﻿Rowland 
  and 
  Penniman 
  — 
  Electrical 
  Measurements. 
  55 
  

  

  4 
  1 
  

  

  In 
  the 
  same 
  way 
  it 
  is 
  found 
  that 
  

  

  R+r+z6L 
  

   r 
  

  

  {R-\-r)r' 
  -^ibhr' 
  

  

  ibc 
  

   Therefore 
  the 
  real 
  part 
  is 
  

  

  (R 
  + 
  r) 
  (R" 
  + 
  r>T' 
  rr' 
  

  

  C,C3 
  cos 
  (<^, 
  - 
  <^3) 
  = 
  C3» 
  -^ 
  -^ 
  a 
  D 
  

  

  where 
  D 
  is 
  the 
  deflection. 
  When 
  D 
  is 
  equal 
  to 
  zero 
  

  

  (R+r)(ir+r')-A 
  = 
  o 
  

  

  c 
  

  

  or 
  

  

  ~ 
  = 
  (R"+»-')(R+r-) 
  

  

  In 
  the 
  experinaents 
  by 
  this 
  method 
  the 
  \ 
  microfarad 
  Elliott 
  

   condenser 
  was 
  used, 
  and 
  it 
  was 
  compared 
  with 
  the 
  different 
  

   coils 
  Pj, 
  P,, 
  A, 
  and 
  C. 
  The 
  connections 
  were 
  made 
  with 
  open 
  

   leads 
  and 
  open 
  resistances 
  were 
  used 
  as 
  far 
  as 
  possible, 
  but 
  it 
  

   was 
  necessary 
  to 
  use 
  resistance 
  boxes 
  for 
  the 
  last 
  adjustments. 
  

   The 
  connections 
  having 
  been 
  made 
  as 
  in 
  figure, 
  the 
  process 
  of 
  

   experimenting 
  was 
  to 
  keep 
  r 
  and 
  r' 
  constant 
  and 
  to 
  adjust 
  ^" 
  

   and 
  P 
  until 
  there 
  was 
  no 
  deflection 
  of 
  the 
  hanging 
  coil. 
  The 
  

   resistance 
  of 
  the 
  circuits 
  P'^ 
  + 
  r' 
  and 
  P 
  H- 
  r 
  were 
  then 
  

   measured 
  on 
  a 
  Wheatstone 
  bridge. 
  The 
  commutator 
  A' 
  was 
  

   reversed 
  and 
  the 
  process 
  was 
  repeated. 
  The 
  condenser 
  had 
  

   absorption 
  (see 
  p. 
  45) 
  which 
  caused 
  the 
  resistance 
  P^^ 
  + 
  / 
  to 
  

   be 
  increased 
  by 
  7*11 
  ohms. 
  When 
  the 
  capacity 
  is 
  calculated, 
  

   taking 
  into 
  account 
  the 
  absorption, 
  it 
  is 
  called 
  the 
  corrected 
  

   capacity, 
  as 
  in 
  the 
  other 
  tables 
  of 
  the 
  paper. 
  

  

  