﻿316 
  Geological 
  Survey 
  of 
  Louisiana 
  [Sect. 
  

  

  can 
  be 
  placed 
  where 
  the 
  mean 
  of 
  the 
  elongation 
  readings 
  was 
  on 
  

   the 
  previous 
  night 
  and 
  the 
  azimuth 
  of 
  the 
  stars 
  at 
  elongation 
  

   laid 
  off 
  in 
  order 
  to 
  establish 
  the 
  true 
  north 
  and 
  south 
  line. 
  The 
  

   position 
  for 
  Polaris 
  and 
  several 
  other 
  circumpolar 
  stars 
  is 
  

   conveniently 
  given 
  for 
  each 
  day 
  of 
  the 
  year 
  in 
  the 
  American 
  

   Ephemeris 
  and 
  Nautical 
  Almanac. 
  The 
  latitude 
  of 
  the 
  place 
  can 
  

   be 
  determined 
  with 
  sufficient 
  accuracy 
  by 
  an 
  inspection 
  of 
  any 
  

   good 
  state 
  map. 
  Then 
  

  

  . 
  ^, 
  Sin. 
  Polar 
  Distance 
  

  

  Sin. 
  Az. 
  at 
  Elong. 
  = 
  z;^ 
  — 
  -. 
  

  

  Cosine 
  Latitude. 
  

  

  The 
  surveyor 
  will 
  find 
  it 
  greatly 
  to 
  his 
  advantage 
  to 
  establish 
  

   his 
  meridian 
  line 
  in 
  the 
  day-time 
  before 
  his 
  night 
  work 
  by 
  equal 
  

   altitudes, 
  or 
  ordinary 
  alt-azimuth 
  observations 
  on 
  the 
  sun 
  to 
  

   within 
  i' 
  of 
  arc. 
  He 
  will 
  thus 
  be 
  able 
  to 
  have 
  the 
  monuments 
  

   placed, 
  but 
  not 
  cemented 
  in, 
  and 
  will 
  also 
  have 
  his 
  scale 
  placed 
  

   already 
  for 
  illumination 
  at 
  night. 
  The 
  final 
  lining 
  up 
  of 
  the 
  

   monuments 
  is 
  but 
  a 
  short 
  task 
  for 
  the 
  next 
  morning. 
  Where 
  

   monuments 
  are 
  small 
  and 
  of 
  local 
  construction, 
  there 
  should 
  

   always 
  be 
  four 
  placed 
  in 
  line 
  so 
  that 
  any 
  disturbance 
  in 
  one 
  can 
  

   be 
  detected 
  by 
  the 
  rest. 
  

  

  Our 
  Outfit 
  and 
  Experiences 
  

  

  We 
  have 
  only 
  to 
  add 
  that 
  our 
  outfit 
  for 
  the 
  past 
  year 
  consisted 
  

   of 
  a 
  good 
  Heller 
  & 
  Brightly 
  engineer's 
  transit, 
  of 
  high 
  magni- 
  

   fying 
  power, 
  but 
  with 
  verniers 
  reading 
  directly 
  to 
  minutes 
  only. 
  

   Great 
  interest 
  seemed 
  everywhere 
  to 
  be 
  manifest 
  in 
  the 
  work 
  

   and 
  we 
  are 
  glad 
  to 
  say 
  that 
  during 
  the 
  coming 
  year 
  this 
  work 
  

   will 
  be 
  greatly 
  facilitated 
  by 
  the 
  use 
  of 
  an 
  instrument 
  of 
  a 
  much 
  

   superior 
  order 
  of 
  construction 
  and 
  refinement. 
  

  

  With 
  our 
  present 
  small 
  staff, 
  no 
  considerable 
  amount 
  of 
  time 
  

   can 
  be 
  spent 
  on 
  work 
  of 
  this 
  nature. 
  It 
  is 
  for 
  this 
  reason 
  we 
  

   have 
  suggested 
  and 
  urged 
  co-operation 
  with 
  the 
  U. 
  S. 
  Coast 
  and 
  

   Geodetic 
  Survey. 
  See 
  Introduction. 
  

  

  As 
  will 
  be 
  seen 
  below, 
  we 
  have 
  been 
  favored 
  by 
  Maj. 
  Willard 
  

   with 
  careful 
  descriptions 
  of 
  many 
  of 
  the 
  Reference 
  and 
  Azimuth 
  

   Points 
  of 
  several 
  of 
  the 
  river 
  surveys. 
  

  

  