﻿306 
  Dr. 
  Russell 
  and 
  Mr. 
  Wright 
  : 
  The 
  Wright 
  Electr 
  ical 
  

  

  that 
  if 
  ?/ 
  be 
  a 
  horizontal 
  ordinate 
  and 
  .^' 
  the 
  vertical 
  abscissa 
  

   on 
  the 
  logarithmic 
  scale, 
  y 
  = 
  hlogf 
  {x), 
  where 
  h 
  is 
  the 
  length 
  

   of 
  the 
  scale 
  on 
  the 
  slide 
  resistances. 
  Similarly 
  the 
  equation 
  

   to 
  the 
  wire 
  through 
  Nf 
  is 
  y 
  = 
  h 
  log 
  F(^). 
  

  

  The 
  contact-fingers 
  through 
  N,n 
  and 
  N,i 
  are 
  set 
  so 
  that 
  their 
  

   inclinations 
  to 
  the 
  vertical 
  are 
  fixed 
  at 
  — 
  tan~^ 
  m 
  and 
  tan"^ 
  n 
  

   respectively. 
  The 
  rod 
  11^ 
  is 
  then 
  gradually 
  lowered 
  and 
  the 
  

   readings 
  on 
  the 
  logarithmic 
  scale 
  S, 
  when 
  the 
  deflexion 
  on 
  

   the 
  galvanometer 
  is 
  zero, 
  give 
  the 
  roots 
  of 
  the 
  equation 
  lying 
  

   between 
  1 
  and 
  10. 
  

  

  The 
  use 
  of 
  a 
  bent 
  contact-finger 
  to 
  take 
  into 
  account 
  the 
  

   ^' 
  hysteresis 
  loop 
  " 
  of 
  iron 
  would 
  be 
  of 
  use 
  in 
  certain 
  electrical 
  

   problems. 
  

  

  XII. 
  Solution 
  of 
  Transcendental 
  Equations. 
  

   Fio-. 
  10. 
  

  

  Let 
  us 
  suppose 
  that 
  the 
  equation 
  we 
  have 
  to 
  solve 
  is 
  

   ai?i^i^ 
  + 
  a^li^^azU^'^ 
  + 
  ^410^= 
  0. 
  

  

  