the  intellectual  elevation  of  the  labour- 
 ing classes  is  hopeless.  But  it  admits  of  doubt  whe- 
 ther the  result  is  not  due  more  to  an  under  than  an 
 over-estimate  of  the  mechanic's  capabilities.  The 
 mechanic  who  could  relish  fluxions,  would  not  long 
 find  advantage  in  attending  the  showy  and  superficial 
 lectures  usually  given  at  such  institutions.  A  system 
 better  calculated  to  develop  his  capabilities  would 
 most  probably  meet  with  more  success. 
 
 We  shall  not,  however,  delay  longer  by  signalising 
 the  names  of  those  who  have  contributed  most  to  the 
 improvement  of  astronomical  instruments,  but  at  once 
 introduce  the  reader  to  the  observatory  itself.  All 
 observatories  have  a  great  family  likeness ;  but,  to  be 
 more  special,  we  shall  suppose  that  the  observatory 
 in  question  is  the  one  erected,  about  twenty  years 
 ago,  in  Glasgow,  in  connexion  with  the  University, 
 and  over  which  Professor  Nichol  presided  with  so 
 much  distinction.  The  handsome  building,  on  the 
 summit  of  the  hill  above  Partick,  owes  its  erection 
 and  completeness  very  much  to  the  munificence  of  the 
 merchants  of  Glasgow,  who  came  forward  with  libe- 
 ral donations.  If  you  wish  to  see  it  in  full  operation, 
 you  must  visit  it  by  night.  The  transit-room  is  the 
 principal  one ;  and  when  you  are  ushered  into  it,  you 
 find  that  it  is  a  large  sombre  apartment,  its  walls 
 painted  black,  and  many  bright  instruments  faintly 
 
THE  OBSERVATORY.  241 
 
 gleaming  in  tlie  light  of  dimly-shaded  lamps.  The 
 room  reauires  to  be  as  dark  as  possible,  and  the  lamps 
 are  used  merely  for  illuminating  the  interior  of  the 
 telescope  and  the  face .  of  the  clock.  As  your  eye 
 gets  accustomed  to  the  gloom,  you  probably  find  the 
 observer  stretched  on  his  back  upon  a  couch,  which 
 is  movable,  so  as  to  bring  his  eye  close  to  the  tele- 
 scope. He  is  situated  between  two  huge  stone  pillars 
 that  serve  as  supports  for  the  transit-circle,  which  is 
 the  grand  instrument  of  the  regular  observatory. 
 You  may  form  a  pretty  fair  conception  of  the  instru- 
 ment, if  3^ou  suppose  a  pair  of  carriage-wheels,  with 
 their  connecting-axle  laid  across  the  tops  of  the  pil- 
 lars, the  axle  resting  upon  two  metal  supports  on 
 which  it  turns.  The  telescope  is  then  to  be  con- 
 ceived as  fixed  across  the  middle  of  the  axle,  so  that 
 it  is  hung  precisely  like  a  cannon  on  its  carriage.  It 
 can  only  move  on  its  axis,  up  and  down ;  it  can  turn 
 neither  to  the  right  nor  the  left.  On  examining  the 
 rim  of  the  wheel,  you  will  find  an  inlaid  narrow  band 
 of  gold  all  round,  and  on  this  are  engraved  very 
 minute  lines,  with  intervals  of  two  seconds.  When 
 the  telescope  is  elevated  to  a  particular  star,  the 
 circle,  of  course,  turns  round,  being  fixed  to  the 
 axis ;  and  the  observer,  when  he  has  placed  the  star 
 exactly  on  a  spider's  line  in  the  centre  of  the  field  of 
 view,  leaves  the  eye-glass  of  the  telescope,  and  views, 
 with  a  powerful  compound  microscope,  the  divided 
 limb.      He  marks  what  particular   division  comes 
 
 Q 
 
242  THE  OBSERVATORY, 
 
 under  a  spider's  line  stretclied  in  the  field  of  view  of 
 the  fixed  microscope,  and  this  gives  him  the  required 
 altitude  of  the  star.  The  measuring  apparatus  is  so 
 perfect,  that  the  position  can  be  read  off  to  the  frac- 
 tion of  a  second.  The  transit-circle  is  one  of  the 
 most  perfect  productions  of  art,  both  in  regard  to  its 
 optical  and  measuring  powers.  It  was  executed  at 
 Munich,  the  metropolis  of  art.  Most  of  the  finest 
 instruments  of  European  and  American  observatories 
 have  been  sent  forth  from  the  workshops  of  this  city. 
 It  is,  however,  satisfactory  to  note,  that  the  tide  seems 
 to  be  once  more  turning  in  favour  of  our  own  country, 
 for  the  recently-executed  transit-circle  at  Greenwich 
 is  entirely  of  home  manufacture,  and  its  performance 
 is  quite  unmatched. 
 
 When  reference  is  made  to  the  delicate  measure- 
 ments of  the  astronomer,  it  is  satisfactory  to  have  a 
 clear  conception  of  what  the  minute  divisions  mean. 
 Now,  what  is  meant  when  it  is  said,  that  such  an  in- 
 strument reads  to  the  fraction  of  a  second  ?  How  far 
 distant  from  one  another  must  the  slender  lines  be 
 which  include  a  second  of  space?  Some  notion  of 
 this  extreme  closeness  may  be  formed,  when  we  state, 
 that  about  six  thousand  lines  would  be  crowded  into 
 the  space  of  an  inch  on  the  limb  of  a  circle  six  feet 
 in  diameter,  and  yet  the  astronomer  has  to  deal  with 
 even  minute  fractions  of  the  intervals  between  these 
 lines.  The  distances  of  the  fixed  stars  depend  on  the 
 measurement  of  quantities  so  minute.     It  was  not  till 
 
THE  OBSERVATORY, 
 
 243 
 
 within  these  few  years  that  Ave  could  with  certaintj 
 determine  the  distance  of  any  of  the  stars,  just  be- 
 cause we  had  not  till  then  the  means  of  dealing  with 
 quantities  so  minute  as  a  second ;  but  so  remarkable 
 is  our  advance  in  this  respect,  that  one  star — viz., 
 Capella — has  a  parallax  (on  which  the  distance  de- 
 pends) of  only  one-twenty-fifth  of  a  second,  or,  on 
 the  circle  in  question,  the  one-twenty-fifth  of  the  six- 
 thousandth  of  an  inch  ;  and  yet  astronomers  speak  of 
 its  distance  as  certainly  determined.  And  what  ren- 
 ders the  thing  all  the  more  wonderful  is,  that  these 
 small  quantities  must  be  extricated  from  errors  far 
 greater.  No  instrument,  as  well  as  no  observer,  is 
 supposed  to  be  faultless.  The  axis  of  the  telescope 
 may  not  be  perfectly  level — -it  may  not  be  precisely 
 east  and  west;  the  telescope  maybe  set  wrong  on 
 the  axis ;  the  observer  may  have  some  obliquity ; 
 and  the  atmosphere  may  turn  the  ray  of  light  out  of 
 its  straight  course ; — and  each  of  these  sources  of 
 error  will  occasion  an  amount  of  deviation  far  greater 
 than  the  quantity  to  be  ascertained.  Yet  the  astro- 
 nomer, by  his  formulae,  hunts  out  truth  so  ingeniously 
 amidst  a  maze  of  error,  that  he  at  last  inevitably  runs 
 it  dowi/.  He  has  a  ton  of  sand  and  gravel  from  which 
 to  extract  a  single  shining  grain  of  gold  ;  and  he  sets 
 to  work  so  systematically,  that,  minute  as  it  is,  it 
 cannot  slip  through  his  fingers. 
 
 We  have  endeavoured  to  give  a  conception  of  a 
 second  on  the  rim  of  a  brass  circle ;  but  it  is  also  sa- 
 
244  THE  OBSERVATORY, 
 
 tisfactory  to  have  some  notion  of  wliat  a  second  is  on 
 the  circle  of  the  heavens.  And,  as  in  the  one  case 
 we  took  an  inch  as  our  nnit,  we  shall  now  take  the 
 apparent  breadth  of  the  moon,  the  most  familiar  of 
 the  heavenly  bodies.  Suppose  a  string  stretched  from 
 one  border  of  the  moon  to  the  opposite  one,  how  many 
 stars  could  be  strung  upon  it  in  order  that  they  would 
 be  a  second  apart  from  each  other,  the  diameter  of  the 
 moon  being  about  half  a  degree  ?  No  fewer  than  two 
 thousand  would  be  required,  each  star  beiug  regarded 
 as  a  mere  point  of  light.  Of  course  this  string  of  in- 
 dividual stars  would  appear  to  the  eye  as  a  perfectly 
 continuous  line  of  light.  Yet  the  astronomer  Striive, 
 with  the  great  equatorial  of  Dorpat,  could  not  only 
 individualise  each  star,  but  though  one  hundred  more 
 were  strung  on  between  any  two  of  the  stars,  he 
 could  still  measure  the  intervals  between  these  inter- 
 polated stars ;  or,  in  other  words,  he  could,  with  his 
 micrometer,  measure,  with  certainty,  a  space  in  the 
 heavens  so  minute  as  the  one-hundredth  part  of  a 
 second. 
 
 We  have  considered  the  measurement  of  space  j 
 but  that  of  time  is  still  more  difficult.  On  entering 
 the  transit-room,  you  will  observe,  on  looking  up, 
 that  there  is  a  narrow  slit  in  the  roof  running  from 
 north  to  south  ;  and  your  view  of  the  heavens  is  con- 
 fined to  the  narrow  strip  of  blue  which  is  seen  through 
 this  slit.  Now,  the  astronomer,  at  his  transit  circle, 
 ignores  all  the  rest  of  the  heavens.    He  has  fixed  his 
 
THE  OBSERVATORY.  245 
 
 telescope  so  that  it  can  point  only  to  tins  small  por- 
 tion of  the  sky.  He  draws  an  imaginary  circle,  called 
 a  meridian,  and  he  will  study  the  deportment  of  the 
 stars  only  at  the  moment  of  crossing  this  line.  He 
 stations  himself  at  this  ideal  barrier,  and  before  al- 
 lowing any  stellar  traveller  to  pass,  he  questions  him 
 minutely  to  determine  his  identity — the  two  essential 
 points  being,  the  time  of  day  when  he  passes,  and  his 
 distance  north  or  south  from  the  equator.  He  ques- 
 tions him  on  these  points,  because,  if  any  discrepancy 
 occurs  on  the  occasion  of  any  future  transit,  it  is  sure 
 to  bring  out  the  secrets  of  his  history.  But  how  is 
 the  time-questioning  effected?  Put  your  eye  to  the 
 telescope,  and  the  process  will  at  once  be  revealed  to 
 you.  You  are  surprised,  when  you  look  in,  to  see  a 
 blaze  of  light,  instead  of  darkness,  as  you  expected. 
 The  light  proceeds  from  a  lamp,  and  its  design  is,  to 
 shew  you  clearly  a  slender  kind  of  grating  spread 
 over  the  field  of  view.  This  consists  of  seven  spiders' 
 threads,  stretched  up  and  down  at  equal  distances, 
 and  one  crossing  in  the  middle.  The  perpendicular 
 line  in  the  middle  corresponds  to  the  imaginary  meri- 
 dian line.  You  soon  discover  a  star  coming  in  at 
 one  side  of  the  field  of  view,  and,  to  your  surprise, 
 marching  rapidly  across  the  lines  to  the  other  side. 
 The  rapidity  invariably  startles  when  first  observed  j 
 and  it  affords  the  most  sensible  proof  of  the  motion  of 
 the  earth.  No  doubt,  you  can  persuade  yourself  of 
 this  motion  by  watching   the  heavens  during   any 
 
246  THE  OBSERVATORY. 
 
 starry  night,  and  observing  how  the  stars  that  were 
 in  the  east  at  one  hour,  are  in  the  west  at  another. 
 But  this  is  a  matter  of  inference.  It  is  not  a  direct, 
 sensible  proof.  You  do  not  see  the  stars  moving  as 
 you  do  the  trees  and  houses  when  you  travel  along  in 
 a  carriage.  But  in  the  transit  instrument,  so  sensible 
 is  the  motion,  that  it  is  a  most  nervous  business  to 
 note  the  precise  moment  when  the  star  passes  across 
 the  various  wires  ,•  but  it  is  needful  to  do  this,  in 
 order  to  determine,  more  accurately,  the  moment 
 when  it  passes  the  central  line.  This  applies,  how- 
 ever, only  to  the  most  rapid  stars ;  for,  as  you  ap- 
 proach the  pole,  the  motion  becomes  slower  and  slower, 
 till  it  is  imperceptible.  The  observer  must  be  within 
 hearing  of  the  clock,  and  as  he  silently  counts  the 
 seconds,  he  must  note  down  when  the  star  passes  each 
 line  ;  and  as  the  star  may  take  but  a  very  few  seconds 
 to  travel  from  one  line  to  another,  he  has  no  sooner 
 noted  the  one  transit,  than  he  has  to  note  another. 
 This  would  be  all  comparatively  easy  if  the  star  passed 
 each  line  precisely  at  the  beat  of  each  second ;  but 
 this  rarely  occurs,  and,  consequently,  the  observer  has  ' 
 to  make  a  hurried  estimate  of  the  fraction  of  a  second; 
 and  the  requirements  of  science  are  such,  that  he  must 
 be  able  to  appreciate  the  tenth  of  a  second.  Listen 
 to  the  beat  of  a  clock,  and  if  you  attempt  to  divide 
 the  interval  between  two  beats  into  ten  smaller  inter- 
 vals, you  will  have  some  idea  of  the  difficulty  of 
 transit  observation. 
 
 I 
 
THE  OBSERVATORY.  247 
 
 One  of  the  most  recent  and  important  improve- 
 ments in  astronomical  observation  is  designed  to  ob- 
 viate this  difficulty ;  and  we  owe  it  to  America, 
 which  is  now  beginning  to  make  valuable  contribu- 
 tions to  science  as  well  as  literature.  The  prin- 
 ciple of  the  contrivance  in  question,  consists  in  the 
 substitution  of  the  sense  of  toucli  for  the  sense 
 of  hearing.  It  is  found,  that  sight  and  touch  will 
 act  in  much  closer  concert  than  sight  and  hearing. 
 Instead,  then,  of  watching  the  clock  with  the  ear, 
 and  the  star  with  the  eye,  the  observer,  when  he 
 notes  the  transit  with  the  eye,  presses  a  key  with  his 
 linger,  which  makes  a  record  of  the  observation.  The 
 finger,  it  is  found,  acts  in  instantaneous  concert  with 
 the  eye.  The  key  acts  upon  a  pen,  which  makes  a 
 mark  on  a  sheet  of  paper  moved  by  machinery.  The 
 beauty  of  the  contrivance  lies  much  in  the  application 
 of  electricity,  which  is  now  made  to  do  duty  in  every 
 possible  way,  from  the  ringing  of  a  bell  in  the  ser- 
 vants' hall,  to  the  exploding  of  a  mine  under  a  for- 
 tress. The  pen  is  connected  with  the  clock  by  an 
 electric  band,  in  such  a  manner  that,  though  the  ob- 
 server be  absolutely  deaf,  he  can,  on  examining  the 
 sheet  of  paper  after  the  observation,  tell,  to  the  hun- 
 dredth part  of  a  second,  the  instant  when  the  star 
 passed  the  wire.  The  sheet  of  paper  need  not  be 
 close  to  the  observer.  It  may  be  at  Paris,  or  St 
 Petersburg,  or  wherever  there  is  electric  communica- 
 tion J    and  the  moment  the  observer  presses  the  key 
 
248  THE  OBSERVATORY.  i 
 
 in  this  countiyj  the  record  maj  he  made  hundreds 
 of  miles  distant. 
 
 It  is  possible,  with  all  this  precision,  that  the 
 observer  may  err.  He  is  only  making  a  report  of 
 a  picture  painted  on  his  retina,  and  we  can  have  no 
 absolute  assurance  that  his  report  of  that  picture  is 
 perfectly  accurate.  Indeed,  it  is  found  that  this  is 
 a  most  important  source  of  error.  It  is  found  that 
 each  observer  has  his  own  individual  obliquity  of 
 judgment ;  and  this  must  be  determined  before  abso- 
 lute reliance  can  be  placed  on  his  observations.  But 
 might  we  not  dispense  with  the  observer  altogether? 
 Could  we  not,  wdien  we  order  a  telescope,  also  order 
 an  eye  to  look  through  the  telescope?  Having  the 
 eye  to  examine  after  the  observation,  we  would  not 
 be  dependent  on  the  errors  of  judgment  at  the  moment 
 of  observation.  It  would  be  a  great  ease  to  the 
 astronomer  himself,  as  there  is  no  task  so  comfortless 
 as  that  of  observing  in  a  transit-room.  The  scientific 
 martyr  has  to  shiver  the  live-long  night  on  his  couch. 
 A  cascade  of  bitterly  cold  air,  often  far  below  the 
 freezing  point,  is  constantly  pouring  down  upon  his 
 head,  and,  unfortunately,  the  most  precious  nights  for 
 observation  are  the  most  bitterly  cold.  If  a  sea-coal 
 fire  were  permitted,  it  would  be  some  consolation; 
 but  such  a  thing  cannot  be  dreamed  of.  Even  the 
 heat  of  the  observer's  body,  cold  as  it  is,  endangers 
 the  delicate  adjustments  of  the  instrument  when  there 
 is  too  close  a  proximity  \  and  anything  like  a  blazing 
 
THE  OBSERVATORY,  249 
 
 fire  would  Ibe  quite  destructive  of  nice  observation. 
 An  artificial  eye  would,  then,  be  an  acquisition  of  no 
 ordinary  value.  This  idea,  although  it  savours  of  the 
 wild  conception  of  Frankenstein,  is  already  partially 
 realised.  The  artificial  eye  consists  of  a  surface 
 sensitive  to  light,  placed  where  the  eye  of  the  ob- 
 server is  now  placed,  and  the  image  of  the  celestial 
 object  is  drawn  at  any  moment  on  this  surface,  in- 
 stead of  on  the  retina  of  the  observer.  The  differ- 
 ence is,  that  the  impression  on  the  artificial  eye  is 
 permanent,  and  we  can  examine  it  at  our  leisure, 
 whereas  the  impression  on  the  living  eye  is  tran- 
 sitory, and  we  have  to  depend  on  a  hurried,  and 
 perhaps  erroneous  report.  An  apparatus  is  erected 
 at  Kew  Observatory  on  this  principle,  for  the  obser- 
 vation of  the  sun's  disc.  To  gain  this  object,  it  is 
 so  arranged  by  clock-work  that  an  artificial  retina 
 is  presented  at  a  certain  moment,  and  after  receiving 
 the  photographic  image  withdrawn.  This  plan  has 
 had  only  partial  success;  but  we  can  readily  con- 
 ceive it  to  be  so  developed  as  to  work  a  revolution  in 
 astronomy. 
 
 After  examining  the  transit-room,  the  visitor  will 
 be  ushered  into  the  dome,  where  the  equatorial  instru- 
 ment is  fixed  on  a  pillar.  The  dome,  of  sheet-iron, 
 is  a  very  conspicuous  object  for  miles  around.  It 
 serves  no  other  purpose  than  that  of  a  convenient 
 shelter  for  the  telescope.  The  equatorial,  unlike  the 
 transit  instrument,  is  made  to  turn  in  every  direction. 
 
250  THE  OBSERVATORY, 
 
 In  the  transit-room,  the  observer  must  wait  till  the 
 star  come  round  to  the  slit  in  the  roof.  In  the  dome, 
 he  turns  the  telescope  to  the  object  at  once.  The 
 dome  has  also  a  slit  like  the  transit-room;  but,  in 
 order  to  accommodate  the  wider  range  of  its  inmate, 
 it  is  made  to  turn  round  on  its  base,  so  that  the  slit 
 may  be  always  opposite  the  mouth  of  the  telescope. 
 An  equatorial  is  a  telescope  so  mounted  that  it  keeps 
 the  object  in  view,  and  does  not  allow  it  to  flit  by 
 as  in  the  transit  instrument.  If,  in  travelling  on  a 
 railway,  you  look  at  some  near  object  through  a  tele- 
 scope, you  will,  in  order  to  keep  the  object  in  view, 
 require  to  be  constantly  changing  the  direction  of 
 the  telescope.  This  is  precisely  the  case  with  the 
 equatorial,  only  it  is  the  motion  of  the  earth,  not 
 the  railway  carriage,  that  requires  to  be  compensated. 
 The  motion  is  produced  by  clock-work  attached  to 
 the  axis  of  the  telescope. 
 
 We  have  now  taken  a  very  rapid  glance  at  the 
 principal  instruments  of  an  observatory ;  but  before 
 leaving  the  scene,  we  must  bestow  a  little  attention 
 on  the  astronomer  himself.  What  should  be  the 
 most  marked  moral  feature  of  his  character  ?  A  dis- 
 tinguished Christian  poet  fixes  on  devotion : 
 
 "  An  undevout  astronomer  is  mad." 
 
 But  poetical  sentiment  does  not  always  coincide  with; 
 stern  fact.  We  fear  that  astronomers,  as  a  class,  are 
 not  marked  very  strongly  by  devotion.      There  is 
 
2Hh  OBSERVATORY.  251 
 
 much  grandeur  in  the  following  conception  of  Long- 
 fellow's : — 
 
 "  And  over  all  is  the  sky,  the  clear  and  crystalline  heaven. 
 Like  the  protecting  hand  of  God  inverted  above  them." 
 
 One  would  think  that,  as  it  is  the  business  of  their 
 lives  to  look  up  to  this  inverted  hand  of  God,  they 
 would  be  habitually  impressed  with  His  glorious  pre- 
 sence. But  an  object  of  grandeur  depends,  for  its 
 effect,  altogether  on  the  point  of  view  from  which  we 
 contemj)late  it.  A  stone  mason  might  have  spent  a 
 good  part  of  his  life  in  helping  to  build  St  Paul's, 
 and  yet,  though  constantly  on  the  building,  with 
 square  and  plumb-line  in  hand,  he  would  not  occupy 
 so  favourable  a  position  for  appreciating  its  propor- 
 tions, and  the  sublime  ideas  which  it  embodies,  as 
 the  man  who  might  know  nothing  about  hewing  and 
 polishing,  but  who  contemplated  it  at  a  distance. 
 The  sailor  on  the  mast-head  of  a  ship-of-war,  at  the 
 mouth  of  the  Alma,  was  in  a  better  position  for  form- 
 ing a  right  judgment  of  the  battle-field  and  the  glory 
 of  the  victory,  than  the  man  who  was  in  the  thick  of 
 the  fight.  In  like  manner,  the  mere  unprofessional 
 man  may  be  in  a  much  better  position  for  drawing 
 from  astronomy  its  divine  teachings,  than  the  man 
 who  spends  his  days  and  nights  in  the  details  of  the 
 science.  The  latter  may  be  so  absorbed  with  these 
 details,  that  he  may  never  think  of  withdrawing  to  a 
 proper  distance  to  contemplate  the  grandeur  of  the 
 temple  on  which  he  is  engaged.     It  is  only  the  man 
 
252  THE  OBSERVATORY. 
 
 who  can,  from  tlie  height  of  Calvary,  project  the 
 glorious  fabric  on  the  background  of  eternity,  that 
 can  exclaim  with  deep,  heartfelt  devotion,  "  The 
 heavens  declare  thy  glory,  and  the  firmament  shew- 
 eth  thy  handiwork.  Day  unto  day  uttereth  speech, 
 and  night  unto  night  sheweth  knowledge.  There  is 
 no  speech  nor  language,  where  their  voice  is  not 
 heard." 
 
 I 
 
Groat  Eefractor,  Cambridge  Observatory,  U.S. 
 
 XVII. 
 ASTEONOMY  IN  AMERICA. 
 
 It  was  witli  no  little  surprise  that^  on  inquiry  for 
 Mr  Alvan  Clarke  in  Boston,  we  could  hardly  find 
 a  clue  to  his  residence.  America  is  proud  of  her 
 great  men,  but  the  name  of  her  great  optician, 
 familiar  to  every  astronomer  in  Britain,  was  almost 
 unknown  in  his  own  city.  It  was  after  consider- 
 able search  that  we  found  his  residence  and  work- 
 shop  in   Cambridge,   a   suburb   of   Boston.      Even 
 
254       ASTRONOMY  IN  AMERICA. 
 
 in  Cambridge  it  was  difficult  to  find  him.  Boston,  at 
 the  time,  was  loud  in  the  praises  of  an  opera-singer, 
 a  native  of  the  city,  who  was  on  the  eve  of  starting 
 for  England  to  exhibit  her  wonderful  powers  in  Lon- 
 don, and  who  afterwards  drew  forth  the  plaudits  of 
 the  passengers  in  the  steamer  in  which  we  crossed  the 
 Atlantic.  There  was  no  such  celebrity  accorded  to 
 the  obscure  worker  in  glass,  who,  with  marvellous 
 art  and  dexterity,  was  fashioning  instruments  to  ex- 
 tend the  limits  of  creation,  and  open  up  to  view  new 
 worlds  and  systems.  Yet,  Mr  Clarke  was  as  proud 
 of  the  limited  circle  that  recognised  his  labours,  as 
 the  opera-singer  was  of  the  applause  of  the  crowd  in 
 the  steamer  or  the  theatre. 
 
 When  we  reached  his  neat  villa,  we  were  shewn 
 to  the  rear,  where  stood  his  observatory  and  work- 
 shop, in  a  building  precisely  similar  to  an  old  Scottish 
 keep,  consisting  of  a  square  tower  of  several  stories, 
 with  a  single  apartment  in  each.  The  middle  story, 
 reached  by  a  ladder,  was  his  reception-room,  in  which 
 the  lighter  work  was  executed.  The  basement  floor 
 was  devoted  to  the  heavier  and  coarser  work,  and  the 
 highest  was  reserved  for  an  observatory,  in  which  a, 
 beautiful  equatorial  was  placed.  We  came  in  upon 
 him  at  an  inopportune  moment.  He  was  bent  on 
 being  courteous,  but  he  was  evidently  preoccupied 
 with  some  grave  care,  which  greatly  perplexed  him. 
 The  cause  of  his  anxiety  we  soon  found  to  be  some 
 tapping  going  on  in  the  workshop  below.     Every 
 
ASTR  ONOM  Y  IN  A  ME  RICA .        255 
 
 successive  blow  seemed  to  intensify  his  apprehension, 
 and  the  rebound  of  his  feelings  was  something  start- 
 ling, when  a  voice  from  beneath  sung  out,  "All's 
 right."     The  tapping  was  the  attempt  of  his  son  to 
 detach  the  greatest  lens  in  the  world  from  the  pitch- 
 bed,  in  wliich  it  was  stuck  fast  for  the  purpose  of 
 grinding.     A  blow,  in  the  slightest  degree  too  strong, 
 would  be  the  destruction  of   the   labour   of   many 
 months,  and  the  loss  of  some  thousands  of  dollars. 
 Now  that  the  lens  was  safely  detached,  and  the  bur- 
 den removed  from  his  mind,  Mr  Clarke  was  free  to 
 pour  out  his  genial  nature,  and  exhibit  the  refreshing- 
 enthusiasm'  of  a  man  whose  heart  is  thoroughly  in 
 his  work.     He  pointed  with  pride  to  a  lens  lying  be- 
 fore him,  the  fellow  of  the  one  that  had  caused  him 
 so  much  anxiety.     Tliis  was  the  great  object  of  our 
 curiosity,  and  well  might  a  lover  of  lenses  make  a 
 long  pilgrimage  to  see  such  a  sight.     It  is  eighteen 
 inches  in  diameter,  a  size  far  exceeding  that  of  any 
 existing  telescope  of  value.      The  telescope  in  the 
 Russian  Observatory  of  Pulkowa,  by  Frauenhofer, 
 and  long  considered  the  best  in  the  world,  is  only 
 fifteen  inches.     The  great  equatorial  of  Cambridge 
 Observatory,    connected   with    Harvard    University, 
 was  executed  by  the  successors   of  Frauenhofer  in 
 Munich,   Merz  and  Mahler,  and  is  believed  to  be 
 somewhat  superior,  besides  being  one-eighth  of  an 
 inch  greater  in  diameter.     This  one-eighth  enabled 
 our   Transatlantic   friends   to   boast   of  having   the 
 
256       ASTRONOMY  IN  AMERICA. 
 
 largest  existing  achromatic  telescope  in  the  world. 
 It  was  like  a  horse  gaining  a  race  by  the  fraction  of 
 a  neck.  Mr  Clarke's  lens  distances  all  competitors, 
 as  its  area  is  half  as  large  again  as  that  of  the  Cam- 
 bridge equatorial.  The  glass  was  from  Chance,  Bir- 
 mingham, and  no  defect  could  be  traced  in  it.  The 
 figure  and  polish  seemed  also  perfect,  but  the  per- 
 formance can  never  be  confidently  predicted  before 
 actual  trial.  The  character  of  ^Ir  Clarke  as  an  opti- 
 cian, however,  gives  good  ground  for  the  belief  that 
 it  will  far  surpass  anything  that  has  been  yet  at- 
 tempted. 
 
 Telescopes,  like  guns,  are  rated  according  to  their 
 calibre.  Everytliing  depends  on  the  size  of  the  lens, 
 all  else  being  equah  The  difficulty  of  obtaining 
 good  glass,  and  working  the  lens,  increases  enor- 
 mously with  the  size.  The  rate  is  something  like 
 that  of  the  speed  of  a  steamer.  Every  successive 
 knot  per  hour  requires  a  rapidly  increasing  rate  of 
 expenditure  of  fuel ;  and  every  increase  of  the  size 
 of  the  object-glass  implies  a  much  higher  proportion 
 of  trouble  and  expense.  The  difficulties  increase  so 
 rapidly,  that  in  the  workshops  even  of  Munich, 
 nothing  greater  than  fifteen  inches  would  be  at- 
 tempted. All  honour  to  the  courageous  attempt  of 
 Mr  Clarke  !  The  astronomical  world  will  not  grudge 
 America  this  triumph.  She  has  unexpectedly  taken 
 the  lead  in  various  departments  of  practical  astro- 
 nomy; and  it  will  be  somewhat  singular  if  a  self- 
 
ASTRONOMY  IN  AMERICA.        257 
 
 tanglit  artist  should  "beat  the  most  skilful  opticians  of 
 Europe. 
 
