﻿Resistance 
  of 
  Metals 
  when, 
  placed 
  in 
  a 
  Magnetic 
  Field. 
  651] 
  

  

  small 
  rectangular 
  parallelepiped. 
  Magnified 
  views 
  in 
  plan 
  

   and 
  elevation 
  are 
  shown 
  in 
  figs. 
  4 
  and 
  5. 
  

  

  Fig. 
  5. 
  

  

  This 
  resistance 
  could 
  be 
  placed 
  so 
  that 
  the 
  current 
  was 
  

   either 
  parallel 
  or 
  perpendicular 
  to 
  the 
  lines 
  of 
  force. 
  A 
  series 
  

   of 
  experiments 
  were 
  made 
  on 
  german-silver, 
  copper, 
  silver, 
  

   tin, 
  and 
  zinc. 
  The 
  german-silver 
  gave 
  no 
  change 
  for 
  a 
  field 
  

   of 
  19,800 
  lines. 
  A 
  number 
  of 
  observations 
  were 
  made 
  on 
  

   each 
  of 
  the 
  others, 
  and 
  the 
  average 
  values 
  obtained 
  are 
  given 
  

   in 
  Table 
  VI. 
  

  

  Table 
  VJ, 
  

  

  Metal. 
  

  

  Magnetic 
  

   field. 
  

  

  Resistance 
  of 
  

   wire 
  in 
  field. 
  

  

  (*)it= 
  increase 
  d^ 
  jqi 
  

  

  due 
  to 
  field 
  . 
  a 
  

  

  Silver 
  

  

  22700 
  

   20300 
  

  

  22700 
  

   20300 
  

  

  22700 
  

   20300 
  

  

  23500 
  

   20800 
  

  

  10-7189 
  

   10-7159 
  

  

  25-5704 
  

   25*5672 
  

  

  19-0671 
  

   19 
  0671 
  

  

  •00105 
  

  

  •00085 
  

  

  •0024 
  

   •0019 
  

  

  •0057 
  

   •0047 
  

  

  •98 
  

  

  Tin 
  

  

  •79 
  

   •93 
  

  

  Zinc 
  

  

  Copper 
  

  

  •74 
  

  

  309 
  

   246 
  

  

  T80 
  

  

  

  1-54 
  

  

  The 
  same 
  piece 
  of 
  copper 
  wire 
  was 
  used 
  to 
  measure 
  the 
  

   change 
  of 
  resistance 
  in 
  both 
  transverse 
  and 
  longitudinal 
  fields. 
  

   The 
  values 
  obtained 
  for 
  the 
  change 
  of 
  resistance 
  in 
  the 
  same 
  

   field 
  appeared 
  to 
  be 
  slightly 
  greater 
  when 
  the 
  field 
  was 
  trans- 
  

   verse 
  than 
  when 
  longitudinal. 
  

  

  In 
  Table 
  V. 
  the 
  values 
  for 
  silver 
  appear 
  somewhat 
  

   discordant 
  as 
  are 
  also 
  those 
  for 
  copper 
  given 
  in 
  Tables 
  I., 
  II., 
  

   & 
  III. 
  These 
  two 
  metals, 
  however, 
  are 
  the 
  best 
  conductors, 
  

   and 
  considerable 
  more 
  difficulty 
  was 
  experienced 
  in 
  measuring 
  

   the 
  change 
  of 
  resistance 
  due 
  to 
  the 
  magnetic 
  field 
  in 
  these 
  

   metals 
  than 
  in 
  the 
  others. 
  

  

  The 
  difficulties 
  connected 
  with 
  measuring 
  such 
  small 
  

   changes 
  are 
  too 
  great 
  to 
  expect 
  very 
  accurate 
  results 
  : 
  hence 
  

   not 
  much 
  more 
  can 
  be 
  claimed 
  for 
  the 
  numbers 
  given 
  in 
  this 
  

   paper 
  than 
  that 
  they 
  represent 
  the 
  order 
  of 
  magnitude 
  of 
  the 
  

   change 
  of 
  resistance 
  in 
  the 
  magnetic 
  field. 
  

  

  Phil. 
  Mag. 
  S. 
  6. 
  Vol. 
  3. 
  No. 
  18. 
  June 
  1902. 
  2 
  X 
  

  

  