﻿152 
  Scientific 
  Intelligence. 
  

  

  ultra-violet 
  rays 
  and 
  the 
  Rontgen 
  rays. 
  — 
  Ann. 
  tier 
  Physik 
  und 
  

   Chemie, 
  No. 
  12, 
  pp. 
  773-781. 
  j. 
  t. 
  

  

  9. 
  Rontgen 
  Rays.. 
  — 
  In 
  some 
  recent 
  experiments 
  conducted 
  in 
  

   the 
  physical 
  laboratory 
  of 
  the 
  University 
  of 
  Glasgow 
  by 
  Lord 
  

   Kelvin, 
  assisted 
  by 
  J. 
  C. 
  Beattie 
  and 
  M. 
  Smoluchowski 
  de 
  Smo- 
  

   lan 
  (Nature, 
  Dec. 
  31, 
  1896), 
  it 
  was 
  shown 
  that 
  air 
  drawn 
  through 
  

   an 
  experimental 
  tube 
  in 
  which 
  it 
  was 
  exposed 
  to 
  the 
  radiation 
  

   from 
  a 
  Crookes 
  tube 
  became 
  electrified, 
  sometimes 
  positively, 
  

   and 
  sometimes 
  negatively. 
  Professor 
  Richard 
  Threlfall 
  and 
  

   James 
  A. 
  Pollock 
  (Phil. 
  Mag., 
  Dec. 
  1896) 
  conclude 
  from 
  careful 
  

   experiments 
  that 
  no 
  sensible 
  amount 
  of 
  matter 
  is 
  projected 
  from 
  

   a 
  Crookes 
  tube, 
  and 
  that 
  the 
  hypothesis 
  that 
  the 
  action 
  of 
  the 
  

   X-rays 
  is 
  due 
  to 
  a 
  projection 
  of 
  matter 
  is 
  untenable. 
  They 
  also 
  

   conclude 
  that 
  the 
  phenomenon 
  is 
  not 
  due 
  to 
  the 
  projection 
  of 
  

   ether 
  streams, 
  and 
  that 
  no 
  disturbance 
  of 
  the 
  ether 
  is 
  caused 
  

   which 
  is 
  sufficient 
  to 
  affect 
  electromagnetic 
  radiations. 
  j. 
  t. 
  

  

  1 
  0. 
  Electric 
  light 
  in 
  Capillary 
  tubes. 
  — 
  O. 
  Schott 
  has 
  observed 
  the 
  

   extraordinary 
  brilliancy 
  of 
  electric 
  discharges 
  through 
  very 
  fine 
  

   capillary 
  tubes. 
  The 
  discharges 
  were 
  excited 
  by 
  an 
  induction 
  

   coil 
  of 
  25 
  cm 
  spark 
  length. 
  If 
  one 
  makes 
  the 
  assumption 
  that 
  the 
  

   duration 
  of 
  the 
  spark 
  discharge 
  is 
  no 
  longer 
  than 
  y^J-fl-g- 
  of 
  a 
  

   second, 
  a 
  capillary 
  of 
  from 
  one 
  to 
  two 
  square 
  millimeters 
  in 
  sec- 
  

   tion 
  radiates 
  as 
  much 
  light 
  as 
  1 
  — 
  2000 
  Hefner 
  flames 
  emit. 
  Since 
  

   the 
  ordinary 
  arc 
  light 
  has 
  a 
  much 
  larger 
  radiating 
  surface, 
  the 
  

   capillary 
  light 
  is 
  far 
  more 
  powerful 
  than 
  is 
  created 
  by 
  any 
  other 
  

   source. 
  — 
  Ann. 
  der 
  Physik 
  and 
  Chemie, 
  No. 
  12, 
  p. 
  768-772. 
  

  

  J. 
  T. 
  

  

  11. 
  Temperature 
  of 
  the 
  sun. 
  — 
  W. 
  E. 
  Wilson 
  and 
  P. 
  L. 
  Geay 
  

   have 
  established 
  (Phil. 
  Trans. 
  Acad., 
  vol. 
  clxxxv, 
  1894, 
  p. 
  361), 
  

   that 
  the 
  radiation 
  of 
  platinum 
  up 
  to 
  the 
  point 
  1600° 
  C. 
  obeys 
  the 
  

   law 
  q 
  = 
  a 
  (T 
  4 
  — 
  T 
  4 
  ), 
  in 
  which 
  T 
  is 
  the 
  absolute 
  temperature 
  of 
  

   platinum, 
  T 
  the 
  absolute 
  temperature 
  of 
  the 
  surrounding 
  medium. 
  

   They 
  have 
  now 
  deduced 
  another 
  formula, 
  q 
  — 
  b 
  (T 
  3 
  — 
  T 
  3 
  ) 
  +a(T 
  i 
  

   — 
  T 
  o 
  4 
  ), 
  which, 
  with 
  suitable 
  choice 
  of 
  the 
  constants 
  a 
  and 
  b, 
  repre- 
  

   sents 
  the 
  radiation 
  of 
  polished 
  platinum 
  or 
  blackened 
  platinum. 
  

   The 
  authors 
  find 
  by 
  extrapolation 
  in 
  their 
  formula 
  that 
  the 
  tem- 
  

   perature 
  of 
  the 
  hottest 
  portion 
  of 
  the 
  positive 
  carbon 
  attains 
  a 
  

   temperature 
  of 
  3300° 
  C. 
  The 
  radiation 
  of 
  the 
  hottest 
  portion 
  of 
  

   the 
  positive 
  carbon 
  is 
  nearly 
  three 
  times 
  as 
  great 
  as 
  that 
  from 
  the 
  

   hottest 
  portion 
  of 
  the 
  negative 
  carbon. 
  Likening 
  the 
  sun 
  to 
  a 
  

   black 
  body, 
  in 
  respect 
  to 
  radiating 
  power, 
  the 
  authors 
  find 
  that 
  

   the 
  temperature 
  of 
  the 
  sun 
  should 
  be 
  in 
  the 
  neighborhood 
  of 
  

   8000° 
  O. 
  — 
  Proc. 
  Roy. 
  Soc, 
  London^ 
  vol. 
  lviii, 
  p. 
  24, 
  1895. 
  j. 
  t. 
  

  

  12. 
  Argon 
  and 
  helium. 
  — 
  Lockyer 
  has 
  examined 
  the 
  spectra 
  of 
  

   the 
  gas 
  obtained 
  from 
  uraninite 
  or 
  cleveite, 
  broggerite, 
  and 
  divers 
  

   other 
  minerals, 
  and 
  cites 
  various 
  cases 
  in 
  which 
  lines 
  are 
  obtained 
  

   in 
  certain 
  gases 
  which 
  do 
  not 
  appear 
  in 
  other 
  gases, 
  and 
  con- 
  

   cludes 
  that 
  argon 
  and 
  helium 
  are 
  mixtures 
  of 
  which 
  the 
  separa- 
  

   tion 
  will 
  be 
  very 
  difficult. 
  He 
  has 
  also 
  compared 
  the 
  wave- 
  

   lengths 
  of 
  the 
  lines 
  of 
  argon 
  with 
  the 
  wave-lengths 
  of 
  lines 
  

  

  