 The  telescopes  of  Mr  Clarke  have  been  brought 
 under  the  notice  of  English  astronomers,  chiefly 
 through  the  Rev.  Mr  Dawes,  one  of  our  most  reliable 
 observers.  He  has  made  some  important  astronomi- 
 cal discoveries;  and  perhaps  there  is  not  a  better 
 judge  of  the  performance  of  telescopes.  The  readers 
 of  the  Notices  of  the  Astronomical  Society  are  fami- 
 liar with  the  achievements  of  Mr  Clarke's  telescope 
 in  the  hands  of  Mr  Dawes.  Admiral  Smyth,  another 
 of  our  most  laborious  astronomers,  bears  ample  testi- 
 mony to  the  perfection  in  his  art,  acquired  by  the 
 American  optician.  We  have,  then,  good  ground 
 for  hoping  that  this  great  telescope  will  mark  another 
 decided  advance  in  astronomical  discovery. 
 
 It  may,  at  first  sight,  appear  strange,  that  the 
 object-glass  of  a  refracting  telescope  cannot  be  made 
 of  great  dimensions  with  as  great  facility  as  the 
 metallic  speculum  of  a  reflecting  telescope.  The 
 speculum  of  Lord  Eosse's  telescope  is  six  feet  in 
 diameter;  and  yet  this  lens  of  Mr  Clarke,  thougli 
 only  eighteen  inches,  is  regarded  as  one  of  monster 
 dimensions.  Apart  from  the  working  of  the  figure, 
 there  is  this  great  difference,  that,  for  the  glass  to 
 perform  well,  it  must  be  perfectly  homogeneous 
 throughout;  while  this  is  of  no  importance  in  the 
 reflecting  telescope.  In  the  one  case,  the  rays  have 
 to  pass  through  the  substance  of  the  glass,  and  any 
 
 R 
 
2S8        ASTRONOMY  IN  AMERICA. 
 
 inequality  in  its  constitution  produces  distortion^  or 
 indistinctness  in  tlie  image.  If  the  glass  is  not  per- 
 fectly homogeneous,  the  refraction  is  disturbed ;  but 
 in  the  case  of  the  reflecting  telescope,  the  reflection 
 is  the  same,  however  much  the  surface  of  the  specu- 
 lum may  vary  in  density.  This  results  from  the  law, 
 that  the  angle  of  reflection  is  the  same,  whatever  be 
 the  nature  of  the  reflecting  substance  ;  while,  in  the 
 case  of  refraction,  the  angle  altogether  depends  on 
 the  nature  of  the  refracting  body.  It  is  obvious, 
 therefore,  that  if  the  lens  be  not  homogeneous 
 throughout,  it  will  not  possess  that  equality  of  action 
 which  perfect  definition  requires.  But  it  is  exceed- 
 ingly difficult  to  obtain  glass  of  large  dimensions 
 free  from  inequalities.  It  may  be  perfectly  good  to  a 
 cursory  inspection,  while,  submitted  to  proper  tests, 
 it  is  wholly  worthless  for  astronomical  purposes. 
 From  this  source  of  difficulty  the  reflecting  telescope 
 is  entirely  free,  and,  consequently,  far  greater  dimen- 
 sions may  be  attained. 
 
 The  reflecting  telescope,  however,  labours  under 
 the  great  disadvantage  of  being  very  cumbrous,  as 
 compared  with  a  refracting  telescope  of  the  same 
 power.  A  small  refracting  telescope,  worked  com- 
 fortably under  the  shelter  of  a  dome,  with  nice 
 adjustment  and  easy  movements,  usually  performs 
 more  satisfactorily  than  reflectors,  with  lofty  and 
 unwieldy  scaff"olding,  standing  out  of  doors  and 
 the    observers    to    the    severities    of  the 
 
 I 
 
ASTRONOMY  IN  AMERICA.        259 
 
 weather.  The  huge  reflector  is  useful  for  occasional 
 star-gazing,  but  the  refracting  telescope  is  the  one 
 always  used  for  regular  scientific  observations ;  and 
 the  great  aim  of  opticians  is  to  improve  the  latter. 
 
 The  length  of  Mr  Clarke's  telescope  is  small  com- 
 pared to  the  telescopes  of  former  days.  At  the  Obser- 
 vatory of  Kew  are  the  glasses  of  a  telescope  executed 
 by  Huygens.  They  belonged  to  the  Philosophical 
 Society,  but  the  focal  length  being  such  as  to  require 
 a  tube  as  long  as  a  tall  church  spire,  they  were  never 
 fitted  up.  Sometimes  the  glasses  of  such  telescopes 
 were  used  without  a  tube,  the  eye-glass  being  placed 
 at  an  immense  distance  from  the  object-glass.  The 
 refracting  telescope  at  once  shrunk  into  small  dimen- 
 sions, at  least  in  regard  to  length,  as  soon  as  the 
 achromatic  principle  was  applied  by  Dolland.  The 
 only  way,  previous  to  this,  of  obviating  the  defect  of 
 colour,  was  by  making  the  focus  very  long;  but 
 Dolland,  by  simply  making  the  object-glass  com- 
 pound, one  part  being  of  flint,  the  other  of  crown- 
 glass,  dispensed  with  long  tubes.  An  achromatic 
 telescope  of  the  present  day,  two  feet  in  length,  per- 
 forms much  better  than  one  of  Huygen's  aerial  tele- 
 scopes 100  feet  long.  But  while,  for  convenience, 
 opticians  try  to  make  their  telescopes  as  short  as 
 possible,  they  are  struggling  to  expand  in  another 
 direction,  and  to  execute  object-glasses  as  large  as 
 possible ;  and  if  three  inches  in  advance  of  any  other 
 telescope  be  eflected,  a  ^reat  triumph  will  be  gained. 
 
26o        ASTRONOMY  IN  AMERICA. 
 
 The  astronomer  has  to  enlarge  his  object-glass,  pre- 
 cisely for  the  same  reason  that  the  owl  expands  its 
 eye  in  the  dark.  The  expanded  eye  does  not  magnify 
 objects ;  it  merely  takes  in  more  light,  and  sees  more 
 clearly.  The  mouse  is  large  enough  to  be  seen  by  the 
 owl  with  contracted  eye,  but  it  is  too  indistinct  to  be 
 visible ;  the  pupil  is  therefore  expanded,  and  the  prey, 
 though  retaining  the  same  apparent  dimensions,  is  at 
 once  descried.  So  the  astronomer  often  fails  to  descry 
 objects,  not  because  they  are  not  large  enough,  but 
 because  they  are  not  clear  enough ;  and  the  only  way 
 of  overcoming  the  difficulty,  is  by  making  his  artificial 
 pupil,  namely,  the  object-glass,  as  large  as  possible. 
 
 M.  Steinheil  of  Munich  has,  at  last,  succeeded  in 
 working  lenses,  according  to  the  formula  of  Gauss, 
 the  effect  of  which  will  be  to  shorten  greatly  the 
 length  of  telescopes.  In  the  best  achromatic  tele- 
 scopes, there  is  an  outstanding  aberration  which  can- 
 not be  compensated,  and  which  increases  with  the 
 size  of  the  object-glass.  •  To  lessen  the  injurious 
 effect,  the  telescope  must  be  lengthened  in  a  certain 
 proportion,  as  the  lens  is-  increased  in  size;  but  in 
 M.  Steinheil's  plan,  this  proportion  is  much  less  than 
 in  ordinary  telescopes.  It  is  impossible  to  over-esti- 
 mate the  advantage  of  this  in  practical  astronomy. 
 Every  advance  in  power  is  at  present  neutralised,  in 
 a  great  measure,  by  the  cumbrous  dimensions  every 
 increase  in  the  size  of  the  lens  involves.  The  mere 
 unwieldiness  is  a  great  drawback  to  accuracy,  while 
 
ASTRONOMY  IN  AMERICA.        261 
 
 it  greatly  increases  the  expense  of  fittings  and  build- 
 ings. The  great  refractors  of  the  Pulkova  and  Cam- 
 bridge Observatories  weigh,  with  their  machinery, 
 about  three  tons  each,  and  require  expensive  and 
 cumbrous  domes.  An  incalculable  benefit  would  be 
 conferred  on  science,  if  the  same  power  could  be 
 obtained  with  half  the  length  of  tube. 
 
 In  Mr  Clarke's  square  keep  we  hoped  to  escape, 
 for  a  little,  from  the  tumult  of  war.  The  whole  na- 
 tion was  stirred  to  its  depths  by  the  war  feeling. 
 Along  the  line  of  lake,  river,  and  rail,  there  was 
 nothing  heard  but  the  war-song,  and  loud  notes  of 
 defiance.  No  one  had  patience  to  talk  of  anything 
 but  the  war,  and  however  people  began,  they  ended 
 always  with  the  all-engrossing  subject.  In  the  Sab- 
 bath-school, the  common  school,  the  missionary  meet- 
 ing, the  prayer-meeting,  and  even  the  church,  their 
 national  and  war-songs  were  sung.  They  might  be 
 omitted  in  the  programme,  but  before  the  meeting 
 closed,  there  was  a  demand  for  some  exciting  song. 
 The  refrain  of  the  most  popular  one  still  sounded  in 
 one's  ears,  long  after  losing  sight  of  the  shores  of 
 America: — 
 
 "  And  the  star-spangled  banner  in  triumpli  shall  wave 
 O'er  the  land  of  the  free  and  the  home  of  the  brave." 
 
 The  star-spangled  banner  floated  from  every  spire 
 and  house-top,  and  waved  in  enormous  folds  from 
 ropes  stretched  across  the  streets.  The  volunteers 
 swarmed  in  every  city,  and  many  were  already  pro- 
 
262        ASTRONOMY  IN  AMERICA. 
 
 vided  with  very  bright  uniforms,  the  most  popular 
 being  that  of  the  Zouave.  They  were  incessant  in 
 their  demands  for  musicj  and  what  with  the  din  of 
 brass  bands,  and  the  boisterous  demonstrations  of 
 undisciplined  troops,  the  whole  country  was  kept  in 
 an  uproar.  The  very  children,  dressed  in  the  Zouave 
 costume,  were  let  loose  to  beat  their  mimic  drums 
 in  the  street,  or  to  charge  with  tiny  bayonets  the 
 unwary  guests  in  the  corridors  of  the  hotels  ,*  so  com- 
 pletely was  the  whole  population  given  up  to  the  war 
 excitement. 
 
 It  was  gratifying  to  find  one  man  engaged  in  the 
 peaceful  pursuits  of  science ;  but  even  in  Mr  Clarke's 
 sanctuary,  the  curse  of  war  had  cast  its  shadow.  For, 
 when  allusion  was  made  to  the  commercial  aspect  of 
 his  great  undertaking,  we  found  that  we  had  touched 
 upon  a  delicate  subject.  The  great  telescope  was 
 ordered  by  the  University  of  Mississippi,  and  a 
 munificent  price  was  agreed  upon;  but  the  war 
 banished  all  thoughts  of  telescopes,  and  of  obliga- 
 tions of  Southern  to  Northern  States.  This  southern 
 institution  was  ambitious  of  possessing  by  far  the 
 most  powerful  telescope  in  the  world ;  but,  by  the 
 stern  exigencies  of  war,  the  money  that  was  to  be 
 paid  for  this  expensive  toy  must  go  to  purchase  bread 
 and  bullets. 
 
 The  case  of  Mr  Clarke  is  one  of  many  illustrations 
 that,  in  the  grinding  and  polishing  of  lenses  and 
 specula,  the  amateur  often  surpasses  the  professional 
 
 1 
 
ASTR  ONOM  Y  IN  A  ME  RICA .         263 
 
 optician.  Witness  Sir  William  Herscliel,  wlio  was 
 a  professional  musician ;  Mr  Ramage,  who  was  a 
 tanner  in  Aberdeen ;  Wx  Lassels,  who  is  a  Liverpool 
 merchant ;  Mr  Nasmyth,  an  engineer ;  and,  above  all, 
 Lord  Rosse,  who  has  carried  the  process  of  casting 
 and  polishing  specula  to  such  a  pitch  of  refinement. 
 Mr  Clarke  started  in  life  as  a  printer,  and  afterwards 
 took  to  portrait-painting,  which  he  still  practises  to  a 
 certain  extent,  as  a  relaxation  from  his  severer  labours. 
 It  was  not  till  he  was  upwards  of  forty  years  of  age, 
 that  he  turned  his  attention  to  telescopes.  He  was 
 first  attracted  to  the  subject,  by  one  of  his  boys  asking 
 his  aid  in  casting  a  speculum  for  a  small  telescope, 
 which  he  had  taken  a  fancy  to  construct.  From  that 
 time,  the  boy's  amusement  became  the  serious  business 
 of  the  father's  life.  What  renders  his  success  more 
 remarkable  is,  that  he,  according  to  his  own  account, 
 is  totally  unacquainted  with  mathematics.  The  signs 
 oiplus  and  minus  are  about  the  sum  of  his  algebraical 
 knowledge.  How  often  does  genius  supersede  what, 
 to  other  men,  would  be  an  essential  element  to  suc- 
 cess !  What  sense  is  more  essential  to  the  student  of 
 natural  history  than  that  of  sight ;  and  yet  Huber, 
 one  of  the  most  successful  and  philosophic  observers 
 of  modern  times,  was  stone-blind !  Mathematics,  to 
 the  optician  or  astronomer,  seem  as  essential  as  sight 
 to  the  student  of  natural  history ;  and,  yet,  some  of 
 the  most  popular  writers  on  astronomy  were  totally 
 destitute   of  the  mathematical  faculty.      Ferguson 
 
264        ASTRONOMY  IN  AMERICA,  ] 
 
 could  never  understand  the  logical  process  by  which 
 the  forty-seventh  proposition  of  the  first  book  of 
 Euclid  is  proved ;  yet  he  perfectly  understood  the 
 property  of  the  right-angled  triangle.  He  convinced 
 himself  of  its  truth  by  cutting  the  squares  out  on 
 pasteboard,  and  weighing  the  largest  one  against  the 
 other  two.  The  late  Dr  Dick,  who  did  so  much  to 
 diffuse  a  knowledge  of  the  facts  cf  astronomy,  never 
 could  master  the  logic  of  thej:>o?2S  asinorum^  though 
 he  quite  understood  the  nature  of  the  property  demon- 
 strated. Mr  Clarke  is  also  a  good  example  of  his 
 order  in  another  respect.  He  is  a  hearty,  hilarious 
 man,  like  all  amateur  workers  in  lenses  and  specula, 
 who  are  always  overjoyed  when  they  meet  a  brother 
 who  can  enter  into  their  tastes,  and  listen  patiently 
 to  the  detail  of  all  their  failures  and  successes.  There 
 is,  certainly,  something  in  the  occupation  that  is 
 calculated  to  bring  out  all  that  is  genial  and  benevo-^ 
 lent  in  a  man's  character.  It  was  very  satisfactory 
 to  hear  ]\Ir  Clarke  describe,  in  glowing  terms,  a  late 
 visit  to  England,  when  he  made  the  acquaintance  and 
 enjoyed  the  hospitality  of  our  English  astronomers. 
 The  gratification,  we  doubt  not,  was  mutual ;  and  no 
 English  astronomer  will  pay  a  visit  to  the  Cambridge 
 optician  without  carrying  away  with  him  pleasant 
 reminiscences  of  his  home  and  his  w^orkshop. 
 
 Though  America  is  now  taking  a  lead  in  the  manu- 
 facture of  the  optical  part  of  telescopes,  American 
 astronomers  freely  admit  that  they  are  far  behind  in 
 
A STRONOMY  IN  AMERICA.        265 
 
 the  mounting  and  graduation.  By  far  the  finest 
 circles  are  executed  in  the  workshops  of  Munich  and 
 London. 
 
 Not  above  half  a  mile  from  the  workshop  of  Clarke, 
 is  the  Cambridge  Observator  j,  superintended  by  Bond 
 the  younger.  We  have  already  referred  to  the  con- 
 tributions of  Bond  the  elder  to  astronomical  science. 
 He  had  the  chief  merit  of  inaugurating  a  new  system 
 of  observing,  which  has  quite  revolutionised  practical 
 astronomy.  We  refer  to  what  is  called  the  American 
 or  Electro-recording  plan ;  and  our  chief  object  in 
 visiting  the  Observatory  was  to  examine  the  details 
 of  the  plan.  America  has  the  undisputed  claim  to  the 
 invention,  which,  if  measured  by  its  result,  is  one  of 
 the  most  important  in  modern  astronomy.  It  is 
 questionable,  however,  whether  it  should  be  rated 
 very  high,  if  measured  by  the  inventive  genius  re- 
 quired. There  are  certain  inventions,  which,  in  the 
 course  of  things,  are  inevitable;  and  it  is  a  mere 
 question  of  time  when  the  fortunate  parties  will 
 stumble  upon  them.  For  example,  the  application 
 of  electricity  to  the  ringing  of  bells  in  large  hotels, 
 such  as  the  Hotel  du  Louvre  in  Paris,  is  a  very 
 obvious  deduction  from  former  applications,  and  no 
 one  would  think  it  worth  while  to  set  up  any  claim 
 to  the  invention.  No  doubt  the  application  of  elec- 
 tricity to  astronomical  observation  was  not  so  obvious 
 as  this.  Still,  it  was  clearly  an  application  that  must 
 necessarily  have  been  made  in  a  short  time.     The 
 
266        ASTRONOMY  IN  AMERICA. 
 
 Bev.  Mr  Ward  Beeclier,  in  an  evening  lecture  in 
 Brooklyn,  which  we  had  the  pleasure  of  hearing, 
 claimed  the  faculty  of  mechanical  invention  as  the 
 grand  prerogative  of  the  N'ew  England  mind,  and 
 gave,  as  a  proof,  that  if  all  the  inventions  in  churns, 
 and  ploughs,  and  reapers  were  placed  in  a  row,  they 
 would  stretch  from  Maine  to  the  Mississippi.  But, 
 granting  this  fertility  of  invention,  would  this  long 
 row  of  ingenious  notions  amount  in  value  to  a  single 
 invention  with  the  stamp  of  genius  ?  James  Watt 
 once  remarked,  that  uneducated  artisans  sometimes 
 stumble  upon  inventions  in  matters  of  detail,  whicli 
 may  be  of  great  practical  value;  but  that  almost 
 never  has  such  a  man  claimed  the  merit  of  an  inven- 
 tion which  involved  some  new  principle  not  hitherto 
 applied ;  and  he  took  the  governor  of  the  steam-engine 
 as  an  illustration.  The  application  of  centrifugal 
 force  to  open  and  shut  the  throttle-valve  has  the  stamp 
 of  genius;  but  the  innumerable  modifications  of  this 
 principle  have  no  such  claim.  It  must  be  acknow- 
 ledged, that  if  we  take  the  higher  class  of  inventions, 
 America  can  claim  but  few  contributions,  notwith- 
 standing the  extreme  ingenuity  displayed  in  agricul- 
 tural implements  and  domestic  appliances. 
 
 There  are  several  claimants  of  the  invention,  but, 
 undoubtedly,  Mr  Bond  has  the  chief  merit  in  reducing 
 it  most  successfully  to  practice.  The  improvement 
 consists  simply  in  this — that  the  sense  of  touch  is 
 substituted  for  that  of  hearing.     In  the  former  plan, 
 
ASTR  ONOM  Y  IN  A  ME  RICA .        267 
 
 you  listened  to  the  beat  of  a  clock  in  tlie  same  room 
 with  the  telescope,  and  the  mind  was  strained  in  the 
 attempt  to  tell  the  exact  second,  or  even  the  tenth  of 
 a  second,  when  a  star  passed  across  a  wire.  In  the 
 new  plan  the  clock  may  be  out  of  sight  and  hearing, 
 and  all  you  have  to  do  is  to  press  an  ivory  key  the 
 moment  the  transit  is  made  5  and,  in  another  room, 
 through  the  intervention  of  the  electric  current,  the 
 record  is  made.  A  pen,  held  as  it  were  in  the  hand 
 of  the  clock,  marks  the  precise  moment  on  a  sheet  of 
 paper,  drawn  by  machinery  under  the  pen  at  an 
 equable  rate.  While  the  machinery  is  in  ojoeration, 
 the  pen  is  marking  off  seconds  by  making  lateral  offsets 
 on  a  straight  line — the  space  between  any  two  offsets 
 being  a  second  of  time.  The  effect  of  pressing  the 
 key  is  to  make  an  additional  mark.  This  mark  indi- 
 cates the  precise  moment  when  the  observation  was 
 made.  Suppose  a  copy  is  given  to  a  school-boy  in 
 which  to  write  during  the  course  of  a  certain  hour, 
 and  that  while  writing  he  receives  a  nudge  from  his 
 neighbour  which  blots  his  copy,  the  moment  when 
 this  happened  can  be  afterwards  ascertained  by  mark- 
 ing the  part  of  the  page  where  the  blot  is  found — this 
 being  on  the  supposition  that  the  boy  wrote  at  an 
 equable  rate  during  the  hour.  Now,  the  pen  held  in 
 the  hand  of  the  clock  writes  at  an  equable  rate,  and 
 when  the  observer  presses  the  ivory  key,  which  is 
 equivalent  to  the  nudge,  it  records  the  event  by  an 
 additional  mark,  the  precise  instant  of  which  may  be 
 
268        ASTR  ONOM  Y  IN  A  ME  RICA , 
 
 I 
 
 ascertained  to  tlie  liundredtli  of  a  second.  On  the 
 wall  of  the  recording  room  there  was  ranged  a  series 
 of  handles  called  switches^  after  the  nomenclature  of 
 the  railway.  By  moving  these  handles,  you  turned 
 on  the  electricity  to  any  particular  instrument;  so 
 that  every  instrument  in  the  establishment  might  he 
 connected  with  the  recording  apparatus.  The  follow- 
 ing figure  shews  the  way  in  which  the  pen  records 
 
 IJ 
 
 the  time  on  the  revolving  barrel.  It  will  be  observed 
 that  the  line  traced  by  the  pen  is  not  continuous,  but 
 that  it  is  broken  by  offsets,  each  of  which  marks  a 
 second  of  time.  When  an  observation  is  taken,  an 
 additional  and  different  offset  is  made  by  the  pen,  and 
 it  is  only  necessary  to  note  the  precise  point  in  this 
 broken  line,  where  this  offset  is  made,  in  order  to 
 determine  the  precise  instant  of  observation.  The 
 intervals  between  the  second's  marks  are  sufficiently 
 great,  to  enable  an  observation  to  be  read  off  to  the 
 hundredth  of  a  second. 
 
 In  the  dome  was  the  great  Frauenhofer  telescope, 
 alluded  to  as  the  best  existing  telescope.     With  the 
 
ASTRONOMY  IN  AMERICA,        269 
 
 exception  of  the  eighth  of  an  inch  in  the  diameter  of 
 the  object-glass,  it  is  precisely  similar  to  the  Pulkova 
 telescope,  the  figm-e  of  which  is  familiar  to  every  stu- 
 dent of  astronomy.  The  sight  of  the  real  instrument 
 was  like  renewing  acquaintance  with  an  old  friend. 
 It  was,  however,  with  a  species  of  reverence  that  one 
 looked  up  to  this  monument  of  human  genius,  bal- 
 anced on  its  massive  pillar,  and  enshrined  in  its  capa- 
 cious dome.  It  was  not  the  Bavarian  artist  you  were 
 inclined  to  do  reverence  to.  No ;  he  merely  put  the 
 last  stone  on  the  pyramid  which  human  genius  had 
 been  rearing  for  ages.  This  telescope  was  the  highest 
 product  of  the  human  intellect ;  it  was  the  combina- 
 tion of  all  sciences,  for  all  had  been  laid  under  con- 
 tribution to  make  a  perfect  instrument.  In  one  point 
 of  view,  man  may  well  be  proud  of  such  an  achieve- 
 ment ;  and,  in  another,  how  humbling  is  it !  For 
 what,  after  all,  is  its  grand  object?  Is  it  not  to  teach 
 us  how  little  we  do  know?  Man  perched  on  the 
 summit  of  the  pyramid  which  his  genius  has  reared, 
 no  doubt  gets  a  somewhat  wider  range  of  view,  but 
 he  has  discovered  only  a  little  more  of  the  fringe  of 
 the  garment  of  the  Omnipotent.  No  doubt  the  tele- 
 scope unfolds  new  worlds  and  systems,  but,  after  all, 
 they  are  only  the  outer  court  of  the  temple  of  the 
 Most  High.  The  unknown  only  becomes  more  over- 
 whelming, the  more  that  we  extend  the  limits  of  the 
 known. 
 
 America  is  famed  for  her  rocking-chairs,  and  all 
 
2/0        ASTRONOMY  IN  AMERICA. 
 
 comfortable  devices,  but  the  perfection  of  comfort  is 
 the  cliair  devised  by  Mr  Bond,  for  observing  with  the 
 great  equatorial.  The  eye  must  follow  the  end  of  the 
 telescope,  which  moves  in  a  circle,  and  the  chair  must 
 therefore  move  in  a  circle  too,  and  so  that  you  may 
 be  sometimes  aloft  in  the  dome,  or  sometimes  down 
 near  the  floor ;  and,  besides  all  this,  it  must  be  moved 
 to  the  right  or  left,  at  pleasure.  Now,  all  these  com- 
 plicated movements  can  be  executed  without  leaving 
 your  chair.  By  tm'ning  handles  attached  to  the  chair, 
 you  move  up  or  down,  along  the  concave  of  a  circle, 
 and  to  the  right  or  left,  at  pleasure.  All  that  you 
 have  to  do  is  to  observe  at  ease,  and  give  an  occasional 
 pressure  or  tap  with  your  finger.  But  may  we  not 
 hope  that  the  time  is  coming  when  it  will  not  even  be 
 necessary  for  the  astronomer  to  use  his  eyes  ?  May 
 he  not  construct  an  eye  more  reliable  than  his  own, 
 so  that,  in  dealing  with  the  stars,  he  will  have  only  to 
 expend  the  force  of  human  intellect  without  any  bodily 
 exertion  ?  Strange  as  it  may  appear,  steps  have  been 
 already  taken  to  supersede  the  human  eye.  At  Kew, 
 the  spots  on  the  sun  are  daily  recorded  by  an  artificial 
 eye,  tlie  object-glass  forming  the  pupil,  and  a  photo- 
 graphic plate  the  retina.  This  retina  has  the  advan- 
 tage over  the  human  one  of  retaining  the  impression, 
 so  that  precise  measurements  may  be  made  at  leisure. 
 At  Dudley  Observatory,  in  the  outskirts  of  Albany, 
 we  found  the  director,  Mr  Mitchell,  formerly  of  Cin- 
 cinnati, in  anything  but  a  calm,  scientific  mood.  Tele- 
 
ASTR  ONOM  Y  IN  A  ME  RICA .        27 1 
 
 scopes  and  stars  had  lost  tlieir  interest  for  the  moment^ 
 and  his  thoughts  were  wholly  of  the  war.  He  had 
 returned,  the  morning  we  called,  from  Washington, 
 where  he  had  been  summoned  to  give  the  benefit  of  his 
 military  skill,  which  has  since  raised  him  to  the  rank 
 of  Brigadier-General.  He  is  one  of  the  claimants  of 
 the  invention  of  the  electro-recording  method  of  obser- 
 vation. His  apparatus  differs  from  Mr  Bond's  in  this, 
 that  his  sheet  of  paper  is  laid  on  a  flat  disc  which 
 turns  round  like  the  turn-table  of  a  railway,  while  Mr 
 Bond's  is  wound  round  a  revolving  cylinder.  The  most 
 valuable  instrument  is  a  transit  circle  from  Munich. 
 
 Miss  Mitchell  has  gained  an  honourable  distinction 
 in  astronomy  by  her  discovery  of  comets.  She  was 
 the  first  American,  and  the  first  lady,  to  receive  the 
 King  of  Denmark's  gold  medal  for  the  discovery  of 
 comets.  There  is  now  so  much  competition  in  this 
 line  of  research,  that  it  requires  a  very  quick  eye  and 
 much  patient  observation  to  be  first  in  the  race. 
 
 It  is  creditable  to  the  United  States  that  so  much 
 has  been  done  for  astronomy,  seeing  that  all  has  been 
 done  by  private  liberality.  Both  Cambridge  and 
 Dudley  Observatories  are  entirely  supported  by  sub- 
 scription or  mortified  funds.  The  only  exception  is 
 the  Observatory  of  Washington,  over  which  Commo- 
 dore Maury  presided  up  to  the  period  of  the  Seces- 
 sion. He  has  cast  in  his  lot  with  the  Southern 
 States,  and  has  now  abandoned  his  office.  It  is  much 
 to  be  regretted  that  the  work  of  this  National  Obser- 
 
2/2        ASTR  ONOM  Y  IN  A  M ERICA . 
 
 vatoiy  has  Ibeen  interrupted ;  as,  from  the  competent 
 staff  of  observers,  some  valuable  results  might  be  ex- 
 pected. It  is  to  be  hoped  that  peace  will  soon  be 
 restored,  and  that  astronomical  science  will  be  culti- 
 vated with  renewed  ardour. 
 
