﻿596 
  Prof. 
  Pollock 
  and 
  Mr. 
  Von 
  wilier 
  : 
  Experiments 
  

  

  occurs 
  whose 
  free 
  period 
  is 
  near 
  to 
  that 
  of 
  the 
  condenser 
  

   oscillation, 
  a 
  condition 
  which 
  has 
  been 
  shown 
  to 
  hold 
  for 
  

   unbridged 
  wires, 
  the 
  results 
  contained 
  in 
  Table 
  II. 
  may, 
  with 
  

   one 
  or 
  two 
  exceptions, 
  be 
  explained 
  in 
  the 
  following 
  manner: 
  — 
  

   In 
  II 
  a 
  for 
  the 
  first 
  maximum 
  that 
  mode 
  of 
  vibration 
  of 
  the 
  

   primary 
  circuit 
  having 
  three 
  nodes 
  would 
  no 
  doubt 
  occur, 
  

   the 
  wave-length 
  in 
  this 
  case 
  12*13 
  being 
  nearer 
  to 
  the 
  wave- 
  

   length 
  of 
  the 
  condenser 
  radiation 
  15*2, 
  than 
  that 
  of 
  any 
  

   other 
  possible 
  mode 
  of 
  vibration. 
  Although 
  the 
  lengths 
  of 
  

   the 
  primary 
  and 
  secondary 
  circuits 
  are 
  as 
  5/1, 
  there 
  is 
  not 
  

   perfect 
  resonance, 
  for 
  this 
  requires 
  that 
  there 
  should 
  be 
  at 
  

   least 
  five 
  nodes 
  in 
  the 
  primary 
  circuit. 
  The 
  maximum 
  is 
  

   therefore 
  low. 
  For 
  the 
  second 
  maximum, 
  the 
  same 
  mode 
  of 
  

   vibration 
  of 
  the 
  primary 
  circuit 
  having 
  a 
  wave-length 
  10' 
  93 
  

   is 
  more 
  out 
  of 
  tune 
  with 
  the 
  condenser 
  circuit 
  than 
  before, 
  

   but 
  the 
  condition 
  for 
  resonance 
  between 
  the 
  primary 
  and 
  

   secondary 
  circuits 
  is 
  now 
  perfect, 
  the 
  lengths 
  being 
  as 
  3/1. 
  

   The 
  more 
  perfect 
  resonance 
  between 
  the 
  primary 
  and 
  secondary 
  

   circuits 
  more 
  than 
  compensates 
  for 
  the 
  lower 
  amplitude 
  of 
  

   vibration 
  in 
  the 
  primary 
  circuit, 
  and 
  the 
  maximum 
  is 
  higher 
  

   than 
  the 
  previous 
  one. 
  

  

  In 
  II 
  b 
  for 
  the 
  first 
  maximum 
  the 
  number 
  of 
  nodes 
  in 
  the 
  

   primary 
  circuit 
  would 
  be 
  five, 
  and 
  as 
  the 
  lengths 
  of 
  the 
  two 
  

   circuits 
  are 
  as 
  5/1, 
  the 
  maximum 
  is 
  high. 
  There 
  is 
  no 
  maxi- 
  

   mum 
  in 
  this 
  case 
  when 
  the 
  lengths 
  of 
  the 
  circuits 
  are 
  in 
  the 
  

   ratio 
  of 
  3/1, 
  the 
  reason 
  apparently 
  being 
  that 
  the 
  vibration 
  

   in 
  the 
  primary 
  circuit 
  is 
  ill-defined 
  on 
  account 
  of 
  the 
  wave- 
  

   length 
  of 
  the 
  condenser 
  radiation 
  9*5 
  being 
  midway 
  between 
  

   those 
  of 
  two 
  of 
  the 
  possible 
  modes 
  of 
  vibration 
  of 
  the 
  primary 
  

   circuit, 
  11*98 
  and 
  7*15. 
  Such 
  a 
  condition 
  is 
  illustrated 
  in 
  

   the 
  case 
  of 
  Melde's 
  well-known 
  experiments 
  on 
  the 
  vibrations 
  

   of 
  strings 
  when 
  the 
  tension 
  is 
  midway 
  between 
  the 
  tensions 
  

   required 
  for 
  two 
  successive 
  modes 
  of 
  vibration. 
  A 
  similar 
  

   explanation 
  accounts 
  for 
  the 
  third 
  maximum 
  being 
  low 
  in 
  the 
  

   case 
  of 
  the 
  experiments 
  with 
  wires 
  8'98 
  long, 
  the 
  results 
  of 
  

   which 
  are 
  given 
  in 
  the 
  first 
  division 
  II 
  «of 
  the 
  Table. 
  

  

  In 
  II 
  b 
  the 
  second 
  maximum, 
  which 
  is 
  a 
  low 
  one, 
  occurs 
  

   for 
  a 
  position 
  of 
  the 
  bridge 
  which 
  makes 
  the 
  lengths 
  of 
  the 
  

   circuits 
  nearly 
  in 
  the 
  ratio 
  of 
  5 
  to 
  9. 
  In 
  this 
  case 
  the 
  

   primary 
  circuit 
  with 
  three 
  nodes 
  is 
  very 
  nearly 
  in 
  tune 
  with 
  

   the 
  condenser 
  circuit, 
  and 
  the 
  amplitude 
  of 
  the 
  vibration 
  in 
  

   it 
  must 
  be 
  considerable; 
  the 
  conditions 
  for 
  perfect 
  resonance 
  

   between 
  the 
  primary 
  and 
  secondary 
  circuits 
  are 
  not, 
  however, 
  

   satisfied. 
  The 
  character 
  of 
  the 
  next 
  maximum 
  is 
  one 
  of 
  the 
  

   exceptions 
  to 
  this 
  general 
  explanation. 
  The 
  primary 
  circuit 
  with 
  

   three 
  nodes 
  is 
  not 
  more 
  out 
  of 
  tune 
  with 
  the 
  condenser 
  circuit 
  

   than 
  it 
  was 
  with 
  five 
  nodes 
  in 
  the 
  case 
  of 
  the 
  first 
  maximum. 
  

  

  