﻿256 
  Scientific 
  Intelligence. 
  

  

  the 
  angle 
  between 
  the 
  two 
  axes, 
  and 
  as 
  the 
  result 
  of 
  the 
  annual 
  

   motion 
  may 
  cause 
  it 
  to 
  rotate 
  in 
  a 
  secular 
  period 
  about 
  the 
  axis 
  

   of 
  figure, 
  or 
  if 
  the 
  magnetization 
  has 
  already 
  become 
  set 
  in 
  the 
  

   body 
  of 
  the 
  earth, 
  may 
  cause 
  a 
  succession 
  of 
  secular 
  waves 
  to 
  

   sweep 
  over 
  it 
  from 
  east 
  to 
  west, 
  as 
  is 
  shown 
  to 
  be 
  the 
  case 
  in 
  

   the 
  history 
  of 
  the 
  agonic 
  lines 
  and 
  the 
  long 
  period 
  deflections 
  

   of 
  the 
  needle. 
  

  

  This 
  surprising 
  identification 
  of 
  magnetic 
  and 
  light 
  action 
  of 
  

   the 
  radiations 
  of 
  the 
  sun 
  in 
  direction 
  will 
  be 
  recognized 
  as 
  

   harmonizing 
  with 
  the 
  conclusions 
  arrived 
  at 
  by 
  Maxwell 
  and 
  

   Hertz 
  in 
  their 
  investigations. 
  If 
  light 
  is 
  to 
  be 
  studied 
  as 
  a 
  

   magnetic 
  phenomenon 
  it 
  adds 
  a 
  large 
  field 
  to 
  the 
  work 
  allotted 
  

   to 
  meteorology. 
  Furthermore, 
  several 
  important 
  physical 
  con- 
  

   stants 
  relating 
  to 
  the 
  cosmical 
  action 
  of 
  the 
  sun 
  and 
  the 
  earth, 
  

   and 
  also 
  the 
  implied 
  nature 
  of 
  the 
  sun 
  and 
  the 
  earth 
  as 
  physical 
  

   bodies 
  are 
  becoming 
  accessible. 
  Attention 
  is 
  directed 
  to 
  the 
  

   fact 
  that 
  such 
  a 
  force 
  acting 
  towards 
  the 
  center 
  of 
  the 
  sun, 
  

   being 
  cosmical 
  or 
  universal, 
  is 
  of 
  the 
  kind 
  required 
  to 
  account 
  for 
  

   the 
  outstanding 
  motion 
  in 
  the 
  perihelion 
  of 
  Mercury, 
  not 
  

   included 
  in 
  the 
  development 
  or 
  the 
  law 
  of 
  gravitation 
  or 
  its 
  

   positive 
  side. 
  My 
  next 
  step 
  is 
  to 
  form 
  the 
  necessary 
  equations 
  

   of 
  condition 
  and 
  solve 
  them 
  for 
  the 
  constants 
  involved 
  in 
  the 
  

   magnetic 
  observations. 
  

  

  Washington, 
  D. 
  C., 
  July 
  31, 
  1891. 
  

  

  SCIENTIFIC 
  INTELLIGENCE. 
  

  

  I. 
  Chemistry. 
  

  

  1. 
  On 
  Boron 
  tri-iodide. 
  — 
  According 
  to 
  Moissan, 
  boron 
  tri- 
  

   iodide 
  can 
  be 
  obtained 
  in 
  three 
  ways 
  : 
  either 
  (1) 
  by 
  passing 
  boron 
  

   chloride 
  and 
  hydrogen 
  iodide 
  through 
  a 
  red 
  hot 
  porcelain 
  tube, 
  

  

  (2) 
  by 
  acting 
  with 
  iodine 
  upon 
  boron 
  directly 
  at 
  700° 
  — 
  800°, 
  or 
  

  

  (3) 
  and 
  most 
  conveniently 
  by 
  acting 
  upon 
  amorphous 
  boron, 
  pre- 
  

   viously 
  dried 
  in 
  a 
  current 
  of 
  hydrogen 
  at 
  200°, 
  with 
  dry 
  hydrogen 
  

   iodide 
  gas, 
  the 
  boron 
  being 
  heated 
  in 
  a 
  combustion 
  tube 
  to 
  a 
  

   temperature 
  near 
  that 
  of 
  the 
  softening 
  of 
  the 
  glass. 
  In 
  this 
  way 
  

   purple 
  colored 
  scales 
  are 
  obtained 
  containing 
  some 
  free 
  iodine 
  ; 
  

   from 
  which 
  they 
  may 
  be 
  freed 
  by 
  solution 
  in 
  carbon 
  disulphide 
  

   agitation 
  with 
  mercury, 
  and 
  evaporation 
  of 
  the 
  solvent. 
  The 
  

   boron 
  tri-iodide 
  thus 
  obtained 
  is 
  colorless 
  but 
  becomes 
  colored 
  on 
  

   exposure 
  to 
  light. 
  It 
  is 
  very 
  hygroscopic, 
  fuses 
  at 
  43°, 
  boils 
  at 
  

   210°, 
  burns 
  in 
  the 
  air 
  at 
  a 
  red 
  heat, 
  has 
  at 
  50° 
  the 
  approximate 
  

   density 
  of 
  3'3 
  and 
  is 
  easily 
  soluble 
  in 
  carbon 
  disulphide, 
  carbon 
  

   tetrachloride 
  and 
  benzene. 
  By 
  water 
  it 
  is 
  decomposed 
  into 
  boric 
  

   and 
  hydriodic 
  acids, 
  and 
  it 
  reacts 
  with 
  phosphorus, 
  silver 
  fluoride 
  

   and 
  magnesium 
  (at 
  500°) 
  with 
  combustion; 
  though 
  not 
  with 
  

  

  