 Besides  the  observatories  above  mentioned  there 
 are  others  at  Yale  College,  Hudson,  Ohio,  Philadel- 
 phia, West  Point,  Georgetown,  Cincinnati,  Tuscaloosa 
 (Alabama),  Dartmouth  College,  Amherst  College,  and 
 Chicago.  Most  of  these,  however,  are  of  no  service 
 to  science,  as  no  provision  has  been  made  for  the 
 regular  working  of  them.  The  popular  interest  is 
 apt  to  exhaust  itself  in  the  purchase  of  instruments, 
 which  are  soon  entirely  neglected,  if  a  staff  of  observers 
 is  not  appointed.  Where  proper  provision  has  been 
 made  for  observers,  an  abundant  harvest  of  discovery 
 and  scientific  fame  has  been  reaped.  The  Observa- 
 tory of  Cambridge,  alone,  has  entitled  the  United 
 States  to  take  rank,  in  astronomical  science,  with  any 
 European  nation.  The  credit  is  all  the  greater,  that 
 the  whole  is  due  to  private  liberality  and  a  generous 
 appreciation  of  the  wants  of  science.  This  institution 
 was  long  contemplated,  but  some  popular  impulse 
 was  needed,  and  this  was  furnished  by  the  great 
 comet  of  1843.  As  the  sudden  apparition  of  a  bright 
 star  decided  the  astronomical  career  of  Tycho  Brahe, 
 so  this  comet  laid  the  foundation  of  Cambridge  Obser- 
 vatory. In  the  case  of  the  other  observatories  also,  a 
 comet  or  eclipse  was  generally  required  to  stimulate 
 
A  S  TR  ONOM  y  IN  A  ME  RICA .         273 
 
 tlie  popular  interest,  and  comets  and  eclipses  are  not 
 useless,  though  they  served  no  other  purpose  than  to 
 found  observatories.  Under  the  cometary  influence, 
 a  meeting  was  held  in  Boston  in  1843,  and  the  sum 
 of  20,000  dollars  was  subscribed  on  the  spot  for 
 the  Cambridge  Observatory.  One-half  the  sum  was 
 contributed  by  ten  individuals ;  and  of  this  half  Mr 
 David  Sears  gave  5000  dollars,  to  build  a  tower  which 
 now  bears  his  name.  The  names  of  the  munificent 
 donors  are,  in  a  business-like  manner,  inscribed  on  a 
 marble  tablet,  built  into  the  internal  wall  of  the  dome. 
 All  honour  to  these  liberal-minded  merchants  who 
 have  made  their  names  historical  by  erecting 'this 
 temple  of  science,  destined  alike  to  throw  a  lustre 
 around  their  country,  and  proclaim  the  glory  of  God 
 in  the  heavens. 
 
 It  is  unfortunate  that,  in  British  America,  the  taste 
 for  astronomy  has  not  been  caught  up  from  the  States. 
 The  people  have  not  yet  been  trained  to  depend  upon 
 themselves  for  the  advancement  of  such  objects,  and 
 the  Provincial  Government  have  imitated  the  States 
 in  leaving  science  to  struggle  for  itself.  A  step  in  ad- 
 vance, however,  has  at  length  been  taken.  The  Govern- 
 ment of  Canada,  along  with  the  city  of  Kingston,  have 
 provided  means  for  the  erection  of  an  observatory  in 
 connexion  with  the  University  of  Kingston.  It  is  to 
 be  hoped,  that  it  will  be  so  equipped  and  worked,  as 
 to  maintain  the  credit  of  the  British  name  in  America, 
 and  extend  the  boundaries  of  astronomical  science. 
 
SoUv  Sysifcui. 
 
 XVIII. 
 
 THE  STABILITY  OF  THE  SOLAE  SYSTEM. 
 
 The  solar  system  may  be  viewed  as  a  machine,  mani- 
 festing intelligent  design.  The  mechanism  of  the  sun, 
 planets,  and  satellites,  suggests,  just  as  a  watch,  the 
 idea  of  a  Contriver.  One  of  the  most  remarkable  evi- 
 dences of  design,  in  the  celestial  machine,  is  the  pro- 
 vision made  for  its  stability. 
 
 Innumerable  other  laws  of  force,  beside  that  of  the 
 inversed  square,  might  be  conceived  •  but  this  is  only 
 
STABILITY  OF  SOLAR  SYSTEM.     27s 
 
 one  consistent  with  stability  in  a  system  subject  to 
 perturbations.  If  the  law  of  gravitation  varied  ac- 
 cording to  the  inverse  cube,  instead  of  square,  the 
 slightest  disturbance  would  precipitate  the  planet  on 
 the  sun,  or  cause  it  to  fly  off  from  its  control.  With 
 the  existing  law  of  gravity,  though  a  planet  were 
 pushed  out  of  its  course  by  an  impulse  from  a  comet, 
 it  would  pursue  its  new  orbit  w^ith  undeviating  regu- 
 larity; the  primitive  disturbance  would  not  have  a 
 progressive  tendency.  When,  however,  we  contem- 
 plate a  system  of  many  planetary  bodies,  the  mere  law 
 of  gravitation  does  not  by  any  means  insure  stability. 
 The  complexity  of  the  scheme  can  at  once  be  under- 
 stood, when  we  keep  in  view,  that  any  given  body  is 
 attracted,  not  merely  by  the  sun,  but  by  all  the  other 
 bodies  of  the  system — and  that  these  attractions  are 
 constantly  varying,  according  to  differences  of  distance 
 and  direction.  The  consequence  is,  that  the  planet, 
 instead  of  describing  the  orbit  which  it  would  do  if 
 undisturbed,  proceeds  along  a  very  complex  and  irre- 
 gular line.  A  planet  thus  disturbed  may  be  com- 
 pared to  a  person  making  his  way  through  a  crowd. 
 He  is  jostled  at  every  step,  and  pushed  out  of  the 
 straight  course  he  would  otherwise  pursue.  Still  his 
 path  may  be  determinate  enough,  though  made  up  of 
 innumerable  irregularities.  The  planet  has,  in  like 
 manner,  to  thread  its  way  through  the  perturbing  in- 
 fluences of  the  other  bodies  of  the  system,  and,  there- 
 fore, pursues  a  disturbed  instead  of  a  regular  course. 
 
2/6  THE  STABILITY 
 
 The  inquiry  naturally  suggests  itself,  Can  such  a 
 system  possibly  remain  stable  ? — must  it  not,  at  last, 
 fall  into  inextricable  confusion?  Newton  saw  how 
 the  mutual  attraction  of  all  the  bodies  of  the  system 
 would  entail  serious  disturbance ;  but  it  was  beyond 
 the  reach  of  even  his  powers  of  analysis  to  discover  the 
 compensation  which  insures  safety.  He,  indeed,  came 
 to  the  conclusion,  that  it  would  be  necessary  for  the 
 hand  of  Omnipotence  occasionally  to  interfere,  in  order 
 to  prevent  the  crash  of  worlds  and  the  ruin  of  the 
 system.  The  machine  was  conceived  to  be  imperfect, 
 and,  therefore,  to  need  readjustment.  Some  have 
 held,  that  this  view  of  the  system  forces  upon  us, 
 more  irresistibly,  the  conviction  of  a  God  than  the 
 admission  of  a  self-adjustment;  but,  undoubtedly, 
 the  self-adjusting  arrangement  only  enhances  the 
 wisdom  of  the  Designing  Intelligence.  It  exhibits 
 one  of  the  most  wondrous  adaptations  of  means  to 
 an  end,  and  consequently  forces  upon  us,  more  con- 
 vincingly, the  necessity  of  Divine  contrivance.  A 
 somewhat  parallel  case  is  furnished  by  the  steam- 
 engine.  Watt,  by  the  contrivance  of  the  governor, 
 enabled  the  machine  to  regulate  itself,  and  to  dis- 
 pense with  the  aid  of  the  attendant  in  proportioning 
 the  supply  of  steam  to  the  work  to  be  done.  The 
 centrifugal  balls  of  the  governor,  performing  their 
 w^ork  according  to  certain  mechanical  laws,  only 
 exalt  our  estimate  of  the  mechanical  genius  dis- 
 played   in    the    construction   of    the    steam-enghie. 
 
OF  THE  SOLAR  SYSTEM.  277 
 
 We  ought,  howeverj  to  keep  always  in  view  that, 
 although  parallel  in  some  points,  there  is  a  wide  dif- 
 ference between  a  machine  executed  by  human  hands 
 and  the  mechanism  of  the  natural  world.  In  the  one 
 case,  the  machine  may  work  independently  of  the 
 contriver ;  in  the  other,  the  working  of  the  machine 
 is  just  the  mode  of  the  Divine  operation. 
 
 We  have,  in  the  mechanism  of  the  human  body,  a 
 principle  somewhat  similar  to  the  self-adjustment  of 
 the  solar  system.  The  body  has  been  well  styled  a 
 "  self-mending  machine."  It  is  constantly  subject  to 
 disturbances  of  its  normal  state  by  disease  and  accident, 
 but  it  possesses  a  wonderful  power  of  readjusting  the 
 disturbed  functions,  so  that  the  stability  of  the  system, 
 or,  in  other  words,  life  is  preserved.  We  regard  this 
 self-regulating  power  as  one  of  the  strongest  evidences 
 of  intelligence ;  and  in  the  same  light  ought  we  to 
 view  the  self-adjustment  of  the  celestial  machine. 
 
 The  solar  system  is  subject  to  incessant  disturb- 
 ance, but  it  is  so  adjusted  that  the  irregularities 
 never  endanger  its  stability.  When  a  rod  is  poised 
 on  the  point  of  the  finger,  it  oscillates  from  one  side 
 to  the  other,  and  the  stability  depends  on  the  oscilla- 
 tions never  going  beyond  a  certain  degree.  In  like 
 manner,  the  orbits  of  the  planets  are  subject  to 
 oscillations,  but  the  stability  of  the  system  is  insured 
 by  these  oscillations  being  subject  to  a  limit.  The 
 perturbations  to  which  the  orbits  of  planets  are  sub- 
 ject may  be  divided,   in   regard  to 
 
278  THE  STABILITY 
 
 kinds — periodic  and  secular.  In  the  first  kind,  the 
 perturbations  are  soon  compensated,  the  oscillations 
 being  comparatively  rajiid.  The  latter  are  those  in 
 which  the  compensation  is  effected  only  after  com- 
 paratively vast  intervals  of  time.  The  former  depend 
 on  the  relative  positions  of  the  planets  themselves; 
 the  latter,  upon  the  positions  of  their  orbits. 
 
 To  illustrate  the  difference  between  periodic  and 
 secular  inequalities,  we  may  suppose  the  orbit  of  a 
 planet  to  be  represented  by  the  margin  of  an  oval  or 
 elliptical  lake,  whose  surface  is  agitated  by  waves. 
 The  observer,  standing  on  the  margin,  will  observe 
 the  waves  advancing  upon  the  beach  and  then  re- 
 ceding. Every  advancing  wave  increases  the  length 
 of  the  lake  by  a  very  minute  quantity ;  but,  then,  it 
 is  shortened  just  as  much  by  the  receding  of  the  wave. 
 There  is  a  complete  compensation,  then,  in  the  period 
 of  each  wave,  and  however  long  the  observer  watches, 
 he  will  find  that  there  is  no  advance  made  up  the 
 beach  beyond  a  certain  point.  If  we,  however, 
 conceive  the  lake  to  be  affected  by  tides,  there  will 
 not  be  a  complete  compensation  in  the  case  of  each 
 successive  wave.  If  it  is  flood,  then  the  recess  does 
 not  fully  compensate  the  advance  of  the  wave ;  so 
 that  although  there  is  a  constant  oscillation,  back- 
 wards and  forwards,  there  is  a  margin  left  for  ad- 
 vance. Still,  this  advance  is,  after  all,  periodical; 
 for,  after  flowing  for  six  hours,  the  tide  begins  to 
 ebb,  and  the  full  compensation  is  effected  in  other 
 
OF  THE  SOLAR  SYSTEAL  279 
 
 six  hours.    Now,  the  wave,  breaking  upon  the  beach, 
 represents  periodic  variations  5  and  the  tide  represents 
 secular  variations.      Both   are  strictly  periodical,  but 
 the  latter  are  called  secular  from  the  comparatively 
 vast  period  necessary  to  effect  a  compensation.     If 
 we  conceive  the  ends  of  the  oval  lake  to  be  affected 
 only  by  the  small  waves  breaking  on  the  beach,  but 
 the  sides  affected  by  tides,  we  shall  have  an  exact 
 representation  of  a  planetary  orbit.    The  small  waves 
 would  not  sensibly  lengthen  or  shorten  the  lake,  but 
 the  tides  would,   in  a  marked   manner.     Now,  the 
 length  of  a  planet's  orbit  is  subject  only  to  these  very 
 small  oscillations,  and  it  may  therefore  be  regarded 
 as  fixed  or  constant.     The  breadth  of  the  orbit,  how- 
 ever, is  subject  to  secular  variations,  which  require 
 ages  for  their  full   compensation.     The  orbit  alter- 
 nately bulges  out  into  a  circle,  and  narrows  into  an 
 ellipse.     The  earth  is  now,  and  has  been  for  many 
 ages,  expanding  into  a  circle,  but  it  will  again  col- 
 lapse into  an  ellipse.    The  orbit  may  be  compared  to 
 a  great  heart  beating  the  pulses  of  eternity,  alter- 
 nately expanding  and  contracting,  and  each  systole 
 and   diastole   occupying   many  thousands   of  years. 
 The  invariable  length  of  the  orbit,  or  rather  of  tlie 
 major  axis,  has  been  justly  styled  the  Magna  Charta 
 of  the  planetary  system,  as  this  is  the  basis  of  its  stabi- 
 lity.    The  oscillations  in  the  breadth  of  the  ellipse 
 are   styled   the  secular  variations  of  the  eccentricity^ 
 the  eccentricity  being  the  amount  of  departure  from 
 
28o  THE  STABILITY 
 
 ia  circle.  The  following  is  the  great  law  regarding  the 
 eccentricities  of  the  planets : — ^'  If  the  mass  of  each 
 planet  be  multiplied  by  the  square  of  the  eccentricity, 
 and  this  product  by  the  square  of  the  mean  distance, 
 the  sum  of  these  quantities  will  always  retain  the 
 same  magnitude."  The  purport  of  this  is,  that  all 
 the  disturbances  of  the  various  planets,  taken  to- 
 gether, can  never  exceed  a  certain  amount,  and  that 
 a  small  one.  The  planets  are  so  related,  that  if  one 
 has  a  large  share  of  eccentricity,  another  must  have 
 a  small  one.  The  case  may  be  familiarly  illustrated 
 by  supposing  that  a  certain  quantity  of  wine  is  given 
 to  be  shared  by  several  individuals,  the  quantity 
 being  so  small,  that  even  though  it  were  consumed 
 by  one  individual,  instead  of  being  divided  equally, 
 it  would  do  no  harm.  There  is,  thus,  only  a  small 
 fund  of  eccentricity  out  of  which  the  various  planets 
 can  draw,  and  though  one  should  monopolise  that 
 fund,  the  equilibrium  of  the  system  would  not  be 
 endangered  j  much  less  can  there  be  danger  when 
 each  enjoys  a  share  of  the  eccentricity.  A  like  law 
 has  been  proved  in  regard  to  the  inclinations  of  the 
 orbits  to  one  another.  They  can  never  vary  much 
 from  their  mean  position,  as  tliey  draw  out  of  a  com- 
 mon fund,  which  is  a  small  one. 
 
 The  stability  of  the  system  would  be  destroyed  by 
 an  unlimited  change — first,  in  the  dimensions  of  the 
 orbit ;  secondly,  in  the  form,  or  eccentricity  ;  and, 
 thirdly,  in  the  inclination  j  but  in  all  these,  compen- 
 
OF  THE  SOLAR  SYSTEM,  281 
 
 sation  is  ultimately  wrought  out.  It  is  easy  to  see 
 how  the  stability  would  be  destroyed  in  any  one  of 
 the  above  ways.  If  the  form  were  subject  to  an  un- 
 limited change  in  its  dimensions,  the  circle  might 
 contract  or  expand,  so  that  the  planet  might  ulti- 
 mately fall  into  the  sun  or  fly  off  into  space.  The 
 gradual  change  would  be  shewn  in  the  length  of  the 
 year,  which  varies  with  the  length  of  the  orbit,  or 
 major  axis.  Again,  if  there  was  no  limit  to  the  eccen- 
 tricity, or  if  the  limit  was  wide,  the  ellipse  would  be- 
 come so  narrow,  and  the  earth  would  approach  so  near 
 the  sun,  that  every  living  thing  would  be  destroyed. 
 If  the  inclination  of  the  orbit  of  the  earth  was  not 
 limited,  as  it  is,  it  might  ultimately  coincide  with 
 the  equator,  and  the  distinctions  of  seasons  would 
 be  obliterated.  The  conditions  of  life  are  so  nicely 
 adjusted  to  the  present  state  of  things,  that  any 
 departure  from  stability,  in  reference  to  the  above 
 three  points,  would  necessarily  entail  destruction 
 upon  the  animal  and  vegetable  world. 
 
 The  admirable  harmony  and  stability  of  the  solar 
 system,  irresistibly  force  upon  us  the  conviction  of  a 
 superintending  Intelligence.  No  random  arrange- 
 ment could  secure  the  needful  stability.  We  may 
 conceive  the  bodies  of  the  system  arranged  in  innu- 
 merable ways,  but  only  one  very  special  arrangement 
 would  suit.  We  might  conceive  the  planets  moving 
 in  orbits  of  great  eccentricity,  but  instead  of  this, 
 they  are  all  nearly  circular.    Were  there  no  presiding 
 
282  THE  STABILITY 
 
 Mind,  we  would  expect  them  to  move  in  all  parts  of 
 the  heavens,  their  orbits  spanning  every  part  of  the 
 celestial  sphere,  like  the  circles  of  longitude  on  a 
 globe.  Instead  of  this,  we  find  their  orbits  com- 
 pressed into  the  narrow  zone  of  the  zodiac ;  and  the 
 essential  thing  to  be  remarked  is,  that  this  limitation 
 to  the  same  plane  is  essential  to  the  stability  of  the 
 system.  The  direction  in  which  the  planets  move, 
 also  exhibits  the  same  remarkable  harmony — this 
 direction  being  from  west  to  east,  a  condition  also 
 essential  to  the  stability  of  the  system.  But  unless 
 we  introduce  the  idea  of  design,  we  would  have  no 
 ground  to  look  for  such  a  striking  uniformity.  La- 
 place has  reduced  to  numbers  the  improbability  of 
 such  a  uniformity  being  a  fortunate  chance.  By 
 the  calculus  of  probabilities,  the  chance  is  above  four 
 millions  of  times  to  one  against  the  supposition  that 
 tlie  forty-three  motions  (corresponding  to  the  number 
 of  planets  then  known)  from  west  to  east,  are  the 
 result  of  mere  chance.  He  puts  the  probability  of 
 a  primitive  cause  in  another  form,  by  shewing  that 
 it  is  two  millions  of  times  greater  than  the  expectation 
 that  the  sun  will  rise  on  the  morrow.  But  Laplace 
 would  by  no  means  acknowledge  that  this  primitive 
 cause  is  an  Intelligent  Cause,  or  an  argument  for  the 
 existence  of  God.  His  idea  of  a  First  Cause  would  be 
 satisfied,  if  it  could  be  shewn  that  the  actual  arrange- 
 ment of  the  heavenly  bodies  necessarily  resulted  from 
 the  nebular  hypothesis ;  and  his  opponents  have,  un- 
 
OF  THE  SOLAR  SYSTEM.  283 
 
 fortunately,  met  this  by  virtually  maintaining  that,  if 
 the  nebular  hypothesis  be  true,  the  stability  of  the 
 system  must  cease  to  be  an  argument  for  a  Designing- 
 Mind.  They  have  accordingly  applied  themselves  to 
 the  task  of  disproving  the  hypothesis. 
 
 But  granting  the  hypothesis  proved,  and  that  the 
 successive  abandoning  of  rings  by  the  revolving  mass, 
 explained  the  circular  character  of  the  orbits,  and  the 
 fact  of  their  moving  nearly  in  the  same  plane  and  in 
 the  same  direction  ;  this,  so  far  from  leading  us  to  dis- 
 pense with  the  necessity  of  a  Designing  Mind,  would 
 only  enhance  the  wonder,  by  shewing  the  simplicity 
 of  the  mode  employed  by  the  Divine  Architect  in 
 rearing  the  celestial  structure.  It  is  of  no  conse- 
 quence, as  far  as  concerns  the  proof  of  design,  whether 
 the  machine  is  executed  mediately  or  immediately  by 
 the  contriver.  A  watch  may  be  executed  by  a  watch- 
 making machine,  but  this  does  not  dispense  with  the 
 idea  of  an  intelligent  watchmaker.  Nay,  the  ingen- 
 uity is  only  increased  by  the  ingenuity  of  the  instru- 
 ment employed.  In  the  case  of  the  bee,  it  has  been 
 attempted  to  explain  away  the  intelligence  involved 
 in  the  construction  of  its  cell,  by  shewing  that  its 
 organs  are  so  formed  as  to  produce  the  requisite 
 angles,  and  thus  solve  the  problem  of  maxima  and 
 minima.  But  granting  this,  it  is  only  proved  that 
 the  intelligence  in  question  works  by  means  of  tools. 
 The  employment  of  tools  by  no  means  lessens  the 
 ingenuity    displayed    in    any   piece    of   mechanism. 
 
284  THE  STABILITY 
 
 And  so  in  regard  to  the  stability  of  the  solar  system  ; 
 the  nebular  hypothesis,  if  established,  would  exhibit 
 only  the  instrument  employed  by  the  all-wise  Creator 
 to  secure  the  stability  of  the  system. 
 
 In  the  same  way  we  must  deal  with  the  argument 
 founded  on  the  arrangement  by  which  the  source  of 
 heat  and  light  is  placed  in  the  centre  of  the  system. 
 Paley  regards  this  as  a  proof  of  design  solely  on  the 
 ground,  that  there  was  no  antecedent  necessity  for 
 the  sun  being  placed  in  the  centre.  But  the  force  of 
 the  argument  by  no  means  rests  on  the  disproof  of  an 
 antecedent  necessity — if  by  this  is  meant,  some  prior 
 physical  arrangement  from  which  it  resulted.  Ac- 
 cording to  the  nebular  hypothesis,  the  sun,  as  source  of 
 light  and  heat,  must  necessarily  be  in  the  centre.  The 
 sun  is  the  incandescent  mass  from  which  the  planets 
 were  thrown  off,  and  while  the  planets  cooled,  the  sun 
 retained  its  high  temperature.  But  all  this  only  re- 
 moves intelligence  a  step  further  back.  The  hypo- 
 thesis, admitting  its  truth,  is  only  the  method  adopted 
 by  the  Divine  Intelligence  to  secure  the  essential  point 
 of  having  the  source  of  light  and  heat  in  the  centre. 
 
 Paley  ascribes  the  difficulty  of  turning  the  mechan- 
 ism of  the  heavens  to  account  as  an  argument  for  a 
 Divine  Intelligence,  to  the  circumstance,  that  it  wants 
 the  complexity  of  the  machines  and  organisms  with 
 which  we  are  familiar  on  the  earth.  This  explanation 
 does  not  meet  the  case.  There  is  no  want  of  com- 
 plexity in  the  celestial  machine,  thoug:h  there  is  no 
 
OF  THE  SOLAR  SYSTEM.  285 
 
 tangible  connexion  between  the  various  bodies.  There 
 is  indeed  no  machine  so  complex,  or  one  that  tries 
 the  human  intellect  more  in  educing  order  from  ap- 
 parent confasion.  The  real  difficulty  lies  in  this,  that 
 in  dealing  with  the  solar  system  as  a  mere  machine, 
 we  have  not  the  element  of  life.  The  fundamental 
 idea  of  use  or  design^  as  employed  by  Paley,  is  the 
 adaptation  of  matter  to  the  necessities  of  life.  A 
 thing  is  useful  in  as  far  as  it  is  adapted  to  pro- 
 mote some  special  object  in  the  phenomena  of  life. 
 A  living  organism  is  just  a  system  of  means  to  ends ; 
 and  every  part  of  the  system  has  its  use.  This  ele- 
 ment is  wanting  in  the  machinery  of  the  heavens. 
 We  cannot  discover  a  use,  in  this  sense,  in  the  ar- 
 rangements for  the  stability  of  the  system.  No  doubt 
 the  stability  of  the  arrangement  is  essential  to  the 
 welfare  of  the  planetary  inhabitants,  and  this  may  be 
 called  the  use  or  design  of  the  stability ;  but  the  real 
 question  is,  Does  the  arrangement  of  the  bodies  of 
 the  solar  system  manifest  no  intelligence  apart  from 
 the  existence  of  life  ?  A  savage  would,  on  picking  up 
 a  watch,  discover  traces  of  intelligence  in  the  struc- 
 ture, altogether  apart  from  its  use  as  a  whole.  He 
 might  not  know  how  it  was  to  benefit  any  being, 
 and  yet  he  would  not  fail  to  detect  an  order  and  a 
 purpose.  He  would  discover  that  the  maintaining 
 power  and  the  wheels  were  so  adjusted  as  to  produce 
 equable  motions  in  the  hands.  He  might  have  no 
 conception  of  the  use  of  such  equable  motion  to  any 
 
286  THE  STABILITY 
 
 living  being,  and  yet  he  might  have  no  difficulty 
 in  discovering  the  use  of  the  various  parts  of  the 
 works  in  producing  this  motion. 
 
 Let  us  apply  this  to  the  celestial  mechanism. 
 Suppose  a  spirit,  wandering  through  space,  came 
 across  our  system,  would  he  not,  in  pausing  to  con- 
 template its  arrangements,  discover  proof  of  intelli- 
 gence, though  ignorant  as  to  the  existence  of  planet- 
 ary inhabitants?  Paley  would  hesitate  to  admit  such 
 a  conclusion.  He  would  maintain  that  you  must 
 shew  the  advantage  of  the  stability  of  the  system  to 
 living  beings  before  you  can  draw  a  proof  of  intelli- 
 gent design.  But,  as  in  the  case  of  the  watch,  though 
 no  idea  might  be  formed  as  to  the  use  of  the  stability 
 to  any  being,  design  might  be  clearly  traced  in  the 
 mode  by  which  the  stability  is  secured.  It  would  be 
 seen  that  planets  are  admirably  arranged  for  this  pur- 
 pose. And  the  inquiring  spirit  would  be  forced, 
 altogether  apart  from  the  idea  of  planetary  inhabi- 
 tants, to  acknowledge  the  hai^d  of  the  Divine  Mecha- 
 nician. Paley  would  insist  that  there  would  be  no 
 use  in  the  stability  if  there  were  no  beings  to  benefit 
 by  it,  and  that  the  planets  might  as  well  be  arranged 
 in  any  random  order.  He  would  be  inclined  to  aban- 
 don the  heavens  as  furnishing  an  argument  j:>er  se  for 
 the  existence  of  a  Designing  Mind. 
 
 All  this  arises  from  the  limited  range  of  the  argu- 
 ment which  Paley  prescribed  to  himself.  He  restricted 
 the  term  use  to  the  bearing  of  material  laws  upon  life. 
 
OF  THE  SOLAR  SYSTE3f.  287 
 
 and  was  disposed  to  find  design  only  wlien  such  use 
 could  be  detected ;  and,  hence,  if  no  use  in  tliis  sense 
 could  be  proved  for  the  stability  of  the  celestial 
 mechanism,  this  part  of  God's  works  could  not  be 
 appealed  to  as  proving  a  Designing  Mind.  But  it 
 looks  like  presumption  to  restrict  the  display  of 
 Divine  Intelligence  to  the  sphere  of  life.  Though 
 man  had  never  been  created,  and  though  no  living 
 thing  existed  on  any  planet,  would  not  the  lieavens 
 still  declare  the  glory  of  God?  Would  not  the 
 mechanism,  by  which  the  stability  of  the  system  is 
 secured,  still  manifest  calculation  and  design?  The 
 material  creation  is  but  the  projection  of  the  Divine 
 ideas  in  space  and  time,  and  it  would  bear  the  impress 
 of  the  Divine  Intelligence,  though  no  finite  spirit  or 
 living  thing  were  called  into  being.  No  doubt  the 
 most  marvellous  display  of  the  Divine  wisdom  lies  in 
 the  correlation  of  matter  to  life  and  created  intelli- 
 gence. Still,  while  admitting  the  higher,  we  are  not 
 called  to  ignore  the  lower  sphere. 
 
 We  have  seen  that  intelligence  may  be  discovered 
 in  the  adaptation  of  means  to  secure  the  end  of  stability, 
 though  we  may  not  be  able  to  assign  any  use  to  the 
 stability,  at  least  in  the  ordinary  sense  of  the  term. 
 But  may  there  not  be  uses  other  than  the  physical 
 welfare  of  living  things?  Is  there  not  a  use  in  the 
 very  order  and  harmony  of  the  solar  system,  apart 
 from  the  more  direct  utilitarian  purposes?  Is  there 
 not  an  adaptation  in  this  order  and  harmony  to  the 
 
288  THE  STABILITY 
 
 training  and  happiness  of  pure  intelligences  ?  Is  not 
 a  great  purpose  served  simply  by  the  revelation  of 
 God  in  nature  ?  And  even  though  there  were  no 
 created  intelligences  to  contemplate  God's  works,  and 
 lay  upon  his  altar  the  tribute  of  adoration,  would  the 
 celestial  mechanism  have  no  use  ?  Would  it  not  serve 
 some  purpose  ?  Has  not  the  material  world  a  purpose 
 simply  in  relation  to  the  Divine  Mind  ?  The  artist 
 has  a  pleasure  in  transferring  to  the  canvas  the  crea- 
 tions of  his  genius  ;  and  though  no  eye  but  his  own 
 ever  beheld  his  pictures,  they  would  not  be  without 
 a  use  or  purpose.  Similarly  we  can  readily  conceive 
 that  the  beauty  and  harmony  of  the  material  world 
 serve  a  purpose,  simply  as  an  object  of  contemplation 
 to  the  Divine  Mind.  God  made  all  things  for  His  own 
 glory ;  and,  no  doubt,  the  highest  tribute  of  glory  is 
 brought  to  Him  by  the  play  of  moral  and  intellectual 
 faculties,  and  the  varied  phenomena  of  organisation 
 and  life  ;  but  this  does  not  hinder,  that  notes  of  praise, 
 though  feebler,  should  ascend  to  God  from  the  play 
 and  harmony  of  mere  physical  laws.  The  nicely- 
 balanced  orbs  of  heaven  speak  the  praises  of  God,  as 
 well  as  the  harmonious  exercise  of  the  faculties  of  man. 
 The  heavens  thus  occupy  an  independent  place  in 
 declaring  the  glory  of  God.  They  w^ould  declare  His 
 glory,  though  they  served  no  utilitarian  purpose  in 
 regard  to  life  and  organisation,  and  though  there 
 were  no  created  intelligences  to  listen  to  their  notes 
 of  praise. 
 
