﻿332 
  Prof. 
  A. 
  A. 
  Michelson 
  

  

  on 
  

  

  same 
  unit 
  measured 
  eiectromagnetically, 
  the 
  ratio 
  usually 
  

   designated 
  as 
  Maxwell's 
  v, 
  must 
  be 
  equal 
  to 
  the 
  velocity 
  of 
  

   light. 
  The 
  verification 
  of 
  this 
  relation 
  would 
  be 
  a 
  powerful 
  

   argument 
  (were 
  any 
  such 
  needed) 
  in 
  favour 
  of 
  the 
  theory 
  ; 
  

   and 
  in 
  fact 
  the 
  value 
  of 
  v 
  agrees 
  as 
  well 
  with 
  V 
  as 
  do 
  the 
  

   separate 
  accepted 
  values 
  of 
  v 
  among 
  themselves. 
  

  

  M. 
  Abraham, 
  in 
  a 
  report 
  to 
  the 
  International 
  Congress 
  of 
  

   Physics, 
  gives 
  the 
  following 
  resume 
  of 
  these 
  determinations 
  :: 
  

  

  Himstedt 
  3*0057 
  x 
  10 
  10 
  

  

  Rosa 
  3-0000xl0 
  10 
  

  

  J. 
  J. 
  Thomson 
  2*9960 
  x 
  10 
  10 
  

  

  H. 
  Abraham 
  2*9913 
  x 
  10 
  10 
  

  

  Pellat 
  3-0092X10 
  10 
  

  

  Hurmuzescu 
  3*0010 
  x 
  10 
  10 
  

  

  Perot 
  and 
  Fabry 
  2*9973 
  x 
  10 
  10 
  

  

  M. 
  Abraham 
  accepts 
  the 
  mean 
  value 
  

  

  ^3'OOOlxlO 
  1 
  

  

  which 
  he 
  regards 
  as 
  probably 
  correct 
  to 
  the 
  thousandth 
  part, 
  

   and 
  concludes 
  with 
  the 
  following 
  significant 
  remark 
  : 
  

  

  u 
  Etant 
  donne 
  Tinteret 
  qui 
  s'attache 
  a 
  la 
  determination 
  de 
  

   la 
  vitesse 
  v, 
  il 
  parait 
  desirable 
  que 
  de 
  nouvelles 
  experiences 
  

   soient 
  entreprises. 
  La 
  precision 
  des 
  anciennes 
  mesures 
  peut 
  

   etre 
  depasses 
  : 
  toutes 
  les 
  methodes 
  s'j 
  pretent. 
  II 
  y 
  a 
  encore 
  

   a 
  reduire 
  quelques 
  corrections 
  trop 
  incertaines 
  ; 
  il 
  y 
  a 
  a 
  

   simplifier 
  quelques 
  mesures 
  auxilinires 
  trop 
  complexes, 
  et 
  par 
  

   ce 
  nouvel 
  effort 
  on 
  pourra 
  sans 
  aucun 
  doute, 
  apporter 
  dans 
  

   la 
  mesure 
  de 
  v 
  une 
  precision, 
  superieure 
  a 
  celle 
  aujourd'hui 
  

   acquise 
  pour 
  la 
  vitesse 
  de 
  la 
  lumiere/' 
  

  

  Again, 
  Blondlot 
  and 
  Gutton, 
  in 
  the 
  same 
  report, 
  give 
  the 
  

   following 
  resume 
  of 
  some 
  of 
  the 
  best 
  determinations 
  of 
  the 
  

   velocity 
  of 
  Hertzian 
  waves 
  : 
  

  

  Blondlot 
  302,200 
  km./sec. 
  

  

  ™ 
  M 
  f 
  f 
  296,400 
  n 
  „ 
  

  

  Blondlot 
  \298,000 
  „ 
  „ 
  

  

  Trowbridge 
  and 
  Duane 
  ... 
  300,300 
  „ 
  „ 
  

  

  MacLean. 
  299,110 
  „ 
  „ 
  

  

  Q 
  , 
  /298,200 
  „ 
  „ 
  

  

  Saunders 
  \299,700 
  „ 
  „ 
  

  

  Messrs. 
  Blondlot 
  and 
  Gutton 
  do 
  not 
  make 
  any 
  estimate 
  of 
  

   the 
  most 
  probable 
  value, 
  but 
  doubtless 
  the 
  mean 
  of 
  the 
  pre- 
  

   ceding 
  results, 
  

  

  299,130 
  + 
  1000 
  

  

  