﻿ISAAC 
  NEWTON 
  ^EINSTEIN 
  205 
  

  

  mine 
  movements 
  in 
  a 
  physical 
  sense. 
  He 
  shows 
  this 
  in 
  the 
  famous 
  

   bucket 
  experiment. 
  There 
  is, 
  therefore, 
  in 
  addition 
  to 
  masses 
  and 
  

   their 
  distances, 
  varying 
  with 
  time, 
  something 
  else, 
  which 
  determines 
  

   what 
  happens; 
  this 
  "something" 
  he 
  conceives 
  as 
  the 
  relation 
  to 
  

   "absolute 
  space." 
  He 
  recognizes 
  that 
  space 
  must 
  possess 
  a 
  sort 
  of 
  

   physical 
  reality 
  if 
  his 
  laws 
  of 
  motion 
  are 
  to 
  have 
  a 
  meaning, 
  a 
  

   reality 
  of 
  the 
  same 
  sort 
  as 
  the 
  material 
  points 
  and 
  their 
  distances. 
  

  

  This 
  clear 
  recognition 
  shows 
  both 
  Newton's 
  wisdom 
  and 
  a 
  weak 
  

   side 
  of 
  his 
  theor3^ 
  For 
  a 
  logical 
  construction 
  of 
  the 
  theory 
  would 
  

   certainly 
  be 
  more 
  satisfactory 
  without 
  this 
  shadowy 
  conception 
  ; 
  only 
  

   those 
  objects 
  (point-masses, 
  distances) 
  would 
  then 
  come 
  into 
  the 
  

   laws 
  whose 
  relation 
  to 
  our 
  perceptions 
  is 
  perfectly 
  clear. 
  

  

  2. 
  The 
  introduction 
  of 
  direct, 
  instantaneously 
  acting 
  forces 
  at 
  a 
  

   distance 
  into 
  the 
  exposition 
  of 
  the 
  effects 
  of 
  gravitation 
  does 
  not 
  

   correspond 
  to 
  the 
  character 
  of 
  most 
  of 
  the 
  phenomena 
  which 
  are 
  

   familiar 
  to 
  us 
  in 
  our 
  daily 
  experience. 
  Newton 
  meets 
  this 
  objection 
  

   by 
  pointing 
  out 
  that 
  his 
  law 
  of 
  reciprocal 
  gravitation 
  is 
  not 
  to 
  be 
  

   taken 
  as 
  an 
  ultimate 
  explanation, 
  but 
  as 
  a 
  rule 
  induced 
  from 
  

   experience. 
  

  

  3. 
  Newton's 
  theory 
  offered 
  no 
  explanation 
  of 
  the 
  very 
  remarkable 
  

   fact 
  that 
  the 
  weight 
  and 
  inertia 
  of 
  a 
  body 
  are 
  determined 
  by 
  the 
  

   same 
  magnitude 
  (the 
  mass). 
  The 
  remarkable 
  nature 
  of 
  this 
  fact 
  

   struck 
  Newton 
  also. 
  

  

  None 
  of 
  these 
  three 
  points 
  can 
  rank 
  as 
  a 
  logical 
  objection 
  against 
  

   the 
  theory. 
  They 
  form, 
  as 
  it 
  were, 
  merely 
  unsatisfied 
  needs 
  of 
  the 
  

   scientific 
  spirit 
  in 
  its 
  effort 
  to 
  penetrate 
  the 
  processes 
  of 
  nature 
  by 
  

   a 
  complete 
  and 
  unified 
  set 
  of 
  ideas. 
  

  

  THE 
  THEORY 
  OF 
  THE 
  ELECTROMAGNETIC 
  FIELD 
  

  

  Newton's 
  theory 
  of 
  motion, 
  considered 
  as 
  a 
  program 
  for 
  the 
  whole 
  

   field 
  of 
  theoretical 
  physics, 
  suffered 
  its 
  first 
  shock 
  from 
  Maxwell's 
  

   theory 
  of 
  electricity. 
  It 
  was 
  found 
  that 
  the 
  reciprocal 
  action 
  be- 
  

   tween 
  bodies 
  tlirough 
  electrical 
  and 
  magnetic 
  bodies 
  does 
  not 
  take 
  

   place 
  through 
  instantaneously 
  acting 
  forces 
  at 
  a 
  distance, 
  but 
  

   through 
  processes 
  which 
  are 
  transmitted 
  with 
  finite 
  velocity 
  through 
  

   space. 
  Alongside 
  the 
  point-mass 
  and 
  its 
  movements 
  there 
  arose, 
  

   in 
  Faraday's 
  conception, 
  a 
  new 
  sort 
  of 
  physically 
  real 
  thing, 
  the 
  

   " 
  field." 
  It 
  was 
  first 
  sought 
  to 
  conceive 
  this, 
  with 
  the 
  aid 
  of 
  mechani- 
  

   cal 
  modes 
  of 
  thought, 
  as 
  a 
  mechanical 
  condition 
  (of 
  movement 
  or 
  

   strain) 
  of 
  a 
  hj^pothetical 
  space-filling 
  medium 
  (the 
  ether). 
  When, 
  

   however, 
  in 
  spite 
  of 
  the 
  most 
  obstinate 
  efforts, 
  this 
  mechanical 
  inter- 
  

   pretation 
  refused 
  to 
  work, 
  students 
  slowly 
  accustomed 
  themselves 
  

   to 
  the 
  conception 
  of 
  the 
  "electromagnetic 
  field" 
  as 
  the 
  ultimate 
  

   irreducible 
  foundation 
  stone 
  of 
  physical 
  reality. 
  We 
  owe 
  to 
  H. 
  

   Hertz 
  the 
  deliberate 
  liberation 
  of 
  the 
  conception 
  of 
  the 
  field 
  from 
  all 
  

  

  