OF  THE  SOLAR  SYSTEM,  289 
 
 But  the  heavens  declare  the  glory  of  God  more 
 emphatically,  when  we  reflect  that  the  stability  of 
 the  whole  solar  system  is  wondrously  related  to  the 
 life  and  enjoyment  of  the  minutest  animalcule  seen 
 by  the  microscope,  and  that  the  heavenly  hosts  are 
 a  theme  of  devout  adoration  to  myriads  of  intelligent 
 worshippers. 
 
THE  ETEFtNITY  OF  MATTER. 
 
 Egbert  Hall,  in  his  Sermon  on  Infidelity,  employs 
 the  following  argument  to  meet  the  position  of  the 
 infidel,  that  the  world  may  have  existed  from  eternity. 
 It  is  an  old  scholastic  argument,  put  in  a  somewhat 
 striking  point  of  view  : — "  Besides,  an  eternal  succes- 
 sion of  finite  heings  involves  in  it  a  contradiction,  and 
 is  therefore  plainly  impossible.  As  the  supposition 
 is  made  to  get  quit  of  the  idea  of  any  one  having 
 
THE  ETERNITY  OF  11 A  TTER.     291 
 
 existed  from  eternity,  each  of  the  beings  in  the  suc- 
 cession must  have  begun  in  time,  but  the  succession 
 itself  is  eternal.  We  have  then  the  succession  of 
 beings  infinitely  earlier  than  any  being  in  the  succes- 
 sion ;  or,  in  other  words,  a  series  of  beings  running  on 
 ad  infinitum^  before  it  reaches  any  particular  beings, 
 which  is  absurd."  This  appears  plausible  ,*  but  no 
 one  can  read  it  without  feeling  that  there  is  a  fallacy 
 somewhere.  To  shew  that  there  is  no  weight  in  the 
 argument,  it  is  only  necessary  to  state  it  in  its  most 
 general  terms.  But  before  doing  so,  let  it  be  re- 
 marked, that  the  present  argument  is  quite  distinct 
 from  that  of  design  or  causation,  and  that  conse- 
 quently the  expression, ''  finite  being,"  is  used  merely 
 as  a  unit  of  time.  The  most  general  statement,  then, 
 of  the  argument  is  this — "  An  infinite  series  of  finites 
 involves  in  it  a  contradiction."  So  far  from  this  in- 
 volving a  contradiction,  it  i§  the  only  intelligible 
 definition  of  infinity  that  can  be  given.  At  any  rate, 
 when  we  attempt  to  form  a  conception  of  infinity 
 either  of  time  or  space,  we  take  a  finite  or  unit  and 
 multiply  it  indefinitely.  We  conceive  of  eternity, 
 for  example,  by  conceiving  of  an  infinite  number  of 
 years.  Let  ^'  years "  be  substituted  in  the  above 
 form  of  the  argument,  and  the  matter  becomes  still 
 more  palpable — "  An  infinite  series  of  years  in- 
 volves in  it  a  contradiction."  The  only  answer  to 
 this  is,  that  there  is  no  contradiction  here,  unless 
 there  is  a  contradiction  involved  in  the  very  idea  of 
 
292      THE  ETERNITY  OF  MATTER. 
 
 eternity  itself.  And^  in  fact,  the  argument  goes  to 
 prove  that  nothing  can  be  eternal — that  eternity  is 
 an  impossible  fiction.  It  is  strange  that  exception 
 should  be  taken  to  an  "  infinity  of  finites/'  seeing 
 that  the  most  familiar  processes  of  algebra  furnish 
 illustrations ;  for  every  diverging  series  presents  the 
 idea  of  infinity  made  up  of  finite  terms.  Dr  Samuel 
 Clarke,  although  he  loved  to  tread  on  slippery  ground, 
 abandoned  the  above  scholastic  argument  as  absurd. 
 The  ground  of  his  objection  does  not,  however,  appear 
 quite  correct.  He  says,  the  misconception  arises  from 
 regarding  finites  as  "  aliquot  parts  of  infinity,  whereas 
 they  are  disparate,"  or,  as  the  geometrician  would 
 term  them,  incommensurable  quantities — finite  being 
 the  same  to  infinite,  as  a  point  to  a  solid,  or  a  line 
 to  a  surface.  On  the  contrary,  a  unit  of  time  and  in- 
 finite duration  are  commensurable  quantities,  though 
 the  proportion  is  indeterminate,  just  as  the  finite 
 terms  of  a  series  and  the  series  itself  are  not  disparate, 
 although  w^e  cannot  determine  the  sum  of  the  series. 
 It  is  not  at  all  necessary  to  have  recourse  to  such 
 recondite  reasoning.  The  argument,  when  stated 
 in  its  most  general  terms,  bears  its  own  refutation 
 in  the  face  of  it.  It  tacitly  assumes  a  certain  de- 
 finition to  be  true,  and  then  asserts  that  it  is  not  true 
 — tliat  it  involves  a  contradiction. 
 
 The  following  scholastic  argument  is  similar  to 
 Hall's,  but  somewhat  more  complicated  and  startling. 
 It  is  taken  from  Hick's   Lectures  on  Theology: — 
 
THE  ETERNITY  OF  MATTER.     293 
 
 "  If  matter  has  existed  from  eternitj,  it  must  have 
 existed  as  we  have  seen  in  the  same  form  which  it 
 at  present  sustains,  for  this  is  the  consequence  of  its 
 necessary  existence.  The  earth  on  which  we  dwell 
 and  the  heavens  above  us  are  eternal  j  and  the  same 
 motions  have  been  incessantly  going  on  in  the  im- 
 mense regions  of  space.  The  earth  has  been  revolv- 
 ing on  its  own  axis,  and,  as  well  as  the  other  planets, 
 has  been  performing  its  circuit  around  the  sun.  Its 
 revolutions  upon  its  axis  have  been  infinite,  and  so 
 have  been  its  revolutions  in  its  orbit,  and  so  have 
 been  the  revolutions  of  Saturn.  Mark  the  conse- 
 quence! We  have  here  three  infinites  which  are 
 made  up  of  unequal  parts,  an  infinite  made  up  of  the 
 revolutions  of  Saturn,  the  time  of  which  is  twenty- 
 nine  times  less  than  the  infinite  made  up  of  the 
 annual  revolutions  of  the  earth,  and  many  thousand 
 times  less  than  the  infinite  made  up  of  the  diurnal 
 revolutions  of  the  latter.  Thus  we  are  landed  in  a 
 palpable  absurdity,  from  which  we  can  only  escape 
 by  renouncing  the  untenable  hypothesis  of  the  eter- 
 nity of  the  universe,  and  admitting  the  scriptural 
 doctrine  of  its  creation."  The  reductio  ad  absurdum 
 consists  in  the  conclusion  that  infinites  may  be  un- 
 equal. Now,  if  this  conclusion  necessarily  follows 
 from  the  assumption  that  the  revolutions  of  the 
 planets  have  been  infinite,  or,  in  other  words,  from 
 the  conception  of  an  infinite  number  of  finites,  we 
 must  admit  that  the  argument  is   good.      But  the 
 
294     THE  ETERNITY  OF  MATTER. 
 
 reductio  ad  ahsurdum  is  obtained  hj  assuming  an 
 absurdity  in  the  process  of  proof.  The  conception  of 
 unequal  infinites  is  absurd,  but  so  is  that  of  equal  in- 
 finites. Neither  equality  nor  inequality  can  be  predi- 
 cated of  infinites.  But  the  author  evidently  thought 
 that  infinites  must  be  equal,  and  it  is  by  assuming 
 this  in  the  course  of  proof  that  he  lands  us  in  an  ab- 
 surdity. He  proceeds  on  the  axiom,  that  if  equals 
 be  multiplied  by  unequals,  the  products  must  be  un- 
 equal. The  unequals  are  the  respective  units  or 
 periods  of  revolution,  the  equals  are  the  infinites  by 
 which  they  are  multiplied  5  and  consequently  the 
 resulting  infinites  are  unequal.  Here  he  assumes  that 
 infinites  must  be  equal ;  which  is  absurd,  for  equality 
 can  be  predicated  only  of  finite  qualities.  The  re- 
 mark, that  the  idea  of  matter  may  be  entirely  dropped 
 from  the  formula  without  in  the  least  affecting  the 
 argument,  is  applicable  to  both  of  the  above  argu-' 
 ments ;  so  that,  if  the  reasoning  have  any  force,  it 
 tells  equally  against  all  existence,  mind  as  well  as 
 matter. 
 
 The  antinomies  of  Kant  involve  the  same  fallacy. 
 He  assumes  one  definition  in  the  thesis,  and  adopts 
 another  in  the  antithesis.  The  essence  of  the  fallacy 
 lies  in  tacitly  assuming  that  infinity  is  a  definite  whole, 
 of  which  equality  and  inequality  may  be  predicated. 
 For  example,  he  proves  the  contradiction  involved  in 
 a  past  eternity  in  this  manner.  If  we  reckon  the 
 past   eternity  from   to-day,   we  have  the  following 
 
THE  ETERNITY  OF  MATTER.     295 
 
 equation  :  "  an  infinite  number  of  years  =  infinity ;  " 
 but  if  we  reckon  from  to-morrow  we  have  the  equa- 
 tion, "  an  infinite  number  of  years  +  one  day  =  infi- 
 nity." If  we  subtract  the  one  equation  from  the 
 other  we  arrive  at  the  result,  '•'•  one  day  =  nothing." 
 But  how  do  we  arrive  at  this  absurd  conclusion? 
 Simply  by  assuming,  in  subtracting  one  infinite  front 
 the  other,  that  infinities  must  be  equal ;  but  such  an 
 assumption  is  opposed  to  the  fundamental  definition 
 of  infinity,  which  admits  neither  of  equality  nor  in- 
 equality being  predicated  of  it.  This  question  is 
 altogether  distinct  from  the  metaphysical  one  in  re- 
 ference to  our  power  of  conceiving  or  cogitating  the 
 infinite.  It  may  be  admitted  that  human  thought 
 is  so  limited  that  we  cannot  picture  infinity  to  our 
 minds.  The  question  is,  simply,  can  we  not  so  define 
 the  idea  of  infinity,  that  it  may  be  validly  employed 
 in  any  process  of  reasoning  ?  We  have  seen  that  the 
 attempts  to  prove  contradictions  in  the  very  concep- 
 tion of  infinity,  are  based  on  the  fallacy  of  using  two 
 distinct  and  contradictory  definitions  of  the  term. 
 The  correct  definition  recognises  infinites  as  incapa- 
 ble of  comparison  j  the  erroneous  and  tacitly-assumed 
 definition  involves  the  idea  that  infinites  must  be 
 equal.  In  metaphysics,  as  well  as  mathematics,  we 
 shall  meet  with  no  antinomies  if  we  use  the  word 
 "  infinity  "  in  a  correct  and  consistent  manner. 
 
 In  his  a  priori  argument,  Dr  Clarke  does  not  think 
 it  necessary  to  prove  the  non-eternity  of  matter.     He 
 
296      THE  ETERNITY  OF  MATTER. 
 
 holds  that  the  chain  is  complete  without  this  forming 
 a  link  in  it.  All  that  is  necessary  for  his  purpose  is 
 to  prove  that  matter  is  not  self-existent ;  so  that  his 
 argument  would  be  equally  strong  though  the  opinion 
 of  the  ancient  philosophers  were  admitted,  that  mat- 
 ter is  an  eternal  effect  of  an  eternal  cause. 
 
 With  regard  to  the  a  ^posteriori  argument^  the  at- 
 tempt to  prove  a  beginning  is  limited  to  the  colloca- 
 tions of  matter.  It  is  satisfied  with  the  proof  of  a 
 plastic  creation,  leaving  the  question  of  an  absolute 
 creation  untouched.  Paley,  for  example,  deals  only 
 with  the  watch.  He  abandons  the  stone  (represent- 
 ing unformed  matter)  as  beyond  his  province.  Dr 
 Chalmers  narrows  still  further  the  sphere  of  Natural 
 Theology.  He  throws  aside  altogether  the  argument 
 of  design  as  an  independent  argument.  He  holds 
 that  we  are  not  warranted  from  design  to  infer  a 
 designer.  He  denies  that  this  is  an  ultimate  prin- 
 ciple in  our  nature,  and  falls  back  on  Dr  Thomas 
 Brown's  doctrine  of  sequence.  According  to  this 
 doctrine,  we,  by  tlie  constitution  of  our  nature,  neces- 
 sarily infer  the  antecedent  from  the  consequent,  and 
 vice  versa.  In  the  case  in  question  the  consequent  is 
 the  design,  the  antecedent  is  the  designing  mind. 
 But  he  holds,  following  the  views  of  Dr  Crombie, 
 that  the  design  must  be  proved  to  be  a  consequent 
 before  we  can  infer  the  antecedent  designer — that  the 
 world  must  be  proved  to  be  an  effect  before  the 
 design  which  it  manifests  can  lead  us  to  the  First 
 
THE  ETERNITY  OF  MATTER.     297 
 
 Cause.  In  sliort,  proof  must  be  obtained  that  the 
 present  order  of  things  had  a  beginning ;  and  to  ob- 
 tain this  proof  he  appeals  to  the  revelations  of  geology. 
 But  geology  serves  his  purpose  onlj  in  as  far  as  it 
 discountenances  the  doctrines  of  transmutation  and 
 spontaneous  generation ;  so  that  his  whole  argument 
 rests  upon  the  truth  or  falsity  of  these  doctrines. 
 Now,  it  is  undoubtedly  the  case  that  the  vast  pre- 
 ponderance of  scientific  evidence  is  in  favour  of  suc- 
 cessive creative  acts,  in  opposition  to  transmutation 
 or  spontaneous  generation ;  still,  we  deplore  the  at- 
 tempt to  base  the  whole  superstructure  of  Natural 
 Theology  on  this  the  obscurest  of  natural  sciences — 
 to  substitute  a  faint  glimmering  light  from  the  dark- 
 est recesses  of  nature  for  the  bright  sunshine  of  design 
 reflected  from  all  God's  works.  According  to  this 
 view,  the  argument  of  design  per  se  is  of  no  use 
 whatever  in  proving  the  being  of  a  God.  Its  bear- 
 ing is  felt  only  after  the  being  of  a  God  is  virtually 
 proved  by  establishing  a  beginning  to  the  colloca- 
 tions of  matter. 
 
 It  is  obvious  fi-om  the  line  of  argument  pursued 
 both  by  Paley  and  Chalmers,  that  tliey  looked  upon 
 the  non-eternity  of  matter  as  a  purely  scriptural  truth 
 beyond  the  reach  of  human  reason.  But  if  we  admit 
 the  argument  of  design,  if  we  admit  that  collocation 
 implies  a  beginning,  may  we  not  legitimately  push 
 the  argument  somewhat  further,  and  hold  that  matter 
 itself  must  have  had  a  beginning  ?  We  observe  marks 
 
298      THE  ETERNITY  OF  MATTER. 
 
 of  design  in  the  collocation  of  parts,  and  at  once  infer 
 a  beginning  to  the  collocation ;  but  may  not  the  same 
 argument  apply  to  the  parts  themselves  ?  Does  not 
 the  adaptation  of  the  parts  to  form  the  collocation 
 evince  design,  and  imply  a  beginning  ?  For  example, 
 the  solar  system  manifests  design,  and  had,  therefore, 
 a  beginning ;  but  the  matter  out  of  which  the  system 
 was  formed  must  have  been  wisely  adapted  for  such 
 a  cosmical  combination ;  and  are  we  not  entitled  to 
 infer  that  this  chaotic  matter  had  a  beginning  also,  or 
 that  matter  is  not  eternal  ? 
 
Relative  Sizes : — 
 1.  The  Earth.;  2.  Jupiter;  3.  Saturn;  4.  Uranus;  5.  Neptune. 
 
 XX. 
 
 THE  PLUKALITY  OF  WORLDS. 
 
 As  soon  as  astronomy  revealed  the  fact,  that  the 
 planets  are,  in  point  of  dimensions  and  density, 
 worlds  like  our  own,  and  that  they,  in  like  manner, 
 share  the  influence  of  the  sun, — the  source  and  centre 
 of  the  light  and  heat  so  essential  to  the  existence 
 of  life, — the  surmise  was  almost  necessarily  forced 
 on  the  mind,  that  they  might  also  be  inhabited. 
 Tins  inference  was  too  palpable   to  be  long  over- 
 
300     THE  PLURALITY  OF  WORLDS, 
 
 looked ;  and,  consequently,  speculations  regarding 
 the  habitableness  of  the  heavenly  bodies,  have  long . 
 been  familiar.  Every  advance  in  telescopic  power 
 revealed  some  new  resemblance,  and  thus  strength- 
 ened the  presumption,  that  the  planets  might  be  the 
 abode  of  life  and  intelligence.  Atmospheres  and 
 atmospheric  phenomena  were  discovered  in  several 
 of  the  planets.  Clouds  and  belts  corresponding  to 
 our  trade-winds  were  plainly  visible  in  Jupiter  and 
 Saturn.  Cyclones  were  detected,  and  the  rate  of 
 the  wind  might  be  calculated.  The  white  spots  at 
 the  poles  of  Mars  indicated  the  existence  of  snow, 
 and  the  progress  of  deposition  and  melting  could 
 actually  be  traced, — the  one  pole  gathering  snow 
 in  winter,  and  the  other  losing  it  in  summer.  In 
 more  recent  times,  still  more  singular  evidence  was 
 afforded  of  the  identity,  as  to  chemical  composition, 
 of  our  globe  with  the  family  of  planets  to  which  it 
 belongs.  The  meteoric  stones,  which  occasionally 
 fall,  may  be  regarded  as  hand  specimens  of  the 
 planetary  bodies.  It  is  not  necessary  to  hold,  that 
 they  are  actually  broken  off  from  tlie  moon  or  any  of 
 the  planets.  It  is  sufficient  that  they  do  not  belong 
 to  the  earth — that  they  are  themselves  cosmical 
 bodies  circulating  round  the  sun,  like  any  of  the 
 planets.  These  stones  are  now,  almost  universally, 
 held  to  be  little  planets ;  and  they  certainly  afford  a 
 presumption,  that  the  other  planets  have  similar 
 chemical    elements.      It   might   be    imagined,   that 
 
P  I.  A  n    X ! 
 
 MARS 
 
THE  PLURALITY  OF  WORLDS,     301 
 
 tliough  the  planets  were  composed  of  matter  sub- 
 ject to  the  law  of  gravitation,  the  matter  might 
 still  be  so  very  dissimilar,  that  we  might  not  be 
 entitled  to  say  that  they  belong  to  the  same  family 
 as  the  earth.  These  meteoric  bodies,  however,  tell 
 us  that  this  is  not  the  case,-^that  the  chemical  ele- 
 ments are  the  same  in  the  celestial  and  terrestrial 
 spaces.  About  a  third  of  the  simple  elements  of 
 chemistry  have  been  found  in  meteoric  stones  ,*  and 
 what  is  still  more  to  the  point,  no  new  element  has 
 been  detected.  There  are  chemical  arrangements 
 peculiar  to  meteorolites,  but  there  is  no  element 
 which  has  not  been  previously  known  in  our  terres- 
 trial chemistry.  It  might,  however,  be  argued  that 
 these  stones  are  not  fair  specimens  of  planetary  mat- 
 ter, and  that  to  produce  complete  conviction,  we  must 
 analyse  the  matter  of  each  heavenly  body,  before  we 
 can  found  upon  it  an  argument  for  the  plurality  of 
 worlds.  Science  has  met  even  this  hard  require- 
 ment, and  the  art  of  analysing  the  heavenly  bodies  is 
 now  practised.  M.  Bunsen  has  begun  upon  the  sun, 
 and  he  has  detected,  as  we  have  seen,  metals  familiar 
 to  us  on  our  globe.  Iron,  which  plays  so  important 
 a  part  in  the  structure  of  our  globe,  and  in  the  in- 
 dustrial arts  of  man,  holds  a  conspicuous  place  in 
 the  sun.  This  is  only  the  first  step.  In  all  proba- 
 bility we  shall  soon  have  our  knowledge  of  celestial 
 chemistry  greatly  enlarged  j  and  there  is  little  doubt, 
 
302     THE  PLURAUTY  OF  WORLDS. 
 
 from  this  fir:  *■  ,.tep,  that  tiie  result  will  be  a  closer 
 bond  of  identity  between  the  earth  and  the  celestial 
 bodies. 
 
 To  understr  Jie  bearing  of  the  speculation  re- 
 garding the  habitableness  of  the  planets,  it  will  be 
 necessary  to  make  a  (iistinction  as  to  the  nature  of 
 the  arguments  employed.  The  astronomical  aspect 
 of  the  question  will  be  best  understood  when  viewed 
 in  connexion  with  the  other  arguments. 
 
 1.  The  first  argument  we  shall  mention  is  the  a 
 priori^  or  that  which  professes  to  demonstrate,  from 
 the  character  of  God,  that  the  planets  must  be  in- 
 habited. Now  it  may  be  observed,  that  all  argu- 
 ments taking  this  ground  ought  to  be  viewed  with 
 suspicion,  for  they  are  based  on  the  supposition,  that 
 we  can  sufficiently  comprehend  the  nature  and  pro- 
 vidence of  God  to  construct  a  demonstration.  We 
 can,  indeed,  with  certainty,  shew  that  the  works  of 
 God  and  the  events  of  providence  illustrate  His  cha- 
 racter ,*  but  the  converse  does  not  hold,  that  we  can, 
 from  our  knowledge  of  God's  character,  demonstrate 
 that  such  works  must  necessarily  be  executed,  or  such 
 events  occur.  And  in  regard  to  the  question  of  a 
 plurality  of  inhabited  worlds,  the  arguments  usually 
 employed  are  no  exception  to  the  general  rule. 
 
 (1.)  Under  the  head  of  the  a  p-iori  argument,  it 
 is  urged,  that  it  would  be  derogatory  to  the  character 
 of  God  to  suppose  that  the  planets  and  other  heavenly 
 bodies  were  created  merely  for  our  use,  as,  in  that 
 
THE  PLURAL.  J .    ?F  WORLDS,     303 
 
 case,  the  means  would  tj  greatly  d^.- -^lOportioned  to 
 the  end.  It  is  held,  that  it  would  be  a  useless  ex- 
 penditure of  power  to  create  so  many  worlds  that 
 affect,  in  no  appreciable  way,  t.  '  riyelfare  of  our 
 earth.  What  benefit,  it  is  asked,  can  a  cluster  of 
 stars  be  to  us,  which  can  be  only  discoverer,  by  the 
 telescope — while,  at  the  same  time,  that  cluster  con- 
 sists of  thousands  of  worlds,  each  as  large  as  our  sun  ? 
 We  are  not,  ho w-ever,  judges  of  what  is  an  adequate 
 end  for  means  employed.  If  disproportion,  according 
 to  our  notions,  were  to  be  the  measure  of  our  judg- 
 ment, we  would  everywhere  quarrel  with  the  works 
 of  God.  Besides,  other  ends  than  tlie  giving  of 
 light  to  us  may  be  served.  We  do  not  know  all  the 
 relations  which  our  world  bears  to  the  rest  of  the 
 universe,  or  will  yet  serve  in  the  course  of  its  history. 
 We  see  an  end  served,  different  from  that  of  light- 
 giving,  by  the  exalted  view  which  the  study  of  celes- 
 tial bodies  gives  us  of  the  Creator ;  and,  in  a  future 
 state  of  being,  the  inhabitants  of  this  globe  may  be 
 brought  into  a  closer  relation  with  these  remote 
 bodies  of  the  universe.  And  even  though  it  should 
 be  proved,  that  the  means  are  disproportioned  to  the 
 assigned  end,  we  are  by  no  means  forced  to  the  con- 
 clusion, that  the  peopling  of  these  worlds  is  the  only 
 adequate  end.  We  can  readily  conceive  of  other 
 ends  besides  this. 
 
 (2.)  It  is  held  that  the  benevolence  of  God  requires 
 that  the  planets  should  be  inhabited,  otherwise  He 
 
304     THE  PLURALITY  OF  WORLDS. 
 
 would  not  Ibe  infinitely  benevolent.  But  this  argu- 
 mentj  carried  out,  would  require  the  whole  universe 
 to  be  filled  with  objects  of  benevolence.  The  fallacy 
 of  the  argument  lies  in  using  the  term  infinite  in  two 
 different  senses ;  or  rather,  it  applies  the  term  in  its 
 literal  sense  to  a  spiritual  element,  which  cannot  be 
 measured  by  time  and  space.  God  may  be  infinitely 
 benevolent,  though  the  objects  of  His  benevolence  be 
 not  infinite.  The  infinity  lies,  not  in  the  object,  but 
 the  subject;  and  all  that  the  doctrine  of  the  Divine 
 benevolence  requires  is,  that  wherevever  sentient 
 beings  exist,  this  benevolence  of  God  shall  be  dis- 
 played. Arguments  from  the  eternity  and  infinity  of 
 God  are  also  employed,  but  they  are  so  transparently 
 fallacious  that  they  need  not  be  dwelt  upon. 
 
 (3.)  Another  branch  of  the  a  jpriori  argument  is, 
 that  as  God  is  one,  all  his  attributes  must  be  exer- 
 cised simultaneously ;  that  as  His  omnipotence  is  dis- 
 played in  the  structure  of  the  heavenly  bodies,  so  His 
 benevolence  must  at  the  same  time  be  exercised; 
 and  that  where  benevolence  is,  there  must  also  be 
 sentient  beings,  as  the  objects  of  that  benevolence. 
 This  argument  cannot  bear  examination.  It  might 
 be  as  well  argued,  that  because  man  is  one  and 
 undivided,  he  must  exercise  the  gift  of  speech  when- 
 ever he  exercises  the  gift  of  hearing,  and  therefore 
 whenever  he  listens  he  must  also  speak.  All  that 
 we  can  say  of  God's  attributes  is,  that  they  must  all 
 be  exercised  in  perfect  harmony. 
 
THE  PLURALITY  OF  WORLDS.     305 
 
 2.  The  metaplijslcal  argument,  in  the  broadest 
 form,  is  put  thus:  Wherever  there  are  objects  of 
 sense,  sentient  beings  must  also  exist.  Or  take  a  par- 
 ticular example :  It  is  held  bj  the  author  of  the  '^  Na- 
 tural History  of  the  Vestiges  of  Creation,"  that  where- 
 ever  light  exists,  there  must  be  eyes  to  perceive  it. 
 Now,  in  one  point  of  view,  this  is  a  mere  circular 
 argument ;  for  if  light  be  so  defined,  that  it  necessa- 
 rily implies  the  exercise  of  vision,  then,  undoubtedly, 
 the  existence  of  light  implies  an  eye.  If  it  be  main- 
 tained that  light  does  not  consist  merely  in  the  un- 
 dulations of  an  ethereal  medium,  but  in  the  sensation 
 which  that  vibration  produces  by  acting  on  the  optic 
 nerve,  then,  unquestionably,  there  can  be  no  light 
 where  there  is  no  sensation.  But,  then,  all  that  the 
 argument  amounts  to  is  this,  that  where  there  is  no 
 eye,  there  can  be  no  sensation  of  light ;  and  in  refer- 
 ence to  the  planets,  that  if  there  is  a  sensation  of 
 light,  then  there  must  be  an  eye  through  which  that 
 sensation  is  produced.  But  that  is  the  very  point  to 
 be  established.  We  know  that  the  vibrations  which 
 cause  the  sensation  of  light  reach  the  planets ;  but 
 the  question  is.  Is  there  an  eye  to  receive  these  vibra- 
 tions, and  through  which  the  sensation  of  light  may 
 be  produced?  We  can  quite  readily  conceive  the 
 vibrations  to  exist  without  the  eye  to  receive  them. 
 It  may  be  argued  that,  in  all  probability,  the  vibra- 
 tions would  not  be  sent  to  these  bodies,  unless  tliere 
 were  eyes  to  receive  them ;  but  this  is  taking  up  new 
 u 
 
3o6     THE  PLURALITY  OF  WORLDS. 
 
 ground,  and  merging  tlie  metaphysical  question  into 
 one  of  design,  and  the  matter  assumes  now  the  form 
 of  probability,  not  of  necessity.  But  even  on  this 
 lower  ground,  light  does  not  necessarily  imply  an 
 eye,  even  when  sentient  beings  exist.  There  are 
 living  beings  on  our  globe  that  have  no  organs  of 
 vision ;  and  we  have  reason  to  believe,  that,  in  the 
 past  history  of  the  earth,  there  was  a  period  when  the 
 sun  dispensed  his  light,  although  there  were  no  ani- 
 mated beings  to  enjoy  it. 
 
