﻿440 
  

  

  ON 
  THE 
  RELATIVE 
  HORIZONTAL 
  INTENSITIES 
  

  

  From 
  Nos. 
  4 
  and 
  2, 
  m 
  = 
  .000,116 
  

   u 
  a 
  4 
  a 
  j 
  5 
  m 
  — 
  .000,120 
  

  

  a 
  

  

  a 
  

  

  a 
  

  

  1, 
  m 
  = 
  .000,115 
  

  

  Mean 
  m 
  = 
  .000,117 
  

  

  It 
  appears 
  distinctly, 
  from 
  comparing 
  these 
  results, 
  that 
  the 
  change 
  

   of 
  intensity 
  of 
  the 
  needle's 
  magnetism 
  is 
  greater 
  at 
  the 
  higher 
  tempera- 
  

   tures 
  than 
  at 
  the 
  lower, 
  for 
  equal 
  changes 
  of 
  temperature. 
  The 
  value 
  

   of 
  m, 
  deduced 
  from 
  observations 
  between 
  72° 
  and 
  90°, 
  is 
  the 
  greatest; 
  

   next 
  the 
  value 
  obtained 
  between 
  34° 
  and 
  90°, 
  and 
  last 
  that 
  between 
  

   34° 
  and 
  72°. 
  This 
  change 
  would 
  have 
  appeared 
  greater 
  if 
  no 
  cor- 
  

   rection 
  had 
  been 
  made 
  for 
  the 
  daily 
  variation. 
  

  

  The 
  second 
  and 
  third 
  sets 
  of 
  observations 
  on 
  needle 
  A, 
  before 
  re- 
  

   ferred 
  to, 
  are 
  given 
  in 
  the 
  annexed 
  table. 
  The 
  object 
  of 
  these 
  sets 
  has 
  

   already 
  been 
  explained. 
  

  

  TABLE 
  No. 
  III. 
  

  

  Observations 
  for 
  the 
  Correction 
  for 
  Temperature 
  of 
  Needle 
  A. 
  

  

  a 
  

  

  

  

  

  

  

  

  > 
  

  

  ci 
  

  

  c 
  c 
  

  

  

  

  Times 
  of 
  Beginning 
  

  

  2 
  s 
  . 
  

  

  3 
  bo 
  W 
  

  

  3.5.9 
  

  

  Cm 
  

  

  ° 
  6 
  

  

  « 
  fcD 
  

  

  a 
  

  

  o 
  

  

  u 
  

  

  a. 
  

  

  o 
  2 
  

  

  O 
  

  

  a. 
  

  

  a 
  ■ 
  

   a 
  8 
  

  

  ».2 
  

  

  

  a 
  

  

  o 
  

  

  and 
  Ending. 
  

  

  ||J 
  

  

  'SO 
  

  

  > 
  

  

  a 
  

  

  a 
  

  

  o 
  

  

  ° 
  2. 
  

   £ 
  

  

  ^2 
  

  

  a 
  

  

  ta 
  

  

  o 
  

  

  o 
  a 
  

  

  Place 
  of 
  Observa- 
  

   tion, 
  &c. 
  

  

  o 
  

  

  d 
  

  

  

  

  H« 
  

  

  

  o 
  

   6 
  

  

  § 
  

  

  &" 
  

  

  a 
  

  

  

  Hours. 
  

  

  Min. 
  

  

  Sees. 
  

  

  Fah.° 
  

  

  Inch. 
  

  

  Fah.° 
  

  

  Sees. 
  

  

  Fali.° 
  

  

  Sees. 
  

  

  

  P.M. 
  

  

  4 
  

  

  10 
  

  

  47.6 
  

  

  31 
  

  

  

  

  

  

  

  

  la 
  small 
  Observatory, 
  

  

  5. 
  

  

  

  

  22 
  

  

  45.2 
  

  

  29| 
  

  

  4 
  

  

  200 
  

  

  30.2 
  

  

  35.88 
  

  

  30.2 
  

  

  35.880 
  

  

  out 
  of 
  doors, 
  Dec. 
  7, 
  

   1835. 
  Bache. 
  

  

  

  P.M. 
  

  

  5 
  

  

  31 
  

  

  36.0 
  

  

  86 
  

  

  

  

  

  

  

  

  

  

  

  43 
  

  

  40.0 
  

  

  90 
  

  

  +4* 
  

  

  200 
  

  

  88 
  

  

  36.20 
  

  

  

  

  

  

  

  5 
  

  

  46 
  

  

  48.8 
  

  

  92 
  

  

  

  

  

  

  

  

  

  6. 
  

  

  

  

  58 
  

  

  53.2 
  

  

  92 
  

  

  + 
  4 
  

  

  200 
  

  

  92 
  

  

  36.24 
  

  

  90.0 
  

  

  36.220 
  

  

  Bache. 
  

  

  

  P.M. 
  

  

  7 
  

  

  49 
  

  

  22.4 
  

  

  31 
  

  

  

  

  

  

  

  

  

  

  8 
  

  

  01 
  

  

  20.8 
  

  

  32 
  

  

  +4 
  

  

  200 
  

  

  31.5 
  

  

  35.92 
  

  

  

  

  

  

  

  8 
  

  

  04 
  

  

  42.8 
  

  

  32 
  

  

  * 
  

  

  

  

  

  

  

  

  7. 
  

  

  

  

  16 
  

  

  42.2 
  

  

  31 
  

  

  +4 
  

  

  200 
  

  

  31.7 
  

  

  35.97 
  

  

  31.6 
  

  

  35.945 
  

  

  Bache. 
  

  

  

  P.M. 
  

  

  11 
  

  

  08 
  

  

  10.6 
  

  

  86 
  

  

  

  

  

  

  

  

  In 
  the 
  house, 
  Feb. 
  1st, 
  

  

  

  

  

  23 
  

  

  05.6 
  

  

  80 
  

  

  31 
  

  

  250 
  

  

  84.0 
  

  

  35.80 
  

  

  

  

  1836. 
  

  

  

  

  11 
  

  

  26 
  

  

  26.4 
  

  

  80 
  

  

  

  

  

  

  

  

  

  8. 
  

  

  

  

  38 
  

  

  21.6 
  

  

  72 
  

  

  +4 
  

  

  200 
  

  

  76.0 
  

  

  35.76 
  

  

  80.0 
  

  

  35.780 
  

  

  Bache. 
  

  

  Feb. 
  2d. 
  

  

  

  A.M. 
  

  

  12 
  

  

  13 
  

  

  02.4 
  

  

  52£ 
  

  

  

  

  

  

  

  

  

  

  

  24 
  

  

  54.4 
  

  

  50 
  

  

  +4 
  

  

  200 
  

  

  50.8 
  

  

  35.60 
  

  

  

  

  

  

  

  12 
  

  

  26 
  

  

  27.4 
  

  

  50 
  

  

  

  

  

  

  

  

  

  9. 
  

  

  

  

  38 
  

  

  20.4 
  

  

  48 
  

  

  +4 
  

  

  200 
  49.2 
  

  

  35.65 
  

  

  50.0 
  

  

  35.625 
  

  

  Bache. 
  

  

  This 
  sign 
  denotes 
  that 
  the 
  gauge 
  was 
  above 
  the 
  mark 
  to 
  which 
  the 
  sign 
  is 
  prefixed. 
  

  

  