﻿Rowland 
  and 
  Pennimcm 
  — 
  Electrical 
  Measurements. 
  57 
  

  

  Queen 
  in 
  Position 
  

  

  current 
  with 
  of 
  Cor. 
  

  

  K 
  Coil. 
  R" 
  + 
  r. 
  Il"+r. 
  R 
  + 
  r. 
  Product. 
  A'. 
  L. 
  C. 
  C. 
  

  

  133 
  C 
  3448-8 
  106+5 
  n40-8 
  3933354' 
  I 
  1-3034 
  

  

  " 
  " 
  3447-0 
  105 
  + 
  5 
  " 
  2 
  '0164 
  -3355 
  "3346 
  

  

  1 
  3198 
  

  

  40 
  P 
  1578-5 
  57+5 
  1088-9 
  1718719-7 
  1 
  -5653 
  

   " 
  " 
  1578-4 
  58 
  + 
  5 
  " 
  2 
  -0164 
  '3384 
  

  

  -5817 
  

  

  This 
  method 
  can 
  be 
  used 
  with 
  great 
  accuracy 
  for 
  the 
  com- 
  

   parison 
  of 
  the 
  capacity 
  of 
  a 
  condenser 
  with 
  a 
  standard 
  con- 
  

   denser. 
  In 
  the 
  comparison, 
  first 
  one 
  condenser 
  and 
  then 
  the 
  other 
  

   would 
  be 
  placed 
  in 
  the 
  R 
  + 
  r 
  circuit. 
  If 
  the 
  two 
  condensers 
  

   are 
  of 
  nearly 
  the 
  same 
  capacity, 
  the 
  degree 
  of 
  accuracy 
  of 
  the 
  

   comparison 
  depends 
  upon 
  the 
  accuracy 
  with 
  which 
  ^" 
  -r 
  t' 
  can 
  

   be 
  set. 
  The 
  degree 
  of 
  accuracy 
  of 
  setting 
  )^" 
  4- 
  r' 
  varies 
  with 
  

   the 
  value 
  of 
  the 
  self-inductance 
  with 
  which 
  the 
  condensers 
  

   are 
  compared. 
  In 
  the 
  experiments 
  just 
  given, 
  using 
  the 
  differ- 
  

   ent 
  coils, 
  the 
  degree 
  of 
  accuracy 
  with 
  which 
  two 
  \ 
  microfarad 
  

   condensers 
  could 
  have 
  been 
  compared 
  would 
  vary 
  from 
  1 
  part 
  

   in 
  2000 
  to 
  one 
  part 
  in 
  11000. 
  The 
  two 
  condensers 
  are 
  sup- 
  

   posed 
  to 
  be 
  without 
  absorption, 
  as 
  its 
  presence 
  would 
  cause 
  

   trouble 
  unless 
  the 
  absorption 
  resistances 
  were 
  known. 
  

  

  Resume. 
  — 
  Summing 
  up 
  the 
  results 
  deduced 
  in 
  this 
  paper, 
  it 
  

   is 
  seen 
  that 
  the 
  methods 
  for 
  the 
  absolute 
  determination 
  of 
  self- 
  

   inductance 
  and 
  capacity 
  do 
  not 
  give 
  as 
  concordant 
  results 
  as 
  

   could 
  be 
  wished. 
  The 
  irregularity 
  of 
  results 
  w^as 
  caused, 
  in 
  

   the 
  most 
  part, 
  both 
  in 
  the 
  determination 
  of 
  self-inductance 
  

   and 
  capacity 
  by 
  the 
  variation 
  of 
  the 
  periods 
  of 
  the 
  currents 
  

   used 
  in 
  the 
  experiments. 
  As 
  the 
  period 
  enters 
  directly 
  into 
  

   the 
  determination 
  of 
  self-inductance 
  and 
  capacity, 
  all 
  variations 
  

   of 
  the 
  period 
  will 
  appear 
  in 
  the 
  results. 
  The 
  determination 
  of 
  

   capacity 
  is 
  complicated 
  by 
  the 
  presence 
  of 
  electric 
  absorption 
  

   (pp. 
  H 
  and 
  -15). 
  The 
  effect 
  of 
  electric 
  absorption 
  is 
  shown 
  to 
  

   be 
  that 
  of 
  an 
  added 
  resistance 
  in 
  series 
  with 
  the 
  condenser, 
  

   called 
  absorption 
  resistance. 
  A 
  direct 
  method 
  is 
  given 
  by 
  

   which 
  absorption 
  resistance 
  can 
  be 
  measured 
  (p. 
  -il), 
  and 
  experi- 
  

   ments 
  are 
  given 
  which 
  show 
  that 
  when 
  condensers 
  possessing 
  

   absorption 
  are 
  in 
  series 
  or 
  in 
  parallel, 
  their 
  absorption 
  resistances 
  

   act 
  under 
  these 
  conditions 
  as 
  ohmic 
  resistances 
  in 
  series 
  with 
  

   the 
  separate 
  condensers 
  (p. 
  45). 
  Absorption 
  resistance 
  is 
  also 
  

   found 
  to 
  be 
  extremely 
  sensitive 
  to 
  temperature. 
  

  

  The 
  methods 
  for 
  the 
  comparison 
  of 
  two 
  self 
  -inductances 
  or 
  

   a 
  self-inductance 
  and 
  a 
  capacity 
  are 
  independent 
  of 
  the 
  period, 
  

   and 
  when 
  the 
  self-inductances 
  are 
  of 
  different 
  magnitudes 
  the 
  

   comparison 
  can 
  be 
  made 
  with 
  an 
  accuracy 
  of 
  1 
  part 
  in 
  10000. 
  

   These 
  methods, 
  therefore, 
  give 
  a 
  means 
  of 
  comparison 
  of 
  a 
  self- 
  

   inductance 
  with 
  a 
  standard 
  self-inductance, 
  or 
  a 
  capacity 
  with 
  

   a 
  standard 
  capacity 
  to 
  an 
  accuracy 
  of 
  1 
  part 
  in 
  10000, 
  or 
  they 
  

   allow 
  the 
  establishment 
  of 
  standards. 
  

  

  