 3.  The  third  argument  is  that  drawn  from  Scripture. 
 The  passages  usually  quoted  are:  ^^ Through  faith 
 we  understand  that  the  worlds  were  framed  by  the 
 word  of  God,  so  that  the  things  which  are  seen  were 
 not  made  of  things  which  do  appear."  "By  whom 
 also  he  made  the  worlds."  "When  I  consider  the 
 heavens,  the  work  of  thy  fingers,  the  moon  and  stars, 
 which  thou  hast  ordained ;  what  is  man,  that  thou  art 
 mindful  of  him?  or  the  son  of  man,  that  thou  shouldst 
 visit  him?"  "All  nations  are  counted  as  nothing." 
 "  The  host  of  heaven  worshippeth  thee."  These  and 
 many  other  passages  may  be  interpreted  in  harmony 
 with  the  doctrine  of  a  plurality  of  worlds ;  but  it 
 would  be  putting  an  undue  strain  on  the  Word  of 
 God  to  draw  from  them  an  independent  argument 
 in  support  of  the  doctrine.  The  Scriptures  undoubt- 
 edly recognise  the  vastness  of  the  material  universe, 
 and  clearly  indicate  the  existence  of  other  intelligences 
 besides  man.     It  is  even  highly  probable  that  the 
 
THE  PLURALITY  OF  WORLDS,    307 
 
 various  orders  of  angels  are  in  some  way  related  to 
 the  orbs  of  heaven;  but  all  this  is  far  from  estab- 
 lishing the  probability,  that  any  given  bodies  are  the 
 abodes  of  life  and  intelligence  in  the  same  sense  that 
 the  earth  is  the  abode  of  man.  The  existence  of 
 material  worlds  is  certain,  and  the  existence  of  angels 
 is  also  certain ;  but  is  it  probable  that  angels  have 
 any  material  abode  ?  and,  if  so,  is  it  probable  that 
 the  planets  of  our  system  are  such  abodes  ?  Scrip- 
 ture throws  no  light  whatever  upon  this  subject. 
 
 4.  The  next  is  the  analogical  or  astronomical  argu- 
 ment. If  the  navigator  discovered  a  new  island,  he 
 might,  from  its  general  appearance,  conclude,  before  he 
 approached  near  enough  to  descry  them,  that  sentient 
 beings  lived  upon  it.  If  he  saw  mountains,  valleys, 
 rivers,  and  all  the  usual  marks  of  a  habitable  region, 
 he  would  have  abundant  ground,  from  his  past  ex- 
 perience, to  conclude  that  it  was  inhabited.  There 
 would  be  no  violence  done  to  this  analogical  prin- 
 ciple, though  we  pushed  it  a  little  further.  Suppose 
 that  the  land  descried  is  not  in  the  ocean,  but  float- 
 ing in  space;  if  we  discovered  the  usual  conditions 
 of  life,  we  would  have  ground  for  the  inference  that  it 
 was  probably  inhabited ;  and  though  the  conditions 
 were  somewhat  different,  we  might  infer  with  proba- 
 bility that  life,  suited  to  these  conditions,  might  never- 
 theless exist. 
 
 We  see  a  wide  range  of  adaptation  under  the  very 
 diverse  conditions  existing  at  present  in  the  earth; 
 
3o8     THE  PLURALITY  OF  WORLDS. 
 
 and  geology  exiiibits  to  us  adaptations  much  more 
 wonderful,  so  that  even  a  considerable  deviation  from 
 the  normal  conditions  would  not  invalidate  the  ana- 
 logical inference.  It  ought  to  be  kept  in  view, 
 however,  that  there  must  be  a  limit  to  the  variation, 
 otherwise  the  argument  ceases  to  be  one  of  analogy. 
 The  argument  is  founded  upon  similarity,  but  if  the 
 variation  is  pushed  to  such  an  extent  as  to  obliterate 
 the  resemblance,  the  logical  inference  is  vitiated.  But 
 how  are  we  to  limit  the  variation,  and  yet  to  pre- 
 serve the  analogical  character  of  the  argument  ?  We 
 must  assign  limits  from  our  knowledge  of  the  varia- 
 tions with  which  we  are  acquainted.  We  see  a  wide 
 range  on  our  globe,  but  we  can  also  detect  a  limit. 
 We  find,  for  example,  that  life  is  consistent  with  a 
 wide  range  of  density  of  atmosphere,  but  we  have 
 no  reason  to  believe  that  life  could  exist  on  our  globe 
 without  an  atmosphere.  There  is  evidently  a  limit 
 far  short  of  total  deprivation.  So  in  regard  to  tem- 
 perature, there  are  vast  wastes  on  the  face  of  the 
 earth  where  life  cannot  exist  on  account  of  the  ex- 
 tremes of  temperature.  But  it  may  be  said,  why 
 should  the  limits  of  our  globe  be  applied  to  the 
 other  planetary  bodies  ?  May  not  this  variation  be 
 so  great  that  life  might  exist  in  a  comet  some  thou- 
 sand times  hotter  than  white-hot  iron  ;  or  on  a  globe 
 without  atmosphere,  and  with  a  temperature  below 
 zero?  But  to  argue  in  this  way  is  to  give  up  en- 
 tirely the  analogical  argument,  which  requires  us  to 
 
THE  PLURALITY  OF  WORLDS.     309 
 
 advance  from  the  known  to  tlie  unknown.  "We  must 
 keep  one  foot  on  this  globe  while  we  place  the  other 
 on  the  unknown  body.  To  argue  that  there  may 
 possibly  be  inconceivably  greater  variations  of  the 
 conditions  of  life  on  the  other  planets,  is  to  change 
 entirely  the  line  of  argument.  Speculations  regard- 
 ing \hQ  joossible  far  transcend  the  region  of  the  astro- 
 nomical or  analogical  argument,  which  deals  only 
 with  the  probable. 
 
 Let  us  now  see  what  are  the  points  of  similarity 
 on  which  an  analogical  argument  for  a  plurality  of 
 worlds  is  founded.  What  conditions  of  life  have  the 
 planets  in  common  with  the  earth  ? 
 
 1.  They  derive  their  light  and  heat  from  the  same 
 source — the  sun. 
 
 2.  They  have  an  annual  revolution  and  change  of 
 seasons. 
 
 3.  They  have  a  diurnal  revolution,  and,  conse- 
 quently, the  alternation  of  day  and  night. 
 
 4.  Some  have  atmosphere  and  clouds. 
 
 5.  Some  have  diversities  of  surface  similar  to 
 mountains  and  valleys. 
 
 6.  Many  of  the  primary  planets  are  provided  with 
 satellites. 
 
 7.  They  are  probably  composed  of  the  same 
 chemical  elements. 
 
 8.  Their  orbits  have  all  the  elements  of  stability. 
 
 The  above  are  the  chief  points  of  similarity;  but  to 
 
310     THE  PLURALITY  OF  WORLDS. 
 
 what  extent  do  the  conditions  of  life  vary?  As  to 
 heat  and  light,  the  range  is  startling.  Neptune  re- 
 ceives 6000  times  less  than  Mercury.  No  doubt  the 
 atmosphere  of  the  planets  may  modify  much  these 
 extremes.  The  small  difference  of  density  in  the 
 atmosphere,  experienced  in  the  ascent  of  mountains, 
 and  the  consequent  cold,  shews  that  the  atmosphere 
 of  the  planet,  as  well  as  its  distance  from  the  Sun, 
 has  much  to  do  with  the  temperature.  Still,  the 
 vast  difference  between  1  and  6000  is  too  much  to 
 be  equalised  by  the  modifying  influence  of  the  at- 
 mosphere. 
 
 Then  as  to  gravity,  there  is  a  range  of  at  least  20 
 to  1,  if  we  take  the  asteroids  into  account.  A  man 
 in  Jupiter  would  be  20  times  heavier  than  in  one  of 
 the  minor  planets.  If  we  descend  in  the  scale,  we 
 shall,  undoubtedly,  find  planets  hardly  large  enough 
 to  accommodate  a  single  family.  Then  as  to  den- 
 sity, there  is  the  widest  range.  The  comets  are 
 members  of  the  solar  system,  and  must  be  dealt 
 with  in  any  general  argument,  but  most  of  them  are 
 probably  not  so  dense  as  the  vacuum  of  an  air- 
 pump.  It  would  require  no  ordinary  stretch  of 
 imagination  to  suppose  them  inhabited.  And  if  we 
 strike  off  the  comets,  we  must  also  include  the  dark 
 transparent  ring  of  Saturn.  Next,  as  to  atmosphere, 
 we  have  a  very  wide  range  if  we  take  the  ]Moon  into 
 account.  If  there  is  a  lunar  atmosphere,  its  weight 
 must  be  1800  times  less  than  that  of  the  Earth. 
 
7 HE  PLURALITY  OF  WORLDS.     311 
 
 It  is  plain  that  the  range  of  the  above  conditions  is 
 far  beyond  anything  we  have  in  our  globe,  and  that 
 we  are  not  warranted,  from  analogy,  to  come  to  the 
 conclusion  that  the  bodies  of  the  solar  system  are,  as 
 a  whole,  inhabited.  But,  surely,  there  is  no  necessity, 
 in  order  to  hold  a  plurality  of  worlds,  to  maintain 
 that  inhabitants  must  be  found  even  in  bodies  exhi- 
 biting extreme  conditions.  Those  who  take  the  broad 
 general  ground  that  matter  implies  life,  must,  in 
 order  to  be  consistent,  hold  that  every  comet,  asteroid, 
 and  meteorolite  must  have  its  inhabitants ;  but  this 
 position  is  quite  antagonistic  to  the  analogical  argu- 
 ment. Analogy  would  lead  us  to  expect  that  parts 
 of  the  solar  system  would  be  unfitted  for  the  pheno- 
 mena of  life,  though  it  was  admitted  that  parts  were 
 habitable.  Our  globe  may  be  taken  as  the  type  of 
 the  whole  solar  system.  Portions  of  its  surface  re- 
 present the  extreme  conditions  of  the  planets.  The 
 summits  of  its  loftiest  mountains  and  the  polar  regions 
 may  represent  Neptune  and  the  other  planets  on  the 
 extreme  range  of  the  solar  system;  the  burning  sands 
 of  the  Sahara  may  represent  Mercury  and  Vulcan,  in 
 the  immediate  neighbourhood  of  the  sun  ;  and  just 
 as  we  find  that  these  extreme  portions  of  the  earth's 
 surface  are  incapable  of  sustaining  inhabitants,  so 
 may  we  legitimately  conclude  that  the  extreme  por- 
 tions of  the  solar  system  may  also  be  destitute  of  life. 
 There  are  desolate  parts  of  the  earth's  surface  of  a 
 much  larger  extent  than  the  vfhole  surface  of  many 
 
312     THE  PLURALITY  OF  WORLDS: 
 
 of  the  minor  planets.  Why  should  we  maintain  that 
 these  planets  must  be  inhabited^  when  the  probability^ 
 is,  that  the  conditions  of  life  are  far  more  extreme 
 than  in  the  waste  regions  of  the  earth's  surface  ?  It 
 is  compatible  with  the  scheme  of  Providence,  that 
 a  large  proportion  of  the  earth's  surface  should  be 
 incapable  of  sustaining  inhabitants.  "Why  should 
 not  a  large  portion  of  the  solar  system  be  barren 
 too? 
 
 The  purport  of  our  remarks  is  simply  to  shew,  that 
 the  analogical  argument  for  a  plurality  of  worlds  is 
 entirely  based  on  a  similarity  of  conditions,  and  that 
 it  can  apply  only  to  these  bodies  that  approximate 
 to  the  earth  in  regard  to  the  conditions  of  life.  The 
 probability  certainly  is,  that  some  of  the  bodies  of 
 the  system,  such  as  Mars,  Jupiter,  and  Saturn,  do 
 not  so  far  vary  from  the  normal  conditions  as  to 
 render  life  improbable. 
 
 If  we  admit,  what  modern  science  has  rendered 
 extremely  probable,  that  the  sun  and  the  various 
 planets  are  all  in  a  state  of  transition,  passing  from 
 one  phase  of  their  history  to  another,  the  probability 
 is  that  the  other  bodies  must  pass  through  stages 
 corresponding  to  the  present  life-stage  of  the  earth. 
 From  the  past  history  of  the  earth,  as  shewn  by 
 geological  history,  and  from  its  probable  future  des- 
 tiny, as  indicated  by  the  law  of  solar  heat  and  attrac- 
 tion, it  is  likely  that  only  a  comparatively  brief  cycle 
 of  its  history  is  set  apart  for  the  display  of  the  phe- 
 
THE  PLURALITY  OF  WORLDS.     313 
 
 nomena  of  life  and  intelligence.     A  time  was  when 
 the  earth  was  without  form  and  void,  and  when  no 
 living  thing  moved  on  its  surface  ;  and  a  time  will  come 
 when  the  sun  will  languish,  and  life  will  decay  and  dis- 
 appear from  the  face  of  the  earth.     The  probability  is, 
 that  other  planets  may  have  their  life  phases   too, 
 though  they  be  not   synchronous  with  that  of  our 
 planet.    The  life  period  of  each  planet  will  depend  on 
 the  balancing  of  the  internal  forces  of  the  planet  and 
 the  influences  radiated  from  the  sun.    The  temperature 
 of  each  planet  depends  both  on  its  own  internal  heat 
 and  that  of  the  sun ;  and  the  probability  is,  that  in 
 some  part  of  its  history  it  will  attain  conditions  ]Dre- 
 cisely  similar  to  those  of  our  globe.  Were  the  planets 
 solely  dependent  on  the  sun  for  their  temperature, 
 they  could  not  pass  exactly  through  the  same  phase ; 
 but  when  we  have  the  varying  element  of  the  internal 
 temperature,  it  is  probable  that  most  of  the  bodies 
 may  have  to  pass  through   a  life  epoch   of  almost 
 identically  the  same  conditions,  at  least  as  far  as  tem- 
 perature is  concerned.     But  it  is  also  plain  that  the' 
 probability  of  this  epoch  occurring  in  any  two  planets 
 simultaneously  is  not   great.     If  by  some  volcanic 
 action  several  islands  were  formed  by  the  elevation 
 of  the  bed  of  the  sea,  the  probability  is  that,  in  the 
 course  of  time,   a  soil  would  be  formed,    and   that 
 vegetable  and  animal  life  would  appear,  so  as  to  fit 
 them  for  the  abode  of  man.     But  if  the  islands  were 
 far  separated  from  one  another, — if  they  were  scattered 
 
314     THE  PLURALITY  OF  WORLDS. 
 
 over  the  torrid,  the  temperate,  and  tlie  frigid  zones, 
 it  is  plain  that  some  would  acquire  the  requisite 
 conditions  sooner  than  others,  and  that  some  might 
 be  so  unfavourably  situated  as  never  to  acquire  them. 
 The  planets  may  be  compared  to  such  islands.  They 
 occupy,  like  the  islands,  different  zones  of  tempera- 
 ture, and  they  are  not  in  equally  favourable  circum- 
 stances. Neptune  occupying  the  frigid,  and  Vulcan 
 the  torrid  zone,  are  probably  in  much  less  favour- 
 able circumstances  than  the  earth,  occupying  the 
 temperate  regions  of  the  solar  system;  and,  possi- 
 bly, the  circumstances  are  so  unfavourable  that  the 
 requisite  conditions  can  never  be  acquired.  Some 
 may  have  been  more  favourably  circumstanced  than 
 the  earth,  and  their  period  of  life  may  have  preceded 
 that  of  the  earth,  while  others  are  only  approaching 
 the  life  conditions.  It  ought,  however,  to  be  kept 
 in  view,  that  there  is  no  analogy  that  would  lead  us 
 to  infer  that  the  conditions  of  life,  and  life  itself,  are 
 so  related  that  the  former  may  be  regarded  as  the 
 ^cause  of  the  latter,  or  that,  by  a  physical  law,  the 
 conditions  of  life  necessarily  develop  living  organisa- 
 tions. All  the  evidence  afforded  by  the  history  of  our 
 globe  points  in  a  very  different  direction.  It  unmis- 
 takeably  indicates  a  creative  hand.  Life,  no  doubt, 
 demands  certain  physical  conditions ;  but  these  con- 
 ditions have  no  tendency  to  produce  life.  Light  is 
 a  necessary  condition  to  seeing,  but  there  is  no  ten- 
 dency in  light  to  produce  a  living  eye.     When  we 
 
THE  PLURALITY  OF  WORLDS,     315 
 
 say,  then,  that  there  is  a  prolbability  of  life  where 
 the  conditions  of  life  exist,  we  mean  nothing  more, 
 than  that  it  is  likely  that  a  creative  intelligence 
 will,  in  similar  circumstances,  act  similarly.  We 
 find  that  it  is  the  usual  plan  of  the  Divine  pro- 
 cedure to  stock  with  living  beings,  regions  which 
 present  the  required  conditions  of  life  ,*  and  when 
 we  discover  in  any  unknown  region  these  conditions, 
 we  draw  the  probable  inference  that  there  are  living 
 beings. 
 
 The  purely  astronomical  argument  is  one  founded 
 simply  on  the  estimation  of  probabilities,  and  is 
 independent  of  any  genetic  theories  regarding  the 
 introduction  of  life  The  theist  and  the  atheist  can 
 alike  weigh  this  probability.  The  principle  of  ana- 
 logy holds,  whether  we  admit  a  necessary  or  an  intel- 
 ligent cause.  But  it  is  plain  that  the  doctrine  of  the 
 plurality  of  worlds,  when  argued  on  astronomical 
 grounds,  can  never  transcend  the  region  of  proba- 
 bility. To  dogmatise  is  wholly  to  misapprehend  the 
 nature  of  the  argument.  The  dogmatic  tone  fre- 
 quently displayed  in  discussions  of  this  subject  grates 
 harshly  on  the  logical  ear. 
 
 If  we  argue  that,  from  the  character  of  God,  we 
 must  infer  that  the  planets  are  inhabited,  the  ground 
 is  entirely  changed,  and  astronomy  given  up.  If  the 
 necessity  can  be  established  from  the  known  attri- 
 butes of  God,  there  is  no  need  of  appealing  to  the 
 analogical  probability  furnished  by  astronomy.     But 
 
3i6     THE  PLURALITY  OF  WORLDS. 
 
 are  we  entitled,  on  the  ground  of  God's  character,  to 
 arrive  at  a  necessary  conclusion  on  this  subject?  No 
 doubt,  if  we  construct  the  Divine  attributes  so  as  to 
 involve  the  conclusion,  the  inference  must  necessarily 
 follow.  We  adapt  the  premises  to  the  desired  re- 
 sult, and  the  conclusion  is  inevitable.  But  have  we 
 certain  ground  for  so  constructing  the  premises,  that 
 habitableness  of  the  planets  follows  as  a  necessary 
 conclusion  ?  Are  we  warranted  so  to  define  the  na- 
 ture of  God,  that  He  must  people  the  orbs  of  heaven  ? 
 It  is  because  the  weakness  of  the  a  priori  argument 
 is  felt  that  we  appeal  to  astronomy.  And  we  have 
 seen  that  astronomy  does  afford  a  probability,  but 
 only  a  probability,  that  some  of  the  planets  have  a 
 life  epoch  in  their  history. 
 
 Some  sanguine  minds  may  turn  with  disappoint- 
 ment from  such  a  conclusion, — and  think  that  no  end 
 is  gained,  because  a  certainty  is  not  established. 
 But  how  often  in  life  is  it,  that  we  can  attain  to  no- 
 thing more  than  probability?  If  we  analyse  our 
 thoughts,  and  feelings,  and  aspirations,  we  shall  fi.nd 
 that  they  are  brought  into  play  more  by  probabilities 
 than  certainties.  It  might  be  thought  much  more 
 satisfactory  that  the  moon  turned  round  her  invisible 
 side  to  us,  and  shewed  us  populous  towns  and  cities, 
 than  that  we  should  have  the  conviction  of  merely 
 the  probable  existence  of  such  scenes.  A  higher  end 
 may  be  served  by  the  mere  probability.  Speculative 
 thought  may  be  more  stirred,  and  more  earnest  in- 
 
THE  PLURALITY  OF  WORLDS.     317 
 
 quiries  instituted.  While  there  were  only  probabilities 
 regarding  the  fate  of  Franklin ^  human  sympathy  and 
 speculation  were  concentrated  on  the  mysteries  of  the 
 Arctic  regions,  and  enterprise  was  called  forth  which 
 resulted  in  a  most  important  geographical  discovery. 
 When  his  fate  was  certain,  the  sympathy  and  specu- 
 lation ceased;  and  we  shall  hear  nothing  more  of 
 Arctic  enterprise.  In  like  manner,  while  the  exist- 
 ence of  life  and  intelligence  in  the  planets  is  only 
 probable,  the  heavenly  orbs  have  a  fascination  which 
 they  might  not  have,  were  we  assured  of  its  certainty. 
 And  the  speculative  spirit  thus  called  forth  may  lead 
 to  more  earnest  study  of  God's  glory  as  declared  in 
 the  heavens.  The  spirit  of  man  also  is  best  trained 
 for  the  highest  service  of  God  by  ascending,  step  by 
 step,  the  ladder  of  probability,  in  order  that  he  may 
 stand  on  the  summit-level  of  absolute  certainty  and 
 conviction. 
 
 The  subject  has  derived  new  interest  from  the  dis- 
 cussion of  it  in  an  anonymous  essay  ascribed  to  Dr 
 Whewell,  Master  of  Trinity  College,  Cambridge. 
 The  reason  given  by  the  author  for  assuming  the 
 anonymous  garb  is  somewhat  singular.  He  was  to 
 question  the  doctrine  of  a  plurality  of  worlds,  and  he 
 wished  to  escape  the  odium  of  such  a  position.  He 
 was  to  run  counter  to  the  prejudices  of  Christians,  and 
 he  thought  it  would  be  more  agreeable  for  himself 
 and  them  that  he  withheld  his  name.  This  indicates 
 a  strange  revolution  of  sentiment  on  the  subject.     At 
 
3i8     THE' PLURALITY  OF  WORLDS. 
 
 one  timej  the  doctrine  formed  one  of  the  most  formid- 
 able weapons  of  the  infidel,  and  was  viewed  by 
 Christians  in  general  with  suspicion.  This  is  only 
 one  illustration  of  what  the  whole  history  of  Christi- 
 anity bears  out — that  the  weapons  stolen  by  the 
 infidel  from  the  armoury  of  science,  are  invariably 
 wrenched  from  his  hands,  and  turned  against  himself. 
 The  doctrine  of  a  plurality  of  worlds,  instead  of  being 
 regarded  as  the  special  property  of  the  infidel,  is  now 
 engrafted  on  the  Christian  faith,  as  a  doctrine  most 
 congenial  to  its  spirit.  Still,  the  doctrine  is  not  held 
 so  strongly  or  so  generally  as  the  delicacy  of  the 
 anonymous  author  of  the  essay  would  lead  us  to  infer. 
 By  the  great  mass  of  Christians,  the  doctrine  is  still 
 regarded  as  a  fanciful  speculation,  and  only  in  a  few 
 sanguine  and  exceptional  cases  does  it  form  a  part  of 
 a  formal  creed. 
 
 To  those  acquainted  with  the  literature  of  the  sub- 
 ject, it  is  somewhat  surprising  that,  in  recent  discus- 
 sions, the  name  of  Andrew  Fuller,  the  distinguished 
 Baptist  divine,  is  never  alluded  to.  No  one  did  more 
 to  make  the  doctrine  a  matter  of  Christian  belief,  or, 
 at  least,  to  divest  it  of  its  infidel  aspect.  He  met  the 
 arguments  of  Paine  in  so  exhaustive  a  manner,  that 
 he  left  little  for  his  successors.  Chalmers,  in  his 
 "  Astronomical  Discourses,"  took  up  the  arguments 
 of  Fuller,  and  animated  them  by  the  fire  of  genius. 
 Fuller  supplied  the  hard  logic,  but,  in  such  a  form, 
 the  subject  was  only  a  dry  skeleton.     The  genius  of 
 
THE  PLURALITY  OF  WORLDS.     319 
 
 Chalmers  gave  it  body  and  life;  and  the  work  of 
 genius  lives,  while  the  dry  logic  is  forgotten. 
 
 The  arguments  of  the  anonymous  essayist  may  he 
 reduced  to  the  following  heads  : — 
 
 1.  We  cannot  conceive  of  intelligence  unaccom- 
 panied by  human  attributes  ;  if  there  be  inhabitants 
 in  the  stars,  they  must  be  men ;  and  they  cannot  be 
 men  unless  they  have  the  conditions  which,  in  this 
 globe,  develop  the  intellectual,  moral,  and  religious 
 character  of  man.  This  argument  has,  properly,  no 
 reference  to  the  question  of  the  habitableness  of  other 
 worlds.  It  is  rather  a  question  of  metaphysics  or 
 psychology.  The  question  is  simply.  Whether  there 
 can  be  other  intelligences  than  man  ?  Whether  there 
 is  only  one  type  of  mind  ?  And  his  argument  is,  that 
 as  he  cannot  conceive  of  minds  different  from  his 
 own,  there  cannot  be  other  minds.  But  this  is  only 
 the  well-understood  fallacy  of  denying  to  be  true 
 what  we  cannot  conceive.  The  mere  power  of  con- 
 ceiving of  a  thing  is  no  criterion  of  its  existence. 
 The  argument,  pushed  to  its  legitimate  length,  would 
 ignore  the  existence  of  angels,  and  all  those  ranks  of 
 spiritual  intelligences  in  whose  existence  we  are  taught 
 to  believe  as  a  part  of  our  Christian  faith.  This  is 
 the  grand  point  which  he  wishes  to  establish,  and  on 
 which  the  whole  argument  turns. 
 
 2.  The  next  argument  is  that  of  analogy.  He 
 denies  that  the  analogy  is  so  strong  as  to  warrant 
 the  inference,  that  the  other  heavenly  bodies  are  in- 
 
320     THE  PLURALITY  OF  WORLDS. 
 
 habited.  This  is  very  much  a  question  of  fact,  but 
 he  concedes  the  point  so  far,  that  in  some  of  the 
 planets  inferior  forms  of  life  may  exist — zoophytes  in 
 Jupiter,  ascending  to  reptiles  in  Mars.  Now,  this  con- 
 cession is  the  relinquishment  of  the  whole  argument ; 
 for  the  grand  point  to  be  established  is  this.  Can  the 
 planets  support  animal  organisations  at  all  ?  This  is 
 the  real  question  in  an  astronomical  point  of  view. 
 The  question  is,  Is  life  possible?  Let  astronomers 
 determine  this  point,  and  the  question  of  intelligence 
 will  be  settled  on  totally  different  grounds.  Now,  the 
 author  is  forced  to  admit  that  life  is  possible ;  but 
 though  he  admits  this,  he  thinks  he  has  gained  his 
 point,  as  he  holds  that  man  could  not  exist  in  any  of 
 the  planets,  and  that  if  there  be  intelligences  at  all, 
 they  must  be  men.  But  not  holding  this  absurd 
 conclusion,  we  feel  that  it  is  enough  to  have  the 
 point  of  life  established,  for  then  conception  of  in- 
 telligence is  an  easy  and  natural  one.  Surely  it  is 
 a  most  unwarranted  supposition  to  hold  that  intelli- 
 gence can  only  have  one  material  wrapping — one  kind 
 of  mortal  coil ;  that  mind,  if  it  is  to  be  clogged  by 
 matter,  the  clog  must  be  a  human  clog  5  that  if  mind 
 is  to  work  throngh  material  machinery,  it  must  have 
 machinery  after  the  human  pattern.  Surely  it  is  no 
 very  unwarrantable  assumption  to  maintain,  that 
 there  may  possibly  be  organisations  widely  different 
 from  our  own,  fitted  to  enclose  the  spiritual  being. 
 What  a  range  of  organisation  do  we  see  in  this  world 
 
THE  PLURALITY  OF  WORLDS.    321 
 
 uuder  tlie  same  planetary  conditions  I  and  though 
 we  here  see  intelligence  linked  only  to  one  pattern, 
 yet  there  is  no  difficulty  in  understanding  how  intel- 
 ligence may  be  linked  to  material  forms  of  a  far 
 different  mould. 
 
 3.  The  author  in  viewing  the  question  in  the  light 
 of  design  says — that  this  world  may  be  the  only  per- 
 fect world,  that  all  the  others  may  be  abortive ;  and 
 he  takes  the  case  of  eggs  and  seeds  to  illustrate  his 
 point.  He  says,  that  in  the  case  of  plants  and 
 animals  there  is  a  great  waste.  More  seeds  are  pro- 
 duced than  there  is  need  for,  and  more  eggs.  But 
 this  is  not  true,  for  provision  must  be  made  for  the 
 necessary  destruction,  so  that  no  more  germs  are  pro- 
 duced than,  in  the  circumstances,  are  needed.  But 
 he  evades  the  real  point  in  question.  The  real  ques- 
 tion is,  Are  the  planets  designed  for  inhabitants? 
 The  question  is  not  so  much,  Are  they  inhabited  at 
 this  moment?  as.  Are  they  fitted  for  inhabitants? 
 When  we  examine  the  seed  or  germ,  and  see  the 
 marks  of  design,  we  do  not  hesitate  to  infer  that  the 
 design  of  it  is  to  be  developed  into  an  organised 
 being.  When  we  examine  a  planet,  the  question  is. 
 Is  it  fitted  to  be  the  abode  of  inhabitants  ?  Is  this 
 the  manifest  design  ?  The  chief  question  we  have  to 
 answer  is  not.  Is  there  a  tenant  in  the  house  ?  but. 
 Is  the  house  habitable?  If  we  found  a  house  in  a 
 desert  island,  we  would  naturally  come  to  the  con- 
 clusion that  it  had  been,  or  was  destined  to  be,  the 
 
 X 
 
322     THE  PLURALITY  OF  WORLDS, 
 
 abode  of  some  tenant  j  and  this  is  all  that  is  aimed  at 
 by  the  analogy  of  worlds. 
 
