﻿138 
  Transactions. 
  — 
  'Miscellaneous. 
  

  

  the 
  tAvo 
  retreating 
  bodies 
  will 
  in 
  many 
  cases 
  cause 
  one 
  or 
  both 
  of 
  them 
  to 
  

   be 
  attracted 
  back 
  to 
  the 
  coalesced 
  mass 
  ; 
  but 
  as 
  the 
  force 
  which 
  produces 
  

   this 
  return 
  is 
  partially 
  due 
  to 
  the 
  other 
  retreating 
  body, 
  and 
  for 
  reasons 
  

   already 
  mentioned, 
  the 
  returning 
  body 
  will 
  not 
  necessarily 
  come 
  nito 
  

   collision 
  with 
  the 
  coalesced 
  mass, 
  but 
  may 
  revolve 
  around 
  it 
  producing 
  

   double 
  stars, 
  or, 
  if 
  both 
  bodies 
  returned, 
  triple 
  stars, 
  and 
  in 
  many 
  cases 
  the 
  

   coalesced 
  mass 
  would 
  also 
  separate 
  and 
  produce 
  even 
  quadruple, 
  or 
  still 
  

   higher 
  multiple 
  stars. 
  I 
  need 
  not 
  say 
  that 
  many 
  thousands 
  of 
  multiple 
  

   stars 
  exist. 
  Generally 
  the 
  returning 
  stars, 
  although 
  sometimes 
  of 
  greater 
  

   magnitude, 
  would 
  be 
  of 
  less 
  luminosity, 
  but 
  this 
  body 
  would 
  collect 
  much 
  

   of 
  the 
  matter 
  revolving 
  around 
  the 
  more 
  luminous 
  body, 
  and 
  so 
  have 
  its 
  

   own 
  temperature 
  raised. 
  In 
  the 
  case 
  of 
  nearly 
  complete 
  collision, 
  the 
  two 
  

   pieces 
  leaving 
  the 
  coalesced 
  mass 
  might 
  reasonably 
  be 
  expected 
  to 
  break 
  

   into 
  pieces. 
  It 
  is 
  possible 
  to 
  show 
  that 
  the 
  rotation 
  of 
  each 
  of 
  these 
  pieces 
  

   must 
  generally 
  be 
  in 
  the 
  same 
  direction 
  as 
  the 
  rotation 
  of 
  the 
  coalesced 
  

   mass, 
  and 
  that 
  most 
  of 
  the 
  forces 
  acting 
  would 
  tend 
  to 
  produce 
  a 
  system 
  

   resembling 
  the 
  solar 
  system. 
  

  

  XelndcE. 
  

   I 
  have 
  already 
  shown 
  how 
  a 
  ring 
  nebula 
  may 
  be 
  produced 
  by 
  a 
  case 
  of 
  

   partial 
  collision. 
  The 
  cometic 
  nebulse 
  would 
  be 
  produced 
  when 
  a 
  high 
  

   resultant 
  velocity 
  was 
  produced 
  in 
  the 
  coalesced 
  mass. 
  It 
  is 
  not 
  difficult 
  

   to 
  conceive 
  that 
  in 
  the 
  collisions 
  of 
  approximately 
  equal 
  bodies 
  the 
  coalesced 
  

   mass 
  might 
  separate 
  chiefly 
  into 
  two 
  other 
  larger 
  masses, 
  and 
  produce 
  

   double 
  nebulae, 
  and 
  ultimately 
  double 
  stars 
  revolving 
  around 
  each 
  other. 
  

   Again, 
  a 
  case 
  of 
  almost 
  complete 
  coalescence 
  appears 
  competent 
  to 
  give 
  rise 
  

   to 
  the 
  conditions 
  we 
  observe 
  in 
  the 
  spiral 
  nebulre, 
  as 
  it 
  will 
  be 
  seen 
  that 
  

   rotation 
  will 
  be 
  very 
  slow 
  in 
  this 
  case, 
  and 
  the 
  expulsion 
  of 
  matter 
  

   irregular, 
  although 
  it 
  must 
  be 
  confessed 
  that 
  it 
  seems 
  probable 
  that 
  

   generally 
  a 
  large 
  nucleus 
  of 
  continuous 
  nebulae 
  would 
  be 
  produced. 
  At 
  

   the 
  same 
  time 
  possibly 
  higher 
  power 
  observations 
  may 
  show 
  this 
  to 
  be 
  the 
  

   case. 
  

  

  Art. 
  IX. 
  — 
  On 
  the 
  Calculation 
  of 
  Distances 
  hy 
  means 
  of 
  Reciprocal 
  Vertical 
  

  

  Anijles. 
  By 
  C. 
  W. 
  Adams. 
  

  

  [Read 
  before 
  the 
  Philosophical 
  Institute 
  of 
  Canterhury, 
  12th 
  September, 
  1S78.] 
  

  

  The 
  distance 
  between 
  any 
  two 
  points 
  on 
  the 
  earth's 
  surface 
  may 
  be 
  found, 
  

  

  if 
  the 
  angle 
  subtended 
  by 
  those 
  points 
  at 
  the 
  C3ntre 
  of 
  the 
  earth 
  is 
  known, 
  

  

  