﻿220 
  Scientific 
  Intelligence. 
  

  

  dynamic 
  laws 
  analogous 
  to 
  the 
  thermodynamic 
  ones, 
  for 
  instance, 
  

   laws 
  of 
  electrical 
  entropy 
  similar 
  to 
  that 
  of 
  heat 
  entropy. 
  

  

  The 
  necessity 
  of 
  such 
  an 
  extension 
  of 
  theory 
  he 
  illustrates 
  by 
  

   the 
  following 
  reference 
  to 
  spectrum 
  analysis 
  : 
  

  

  In 
  the 
  usual 
  light 
  theory, 
  a 
  bundle 
  of 
  rays 
  of 
  light, 
  for 
  instance 
  

   that 
  of 
  the 
  D 
  line, 
  is 
  fully 
  defined, 
  if 
  its 
  plane 
  of 
  polarization, 
  its 
  

   color 
  and 
  intensity 
  are 
  given, 
  together 
  with 
  its 
  range 
  of 
  wave 
  

   length. 
  In 
  the 
  electrodynamic 
  theory 
  there 
  is 
  no 
  such 
  definite- 
  

   ness. 
  Even 
  if 
  we 
  take 
  a 
  millionth 
  part 
  of 
  the 
  visible 
  spectrum, 
  

   with 
  a 
  vibration-interval 
  represented 
  by 
  the 
  ratio 
  1 
  : 
  1,000,001 
  ; 
  

   the 
  period 
  of 
  the 
  wave 
  must 
  be 
  selected 
  from 
  all 
  waves 
  comprised 
  

   between 
  510 
  billion 
  and 
  510,000,510,000,000, 
  that 
  is 
  from 
  510 
  

   million 
  different 
  vibration-periods. 
  If 
  the 
  electric 
  force 
  is 
  devel- 
  

   oped 
  as 
  a 
  function 
  of 
  the 
  time 
  in 
  a 
  Fourier 
  series, 
  these 
  510 
  mil- 
  

   lion 
  vibration 
  numbers 
  will 
  enter, 
  for 
  the 
  determination 
  of 
  which 
  

   we 
  have 
  only 
  the 
  intensity 
  and 
  the 
  breadth 
  of 
  the 
  spectrum 
  of 
  the 
  

   ray. 
  The 
  author 
  proceeds 
  to 
  develop 
  the 
  theory 
  and 
  to 
  show 
  the 
  

   necessity 
  of 
  electrodynamic 
  relations, 
  analogous 
  to 
  the 
  thermody- 
  

   namic 
  ones 
  already 
  recognized 
  in 
  the 
  subject 
  of 
  heat. 
  — 
  Ann. 
  

   JPhys., 
  i, 
  No. 
  1, 
  pp. 
  69-122, 
  1900. 
  j. 
  t. 
  

  

  4. 
  A 
  Radio-active 
  Substance 
  emitted 
  from 
  Thorium 
  Compounds. 
  

   — 
  Professor 
  Rutherford 
  of 
  McGill 
  University, 
  Montreal, 
  has 
  

   discovered 
  that 
  thorium 
  compounds 
  continuously 
  emit 
  radio-active 
  

   particles 
  of 
  a 
  certain 
  kind 
  which 
  retain 
  their 
  radio-active 
  pow- 
  

   ers 
  for 
  some 
  time. 
  This 
  emanation 
  has 
  the 
  power 
  of 
  ionizing 
  gas 
  

   and 
  of 
  passing 
  through 
  thin 
  layers 
  of 
  metal 
  and 
  through 
  layers 
  of 
  

   paper. 
  He 
  considers 
  the 
  question 
  of 
  the 
  origin 
  of 
  the 
  emanations 
  

   and 
  finds 
  that 
  they 
  are 
  not 
  due 
  to 
  dust 
  particles. 
  They 
  may, 
  

   however, 
  be 
  due 
  to 
  vapor 
  given 
  off 
  by 
  the 
  compounds. 
  The 
  evi- 
  

   dence 
  on 
  this 
  head 
  is 
  negative. 
  The 
  compounds 
  have 
  the 
  remark- 
  

   able 
  property 
  of 
  producing 
  radio-activity 
  in 
  all 
  substances 
  on 
  

   which 
  the 
  emanation 
  falls. 
  This 
  power 
  lasts 
  for 
  several 
  days 
  

   and 
  the 
  radiation 
  is 
  of 
  a 
  more 
  penetrating 
  character 
  than 
  that 
  of 
  

   thorium 
  or 
  uranium, 
  and 
  thus 
  has 
  properties 
  which 
  thorium 
  

   itself 
  does 
  not 
  possess. 
  — 
  Phil. 
  Mag., 
  Jan. 
  1900, 
  pp. 
  1-14. 
  j. 
  t. 
  

  

  5. 
  Nature 
  of 
  White 
  Light. 
  — 
  M. 
  E. 
  Carvallo 
  believes 
  that 
  

   white 
  light 
  cannot 
  be 
  expressed 
  by 
  the 
  usual 
  formula 
  e~ 
  kt 
  sinht, 
  

   which 
  denotes 
  a 
  damped 
  vibration, 
  for 
  he 
  finds 
  that 
  this 
  gives 
  a 
  

   maximum 
  of 
  intensity 
  which 
  does 
  not 
  agree 
  with 
  the 
  results 
  of 
  

   Langley 
  and 
  Mouton. 
  Moreover 
  when 
  this 
  formula 
  is 
  used 
  in 
  the 
  

   theory 
  of 
  the 
  grating 
  white 
  light 
  results 
  and 
  not 
  colored 
  spectra. 
  

   The 
  error 
  comes 
  from 
  retaining 
  only 
  those 
  radiations 
  which 
  are 
  

   sensible 
  to 
  the 
  eye 
  and 
  in 
  neglecting 
  those 
  intensities 
  which 
  are 
  

   spread 
  out 
  in 
  all 
  azimuths. 
  — 
  Gomptes 
  Rendus, 
  No. 
  2, 
  Jan. 
  1900, 
  

   pp. 
  81-82. 
  j. 
  t. 
  

  

  6. 
  N~ew 
  Electrical 
  Condenser. 
  — 
  Bradley 
  has 
  discovered 
  a 
  new 
  

   substance 
  which 
  has 
  a 
  specific 
  inductive 
  capacity 
  fifteen 
  times 
  

   greater 
  than 
  paraffined 
  paper 
  and 
  about 
  nine 
  times 
  greater 
  than 
  

   that 
  of 
  mica. 
  The 
  material 
  is 
  stearate 
  of 
  lead 
  (stearinsaures 
  

   Blei). 
  — 
  Zeitshrift 
  fur 
  InstrumentenJcunde, 
  Dec. 
  1899, 
  p. 
  215. 
  

  

  J. 
  T. 
  

  

  