﻿442 
  

  

  ON 
  THE 
  RELATIVE 
  HORIZONTAL 
  INTENSITIES 
  

  

  correction 
  that 
  the 
  observations 
  upon 
  it 
  were 
  quite 
  laboured. 
  It 
  will 
  

   probably 
  be 
  better 
  not 
  to 
  go 
  into 
  the 
  same 
  detail 
  in 
  stating 
  these 
  re- 
  

   sults 
  as 
  in 
  the 
  former 
  ones. 
  With 
  this 
  impression 
  we 
  present 
  the 
  fol- 
  

   lowing 
  table. 
  The 
  first 
  column 
  contains 
  the 
  number 
  of 
  the 
  observa- 
  

   tion 
  ; 
  the 
  second, 
  the 
  designation 
  of 
  the 
  needle 
  ; 
  the 
  third, 
  the 
  mean 
  

   time 
  at 
  which 
  the 
  set 
  of 
  observations 
  was 
  made 
  ; 
  the 
  fourth, 
  the 
  num- 
  

   ber 
  of 
  oscillations 
  from 
  which 
  the 
  time 
  of 
  ten 
  contained 
  in 
  the 
  sixth 
  

   has 
  been 
  calculated 
  ; 
  the 
  fifth, 
  the 
  mean 
  temperature 
  ; 
  the 
  seventh, 
  re- 
  

   marks, 
  &c. 
  

  

  TABLE 
  No. 
  IV. 
  

  

  Observations 
  for 
  the 
  Correction 
  for 
  Temperature 
  of 
  Needles 
  C 
  and 
  B. 
  

  

  a 
  

  

  o 
  

  

  > 
  

  

  u 
  

   o 
  

  

  DQ 
  

  

  .a 
  

  

  o 
  

  

  o 
  

   6 
  

  

  O 
  

   O 
  

  

  tn 
  

  

  o 
  

  

  C 
  a! 
  

  

  .2 
  — 
  

  

  a 
  

  

  'ai 
  

  

  <L> 
  

  

  Q 
  

  

  

  a 
  

   o 
  

  

  ci 
  

  

  > 
  

  

  en 
  

  

  o 
  

  

  6 
  

  

  t5 
  

  

  f-t 
  

  

  h 
  

  

  s 
  

  

  l_, 
  to 
  

  

  o 
  a 
  

   o 
  

  

  go 
  

  

  Remarks, 
  &c. 
  

  

  Hours. 
  

  

  Fah.° 
  

  

  Sees. 
  

  

  1 
  

   2 
  

   3 
  

  

  4 
  

  

  C. 
  

  

  2.1 
  

   4.5 
  

  

  7.7 
  

   9.4 
  

  

  550 
  

  

  1226 
  

  

  400 
  

  

  450 
  

  

  47.8 
  

   87.8 
  

   65.5 
  

   48.0 
  

  

  32.005 
  

   32.044 
  

   31.980 
  

   31.930 
  

  

  Bache, 
  observer. 
  

   February 
  1, 
  1836. 
  In 
  doors. 
  Gauge 
  3| 
  to 
  +4. 
  

   Jar 
  leaks 
  much, 
  frequently 
  exhausted. 
  Sets 
  of 
  from 
  

   Gauge 
  3J 
  to 
  4. 
  [150 
  to 
  250 
  observations. 
  

   " 
  4 
  and 
  above. 
  

  

  5 
  

   6 
  

  

  7 
  

  

  B. 
  

  

  5.3 
  

  

  7.7 
  

   9.6 
  

  

  400 
  

   320 
  

  

  284 
  

  

  37.7 
  48.230 
  

   89.9 
  49.085 
  

   45.2| 
  48.260 
  

  

  Bache, 
  observer. 
  

   In 
  doors. 
  February 
  4th. 
  Gauge 
  about 
  4 
  inches. 
  

   Gauge 
  3 
  J 
  to 
  4. 
  

  

  " 
  above 
  4. 
  Jar 
  leaks 
  badly. 
  

  

  Needle 
  B 
  presents 
  a 
  curious 
  case 
  of 
  correction 
  for 
  temperature. 
  

   The 
  diurnal 
  variation 
  shown 
  from 
  observations 
  1 
  and 
  3 
  is 
  greater 
  than 
  

   the 
  correction 
  for 
  eighteen 
  degrees 
  of 
  temperature. 
  This 
  fact 
  was 
  per- 
  

   ceived 
  during 
  the 
  experiments, 
  and 
  led 
  to 
  the 
  very 
  frequent 
  repeti- 
  

   tions 
  of 
  the 
  experiment 
  at 
  87.8°, 
  No. 
  2 
  of 
  the 
  table. 
  Using 
  observa- 
  

   tions 
  1 
  and 
  4 
  for 
  the 
  correction 
  for 
  change 
  of 
  intensity, 
  and 
  assuming 
  

   that 
  change 
  to 
  have 
  been 
  regular, 
  observations 
  1 
  and 
  2 
  give 
  for 
  the 
  

   coefficient 
  of 
  the 
  correction 
  for 
  temperature, 
  

  

  m 
  = 
  .000,049, 
  

   And 
  1 
  and 
  3 
  give 
  m 
  — 
  .000,056 
  

  

  Mean 
  m 
  = 
  .000,052 
  

  

  