 4.  The  author  argues,  that  geology  tells  us  that 
 there  was  a  period  in  our  world's  history  when  man 
 did  not  exist,  and  when,  possibly,  no  living  creature 
 existed  upon  the  earth.  Now,  we  admit  the  force  of 
 this  argument  so  far.  It  shews  us  that  we  are  not 
 entitled  to  point  to  any  planet,  and  say  that  it  is  at 
 this  moment  inhabited ;  but  surely  the  natural  infer- 
 ence is,  that  if  it  is  not  now  inhabited,  it  may  in  the 
 course  of  time  be  inhabited.  This  is  the  conclusion  to 
 which  the  analogy  of  the  earth  leads. 
 
 The  infidel  objection  of  Paine  is : — ^'  Though  it 
 be  not  a  direct  article  of  the  Christian  faith  that  the 
 world  w^e  inhabit  is  the  whole  of  the  habitable  crea- 
 tion, yet  it  is  so  w^orked  up  therewith,  from  what  is 
 called  the  Mosaic  creation,  the  story  of  Eve  and  the 
 apple,  and  the  counterpart  of  the  story,  the  death 
 of  the  Son  of  God,  that  to  believe  otherwise — that  is, 
 to  believe  that  God  created  a  plurality  of  worlds,  at 
 least  as  numerous  as  what  we  call  stars — renders  the 
 Christian  faith  at  once  little  and  ridiculous,  and  scat- 
 ters it  in  the  mind  like  feathers  in  the  air.  The  two 
 beliefs  cannot  be  held  together  in  the  same  mind,  and 
 he  who  thinks  he  believes  both  has  thought  but  little 
 of  either."  The  force  of  this  'argument  is  based  on 
 the  contrast  between  man's  littleness,  and  the  great- 
 ness, first,  of  the  material  universe,  and,  secondly,  of 
 the  number  of  spiritual  intelligences  in  other  parts  of 
 
THE  PLURALITY  OF  WORLDS.     323 
 
 creation.  As  to  tlie  greatness  of  the  material  universe, 
 it  is  illogical  to  contrast  it  with  man's  moral  nature. 
 The  things  compared  are  quite  disparate.  We  might 
 as  well  speak  literally  of  the  weight  of  a  sigh,  or  the 
 length  and  breadth  of  a  thought,  as  calculate  the 
 value  of  a  soul  in  material  cubic  feet. 
 
 The  chief  difficulty  lies  in  the  other  part  of  the  con- 
 trast— viz.,  man's  insignificance,  as  compared  with  the 
 world  of  intelligences  in  other  parts  of  creation.  It 
 is  not  true,  as  Paine  insinuates,  that  Scri^^ture  denies 
 the  existence  of  intelligences  other  than  man.  The 
 existence  of  angelic  beings  is  prominently  taught, 
 and  no  limit  is  set  to  their  number.  No  doubt,  the- 
 Scriptures  do  not  assign  material  orbs  as  their  special 
 abode ;  but  the  difficulty  lies,  not  with  the  material 
 idea,  but  with  the  existence  of  innumerable  other  in- 
 telligences. The  grand  objection,  then,  is  this — If 
 man  be  only  a  unit  in  the  universe  of  intelligence,  it 
 is  incredible  that  the  Son  of  God  should  have  come  to 
 this  world,  a  mere  atom  in  space,  to  die  for  man.  One 
 answer  to  this  argument  is,  that  the  death  of  Christ, 
 in  its  effects,  is  not  confined  to  man,  but  extends  be- 
 yond this  world,  and  may  be  designed  to  tell  on  all 
 other  intelligences.  The  difficulty,  however,  lies  in 
 defining  the  manner  in  which  the  death  of  Christ  may 
 bear  on  other  spiritual  beings.  Chalmers  is  disposed 
 to  hold  it  possible,  that  the  atonement  proper  may 
 extend  to  other  worlds  which  may  have  fallen  like 
 our  own.     Such  a  view,  however,  is  inconsistent  with 
 
324     THE  PLURALITY  OF  WORLDS, 
 
 the  Scripture  doctrine,  which  regards  Christ  as  the 
 second  Adam,  it  being  essential  to  the  work  of  redemp- 
 tion that  there  should  be  an  identity  of  nature  between 
 the  Saviour  and  the  sinner.  Sir  David  Brewster,  in 
 his  work,  "  More  Worlds  than  One,"  holds  the  same 
 view  as  Chalmers,  but  in  a  more  positive  manner.  It 
 is  not  with  him  a  surmise  that  other  worlds  have 
 fallen,  but  a  fair  analogical  deduction.  This  world 
 has  sinned,  therefore  it  is  probable  that  other  worlds 
 have  sinned.  This  is  stretching  the  analogical  argu- 
 ment too  far ;  for  sin  is  an  accident,  not  an  essential 
 element  of  the  constitution  of  man.  Having  extended 
 sin  to  other  worlds,  the  direct  benefit  of  Christ's  death 
 is  also  extended  to  them.  The  argument  is  this — 
 If  the  benefit  of  Christ's  death  extends  to  distant  isles 
 of  the  sea,  why  should  it  not  extend  as  well  to  the 
 globes  floating  in  space  ?  If  the  earth  were  to  split 
 in  two,  like  Biela's  comet,  would  not  the  benefit  of 
 Christ's  death  belong  to  the  one  half  as  well  as  to 
 the  other?  Why  should  not  this  benefit  extend  to 
 different  worlds,  as  well  as  to  different  halves  of  the 
 same  world  ?  This  argument,  however,  overlooks  the 
 fact  that  redemption  has  to  do,  not  with  the  matter  of 
 the  globe,  but  with  mankind — not  with  the  identity 
 of  worlds,  but  of  race.  If  the  earth  were  to  split  in 
 halves,  two  distant  worlds  would  be  formed,  but  the 
 race  would  still  be  the  same.  The  guilty  nature, 
 needing  salvation,  would,  notwithstanding  the  terres- 
 trial disruption,  remain  the  same.     The  case  is  not 
 
THE  PLURALITY  OF  WORLDS.    325 
 
 at  all  parallel  when  we  deal  with  different  worlds, 
 inhabited  bj  beings  of  different  natures. 
 
 Another  supposition  of  the  same  distinguished 
 author  is,  that  Christ  might  be  supposed  going  from 
 world  to  world  to  die  for  sinners.  He  died  on  our 
 globe,  but  He  afterwards  assumed  life,  and  He  may- 
 do  this  in  indefinite  succession,  so  that  our  world 
 does  not  stand  out  as  an  exceptional  case.  But  the 
 same  difficulty,  as  before,  is  felt.  When  Christ  rose 
 from  the  dead,  it  was  in  the  nature  of  man.  A 
 nature  different  from  man's  cannot  be  redeemed  bj 
 human  sufferings  and  death.  To  carry  out  the 
 analogy,  it  would  be  necessary  to  suppose  that 
 Christ  assumes  a  new  nature,  corresponding  to  that 
 of  the  intelligences  for  whom  He  lays  down  His  life 
 in  different  worlds.  But  this  supposition  is  in  direct 
 opposition  to  Scripture,  which  declares  that  He 
 will  for  ever  bear  His  human  nature.  The  objection 
 to  all  such  hypotheses  as  these  is,  that  they  are  far 
 more  improbable  than  the  simple  proposition  they 
 are  intended  to  support.  The  naked  doctrine,  that 
 there  are  other  intelligences  beside  man,  is  far  more 
 probable  than  the  hypothesis  that  Christ  goes  from 
 world  to  world  laying  down  His  life  for  sinners.  If 
 there  is  a  difficulty  in  supposing  man  alone  to  be 
 benefited  by  redemption,  the  difficulty  is  not  at  all 
 lessened  by  such  improbable  suppositions.  Even 
 granting  that  the  benefits  of  Christ's  death  did  not 
 extend  beyond  this  world,  there  is  no  appalling  diffi- 
 
326     THE  PLURALITY  OF  WORLDS. 
 
 culty  in  the  idea  that  there  are  other  inhabited  worlds 
 beyond  our  own.  The  fallacy  at  the  root  of  Paine's 
 argument  is  the  applying  to  moral  subjects  the  com- 
 mercial axiom,  that  abundance  depreciates  the  value 
 of  an  article.  If  there  were  but  one  soul  in  the  uni- 
 verse, then  it  would  be  of  sufficient  value  to  warrant 
 the  death  of  Christ;  but  if  there  were  millions  more, 
 it  would  be  out  of  the  question  that  such  a  price 
 should  be  paid  for  one  soul.  And  so  in  regard  to 
 worlds :  if  there  were  no  other  worlds  than  ours,  it 
 would  not  be  improbable  that  Christ  should  die  for 
 it,  but  as  there  are  many  other  worlds,  it  is  highly 
 improbable  that  God  should  esteem  it  so  highly  as 
 redeem  it  at  such  a  cost.  But  the  absurdity  of  this 
 argument  is  at  once  seen  in  the  light  even  of  human 
 feelings.  A  parent  does  not  love  his  children  less  in 
 proportion  as  their  number  increases.  He  does  not, 
 by  an  arithmetical  rule,  divide  his  love,  as  he  must 
 often  do  his  slender  pittance,  among  them.  His 
 joy  in  each  may  be  only  enhanced  by  the  play  of 
 domestic  affection  in  the  enlarged  family  circle ;  and 
 when  one  falls,  his  grief  may  be  all  the  greater  be- 
 cause of  the  shame  and  sorrow  that  come  upon  all. 
 If  man  be  only  one  of  a  large  family  circle,  God 
 does  not  value  his  soul  the  less ;  and  He  will  not  be 
 less  disposed  to  make  a  sacrifice  to  redeem  him  from 
 the  sin  and  sorrow  which  he  has  brought  upon  himself 
 by  the  fall.  If  a  father  were  reported  to  have  made 
 a  great  sacrifice  to  rescue  one  member  of  his  family 
 
THE  PLURALITY  OF  WORLDS.     327 
 
 from  disgrace,  would  it  be  reasonable  to  doubt  tlie  story 
 because  he  had  not  made  similar  sacrifices  for  his  chil- 
 dren who  had  not  fallen  ?  Would  it  at  all  increase  the 
 probability  to  suppose  that  all  the  other  members  had 
 fallen,  and  that  similar  sacrifices  had  been  made  ?  In 
 the  same  way,  it  would  not  at  all  increase  the  credi- 
 bility of  the  scheme  of  redemption  to  suppose  that 
 other  intelligences  had  fallen,  or,  rather,  the  redemp- 
 tive act  needs  no  such  hypothesis  for  its  support. 
 
 Are  we  to  conclude,  then,  that  the  influence  of  the 
 work  of  redemption  does  not  extend  beyond  our 
 world  or  the  human  race  ?  By  no  means.  Though 
 the  merits  of  Christ's  death  be  not  applicable  to  the 
 pardon  of  sin  beyond  the  limits  of  the  human  race, 
 yet  the  influence  may  be  felt  by  all  created  intelli- 
 gences. When  a  monarch  exercises  his  prerogative 
 of  mercy,  and  pardons  the  oflcnder,  there  is  only 
 one  person  pardoned,  but  thousands  may  share  in  the 
 emotions  of  joy  and  gratitude.  The  great  act  of 
 mercy  to  man  may,  in  like  manner,  convey  to  thou- 
 sands of  bright  orbs  tidings  of  great  joy.  The  whole 
 tenor  of  Scripture  sanctions  the  idea,  that  while  man 
 alone  is  pardoned,  all  holy  intelligences  share  his  joy. 
 Astronomy  has  revealed  the  great  truth,  that  the 
 whole  universe  is  bound  together  by  one  all-pervad- 
 ing influence.  Worlds,  and  systems,  and  firmaments 
 are  linked  together  by  the  mysterious  power  of  gravi- 
 tation. No  atom  in  the  universe  exists  merely  for 
 itself.     The  very  mote  that  dances  in  the  sunbeam 
 
328     THE  PLURALITY  OF  WORLDS. 
 
 is  allied  to  the  simg  burning  in  the  depths  of  space. 
 There  is  the  universal  law  of  mutual  influence,  and 
 the  universe  is  one  grand  unit,  one  organic  whole. 
 
 But  is  this  union,  this  mutual  influence,  confined 
 to  the  mere  matter  of  worlds  ?  Have  we  not  reason 
 to  believe  that  a  closer  bond  than  gravity  will  unite 
 all  holy  intelligences  ?  At  present,  indeed,  we  feel 
 that  there  is  no  bond  of  sympathy  between  us  and 
 the  inhabitants  of  other  worlds.  We  are  only  grop- 
 ing our  way  to  the  conviction  that  there  may  be  other 
 worlds  teeming  with  inhabitants.  But  why  is  man 
 doomed  to  this  isolation  in  space?  Why  do  we 
 dwell  apart,  and  feel  that  our  world  is  wrenched  from 
 the  community  of  worlds  that  circle  in  space  ?  We 
 have  reason  to  believe  that  sin  has  doomed  us  to  this 
 isolation, — that  it  has  made  this  world  our  prison- 
 house  instead  of  an  abode  of  liberty,  where  we  might 
 hold  intercourse  with  other  pure  spirits. 
 
 But  are  we  for  ever  doomed  to  this  isolation  ?  Are 
 we  never  mare  to  be  linked  to  the  sympathies  of  the 
 universe  around  us  ?  No !  the  yearnings  of  our 
 hearts  tell  us,  the  teachings  of  our  holy  faith  warrant 
 the  belief,  that  one  grand  aim  of  the  scheme  of  re- 
 demption is  to  remedy  and  perfect  the  bond  of  sym- 
 pathy that  was  broken  by  the  fall,  and  to  bring  us 
 into  closer  alliance  with  all  the  various  grades  of 
 moral  intelligences  throughout  the  universe. 
 
 It  was  a  beautiful  instinct  that  made  man  in  other 
 days  endow  the  celestial  spheres  with  music : — 
 
THE  PLURALITY  OF  WORLDS.     329 
 
 "  Look  how  the  floor  of  heaven 
 Is  thick  inlaid  with  patines  of  bright  gold ! 
 There 's  not  the  smallest  orb  which  thou  behold'st 
 But  in  his  motion  like  an  angel  sings, 
 Still  choiring  to  the  young-eyed  cherubim : 
 Such  harmony  is  in  immortal  souls  ; 
 But,  whilst  this  muddy  vesture  of  decay 
 Doth  grossly  close  it  in,  we  cannot  hear  it." 
 
 The  universe  is  a  great  harp,  and  each  orb  a  string 
 in  that  harp  ;  but  one  string,  at  least,  is  untuned.  Sin 
 has  broken  that  string,  and  now  there  is  a  jarring  in 
 the  notes  that  ascend  to  the  throne  of  the  Eternal.  One 
 great  end  of  redemption  is  to  re-adjust  this  jarring 
 string  of  our  world.  The  whole  universe,  in  some  mea- 
 sure, felt  the  fall  of  man,  just  as  one  discordant  string 
 tells  upon  the  harmony  of  all  the  strings  of  a  musical 
 instrument ;  and  the  whole  universe  will  feel  the  effects 
 of  redemption,  when  this  world  is  once  more  put  in 
 tune  by  the  hand  of  love  and  mercy.  Then  sweeter 
 melodies  and  sublimer  harmonies  will  arise  than  any 
 that  have  yet  ascended  to  the  throne  of  the  Eternal. 
 
 This  world  is  no  longer  the  material  centre  of  the 
 universe,  but  revelation  teaches  us  that  it  is  still  the 
 sjnritual  centre.  From  this  centre  emanate  those 
 influences  which  shall  bind  for  ever  all  the  sons  of 
 God  into  one  great  family.  Well  may  we  exclaim, 
 when  we  contemplate  man's  original  inferiority  in 
 the  scale  of  intelligence,  and  the  meanness  of  his 
 abode,  "What  is  man,  that  thou  art  mindful  of 
 him?  or  the  son  of  man,  that  thou  shouldest  visit 
 him?"— but  well  may  we  rejoice  and  say,  "Thou 
 
330     THE  PLURALITY  OF  WORLDS. 
 
 hast  crowned  him  with  glory  and  honour !  " — when 
 we  remember  what  he  is  now. 
 
 With  the  light  of  revelation  and  astronomy  com- 
 mingled, we  can  take  a  loftier  view  of  the  work  of 
 redemption.  We  can  see  that  the  decease  accom- 
 plished on  Calvary  was  not  only  to  save  man,  but 
 to  reunite  all  the  spiritual  family  of  God.  Heaven 
 will  be  the  reunion  of  all  holy  spirits  into  one 
 great  company.  The  visions  of  John  in  the  book  of 
 Kevelation,  naturally  force  upon  us  the  conviction 
 that  heaven  will  be  such  a  reunion.  "  I  heard  the 
 voice  of  many  angels  round  about  the  throne,  and  the 
 living  creatures,  and  the  elders,  and  the  number  of 
 them  was  ten  thousand  times  ten  thousand."  But 
 amidst  the  ranks  of  heaven  man  will  still  retain  his 
 pre-eminence ;  he  will  still  be  crowned  with  glory  and 
 honour.  Man  will  occupy  the  inner  circle  nearest  the 
 throne.  The  redeemed  will  be  kin  to  Him  who  sitteth 
 upon  the  throne,  and  there  will  be  a  bond  stronger 
 than  any  seraph  can  feel.  When  we  contemplate  this 
 glorious  reunion,  enhanced  in  wonder  by  the  light  of 
 astronomy,  what  should  be  the  most  ardent  aspiration 
 of  our  hearts  ?  what  the  deepest  longing  of  our  souls, 
 and  the  aim  of  our  life  on  earth?  Must  it  not  be 
 to  stand  in  the  midst  of  that  glorious  throng,  and 
 swell  the  anthems  of  the  heavenly  temple,  '^  Allelujah, 
 Allelujah,  for  the  Lord  God  omnipotent  reigneth! 
 Blessing,  and  glory,  and  power,  be  to  Him  who 
 sitteth  upon  the  throne,  and  to  the  Lamb  for  ever!  " 
 
SYNOPTICAL  TABLES. 
 
 N.B.— The  epoch  for  the  elements  in  the  following  tables  is,  unless  otherwise 
 stated,  the  beginning  of  the  present  century. 
 
 THE  SOLAR  SYSTEM. 
 
 LAWS  OF  MOTION. 
 
 1.  Every  body  continues  in  a  state  of  rest  or  uniform  recti- 
 lineal motion,  unless  affected  by  some  mechanical  force. 
 
 2.  Every  change  of  motion  is  proportionate  to  the  force 
 impressed,  and  is  made  in  the  direction  of  that  force. 
 
 3.  Action  must  always  be  equal  and  contrary  to  reaction, 
 or  the  actions  of  two  bodies  on  each  other  are  always  equal 
 and  directed  to  contrary  sides. 
 
 Kepler's  laws. 
 
 1.  The  orbit  of  each  planet  is  an  ellipse,  of  which  the  sun 
 occupies  one  of  the  foci. 
 
 2.  The  areas  described  about  the  sun  by  the  radius  vector 
 of  the  planet  are  proportional  to  the  times  employed  in  de- 
 scribing them. 
 
 3.  The  squares  of  the  times  of  the  sidereal  revolutions  of 
 the  planets  are  to  each  other  as  the  cubes  of  their  mean  dis- 
 tances from  the  sun. 
 
 LAW  OP  GRAVITATION. 
 
 Any  two  bodies  attract  each  other  with  a  force  proportional 
 directly  to  the  quantity  of  matter  they  contain,  and  inversely 
 to  the  square  of  their  distances. 
 
332  SYNOPTICAL  TABLES, 
 
 ELEMENTS  OF  ELLIPTICAL  MOTION. 
 
 1.  The  mean  distance  of  the  planet  from  the  sun,  or  half 
 the  major  axis  of  the  orbit. 
 
 2.  The  duration  of  a  mean  sidereal  revolution  of  a  planet. 
 
 3.  The  mean  longitude  of  the  planet  at  a  given  epoch. 
 
 4.  The  longitude  of  the  periheHon  at  a  given  epoch. 
 
 5.  The  inclination  of  the  orbit  to  the  ecliptic  at  a  given 
 epoch. 
 
 6.  The  longitude  of  the  nodes  at  a  given  epoch. 
 
 7.  The  eccentricity  of  the  orbit. 
 
 SECULAR  VARIATIONS  IN  ORBIT. 
 
 The  position  of  the  apsides. 
 The  inclination  of  the  orbit  to  the  ecliptic. 
 ■  The  position  of  the  nodes. 
 The  amount  of  eccentricity. 
 
 NUMBER  OP  BODIES  OF  SOLAR  SYSTEM. 
 
 Principal  planets,  including  Vulcan,        ....  9 
 
 Asteroids,  (1861,) 71 
 
 Satellites, 18 
 
 Periodic  comets, 27 
 
 Planetary  rings, 3 
 
 Zones  of  asteroids,  probably 3 
 
 LAWS  OF  LIGHT. 
 
 Intensity  inversely  proportional  to  the  square  of  the  dis- 
 tance from  source. 
 
 Velocity  in  miles,  per  second,      ....       192,000 
 
 BODE'S  law  of  PLANETARY  DISTANCES. 
 
 The  intervals  between  the  orbit  of  Mercury  and  the  other 
 planetary  orbits  go  on  doubling  as  we  recede  from  the  sun. 
 
 The  first  of  the  following  series  represents  the  distances 
 from  the  orbit  of  Mercury ;  the  second,  by  adding  4  as  the 
 distance  of  Mercury  from  the  Sun,  represents  the  planetary 
 distances  from  the  centre  of  the  system  : — 
 
SYNOPTICAL  TABLES, 
 
 III 
 
 Mer.  Ven.  Earth,  Mars.  Ast.    Jup.   Sat.  Uran.  Nep. 
 
 Distance  from  Mercury,    0        3        6        12        24       48      96       192     384 
 
 444  4  444  44 
 
 Distance  from  Sun, 
 Actual  distances. 
 
 7 
 7-3 
 
 16 
 15.2 
 
 27-4 
 
 52     100       196 
 62     95-4      192 
 
 300 
 EXTERIOR  AND  INTERIOR  PLANETS. 
 
 Average  density  of  planets  exterior  to  asteroids 
 
 (water =1), l-O; 
 
 Average  density  of  interior  planets,    ....  5-33 
 Proportion  of  average  diameter  of  interior  planets 
 
 to  that  of  exterior, 1-lOth 
 
 Average  rotation  of  exterior  planets,  in  hours,  nearly  10 
 
 interior  planets,  nearly        .        ,  24 
 
 Number  of  satellites  of  exterior  planets,              .        ,  18 
 interior  planets,              .  \ 
 
 KIRKWOOD'S  LAW. 
 
 The  square  of  the  number  of  times  that  each  planet  rotates 
 during  one  revolution  in  its  orbit  is  proportional  to  the  cube 
 of  the  diameter  of  its  sphere  of  attraction. 
 
 The  sphere  of  attraction  is  that  within  which  the  attraction 
 of  one  planet  is  greater  than  that  of  the  next  interior  or  ex- 
 terior planet. 
 
 PLANETARY  ELEMENTS. 
 
 Name 
 
 of 
 Body. 
 
 Volume. 
 
 Density. 
 
 LlRht 
 and 
 Heat. 
 
 Gravity. 
 
 Time  of 
 Rotation. 
 
 Distance 
 from 
 Sun. 
 
 Sun 
 
 1415225 
 
 •250 
 
 28-36 
 
 h.     VI. 
 607  48 
 
 Vulcan 
 
 •0035 
 
 30-32 
 
 •19 
 
 Mercury 
 
 •0595 
 
 1-225 
 
 7-58 
 
 0-48 
 
 24    6 
 
 •39 
 
 Venus 
 
 •9960 
 
 •908 
 
 1-91 
 
 0-9 
 
 23  21 
 
 •73 
 
 Earth 
 
 1-0 
 
 1-0 
 
 1-0 
 
 1-0 
 
 23  56 
 
 1-00 
 
 Mars 
 
 •1364 
 
 •972 
 
 0-43 
 
 0-49 
 
 24  37 
 
 1-52 
 
 Asteroids 
 
 ... 
 
 2-74 
 
 Jupiter 
 
 1491-0 
 
 •227 
 
 -0372 
 
 2-45 
 
 9  55 
 
 5-20 
 
 Saturn 
 
 772-0 
 
 •131 
 
 •0111 
 
 1-09 
 
 10  29 
 
 9-54 
 
 Uranus 
 
 86-5 
 
 •167 
 
 •0026 
 
 0-76 
 
 19-18 
 
 Neptune 
 
 76-6 
 
 •321 
 
 -0011 
 
 1-36 
 
 ... 
 
 30-03 
 
334  SYNOPTICAL  TABLES, 
 
 THE  SUN. 
 
 Volume  (Earth's  =  1),         .           .           .           .  1,415,225 
 
 Mass  (Earth's  =  1),              ....  354,936 
 
 Density  (Earth's  =  1),        .            .            .            .  0-2543 
 
 Diameter  (Earth's  =  1),       .            .            .            .  111-454 
 
 in  miles, 882,646 
 
 apparent,  mean,   .  ,  •  .32'  12"-6 
 
 Gravity  at  equator  (Earth's  =  1),  .            .            ,  28 
 
 In  one  second  of  time  bodies  fall,  in  feet,  ,            .  335 
 
 Period  of  rotation  in  days,  ....  25-5 
 
 Zone  of  maximum  spots  north  from  the  equator,  11° — 15° 
 
 Usual  limit  of  spots  from  the  equator,       .            .  33° 
 
 Period  of  maximum  number  of  spots,  in  years,     .  10 
 
 Diameter  of  maximum  spot  (Sun's  =  1),    .            .  0-05 
 Breadth  of  zone  of  drift,  at  equator,  dii-ection  of 
 
 rotation,       .            .  30° 
 in  each  hemisphere,  op- 
 posite direction,   .            .            .            .            .  30° 
 Light  of  the  Sun  (light  of  star  of  1st  Mag.  =  1),  108,000,000,000 
 Intensity  of  Sun's  light  (electric  light  =  1),            .  4 
 
 ' : (wax  candle  =  1),               .  15,000 
 
 Heat  of  each  square  foot  of  surface,  mechanical 
 
 efifect,  in  horse-power,      ....  7,000 
 Heat  of  each  square  foot  of  surface,  equal  the  com- 
 bustion of  cwts.  of  coals  per  hour,           .            .  13-5 
 Heat  of  each  square  foot  of  surface,  equal  5  lbs. 
 
 matter  falling  with  velocity  per  second,  in  miles,  390 
 Heat  at  centre  of  disc  (heat  at  border  =  1),  .  2 
 Diameter  of  largest  spots,  in  miles,  .  .  50,000 
 Number  of  strata  in  atmosphere,  ...  4 
 Spots  seen  to  rotate  on  their  axis  (in  days),  about  18 
 Heat  equivalent  to  loss  of  mechanical  force  by  Mer- 
 cury falling  into  Sun  (a  year's  heat  of  Sun  =  1),  3 
 Velocity  of  bodies  near  the  Sun  (miles  per  second),  about  400 
 Point  in  Hercules  to  which  the  Sun  is  advancing, 
 
 declination  35°  N.,  right  ascension,         .           .  250° 
 
SYNOPTICAL  TABLES. 
 
 335 
 
 Velocity  of  Sun  in  its  orbits,  miles  per  year,  150,000,000 
 
 Mean  distance  from  the  earth  in  miles,      .  95,000,000 
 
 — • (Earth's  radius  =  1),        23,984 
 
 Light  of  Sun  reaches  the  Earth  in  .  .  g"- 
 
 Inclination  of  axis  to  ecliptic,  .  .  .    82°  40'  0" 
 
 Time  of  passing  over  one  degree  of  mean  longitude,  24''-  20"-  58'- 
 
 •01685 
 
 280°  34'  10" 
 
 270°  30'  5" 
 
 .     1°55'27" 
 
 V  1" 
 
 Eccentricity  of  orbit  (semi-axis  major  =  1), 
 \Mean  longitude,  .... 
 Longitude  of  the  perigee,     .  , 
 
 Greatest  equation  of  centre, 
 Motion  of  perigee  in  a  year, 
 
 MERCURY. 
 
 Volume  (Earth's  =  1), 
 Mass  (Earth's  =  1), 
 Density  (Earth's  =  1), 
 Diameter  (Earth's  =  1), 
 
 in  miles,    . 
 
 ■ apparent,  mean, 
 
 Gravity  (Earth's  =  1), 
 In  one  second  of  time  bodies  fall,  in  feet,  . 
 Period  of  rotation,  .... 
 Light  and  heat  received  at  perihelion  (Earth's  = 
 
 ^    at  aphelion, 
 
 at  mean  distance. 
 
 Least  elongation  from  Sun, 
 
 Greatest  elongation. 
 
 Height  of  mountain  at  southern  horn  in  miles. 
 
 Height  of  same  (radius  of  Mercury  =  1),    . 
 
 Mean  distance  from  the  Sun  in  miles, 
 
 ' ■- (Earth's  distance 
 
 Greatest  distance  (Earth's  distance  =  1),    . 
 Least  distance  (Earth's  distance  =  1), 
 Eccentricity  (semi-major  axis  =  1), 
 Sidereal  revolution  in  days, 
 Synodical  revoultion  in  days,  .  , 
 
 1), 
 
 1) 
 
 24' 
 
 0-06 
 
 0-0769 
 
 1-225 
 
 0-389 
 
 3,200 
 
 6"-9 
 
 0-48 
 
 7-07 
 
 5^-  28^- 
 
 10-58 
 
 4-59 
 
 7-58 
 
 16°  12' 
 
 28°  48' 
 
 12 
 
 •008 
 
 36,725,000 
 
 •3870084 
 
 •40666927 
 
 •3075041 
 
 •2056178 
 
 37-9692824 
 
 115-877 
 
336 
 
 SYNOPTICAL  TABLES. 
 
