﻿406 
  Rowland 
  — 
  The 
  Highest 
  Aim 
  of 
  the 
  Physicist. 
  

  

  actions 
  miglity 
  from 
  inter-molecular 
  distances 
  throngli 
  inter- 
  

   planetary 
  and 
  inter-stellar 
  distances 
  until 
  we 
  reach 
  the 
  mighty 
  

   distances 
  which 
  bound 
  the 
  Universe 
  — 
  all 
  have 
  their 
  being 
  in 
  this 
  

   wondrous 
  ether. 
  

  

  And 
  yet, 
  however 
  wonderful 
  it 
  may 
  be, 
  its 
  laws 
  are 
  far 
  

   more 
  simple 
  than 
  those 
  of 
  matter. 
  Every 
  wave 
  in 
  it, 
  what- 
  

   ever 
  its 
  length 
  or 
  intensity, 
  proceeds 
  onwards 
  in 
  it 
  according 
  

   to 
  well 
  known 
  laws, 
  all 
  with 
  the 
  same 
  speed, 
  unaltered 
  in 
  direc- 
  

   tion 
  from 
  its 
  source 
  in 
  electrified 
  matter, 
  to 
  the 
  confines 
  of 
  the 
  

   Universe 
  unimpaired 
  in 
  energy 
  unless 
  it 
  is 
  disturbed 
  by 
  the 
  

   presence 
  of 
  matter. 
  However 
  the 
  waves 
  may 
  cross 
  each 
  other, 
  

   each 
  proceeds 
  by 
  itself 
  without 
  interference 
  with 
  the 
  others. 
  

  

  So 
  with 
  regard 
  to 
  gravitation, 
  we 
  have 
  no 
  evidence 
  that 
  the 
  

   presence 
  of 
  a 
  third 
  body 
  affects 
  the 
  mutual 
  attraction 
  of 
  two 
  

   other 
  bodies 
  or 
  that 
  the 
  presence 
  of 
  a 
  third 
  quantity 
  of 
  elec- 
  

   tricity 
  affects 
  the 
  mutual 
  attraction 
  of 
  two 
  other 
  quantities. 
  

   The 
  same 
  for 
  magnetism. 
  

  

  For 
  this 
  reason 
  the 
  laws 
  of 
  gravitation 
  and 
  of 
  electric 
  and 
  

   magnetic 
  action 
  including 
  radiation 
  are 
  the 
  simplest 
  of 
  all 
  laws 
  

   when 
  we 
  confi.ne 
  them 
  to 
  a 
  so-called 
  vacuum, 
  but 
  become 
  more 
  

   and 
  more 
  complicated 
  when 
  we 
  treat 
  of 
  them 
  in 
  space 
  contain- 
  

   ing 
  matter. 
  

  

  Subject 
  the 
  ether 
  to 
  immense 
  electrostatic, 
  magnetic 
  or 
  

   gravitational 
  forces 
  and 
  we 
  find 
  absolutely 
  no 
  signs 
  of 
  its 
  

   breaking 
  down 
  or 
  even 
  change 
  of 
  properties. 
  Set 
  it 
  into 
  

   vibration 
  by 
  means 
  of 
  an 
  intensely 
  hot 
  body 
  like 
  that 
  of 
  the 
  

   sun 
  and 
  it 
  conveys 
  many 
  thousand 
  horse-power 
  for 
  each 
  square 
  

   foot 
  of 
  surface 
  as 
  quietly 
  and 
  with 
  apparently 
  unchanged 
  laws 
  

   as 
  if 
  it 
  were 
  conveying 
  the 
  energy 
  of 
  a 
  tallow 
  dip. 
  

  

  Again, 
  subject 
  a 
  millimeter 
  of 
  ether 
  to 
  the 
  stress 
  of 
  many 
  

   thousand, 
  nay 
  even 
  a 
  million, 
  volts 
  and 
  yet 
  we 
  see 
  no 
  signs 
  of 
  

   breaking 
  down. 
  

  

  Hence 
  the 
  properties 
  of 
  the 
  ether 
  are 
  of 
  ideal 
  simplicity 
  and 
  

   lead 
  to 
  the 
  simplest 
  of 
  natural 
  laws. 
  All 
  forces 
  which 
  act 
  at 
  

   a 
  distance, 
  always 
  obey 
  the 
  law 
  of 
  the 
  inverse 
  square 
  of 
  the 
  

   distance 
  and 
  we 
  have 
  also 
  the 
  attraction 
  of 
  any 
  number 
  of 
  

   parts 
  placed 
  near 
  each 
  other 
  equal 
  to 
  the 
  arithmetical 
  sum 
  of 
  

   the 
  attractions 
  when 
  those 
  parts 
  are 
  separated. 
  So 
  also 
  the 
  

   simple 
  law 
  of 
  etherial 
  waves 
  which 
  has 
  been 
  mentioned 
  above. 
  

  

  At 
  the 
  present 
  time, 
  through 
  the 
  labors 
  of 
  Maxwell 
  supple- 
  

   mented 
  by 
  those 
  of 
  Hertz 
  and 
  others, 
  we 
  have 
  arrived 
  at 
  the 
  

   great 
  generalization 
  that 
  all 
  wave 
  disturbances 
  in 
  the 
  ether 
  are 
  

   electromagnetic 
  in 
  their 
  nature. 
  We 
  know 
  of 
  little 
  or 
  no 
  

   etherial 
  disturbance 
  which 
  can 
  be 
  set 
  up 
  by 
  the 
  motion 
  of 
  

   matter 
  alone: 
  the 
  matter 
  must 
  be 
  electrified 
  in 
  order 
  to 
  have 
  

   sufficient 
  hold 
  on 
  the 
  ether 
  to 
  communicate 
  its 
  motion 
  to 
  the 
  

   ether. 
  The 
  Zeeman 
  effect 
  even 
  shows 
  this 
  to 
  be 
  the 
  case 
  

  

  