﻿142 
  

  

  Prof. 
  E. 
  H. 
  Barton 
  on 
  Range 
  and 
  

  

  capacity 
  of 
  the 
  responding 
  circuit, 
  we 
  can 
  control 
  both 
  its 
  

   frequency 
  and 
  its 
  sharpness 
  of 
  resonance 
  to 
  suitable 
  forcing 
  

   oscillations 
  provided 
  they 
  are 
  of 
  sustained 
  amplitude. 
  More- 
  

   over, 
  this 
  can 
  be 
  done 
  in 
  a 
  variety 
  of 
  ways 
  so 
  as 
  to 
  fulfil 
  

   some 
  other 
  condition, 
  such 
  as 
  keeping 
  the 
  inductance 
  of 
  a 
  

   given 
  value, 
  halving 
  the 
  resistance 
  or 
  quadrupling 
  the 
  

   capacity. 
  A 
  few 
  of 
  the 
  alternative 
  ways 
  of 
  doubling 
  the 
  

   sharpness 
  of 
  response 
  under 
  sustained 
  forcing 
  are 
  shown 
  in 
  

   Table 
  VI. 
  

  

  Table 
  VI. 
  

   Sharpness 
  of 
  Electric 
  Response 
  under 
  Sustained 
  Forcing. 
  

  

  Electrical 
  Quantities. 
  

  

  Coefficients 
  for 
  

  

  Sharpness 
  of 
  

  

  

  

  

  

  Response. 
  

  

  

  

  

  

  

  Inductance 
  

   L. 
  

  

  Resistance 
  

   R. 
  

  

  Capacity 
  

  

  o. 
  • 
  

  

  Damping. 
  

   k=~R/L. 
  

  

  Frequency. 
  

  

  H=p/k 
  

  

  4L 
  

  

  R 
  

  

  

  

  £/4 
  

  

  p/2 
  

  

  

  L 
  

  

  R/2 
  

  

  c 
  

  

  k/2 
  

  

  P 
  

  

  ness 
  

  

  cuit 
  

   Le 
  tl 
  

   al 
  o 
  

  

  L 
  

  

  R 
  

  

  0/4 
  

  

  1c 
  

  

  2p 
  

  

  

  L 
  

  

  R/4 
  

  

  40 
  

  

  w 
  

  

  p/2 
  

  

  

  2L 
  

  

  R 
  

  

  0/2 
  

  

  k/2 
  

  

  V 
  

  

  

  L/4 
  

  

  R/4 
  

  

  C 
  

  

  k 
  

  

  2p 
  

  

  S 
  3 
  cq 
  £ 
  

  

  It 
  was 
  hoped 
  that 
  some 
  electrical 
  experiments 
  in 
  confirma- 
  

   tion 
  of 
  this 
  table 
  could 
  be 
  mnde 
  on 
  Dr. 
  Fleming's 
  cymometer 
  

   and 
  included 
  in 
  the 
  present 
  paper. 
  But 
  a 
  little 
  reflexion 
  

   sufficed 
  to 
  show 
  that 
  the 
  ordinary 
  conditions 
  of 
  using 
  the 
  

   cymometer 
  are 
  too 
  complicated 
  for 
  the 
  suppositions 
  of 
  

   equation 
  (11) 
  and 
  must 
  be 
  referred 
  to 
  the 
  more 
  general 
  

   form 
  (10). 
  

  

  For 
  the 
  forcing 
  circuit 
  usually 
  has 
  a 
  spark-gap, 
  and 
  its 
  

   oscillations 
  are 
  accordingly 
  strongly 
  damped. 
  Thus 
  //, 
  as 
  

   well 
  as 
  Jc, 
  needs 
  to 
  be 
  taken 
  into 
  account. 
  And, 
  although 
  

   both 
  k 
  and 
  h 
  may 
  he 
  small 
  compared 
  with 
  n 
  and 
  p, 
  yet 
  they 
  

   cannot 
  be 
  small 
  compared 
  with 
  (p 
  2 
  — 
  n 
  2 
  ) 
  when 
  (his 
  difference 
  

   is 
  itself 
  on 
  the 
  point 
  of 
  vanishing. 
  And 
  this 
  is 
  precisely 
  the 
  

   state 
  of 
  things 
  in 
  which 
  we 
  are 
  most 
  interested, 
  because 
  it 
  

   is 
  then 
  that 
  the 
  tuning 
  is 
  close 
  and 
  the 
  response 
  full. 
  In 
  

   other 
  words, 
  we 
  are 
  then 
  near 
  the 
  peak 
  of 
  the 
  resonance 
  

   curve. 
  

  

  A 
  preliminary 
  trial 
  with 
  the 
  cymometer 
  was, 
  however, 
  

   made 
  by 
  Mr. 
  W. 
  B. 
  Kilby, 
  B.Sc, 
  with 
  the 
  values 
  of 
  L 
  and 
  

   R 
  remaining 
  unchanged 
  but 
  with 
  the 
  capacities 
  of 
  values 
  C 
  

  

  