﻿194 
  ANNUAL 
  EEPORT 
  SMITHSONIAN 
  INSTITUTION, 
  192 
  9 
  

  

  side 
  of 
  the 
  Milky 
  Way. 
  Similar 
  diagrams, 
  showing 
  very 
  similar 
  curves, 
  

   were 
  also 
  prepared 
  for 
  limiting 
  magnitudes 
  9. 
  0, 
  11.0, 
  13.5, 
  and 
  18.0. 
  

   Positions 
  along 
  the 
  Milky 
  Way, 
  or 
  along 
  one 
  of 
  the 
  parallel 
  circles 
  

   identified 
  by 
  the 
  galactic 
  latitudes 
  on 
  the 
  left 
  of 
  the 
  diagram, 
  are 
  indi- 
  

   cated 
  by 
  longitudes 
  at 
  the 
  top, 
  measured 
  from 
  a 
  standard 
  meridian, 
  

   just 
  as 
  in 
  the 
  case 
  of 
  longitudes 
  on 
  the 
  earth. 
  Portions 
  of 
  curves 
  which 
  

   lie 
  above 
  the 
  horizontal 
  axes 
  mean 
  that 
  the 
  observed 
  numbers 
  of 
  stars 
  

   in 
  the 
  corresponding 
  regions 
  of 
  the 
  sky 
  are 
  greater 
  than 
  the 
  average 
  

   number 
  for 
  the 
  whole 
  circuit; 
  points 
  below 
  the 
  axes 
  represent 
  observed 
  

   numbers 
  which 
  are 
  less 
  than 
  the 
  average. 
  

  

  In 
  spite 
  of 
  numerous 
  irregularities, 
  most 
  of 
  the 
  curves 
  show 
  a 
  gen- 
  

   eral 
  similarity 
  in 
  that 
  in 
  longitudes 
  240° 
  to 
  360°, 
  and 
  on 
  to 
  60°, 
  they 
  

   lie 
  above 
  their 
  respective 
  axes, 
  while 
  in 
  longitudes 
  60° 
  to 
  240° 
  they 
  

   drop 
  below. 
  This 
  general 
  statement 
  disregards 
  a 
  conspicuous 
  drop 
  

   in 
  the 
  curves 
  for 
  low 
  latitudes 
  near 
  longitude 
  360°. 
  This 
  irregularity 
  

   must 
  be 
  disregarded, 
  for 
  it 
  represents 
  the 
  great 
  rift 
  between 
  the 
  two 
  

   branches 
  of 
  the 
  Milky 
  Way, 
  where 
  the 
  number 
  of 
  stars 
  counted 
  is 
  not 
  

   representative 
  of 
  those 
  probably 
  present. 
  There, 
  we 
  have 
  reason 
  to 
  

   believe, 
  great 
  numbers 
  of 
  stars 
  are 
  blotted 
  out 
  by 
  obscuring 
  clouds 
  of 
  

   dust 
  and 
  nebulous 
  material. 
  

  

  With 
  allowance 
  for 
  this 
  anomaly, 
  a 
  systematic 
  departure 
  from 
  the 
  

   average 
  numbers 
  of 
  stars 
  is 
  c 
  early 
  revealed 
  in 
  the 
  counts, 
  which 
  can 
  

   be 
  traced 
  to 
  a 
  great 
  distance 
  from 
  the 
  Milky 
  Way. 
  Figure 
  1 
  shows 
  

   that 
  in 
  all 
  latitudes 
  we 
  have 
  counted 
  the 
  largest 
  number 
  of 
  stars 
  in 
  

   the 
  same 
  general 
  longitude, 
  the 
  smallest 
  in 
  the 
  opposite 
  longitude. 
  

   The 
  longitudes 
  of 
  the 
  richest 
  regions 
  found 
  by 
  a 
  numerical 
  discussion 
  

   of 
  the 
  data 
  run 
  as 
  in 
  Table 
  III. 
  

  

  Table 
  III 
  

  

  Latitude 
  0° 
  5° 
  10° 
  20° 
  30° 
  40° 
  50° 
  60° 
  70° 
  

  

  ■* 
  A 
  QnQ^^^l 
  298 
  301 
  307 
  334 
  336 
  299 
  277 
  north 
  of 
  M. 
  W. 
  

  

  Longitude 
  '^^^jsiy 
  328 
  328 
  332 
  331 
  345 
  354 
  340 
  south 
  of 
  M. 
  W. 
  

  

  These 
  numbers 
  are 
  by 
  no 
  means 
  equal; 
  indeed 
  they 
  range 
  over 
  a 
  

   good 
  many 
  degrees, 
  especially 
  in 
  high 
  latitudes. 
  But 
  it 
  must 
  be 
  

   remembered 
  that 
  the 
  stars 
  are 
  not 
  distributed 
  with 
  exact 
  uniformity 
  

   and 
  that 
  local 
  and 
  purely 
  random 
  irregularities 
  tend 
  to 
  obscure 
  any 
  

   structural 
  feature, 
  however 
  important, 
  when 
  we 
  attempt 
  to 
  trace 
  that 
  

   feature 
  in 
  Umited 
  portions 
  of 
  the 
  data. 
  In 
  the 
  present 
  instance 
  the 
  

   individual 
  longitudes 
  cluster 
  around 
  a 
  mean 
  value 
  of 
  319°7 
  with 
  an 
  

   average 
  departure 
  of 
  15°. 
  Local 
  deviations 
  from 
  uniformity 
  in 
  the 
  

   distribution 
  fully 
  account 
  for 
  the 
  scatter 
  in 
  the 
  individual 
  values, 
  

   whence 
  we 
  conclude 
  that 
  we 
  have 
  brought 
  to 
  hght 
  something 
  funda- 
  

   mental 
  in 
  the 
  arrangement 
  of 
  stars 
  in 
  space. 
  The 
  importance 
  of 
  the 
  

   phenomenon 
  becomes 
  clear 
  only 
  when 
  we 
  translate 
  the 
  deviations 
  in 
  

   l6ngitude 
  into 
  numbers; 
  then 
  we 
  find 
  that 
  nearly 
  five 
  times 
  as 
  many 
  

  

  