﻿J. 
  Trowbridge 
  — 
  Electrical 
  Oscillations 
  on 
  Iron 
  Wires. 
  223 
  

  

  The 
  paper 
  upon 
  the 
  determination 
  of 
  iodine, 
  to 
  which 
  

   reference 
  has 
  been 
  made 
  and 
  upon 
  which 
  this 
  process 
  is 
  based, 
  

   prescribes 
  corrections 
  for 
  the 
  volatility 
  of 
  arsenious 
  chloride 
  and 
  

   the 
  slight 
  deoxidation 
  of 
  arsenic 
  acid 
  when 
  chlorides 
  and 
  

   bromides 
  are 
  also 
  present 
  in 
  considerable 
  amount. 
  In 
  this 
  pro- 
  

   cess, 
  however, 
  the 
  amount 
  of 
  hydrochloric 
  acid 
  evolved 
  from 
  

   the 
  maximum 
  weight 
  of 
  chlorate 
  treated 
  —0*2 
  grm. 
  of 
  the 
  

   potassium 
  salt 
  — 
  calls 
  for 
  a 
  correction 
  so 
  small 
  as 
  to 
  be 
  insig- 
  

   nificant. 
  

  

  Art. 
  XXI. 
  — 
  Dampening 
  of 
  Electrical 
  Oscillations 
  on 
  Iron 
  

   Wires 
  ; 
  by 
  John 
  Tbowbridge. 
  

  

  [Presented 
  to 
  the 
  American 
  Academy 
  of 
  Sciences, 
  May 
  27, 
  1891.] 
  

  

  It 
  has 
  generally 
  been 
  assumed 
  by 
  those 
  who 
  have 
  studied 
  

   the 
  subject 
  of 
  very 
  rapid 
  oscillations 
  of 
  electricity, 
  such 
  as 
  

   occur 
  in 
  Leyden 
  jar 
  discharges, 
  that 
  the 
  magnetic 
  character 
  of 
  

   the 
  conductor 
  has 
  very 
  little 
  influence 
  upon 
  the 
  character 
  of 
  

   the 
  discharge. 
  Thus, 
  in 
  a 
  note 
  to 
  an 
  article 
  on 
  electrical 
  waves, 
  

   W. 
  Feddersen 
  states 
  that 
  electrical 
  oscillations 
  may 
  suffer 
  a 
  

   slight 
  weakening 
  on 
  iron.; 
  but 
  this 
  diminution 
  is 
  very 
  slight 
  : 
  — 
  

  

  " 
  Beim 
  Eisen 
  konnte 
  in 
  Folge 
  der 
  Magnetisirungen 
  eine 
  

   Abweichung 
  hervortreten 
  ; 
  in 
  dess 
  zeigt 
  der 
  Yersuch, 
  dass 
  

   dieselbe 
  keinenfalls 
  bedeutend 
  ist, 
  iibrigens 
  in 
  dem 
  Sinne 
  erfol- 
  

   gen 
  miisste, 
  als 
  wenn 
  die 
  Elektricitat 
  beim 
  Eisen 
  ein 
  grossere 
  

   Hinderniss 
  fande, 
  wie 
  bei 
  den 
  ubrigen 
  Metallen."* 
  

  

  In 
  Dr. 
  Lodge's 
  treatise 
  on 
  Modern 
  Views 
  of 
  Electricity 
  (ed. 
  

   1889), 
  we 
  find 
  the 
  following 
  : 
  — 
  

  

  " 
  But 
  in 
  the 
  case 
  of 
  the 
  discharge 
  of 
  a 
  Leyden 
  jar 
  iron 
  is 
  of 
  

   no 
  advantage. 
  The 
  current 
  oscillates 
  so 
  quickly 
  that 
  any 
  iron 
  

   introduced 
  into 
  its 
  circuit, 
  however 
  subdivided 
  into 
  thin 
  wires 
  

   it 
  may 
  be, 
  is 
  protected 
  from 
  magnetism 
  by 
  inverse 
  currents 
  

   induced 
  in 
  its 
  outer 
  skin, 
  and 
  accordingly 
  does 
  not 
  get 
  mag- 
  

   netized 
  ; 
  and 
  so 
  far 
  from 
  increasing 
  the 
  inductance 
  of 
  the 
  dis- 
  

   charge 
  circuit, 
  it 
  positively 
  diminishes 
  it 
  by 
  the 
  reaction 
  effect 
  

   of 
  these 
  induced 
  currents 
  ; 
  it 
  acts, 
  in 
  fact, 
  much 
  as 
  a 
  mass 
  of 
  

   copper 
  might 
  be 
  expected 
  to 
  do." 
  (p. 
  365.) 
  

  

  Fleming 
  writes 
  as 
  follows 
  : 
  

  

  " 
  With 
  respect 
  to 
  the 
  apparent 
  superiority 
  of 
  iron 
  it 
  would 
  

   naturally 
  be 
  supposed 
  that, 
  since 
  the 
  magnetic 
  permeability 
  of 
  

   iron 
  bestows 
  upon 
  it 
  greater 
  inductance, 
  it 
  would 
  form 
  a 
  less 
  

   suitable 
  conductor 
  for 
  discharging 
  with 
  great 
  suddenness 
  of 
  

   electric 
  energy. 
  Owing 
  to 
  the 
  fact 
  that 
  the 
  current 
  only 
  pene- 
  

   trates 
  just 
  into 
  the 
  skin 
  of 
  the 
  conductor, 
  there 
  is 
  but 
  little 
  of 
  

  

  * 
  Annalen 
  der 
  Physik 
  und 
  Chemie, 
  No. 
  108, 
  1859, 
  p. 
  499. 
  

  

  