 Longitude  of  perihelion, 
 
 Longitude  of  ascending  node, 
 
 Inclination  of  orbit  to  ecliptic, 
 
 Mean  daily  motion  in  orbit,  .  . 
 
 miles  per  hour, 
 
 Inclination  of  bands  to  the  planet's  orbit, . 
 Days  in  falling  to  the  Sun, 
 
 .  74° 
 
 57'  21" 
 
 .46° 
 
 23'  55" 
 
 .  r 
 
 0'  13" 
 
 .    2° 
 
 11'  23" 
 
 . 
 
 109,360 
 
 • 
 
 70° 
 
 • 
 
 15-6 
 
 VENUS. 
 
 Volume  (Earth's  =  1), 
 
 Mass  (Earth's  =  1),       . 
 
 Density  (Earth's  =  1), 
 
 Diameter  (Earth's  =  1),        .  • 
 
 in  miles,   .  .  • 
 
 aj)parent,  mean,   . 
 
 Gravity  (Earth's  =  1), 
 
 In  one  second  of  time  bodies  fall,  in  feet, 
 
 Period  of  rotation,    . 
 
 Light  and  heat  (Earth's  =  1), 
 
 Least  elongation, 
 
 Greatest  elongation. 
 
 Greatest  height  of  mountains  in  miles. 
 
 Mean  distance  from  the  Smi  in  miles, 
 
 (Earth's  =  1), 
 
 Eccentricity  (semi-major  axis  =  1), 
 Sidereal  revolution  in  days. 
 Mean  synodical  revolution  in  days, 
 Longitude  of  perihelion. 
 Longitude  of  ascending  node. 
 Inclination  of  orbit  to  ecliptic, 
 Mean  daily  motion  in  orbit, 
 
 _ ■  miles  per  hour 
 
 Inclination  of  axis  to  ecliptic. 
 
 Next  transit  of  Venus  on  December  8,  1874. 
 
 Days  in  falUng  to  the  Sun, 
 
 224' 
 
 23'= 
 
 0996 
 
 0-908 
 
 0-923 
 
 0-975 
 
 7700 
 
 16"-9 
 
 0-98 
 
 14-5 
 
 21"-  7^ 
 
 1-91 
 
 45° 
 
 47°  12' 
 
 27 
 
 68,000,000 
 
 0-7233316 
 
 0-00686074 
 
 1.  gh.  490^  3^ 
 
 583-920 
 
 128°  43'  53" 
 
 74°  54'  12" 
 
 3°  23'  28" 
 
 1°  36'  7" 
 
 80,000 
 
 Uncertain 
 
 39-7 
 
SYNOPTICAL   TABLES. 
 
 ZZ7 
 
 THE  EAETH. 
 
 Volume,         ......  1-000 
 
 Mass  (Sun's  =  1),      .  .  .  .  0-0000028173 
 
 Density  (water  =  1),  .  ,  .  .         5-6747 
 
 Diameter,  mean,  in  miles,    .  .  .  ,  7916 
 
 polar,  in  miles,    ....  7898 
 
 equatorial,  in  miles,        .  ,  .  7924 
 
 Circumference  in  miles,        ....  25,000 
 
 In  one  second  of  time  bodies  fall,  latitude  of  Lon- 
 don, in  feet,  .....  16-835 
 Centrifugal  force  at  equator  (gravity  =  1),  .  0'00346 
 Times  rotation  requires  to  be  increased  to  neutral- 
 ise gravity  at  equator,  .  .  .  .  17 
 Period  of  rotation  in  sidereal  hours,  .  .  24 
 Length  of  a  mean  solar  day  in  sidereal  time,        24^-  3""-  56~'-55 
 
 sidereal  day  in  mean  solar  time,        23''-  Se""-  4'-09 
 
 Daily  acceleration  of  sidereal  time  in  mean  solar 
 time,  ...... 
 
 Greatest  difference  between  the  mean  and  apparent 
 solar  time,  .  .  .  . 
 
 Greatest  height  of  mountains  in  miles, 
 Axis  of  the  poles  (axis  of  diameter  of  equator 
 =  305),       .  .  .... 
 
 Greatest  depth  of  ocean  in  miles,    . 
 
 Mean  distance  from  the  Sun  (Earth's  radius  =  1), 
 
 in  miles, 
 
 3"-  55'-09 
 
 le*"-  16' 
 
 Distance  at  perihelion  (mean  distance  =  1), 
 aphelion  (mean  distance  =  1), . 
 
 Eccentricity  (semi-major  axis  =  1), 
 Sidereal  revolution  in  mean  solar  days. 
 Anomalistic  revolution  in  mean  solar  days. 
 Tropical  revolution  in  mean  solar  days,      .    365' 
 Interval  between  vernal  and  autumnal  equi- 
 noxes,       .  ... 
 Interval  between  autumnal  and  vernal  equi- 
 noxes,       ..... 
 
 304 
 9 
 23,984 
 .  95,000,000 
 •9832 
 1-0168 
 0-016783568 
 365^-  6''-  9'"-  9-6 
 365<'-  6"-  13'°-  49'- 
 
 5h.   4gm.   49s.  7 
 
 186^-  ll"^-  34'"- 
 
 '8^-  IS*--  7° 
 
333 
 
 SYNOPTICAL   TABLES. 
 
 The  latter  shorter  than  the  former,  by      ,  T-  17''  27'- 
 
 Time  required  by  Sun's  light  to  reach  the  Earth,  S"-  13'-3 
 
 Constant  of  aberration,        .            .            »            .  20"-36 
 
 Average  horizontal  refraction,          .            .            .  33'  6 
 
 Average  refraction  at  45°  of  altitude,          .            •  57" 
 
 Height  of  atmosphere  in  miles,       ...  40 
 Height  of  atmosphere,  supposing  no  decrease  of 
 
 density,     ......  5 
 
 Greatest  height  at  which  clouds  exist,  in  miles,  .  10 
 Distance  to  which  a  body  must  be  projected  hori- 
 zontally to  revolve  as  a  satellite,  in  miles,  4*35 
 Action  of  the  Moon  on  the  tides  (Sun's  =  1),  .  3 
 Daily  mean  retardation  of  high-water,  ,  .  50™-  28'- 
 Mean  retardation  in  syzygies,  .  .  .  39™-  12'- 
 Mean  retardation  in  quadratures,  .  .  .  l*"-  14™-  58'- 
 EevolutioD  of  the  Sun's  perigee  in  mean  solar  days,  7,645,793 
 Mean  longitude  of  perigee,  .  .  100°  30'  10" 
 Earth's  motion  in  perihelion  in  a  mean  solar  day,  1°  1'  9" 
 Mean  motion  in  a  mean  solar  day,              .            .  59'  8"'33 
 
 in  a  sidereal  day,        .  .  .59'  58"'64 
 
 Motion  in  aphelion  in  a  "mean  solar  day,    .            .  57'  ll"-50 
 
 Mean  longitude  of  perihelion,          .             .             ,  90°  30'  5" 
 
 Annual  motion  of  perihelion,           .            .             .  ll"-8 
 
 Same  referred  to  the  ecliptic,           ...  1'  l"-9 
 Tropical  revolution  of  perihelion  in  mean  solar 
 
 years,         ......  20,984 
 
 Obliquity  of  the  ecliptic,      ...  23°  27'  56"-5 
 
 Annual  diminution  of  obliquity,      .             .            .  0"*457 
 
 Limit  of  variation,    .             .             .             .             .  2°  42' 
 
 Nutation  lunar,  semi-axis  major  of  the  ellipse,      .  9""4 
 
 solar,  maximum,  ....  0"*493 
 
 Luni-solar  precession  of  the  equinoxes,  annual,     .  50"'41 
 
 Planetary  precession,            ....  0"'31 
 
 General  precession,               ....  50"'U 
 
 Complete  revolution  of  the  equinoxes  in  years,     .  25,868 
 
 Lunar  nutation  in  longitude,           ,             .            .  17""579 
 
 Solar  nutation  in  longitude,                        .            .  1"-137 
 
SYNOPTICAL  TABLES. 
 
 339 
 
 Rate  per  minute  at  which  equator  rotates,  in  miles,  17 
 
 Rate  per  second  of  her  velocity  in  orbit,  in  miles,  20 
 
 Days  in  falling  to  the  Sun,  .  ,  ,  .  64-6 
 
 THE  MOON. 
 
 Volume  (Earth's  =  1), 
 Mass  (Earth's  =  1),  . 
 Density  (Earth's  =  1), 
 
 (water  =  1),  , 
 
 Diameter  (Earth's  =  1), 
 
 in  miles,    . 
 
 apparent,  mean,   . 
 
 minimum, 
 
 maximum. 
 
 Gravity  at  surface  (Earth's  =  1), 
 
 In  one  second  of  time  bodies  fall,  in  feet. 
 
 Centre  of  figure  nearer  the  earth  than  centre  of 
 
 gravity,  in  miles,  . 
 Elevation  of  highest  mountain  in  the  Moon  (Doer- 
 
 fel),  in  feet, 
 
 (Moon's  diam.  =  1), 
 
 on  the  Earth,  in  feet, 
 
 (Earth's  diam.  =  1) 
 
 Greatest  depth  of  craters  below  the  general  sur- 
 face in  feet,  ..... 
 Greatest  diameter  of  craters,  or  cavities  with  or 
 without  raised  walls,  in  miles, 
 of  walled  plains,  in  miles, 
 
 Greatest  height  of  central  cone,  in  feet. 
 Longest  bright  ray  (Tycho), 
 Rills,  greatest  length  in  miles, 
 
 greatest  breadth  in  feet, 
 
 number, 
 
 l-49th 
 l-80th 
 
 0-615 
 3-37 
 
 0-264 
 2164-6 
 
 zv  r 
 
 29'  21"-9 
 
 33'  3r'-i 
 
 l-6th 
 2-6 
 
 33 
 
 24,945 
 l-454th 
 
 28,180 
 l-1480th 
 
 17,000 
 
 55 
 
 150 
 
 5000 
 
 1800 
 
 150 
 
 6000 
 
 90 
 
340 
 
 SYNOPTICAL  TABLES. 
 
 Number  of  mountains  higner  than  Mont  Blanc,    ,  28 
 
 Length  of  the  range  of  the  Lunar  Appenines,  in  miles,       200 
 Proportion  of  surface  covered  with  craters,  .  3-5ths 
 
 Tycho,  height  in  feet,  ....         20,180 
 
 diameter  in  miles,    .  .  .54 
 
 .  longest  ray,  .  .  .  1800 
 
 number  of  bright  rays,  about  .  .  54 
 
 Diameter  of  Mt.  Vesuvius  in  feet,  .  .  .  500 
 
 Height  of  Pico,  a  bright  isolated  peak,  in  feet,      .  7060 
 
 Disc  of  the  Earth,  as  seen  from  Moon  (IVIoon's 
 
 disc  =  1), 14 
 
 Proportion  of  the  Moon's  surface  alternately  hid 
 
 and  visible,  .  .  .  .  , 
 
 Light  of  the  Moon  at  mean  distance  (Sun's  =  1)    . 
 Heat  of  the  Moon  (heat  of  a  candle  at  distance  of 
 
 15  feet  =  1),  .  .  .  .  . 
 
 Velocity  of  projection  necessary  for  a  lunar  body 
 
 to  reach  the  Earth,  feet,  per  second. 
 Distance  in  miles  of  Moon's  sm-face  under  a  mag- 
 nifying power  of  1000,      .... 
 A  circle  of  one  second  in  diameter  as  seen  from 
 
 the  Earth,  in  square  miles. 
 Limit  of  vision  in  the  case  of  a  circle  or  square,  . 
 Limits  of  vision  in  an  indefinitely  extended  ob- 
 
 ject, 6" 
 
 Magnifying  power  required  to  see  an  embankment, 
 
 6  feet  broad, COOO 
 
 Highest  power  attained  with  distinct  vision,  .  2000 
 
 Maximum  limit  of  atmosiDhere  (one  inch  of  mer- 
 cury =  1),        .  .  .  l-45th 
 
 refraction  (at  surface  of  earth 
 
 =  1),     .  .  .  .     l-1980th 
 
 horizontal  refraction  at  Moon,  1" 
 
 Eclipses,  annual  number,  minimum  (only  solar),    .  2 
 
 . maximum,  .  .  7 
 
 maximum  of  annular  phase,       .  .        12""-  24'- 
 
 totality  (solar),  7"-  58'- 
 
 l-7th 
 l-800000th 
 
 l-3d 
 
 8200 
 240 
 
 1 
 
 60" 
 
SYNOPTICAL   TABLES.  341 
 
 Eclipses,  length  of  Earth's  shadow  (distance  of 
 
 moon  =  1),         .  .  .  .  3-5 
 
 ' period  of  recurrence  in  same  order  and 
 
 magnitude  in  years,      .  .  .  18-6 
 
 total  number  in  period  (29  lunar,  41  solar), 
 
 about         ...... 
 
 Mean  distance  from  the  Earth  (Earth's  radius  =  1), 
 
 in  miles 
 
 Period,  in  days,  of  rotation, 
 
 revolution,  mean  tropical, 
 
 mean  sidereal, 
 
 mean  synodical, 
 
 mean  anomalistic, 
 
 mean  revolution  of  node, 
 
 apsides. 
 
 Motion  eastwards  of  line  of  apsides  in  each  luna- 
 tion. 
 Mean  longitude  of  Moon, 
 
 node, 
 
 perigee 
 
 70 
 
 60-2734 
 
 237,000 
 
 27-3215824 
 
 27-3215824 
 
 27-321661 
 
 29-530588 
 
 27h.  18--  37'- 
 
 .  6793-39108 
 
 3232-575343 
 
 Mean  inclination  of  orbit  to  ecliptic, 
 
 maximum  variation. 
 
 Eccentricity  of  orbit  (semi-axis  major 
 '  Inclination  of  axis  to  ecliptic, 
 Mean  motion  in  a  solar  day, 
 Maximum  variation,  .  , 
 
 annual  equation, 
 
 equation  of  centre,  ^ 
 
 Horizontal  parallax,  maximum, 
 
 mean, 
 
 minimum,        , 
 
 1), 
 
 .  118°  17'  8" 
 
 13°  53'  17"-7 
 
 266°  10'  7"-5 
 
 5°  8'  47"-9 
 
 8'  47"-l 
 
 0-0549080 
 
 1°  30'  10"-8 
 
 13°  10'  35" 
 
 35'  42" 
 
 11'  ll"-97 
 
 6°  17'  12" 
 
 1°  1'  24" 
 
 57'  0"-9 
 
 53'  48" 
 
342 
 
 SYNOPTICAL  TABLES, 
 
 MAES. 
 
 Volume  (Earth's  =  1), 
 Mass  (Earth's  =  1),  . 
 Density  (Earth's  =  1), 
 Diameter  (Earth's  =  1), 
 
 in  miles,    . 
 
 ,  apparent,  mean, 
 
 minimum,        • 
 
 maximum. 
 
 Gravity  (Earth's  =  1), 
 In  one  second  of  time  bodies  fall,  in  feet, 
 Time  of  rotation  on  axis,     . 
 Eevolution,  sidereal,  in  days, 
 
 synodical. 
 
 Light  and  heat  from  Sun  (Earth's  =  1), 
 Polar  less  than  equatorial  diameter. 
 Distance  from  the  Sun,  mean,  in  miles, 
 
 (Earth's  =  1), 
 
 maximum, 
 
 minimum. 
 
 Eccentricity  of  orbit  (semi-axis  major  =  1) 
 
 ,  annual  increase, 
 
 Longitude  of  perihelion, 
 
 annual  increase, 
 
 ascending  node. 
 
 Inclination  of  orbit  to  ecliptic, 
 
 annual  decrease. 
 
 Mean  daily  motion  in  orbit. 
 
 Inclination  of  axis  to  the  ecliptic,  . 
 
 Greatest  arc  of  retrogradation, 
 
 Edge  of  south  polar  spot  from  pole  in  winter, 
 
 in  summer. 
 
 Brightness  of  polar  spots  (mean  brightness  =  1), 
 
 0-1364 
 
 0-1324 
 
 0-972 
 
 0-519 
 
 4070 
 
 5"-8 
 
 3"-3 
 
 23"-5 
 
 0-49 
 
 7-9 
 
 24h.  37m.  22'- 
 
 686-97945 
 
 779-836 
 
 0-43 
 
 l-16th 
 
 145,750,000 
 
 1-523691 
 
 1-665779 
 
 1-381602 
 
 0-93258 
 
 0-00000090176 
 
 332°  23'  56"'6" 
 
 15"-8 
 
 48°  0'  3"-5 
 
 26"-8 
 
 0"-014 
 
 31'  26"-7 
 
 59°  41'  49" 
 
 19°  35' 
 
 35° 
 
 5° 
 
 2 
 
SYNOPTICAL   TABLES. 
 
 343 
 
 ASTEROIDS. 
 
 Name. 
 
 Length  of 
 
 Sidereal 
 
 Revolution 
 
 in  D  ays. 
 
 Inclination  of 
 
 Orbit 
 
 to  Ecliptic. 
 
 Discoverer. 
 
 1 
 Year  of 
 
 Dis- 
 covery. 
 
 1.  Ceres 
 
 1681-271 
 
 O          /          // 
 
 10  36  30-9 
 
 Piazzi 
 
 1801 
 
 2.  Pallas 
 
 1686-089 
 
 34  37  20 
 
 Olbers 
 
 1802 
 
 3.  Juno 
 
 1592-736 
 
 13     3  17 
 
 Harding 
 
 1804 
 
 4.  Vesta 
 
 1325-669 
 
 7     8  25 
 
 Olbers 
 
 1807 
 
 5.  Astrsea 
 
 1511-369 
 
 5  19  23 
 
 Hencke 
 
 1845 
 
 6.  Hebe 
 
 1379-635 
 
 14  46  32 
 
 Hencke 
 
 1847 
 
 7.  Iris 
 
 1345-600 
 
 5  28  16 
 
 Hind 
 
 1847 
 
 8.  Flora 
 
 1193-281 
 
 5  53     3 
 
 Hind 
 
 1847 
 
 9.  Metis 
 
 1346-940 
 
 5  35  55 
 
 Graham 
 
 1848 
 
 10.  Hygeia 
 
 2043-386 
 
 3  47  11 
 
 De  Gasparis 
 
 1849 
 
 11,  Parthenope 
 
 1399-074 
 
 4  36  54 
 
 De  Gasparis 
 
 1850 
 
 12.  Victoria 
 
 1303-255 
 
 8  23     7 
 
 Hind 
 
 1850 
 
 13.  Egeria 
 
 1515-850 
 
 16  33     7 
 
 De  Gasparis 
 
 1850 
 
 14.  Irene 
 
 1515-373 
 
 9     5  33 
 
 Hind 
 
 1851 
 
 15.  Eunomia 
 
 1576-493 
 
 11  43  50 
 
 De  Gasparis 
 
 1851 
 
 16.  Psyche 
 
 1834-658 
 
 3     3  37 
 
 De  Gasparis 
 
 1852 
 
 17.  Thetis 
 
 1441-859 
 
 5  35  39 
 
 Luther 
 
 1852 
 
 18.  Melpomene 
 
 1270-498 
 
 10  10  38 
 
 Hind 
 
 1852 
 
 19.  Fortuna 
 
 1397-192 
 
 1  33  18 
 
 Hind 
 
 1852 
 
 20.  Mn,RRilia 
 
 1365-095 
 
 0  41     5 
 
 De  Gasparis 
 
 1852 
 
 21.  Lutetia 
 
 1542-318 
 
 3     5     6 
 
 Goldschmidt 
 
 1852 
 
 22.  Calliope 
 
 1814-762 
 
 13  44  39 
 
 Hind 
 
 1852 
 
 23.  Thalia 
 
 1554-131 
 
 10  13  59 
 
 Hind 
 
 1852 
 
 24.  Themis 
 
 2051-993 
 
 0  49  24 
 
 De  Gasparis 
 
 1853 
 
 25.  Phocea 
 
 1350-281 
 
 21  42  30 
 
 Chacornac 
 
 1853 
 
 26.  Proserpine 
 
 1580-714 
 
 5     0  26 
 
 •Luther 
 
 1853 
 
 27.  Euterpe 
 
 1332-301 
 
 1  39  42 
 
 Hind 
 
 1853 
 
 28.  Bellena 
 
 1700-541 
 
 9  31  21 
 
 Luther 
 
 1854 
 
 29.  Amphitrite 
 
 1499-309 
 
 6     8  20 
 
 Chacornac 
 
 1854 
 
 30.  Urania 
 
 1332-083 
 
 2  10     9 
 
 Hind 
 
 1854 
 
 31.  Euphrosene 
 
 2083-297 
 
 26  53  26 
 
 Fergusson 
 
 1854 
 
 32.  Pomona 
 
 1516-367 
 
 5  29  14 
 
 Goldschmidt 
 
 1854 
 
 33.  Polyhymnia 
 
 1770-912 
 
 1  56  48 
 
 Chacornac 
 
 1854 
 
 34.  Circe 
 
 1606-575 
 
 5  26  55 
 
 Chacornac 
 
 1855 
 
 35.  Leucothia 
 
 1873-018 
 
 8  15  18 
 
 Luther 
 
 1855 
 
 36.  Atalanta 
 
 \^^^-m^ 
 
 18  42     9 
 
 Goldschmidt 
 
 1855 
 
 37.  Fides 
 
 1568-671 
 
 3     7  10 
 
 Luther 
 
 1855 
 
 38.  Leda 
 
 1656-340 
 
 6  58  32 
 
 Chacornac 
 
 1856 
 
 39.  Lsetitia 
 
 1683-348 
 
 10  20  51 
 
 Chacornac 
 
 1856 
 
 40.  Harmonia 
 
 1246-846 
 
 4  15  48 
 
 Goldschmidt 
 
 1856 
 
344  SYNOPTICAL  TABLES. 
 
 ASTEROIDS— conimwecZ. 
 
 Length  of 
 Sidereal 
 
 Kevolution 
 in  Days. 
 
 Inclination  of 
 
 Year  of 
 
 Name. 
 
 Orl.it 
 to  Ecliptic. 
 
 Discoverer. 
 
 Dis- 
 covery. 
 
 41.  Daphne 
 
 1358-334 
 
 O          '          " 
 
 15  48  23 
 
 Goldschmidt 
 
 1856 
 
 42.  Isis 
 
 1386-914 
 
 8  34  40 
 
 Pogson 
 
 1856 
 
 43.  Ariadne 
 
 1191-108 
 
 3  20     0 
 
 Pogson 
 
 1857 
 
 44.  Nysa 
 
 1599-700 
 
 3  53    0 
 
 Goldschmidt 
 
 1857 
 
 45.  Eugenia 
 
 1617-641 
 
 6  35     0 
 
 Goldschmidt 
 
 1857 
 
 46.  Hestia 
 
 1406-614 
 
 2  18     0 
 
 Pogson 
 
 1857 
 
 47.  Aglaia 
 
 1793-933 
 
 5     6     0 
 
 Luther 
 
 1857 
 
 48.  Doris 
 
 2000-220 
 
 6  30     0 
 
 Goldschmidt 
 
 1857 
 
 49.  Pales 
 
 1980-255 
 
 3     8     0 
 
 Goldschmidt 
 
 1857 
 
 50.  Virginia 
 
 1596-140 
 
 2  52     0 
 
 Fergusson 
 
 1857 
 
 51.  Nemausa 
 
 ... 
 
 9  36  38 
 
 Laurent 
 
 1857 
 
 52.  Europa 
 
 ... 
 
 7  24  41 
 
 Goldschmidt 
 
 1858 
 
 53.  Calypso 
 
 5     6  59 
 
 Luther 
 
 1858 
 
 54.  Alexandra 
 
 ... 
 
 11  47     9 
 
 Goldschmidt 
 
 1858 
 
 h^.  Pandora 
 
 ... 
 
 7  13  30 
 
 Searle 
 
 1858 
 
 h'o.  Pseudo  Daphne 
 
 ... 
 
 7  56     2 
 
 Schubert 
 
 1858 
 
 57.  Mnemosyne 
 
 15     7  40 
 
 Lvither 
 
 1859 
 
 58.  Concordia 
 
 ... 
 
 Luther 
 
 1860 
 
 59.  (Not  named) 
 
 ... 
 
 Chacornac 
 
 1860 
 
 60.  Titania 
 
 ... 
 
 4  40  18 
 
 Fergusson 
 
 1860 
 
 61.  Danae 
 
 ... 
 
 ... 
 
 Goldschmidt 
 
 1860 
 
 62.  Erato 
 
 ... 
 
 2  14  15 
 
 Forsten 
 
 1860 
 
 63.  Ansonia 
 
 ... 
 
 De  Gasparis 
 
 1860 
 
 64.  Angelina 
 
 ... 
 
 ... 
 
 Tempel 
 
 1861 
 
 65.  Maximiliana 
 
 ... 
 
 ... 
 
 Tempel 
 
 1861 
 
 ^%.  Maia 
 
 ... 
 
 Tuttle 
 
 1861 
 
 ^1.  Asia 
 
 ... 
 
 ... 
 
 Pogson 
 
 1861 
 
 %^.  Leto 
 
 ... 
 
 Luther 
 
 1861 
 
 69.  Hesperia 
 
 ... 
 
 Schiaparelli 
 
 1861 
 
 70.  Ponopea 
 
 ... 
 
 Goldschmidt 
 
 1861 
 
 71.  Niobe 
 
 ... 
 
 ... 
 
 Luther 
 
 1861 
 
 Aggregate  mass  (Earth's  =  1),  less  than 
 Inclination  of  orbit  to  ecliptic,  greatest  (Pallas), 
 
 least  (Massilia), 
 
 Distance    from  Sun   (Earth's  =  1),  greatest  (Eu- 
 
 phrosene) 
 
 l-4th 
 
 34°  37'  20" 
 
 0°  41'  5" 
 
 3-192282 
 
 least  (Ariadne),     2-19904 
 
SYNOPTICAL   TABLES, 
 
 345 
 
 Distance,  supposed  planet,  according  to  Bode's  law,  2-8 
 Pallas,  diameter  in  miles,  ....  672 
 sm-face  (Earth's  =1),           .            .            .  l-40th 
 
 supposed  density  (Earth's  =  1),       .            .  1 
 
 gravity  (Earth's  =1),            .             .            .  1-1 2th 
 
 length  of  seconds'  pendulum,  in  inches,      .  3 
 
 Magnitudes  through  which  some  vary  on  succes- 
 sive nights,            .....  9-1 2th 
 
 Supposed  disrupted  planet,  according  to  Kirkwood's, 
 
 law,  diameter  in  miles,  5000 
 
 period   of    rotation,   in 
 
 hours,        ...,»•  67-5 
 
 JUPITER. 
 
 \  Volume  (Earth's  =  1), 
 
 \  Mass  (Earth's  =  1), 
 
 '  Density  (Earth's  =  1), 
 I  Diameter  (Earth's  =  1), 
 
 in  miles, 
 
 apparent,  mean, 
 
 minimum, 
 
 maximum, 
 
 Gravity  (Earth's  =  1), 
 
 feet  fallen  in  one  second  of  time, 
 
 Rotation  on  axis,      ....  ^' 
 
 Light  and  heat  from  Sun  at  perihelion  (Earth's  =  1), 
 
 aphelion, 
 
 mean  distance, 
 
 Polar  less  than  equatorial  diameter, 
 
 if  planet  were 
 
 equally  dense  throughout,  .  .  • 
 
 Magnifying  power  required  to  see  the  belts. 
 
 well, 
 
 1491 
 
 338-718 
 
 •227 
 
 11-225 
 
 92-164 
 
 38".4 
 
 30" 
 
 46" 
 
 2-45 
 
 39.4 
 
 55'"-  50'- 
 
 •0408 
 
 •0336 
 
 •0372 
 
 l-20th 
 
 1-lOth 
 
 30 
 
 300 
 
346 
 
 SYNOPTICAL  TABLES. 
 
 Greatest  number  of  belts  observed, 
 
 Number  of  permanent  belts, 
 
 Time  Cassini's  spot  was  seen  at  intervals,  in  years, 
 
 Proper  motion  in  longitude,  for  one  revolution, 
 
 of  some  spots,       ..... 
 Velocity  of  the  wind  from  slower  moving  spots, 
 
 feet  in  a  second,  .... 
 
 Velocity  of  wind  in  greatest  hurricane  on  the  earth, 
 
 feet  in  a  second,  .  .  .  . 
 
 Distance,  east  and  west,  of  centre  of  disc  beyond 
 
 which  spots  are  not  usually  visible, 
 Proportion  of  brightness  at  poles  to  that  of  the 
 
 equator,     .  .  .  .  • 
 
 Distance  from  the  Sun,  mean,  in  miles, 
 
 (Earth's  =  1), 
 
 . ^ maximum 
 
 40 
 
 2 
 
 43 
 
 350 
 
 50 
 
 minimum, 
 
 Eccentricity  of  orbit  (semi-axis  major  =  1), 
 . annual  increase. 
 
 Longitude  of  perihelion, 
 
 annual  increase. 
 
 ascending  node, 
 
 annual  decrease. 
 
 annual  decrease, 
 
 Inclination  of  orbit  to  ecliptic, 
 
 Motion,  mean  daily, 
 
 in  365  days, 
 
 Inclination  of  axis  to  ecliptic. 
 Mean  arc  of  retrogradation. 
 Revolution,  sidereal,  in  mean  solar  days, 
 synodical, 
 
 ^h.  27-. 
 
 l-2d 
 
 494,256,000 
 
 .      5-202767 
 
 .      5-453663 
 
 .      4-951871 
 
 .      -0482235 
 
 ■000001593 
 
 11°  8'  35" 
 
 6"-96 
 
 98°  26'  19" 
 
 34^'-3 
 
 1°  18'  51" 
 
 0"-226 
 
 4'  59" 
 
 30°  20'  32" 
 
 3°  5'  30" 
 
 9°  54' 
 
 4332-584821 
 
 .       398-867 
 
SYNOPTICAL   TABLES, 
 
 347 
 
 Jupiter's  satellites. 
 
 Na 
 
 1 
 
 2 
 3 
 
 4 
 
 Sidereal 
 Revolution. 
 
 Distance. 
 
 Jupiter's 
 
 radius 
 
 Orbit 
 
 inclined  to 
 
 Jupiter's 
 
 equator. 
 
 Diame- 
 ter in 
 miles. 
 
 Mass. 
 
 Jupiter 
 
 =  1. 
 
 Apparent 
 Diameter 
 
 from 
 Jupiter. 
 
 d.    h.    m.    s. 
 1   18   27  23 
 3  13  13  42 
 7    3  42  33 
 
 16  16  32  11 
 
 6-048 
 
 9-623 
 
 15-350 
 
 26-998 
 
 O     /        J' 
 
 0  0    7 
 0  1     6 
 0  5    3 
 0  0  24 
 
 2436 
 
 2187 
 3573 
 3057 
 
 •000017 
 •000023 
 •000088 
 •000043 
 
 31  11 
 
 17  35 
 
 18  0 
 8  46 
 
 *  (Mean  longitude  of  the  1st  +  twice  mean  longitude  of  3d) 
 
 3  times  mean  longitude  of  2d  is  always  =  ,  180° 
 
 SATUEN. 
 
 Volume  (Earth's  =  1), 
 Mass  (Earth's  =  1),  . 
 Density  (Earth's  =  1), 
 Diameter  (Earth's  =  1), 
 
 in  miles, 
 
 apparent,  mean, 
 
 minimum. 
 
 maximum. 
 
 Gravity  (Earth's  =  1), 
 
 bodies  fall  in  one  second,  in  feet, 
 
 Light  and  heat  from  Sun,  periheHon  (Earth's  =  1) 
 
 aphelion,    . 
 
 mean, 
 
 Polar  less  than  equatorial  diameter. 
 Distance  from  the  Sun,  mean,  in  miles, 
 (Earth's  = 
 
 772 
 
 101^364 
 
 •131 
 
 9-022 
 
 75,070 
 
 17"-1 
 
 15"^0 
 
 20"-0 
 
 1-09 
 
 17-6 
 
 •0123 
 
 •0099 
 
 •0111 
 
 1-lOth 
 
 1), 
 
 .  9,538,850 
 
 ■ — ■ —  maximum,  10,073,270 
 
 minimum,  9,004,422 
 
 Eccentricity  of  orbit  (semi-axis  major  =  1),            .  •0560265 
 
 *  In  consequence  of  this  remarkable  relation,  the  1st,  2d,  and  3d  satellites 
 can  never  be  echpsed  all  at  once. 
 
348 
 
 SYNOPTICAL  TABLES. 
 
 Eccentricity  of  orbit,  annual  decrease, 
 
 Longitude  of  perihelion, 
 
 — annual  increase, 
 
 ascendincf  node, 
 
 .      -0312402 
 
 89°  9'  29"-8 
 
 i9"-4 
 
 '111°  56'  37"-4 
 
 annual  decrease,      .  19"-4 
 
 Inclination  of  orbit  to  ecliptic,        .  .  2°  29'  35"-7 
 
 annual  decrease,     .  0"-155 
 
 Motion,  mean  daily,  ....  2'  0"-6 
 
 in  365  days,  .  ...  i2^13'36"-08 
 
 Inclination  of  axis  to  ecliptic,  .  .  .      31°  19'-0 
 
 Rotation  on  axis,      ....  18'^-  29™-  XT'- 
 
 Eevolution,  sidereal,  in  days,  .  .        10759*2197106 
 
 synodical,  ....       378-090 
 
 Mean  arc  of  retrogradation,  .  .  .6°  44' 
 
 SATURX'S  RINGS. 
 
 Bright  ring,  exterior  diameter  in  miles,                  ,  176,418 
 breadth  of  exterior  division,   .            .  10,573 
 
 interval  between  the  two  divisions,    .  1,791 
 
 exterior  diameter  of  interior  division,  151,690 
 
 breadth  of  interior  division,    .            .  17,175 
 
 time  of  rotation,                       .            lO'^-  35'"-  15'- 
 
 Dusky  ring,  breadth,            ....  6,350 
 
 interval  between  inner  edge  and  Saturn,  7,460 
 
 Divisions,  seen  by  Bond,      ....  2 
 
 discovered  by  Bond  in  the  year             .  1850 
 
 Years  in  which  it  will  reach  the  planet  by  increase 
 
 of  breadth  of  system  of  rings  (0.  Striive),           .  125 
 
 Breadth  of  whole  system  of  rings,  .            .            .  35,889 
 
 Exterior  division  of  bright  ring,  exterior  diameter,  40" -44 
 
 .  new  sub-division,  exterior  diameter 
 
 (Encke),          .  37"-47 
 
 interior  diameter,  36"*04 
 
 Divisions  of  exterior  bright  ring,  seen  by  Kater,  .  4 
 
SYNOPTICAL  TABLES,  349 
 
 Divisions  in  inner  bright  ring,  seen  by  De  Vico,  .  2 
 
 Dawes,     .  4 
 
 Isolated  stationary  bright  spots  on  disappearance 
 
 of  rings,  at  least   .                        ...  4 
 
 SATURN  S  SATELLITES. 
 
 Sidereal 
 Revolution. 
 
 Distance. 
 
 Year  of 
 
 No. 
 
 Name. 
 
 Saturn's 
 radius  =  1. 
 
 Discoverer. 
 
 Dis- 
 covery. 
 
 d.     h.    m.    s. 
 
 1 
 
 Mimas 
 
 0  22  36  18 
 
 3-1408 
 
 Herschel 
 
 1789 
 
 2 
 
 Enceladus 
 
 0     8  53     3 
 
 4-0319 
 
 Herschel 
 
 1789 
 
 3 
 
 Tethys 
 
 1  21  18  33 
 
 4-9926 
 
 Cassiui 
 
 1684 
 
 4 
 
 Dione 
 
 2  17  44  51 
 
 6-399 
 
 Cassini 
 
 1684 
 
 5 
 
 Rhea 
 
 4  12  25  11 
 
 8-932 
 
 Cassini 
 
 1672 
 
 6 
 
 Titan 
 
 15  22  41  25 
 
 20-706 
 
 Huyghens 
 
 1655 
 
 7 
 
 Hyperion 
 
 21     4  20     0 
 
 25-029 
 
 Bond  &  Lassell 
 
 1848 
 
 8 
 
 Japetus 
 
 79     7  54  41 
 
 64-359 
 
 Cassini 
 
 1671 
 
 Hyperion  discovered  by  Bond  and  Lassell  on  same 
 night,  year  .....  1848 
 
 Greatest  inclination  to  the  plane  of  the  ring 
 (Japetus), 12°  14' 
 
 Apparent  diameter  of  the  largest.  Titan,  (diam.  of 
 
 Saturn  =  1), 1-lCth 
 
 Length  of  telescope  with  which  Huyghens  dis- 
 covered Titan,  in  feet,      ....  124 
 
 Length  of  telescope  with  which  Cassini  discovered 
 
 Tethys  and  Dione,  in  feet,  .  .  145 
 
 UEANUS. 
 
 Volume  (Earth's  =  1) 
 Mass  (Earth's  =  1),  . 
 
 86-5 
 14-251 
 
350 
 
 SYNOPTICAL  TABLES. 
 
 Density  (Earth's  =  1), 
 Diameter  (Earth's  =  1), 
 
 in  miles    . 
 
 ■ apparent,  mean, 
 
 Gravity  (Earth's  =  1), 
 
 bodies  fall  in  one  second  of  time,  in  feet, 
 
 Light  and  heat  from  Sun,  perihelion, 
 
 aphelion. 
 
 Polar  less  than  equatorial  diameter, 
 
 Observed  by  Flamstead  in 
 
 Discovered  by  Herschel  in  . 
 
 Magnitude  of  Uranus  as  a  star  (occasionally  seen 
 
 with  naked  eye),   .... 
 Distance  from  the  Sun,  mean,  in  miles, 
 
 (Earth's  =  1), 
 
 maximum 
 
 •167 
 
 4-575 
 
 36,216 
 
 4"-l 
 
 0-76 
 
 12-3 
 
 •0027 
 
 •0025 
 
 l-9th 
 
 1690 
 
 1781 
 
 6th 
 
 822,328,000 
 
 19-18239 
 
 ,     20-07630 
 
 minimum,      18-28848 
 
 Eccentricity  of  orbit  (semi-axis  major  =1), 
 Longitude  of  perihelion, 
 annual  increase,     . 
 
 ascending  node, 
 
 annual  decrease, 
 
 Inclination  of  orbit  to  ecliptic. 
 
 Motion,  mean  daily, 
 
 in  365  days. 
 
 Inclination  of  axis  to  ecliptic, 
 Eotation  on  axis, 
 Eevolution,  sidereal,  in  days, 
 
 synodical, 
 
 Mean  arc  of  retrogradation, 
 
 annual  increase, 
 
 .  0-04667938 
 167°  31'  16"-1 
 
 2"-28 
 
 .  72°  59'  35" 
 
 36"-05 
 
 .     46'  28"-44 
 
 0-03 
 
 42"-35 
 
 .    4°  17'  45" 
 
 .     unknown 
 
 .     unknown 
 
 30686-820829 
 
 369-656 
 
 3°-36 
 
SYNOPTICAL  TABLES, 
 
 351 
 
 URANUS   SATELLITES. 
 
 No. 
 
 Name. 
 
 Sidereal 
 Revolution. 
 
 Mean 
 Apparent 
 Distance. 
 
 Discoverer, 
 
 Year  of 
 
 Dis- 
 covery. 
 
 1 
 2 
 3 
 4 
 
 Ariel 
 
 Umbriel 
 
 Titania 
 
 Oberon 
 
 d.    h.   m.    s. 
 2  12   29   21 
 4     3  28     8 
 8  16  56  31 
 13  11     7  13 
 
 13-54 
 
 19-28 
 31-44 
 
 42-87 
 
 Lassell 
 Lassell 
 Herschel 
 Herschel 
 
 1851 
 1851 
 
 1787 
 1787 
 
 Additional  satellites  seen  by  Herschel,  but  not 
 
 re-observed,  .....  4 
 
 Direction  of  movement  of  satellites  .  .  retrograde 
 
 Inclination  of  the  orbits  of  Titania  and  Oberon  to 
 
 ecliptic,^ 78°  58' 
 
 Distance  from  the  planet  -when  satellites  become 
 
 invisible  (Herschel),         ....  14" 
 
 Iklagnifying  power  required  for  sustained  view,      .  300 
 
 NEPTUNE. 
 
 Volume  (Earth's  =  1), 
 Mass  (Earth's  =  1),  . 
 Density  (Earth's  =  1), 
 Diameter  (Earth's  =  1), 
 
 in  miles,    . 
 
 apparent,  mean, 
 
 Gravity  (Earth  =  1), 
 
 bodies  fall  in  one  second,  in  feet, 
 
 Light  and  heat  from  Sun,  perihelion, 
 
 ■ aphelion, 
 
 Year  in  which  Adams  computed  its  place  within 
 
 2  degrees,  .... 
 
 Year  in  which  Leverrier  computed  its  place, 
 First  observed  by  M.  Galle,  from  Leverrier's  indi 
 
 cations,  23d  Sept., 
 
 76-6 
 
 18-900 
 
 •321 
 
 4-246 
 
 33,610 
 
 2-"4 
 
 1-36 
 
 21-8 
 
 •0011 
 
 •0011 
 
 1845 
 1846 
 
 1846 
 
352 
 
 SYNOPTICAL  TABLES, 
 
 Observed  by  M.  Challis,  but  not  recognised,  from 
 
 Adams'  indications,  4th  Aug., 
 Observed  as  a  fixed  star  by  Lalande  in 
 Magnitude  as  a  star, 
 Disc  seen  with  a  magnifying  power  of 
 Distance  from  the  Sun,  mean  in  miles, 
 
 (Earth's  =  1), 
 
 maximum, 
 
 minimum. 
 
 Eccentricity  of  orbit  (semi-axis  major  =  1), 
 Longitude  of  perihehon,  epoch  1854, 
 ascending  node. 
 
 Indmation  of  orbit. 
 Motion,  mean  daily, 
 ■    "■■■■    in  365  days,  . 
 Inclination  of  axis  to  ecliptic, 
 Rotation  on  axis. 
 Revolution,  sidereal,  in  days, 
 synodical, 
 
 1846 
 1795 
 
 7-8th 
 150 
 853,420,000 
 30-03627 
 30-29816 
 29-77438 
 •0087193 
 47°  17'  58" 
 130°  10'  12" 
 1°  46'  59" 
 21"-6 
 2°  11'  24" 
 unknown 
 imknown 
 60126-722 
 367-488 
 
 Neptune's  satellite. 
 
 Sidereal  revolution, 
 
 mean  distance,  apparent, 
 
 in  miles, 
 
 Orbit  inclined  to  plane  of  ecli]3tic. 
 Longitude  of  the  ascending  node. 
 
 5a.  24h.  o™-  17'- 
 
 16"-75 
 
 232,000 
 
 29° 
 
 .      175°  40' 
 
 COMETS. 
 
 Halley's — Time  of  perihelion  passage,  15th  Nov. 
 
 1835,       ....  22''-  41™-  22'- 
 
 longitude  of  perihelion,  .  304°  31'  32" 
 
 ascending  node,        .  .     55°  9'  59' 
 
 inclination  of  orbit  to  ecliptic,    .  .17°  45'  5'' 
 
SYNOPTICAL   TABLES.  353 
 
 Halley's — Eccentricity,         ....      0*967391 
 
 semi-axis,  ....      17-98796 
 
 period  in  days,  motion  retrograde,  .      27865-74 
 
 Encke's — Timeof  perihelion  passage,  9th  Aug.  1845, 15''-  ll""-  ll"- 
 
 longitude  of  periheUon,       .  .  157"^  44'  21" 
 
 a,scending  node,  .  334°  10'  33" 
 
 inclination  to  the  ecliptic,  .     13°  7'  34' 
 
 semi-axis,      .  .  .  .  .       22 1640 
 
 eccentricity,  ....      0-847436 
 
 period,  motion  direct,  .  .  .       1203*^  23 
 
 Biela's — Time  of  perihelion  passage,  11th  Feb.  1846,  O**-  2"-  50'- 
 
 longitude  of  perihelion,        .  .  .  109°  5'  47" 
 
 ascending  node,  .  245°  56'  58" 
 
 inclination  to  the  echptic,  .  .  12°  34'  14" 
 
 semi-axis,      .....        3-50182 
 
 eccentricity,  .  ...  .      0-755471 
 
 period,  motion  direct,  .  .  .       2393*^-52 
 
 Faye's — Time  of  perihelion  passage,  17th  Oct.  1843,  3*'-  42"- 16'- 
 
 longitude  of  perihelion,        .  .  .  49°  34'  19" 
 
 ascending  node,  .  209°  29'  19" 
 
 inclination  to  ecliptic,  .  .  11°  22'  31" 
 
 semi-axis,      .  .  .  .  .3-81179 
 
 eccentricity,  ....      0-555962 
 
 period,  motion  direct,  .  .  .       2718'' 26 
 
 DeVico's — Time  of  passing  perihelion,  2d  Sept.  1844,  ll*"-  36"^  53'- 
 
 longitude  of  perihelion,        .  .  342°  31'  15" 
 
 ascending  node,  .  .  63°  49'  31" 
 
 inclination  to  ecliptic, 
 
 semi-axis, 
 
 eccentricity, 
 
 i3eriod,  motion  direct, 
 
 2°  54'  45" 
 3-09946 
 0-617256 
 1993^09 
 Brorsen's — Time  of  passing  perihelion,  25th  Feb. 
 
 1S46,  ...  9^^  13-"  35'- 
 
 longitude  of  perihelion,        .  .  116°  28'  34" 
 
 ascending  node,  .  102°  39'  36" 
 
 inclination  to  ecliptic,  .  .  .     30°  55'  7' 
 
 semi-axis,      .  .  .  .       3-15021 
 
354  SYNOPTICAL  TABLES. 
 
 Brorsen's— Eccentricity,       ....  0-793629 
 
 period,  motion  direct,          .             .            .  2042^24 
 
 Number  of  calculated  non-periodic  comets  up  to 
 
 end  of  1855,         ....  206 
 
 with  short  periods,  .             .             .            .  12 
 
 with  medium  periods  (Halley's  included),  5 
 
 . with  long  periods,  probably             .            .  10 
 
 moving  in  hyperbolas,          ...  3 
 
 of  comets  observed  down  to  1850,  .             .  607 
 
 to  which  periods  have,  with  probability, 
 
 been  assigned,  about         ....  30 
 
 Probable  number  of  comets,  supposing  perihelia 
 
 equally  distributed  within  the  sphere  of  the 
 
 orbit  of  Neptune,  ....   17,558,424 
 
 Biela's  comet  separated  into  two  on  13th  January  1846 
 
 interval  between  the  two  parts  on 
 
 5th  March,  .  .  .  9' 19" 
 
 _ earth  escaped  collision  in  1832  by  .  30'*- 
 
 on  return  in  1852,  the  two  parts 
 
 were  separated,  in  miles  ....     1,250,000 
 Length  of  tail  of  great  comet  of  1680  in  miles,       140,000,000 
 
 in  arc,  .  90' 
 
 Time  in  which  tail  was  developed,  in  days,  .  2 
 
 Number  of  tails  of  comet  of  1744,  ...  6 
 
 Maximum  limit  of  density  of  Donati's  comet,  0-00000017 
 
 Arc  described  by  comet  of  1472  in  a  day,  .  .  40° 
 
 Comet  of  1680,  distance  from  Sun  at  perihelion 
 
 (Sun's  diameter  =  1),        .  .  .  .  l-6th 
 
 heat,  according  to  Newton  (red 
 
 hot  iron  =  1),    .  .  .  2000 
 — —  heat,  according  to  Newton,  time 
 
 required  to  lose  it,  in  years,        .  .  .  50,000 
 
 Halley  predicted  the  return  of  the  comet  of  1531 
 
 and  1607  in  ....  .  1759 
 
 Halley's  comet,  maximum  length  of  tail,  15th  Oct., 
 
 1S35, 20° 
 
SYNOPTICAL   TABLES.  355 
 
 Halley's  comet,  length  on  5th  Nov.  1835  (peri- 
 helion 15th  Nov.),  .  .  2°  30' 
 
 jet  and  tail  commenced    .  .  Oct.  2 
 
 oscillation  of  jet  obvious  in  the 
 
 com^se  of  .  .  .  l"*- 
 
 invisible  after  the  perihelion,  in 
 
 months,  ....  2 
 
 diameter  of  disc  when  seen,  not 
 
 including  coma,  ...  2' 
 
 increase  of  volume  of  illuminated 
 
 space  during  six  days,  from  Jan.  25,         .  .      40  times 
 
 Eeturn  of  Charles  V.  comet  of  1556,  predicted  by 
 
 Hind  in  period  .....  1856-Gl 
 Period  of  Encke's  comet,  shortening  at  the  rate, 
 
 per  revolution,  of  .  .  .  .  O'^-ll 
 Lexell's  comet  of  1770,  period  in  years,  .  .  55 
 thrown  out  of  the  system 
 
 by  attraction  of  Jupiter  in  1 779 
 distance  from  Sun  at  peri- 
 
 heHon  (Sun's  radius  =  1),  l-7th 
 angular  diameter  of  Sun  tit 
 
 perihelion,  .  .       121°  32" 
 disc  of  Sun  at  perihelion 
 
 (disc  from  Earth  =  1),    .  47,000 
 heat  at  perihelion  (heat  of 
 
 32  inch  burning  lens  =  1),  25 
 velocity  at  perihelion,  miles, 
 
 in  one  second,      .  .  366 
 
 ■  tail  stretching  to  the  Earth's 
 
 orbit,  whirled  round  in  two 
 
 hours,       .  .  .  180° 
 
 . radius    of    head    on   29th 
 
 March,  in  miles,  .  .         47,000 
 
 . length  of  tail,         .  150,000,000 
 
 .  breadth  of  tail,       .  .     3,000,000 
 
 f-O 
 
 Periodic  comets,  all  direct  w^hen  inclination  under  1 
 
 Comets  calculated  before  1849,  direct,       .  .  94 
 
356 
 
 SYNOPTICAL   TABLES. 
 
 Comets  calculated  before  1849,  retrograde, 
 Great  comet  of  1861,  distance  from  the  Earth  on 
 June  30,     . 
 
 surmised  by  Hind  that  the 
 
 Earth  passed  through  its 
 tail, 
 
 ■ length  of  tail  as  seen  at  Rome 
 
 as  seen  at  Paris 
 
 polarisation   of  tail    strong, 
 
 but  no  trace  in  nucleus  till 
 ■ tail  seen  to  flicker  and  dis- 
 appear for  an  instant. 
 
 Encke's  comet,  before  perihelion,  diameter  dimin- 
 ished in  two  months  to 
 after     perihelion,     diameter     in- 
 
 100 
 17,000,000 
 
 30th  June 
 
 118° 
 
 45° 
 
 3d  July 
 
 4th  July 
 
 l-90th 
 
 creased  in  six  days  from  1  to       . 
 Rotation  of  comet  of  1825  (doubtful), 
 Mass  of  LexelFs  comet  less  than  (Earth's  =  1) 
 Chances  unfavourable  to  collision  between  earth 
 
 and  a  comet  (comet's  diam.  =  l-4th  of  earth's),  281,000,000 
 
 40 
 
 19"-  37"- 
 
 l-5000th 
 
 DOUBLE  STARS. 
 Number  of  binary  systems  with  assigned  periods, 
 
 about         ..... 
 Period  of  Castor,  with  semi-axis  of  8",  in  years, 
 
 X  Ursro  Majoris,  with  semi-axis  of  3"-i 
 
 7  Virginis,  with  semi-axis  of  3"-6, 
 
 Causes  of  colour  in  stars,  intrinsic  and  complc' 
 
 mentary,    .  .  .  .  , 
 
 15 
 
 252 
 
 59 
 
 182 
 
 NEBULA. 
 Number  of  stars  covered  by  the  Moon  in  parts 
 
 of  the  Milky  Way,     . 
 in  some  clusters,  . 
 
 2000 
 50,000 
 
SYNOPTICAL   TABLES.  2>S7 
 
 Number  of  typical  forms  of  nebulDS  (globular  and 
 spiral),       ......  2 
 
 Hour  of  ascension  richest  in  nebulce,  .  .  12 
 
 Nebula  in  Andromeda,  largest  elliptical  nebula 
 visible  to  naked  eye. 
 
 dark  streaks  running  par- 
 allel to  longer  axis,  ....  2 
 
 Largest  annular  nebula  in  Lyra. 
 
 Planetary  nebuloe,  number  of,  about  .  .  25 
 
 largest,  distance  from  /3  Urss9 
 
 Majoris,  .  .  .  12' 
 
 largest,  apparent  diameter,       .  2'  40'' 
 
 Light  of  nebula  of  1'  diameter  if  as  bright  as  the 
 
 Sun,  in  full  Moons,  ....  780 
 
 Double  nebulce,  probable  physical  connexion  as  in 
 double  stars. 
 
 Most  brilliant  nebulous  star  in  Andromeda,  No.    .  65 
 
 Regions  of  amorphous  nebulse — Orion,  Argo,  Sag- 
 
 gitarius,  Cygnus,  ....  4 
 
 Nebula  in  sword-handle  of  Orion,  discovered  by 
 
 Huyghens  in  1656 
 
 diameter,  hori- 
 zontal, .  30' 
 
 ver- 
 
 tical, ......  24' 
 
 Variable  nebula,       .....  1 
 
 METEORIC  ZONES. 
 
 Zodiacal  light,  maximum  distance  of  vertex  from 
 
 Sun,            ....  90° 
 
 maximum  breadth  at  base,              .  30° 
 
 November    meteors,  passing   through  y  Leonis, 
 
 period,       ......  12tb-14th 
 
 Number  of  zones  of  asteroids,        ...  3 
 
358  SYNOPTICAL   TABLES. 
 
 FIXED  STAES. 
 
 Magnitude  of  the  smallest  stars  visible,      .            .  7th 
 stars  visible  by  the  most  power- 
 ful telescopes,       .....  IGth 
 Light  of  a  star  of  the  6th  magnitude  (1st  magni- 
 tude =  1),              1-lOOth 
 
 Number  of  stars  of  1st  magnitude,              .            .  24 
 
 2d  magnitude,              .            .  50-60 
 
 3(i  magnitude,              .            .  200 
 
 total   registered   to    7th  magni- 
 tude, about 
 total  visible  in  Herschel's  20-feet 
 
 telescope,  ......     5,500,000 
 
 Rate  at  which  light  travels  per  second,  in  miles,  .  200,000 
 Time  required  by  light  to  traverse  the  distance  of 
 
 a  star  with  one  second  of  parallax,  in  years,       .  3^-  83^ 
 
 Corresponding  distance  in  billions  of  miles,           .  20 
 Distance  of  smallest  stars  seen  in  telescopes  of  75 
 
 space  penetrating  power,  measured  by  light  in 
 
 years,         ......  2,000 
 
 Star  61  Cygni,  parallax  first  detected  in  it,  by  Bessel,  0"*349 
 
 proper  motion  annually,      .             .  5" 
 
 distance  of  component  stars,           .  15' 
 
 sum  of  masses  of  the  component 
 
 stars  (Sun  =  1),    .            .            .            .            .  0-353 
 
 a  Centauri,  parallax,             ....  0""912S 
 
 nearest  star,  distance    measured  by 
 
 light,  in  years,  about            .             .  3*5 
 
 proper  motion,             ...  4" 
 
 Number  of  stars  to  which  parallax  has  been  assigned,  9 
 Probable  average  distance  of  stars  of  1st  magnitude, 
 
 measured  by  light,  in  years,         .             .             .  15-5 
 
 2d  magnitude,  28 
 
 3d  magnitude,  43 
 
 — 4th  magnitude,  60 
 
 5th  magnitude,  84 
 
SYNOPTICAL   TABLES.  359 
 
 Probable  average  distance  of  stars  of  6th  magnitude,  120 
 
 iS^ebulse,  proportion  of  sphere  containing  one-third 
 
 of  whole  mass,  near  north  pole  of  the  galaxy,  l-8th 
 
 Largest  proper  motion,  1830,  Groombridge,  .  7" 
 
 Diameter  of  the  Sun  removed  to  a  distance  corre- 
 sponding to  one-second  parallax,  .  .         0"-0093 
 Light  of  Sirius  (Sun's  =  1  at  the  same  distance),  63 
 Light  of  the  Sun  (Sirius  =  1)  at  the  Earth,        20,000,000,000 
 Variable  star  Algole,  period,             .            .               2'^-  SO"*-  48^- 
 
 variation  in  magnitude,         .  2-4 
 
 S  Cephei,  period,        .  .  5<i-  ^-  47'=. 
 
 variation  in  magnitude,     .  3-5 
 
 /3  Ljrse.,  period,  .  .  12^-  23''-  53'"- 
 
 variation  in  magnitude,       .  3-4 
 
 Number  of  variable  stars,  with  assigned  periods, 
 
 about  ......  CO 
 
 Double  stars,  odds  against  one  chance  combina- 
 tion of  4"  closeness,  .  .    9570  to  1 
 number  of  such  combinations,  up- 
 wards of               •              .             .             .  .  100 
 
 Sun's  distance  from  Alcyone,  the  centre  of  the 
 stellar  system  (MaDdlar),  (radius  of  Earth's 
 orbit  =  1),    .  .  .  .  .  34,000,000 
 
 time  of  revolution  round  Alcyone,  in  years,  .  19,256,000 
 
 velocity  in  space  (Earth's  annual  motion  =  1),  1-4 
 
 Sun,  point  in  Hercules,  to  which  it  is  moving, 
 
 north  declination,       .         34°  37' 
 right  ascension, .  .        259°'90 
 
 TELESCOPE. 
 
 Lord  Eosse's  Great  Eeflector,  diameter  of  mirror, 
 in  feet,       ...... 
 
 thickness  of  mirror, 
 
 in  inches,  ..... 
 
36o  SYNOPTICAL  TABLES, 
 
 Lord  Rosse's  Great  Eeflector,  focal  length,  in  feet,  54 
 
 length  of  tube,  in  feet,  56 
 
 diameter  of  tube,  in  feet,         7 
 
 weight  of  speculum,  in  tons,  3 
 
 expense,      .  .      £12,000 
 
 Cambridge,  U.S.,  refractor,  diameter  of  object  glass,  in 
 
 inches,  .  .  15"125 
 
 . length  of  tube,  in  feet,  23 
 
 . magnifying  powers,  180-2000 
 
 .  weight  in  tons,  .  3 
 
 ._ diameter  of  declination- 
 circle,  in  inches,  26 
 
 . — hour  circle,  IS 
 
 cost,     .  .  .         „£'4,000 
 
 Object-glass  by  Clarke,  diameter,  in  inches,  .  lS-5 
 
 contract  price,        .  .  £2237 
 
 Diameter  of  object-glass  in  process  of  execution  by 
 
 Cooke,  in  inches,  ^         .  .  .  .  24 
 
 THE  ENC* 
 
 1.65 
 
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DATE  DUE 
 
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