﻿482 
  Scientific 
  Intelligence. 
  

  

  produced 
  between 
  carbon 
  terminals 
  in 
  an 
  atmosphere 
  of 
  hydrogen, 
  

   methane 
  and 
  acetylene 
  are 
  both 
  formed 
  ; 
  on 
  continuing 
  the 
  pas- 
  

   sage 
  of 
  the 
  arc 
  a 
  state 
  of 
  equilibrium 
  between 
  hydrogen, 
  methane 
  

   and 
  acetylene 
  is 
  finally 
  established. 
  (3) 
  The 
  same 
  state 
  of 
  equi- 
  

   librium 
  is 
  produced 
  when 
  the 
  electric 
  arc 
  is 
  passed 
  in 
  an 
  atmos- 
  

   phere 
  of 
  either 
  methane 
  or 
  acetylene 
  under 
  similar 
  conditions. 
  — 
  J. 
  

   Ghem. 
  Soc, 
  lxxi, 
  41-61, 
  January, 
  1897. 
  g. 
  f. 
  b. 
  

  

  5. 
  On 
  the 
  Preparation 
  of 
  Rubidium 
  and 
  its 
  Dioxide. 
  — 
  An 
  

   improved 
  process 
  of 
  obtaining 
  metallic 
  rubidium 
  has 
  been 
  devised 
  

   by 
  Erdmann 
  and 
  Kothner, 
  giving 
  a 
  yield 
  of 
  85 
  per 
  cent. 
  

   Rubidium 
  hydroxide, 
  20 
  grams, 
  coarsely 
  pulverized 
  and 
  mixed 
  

   with 
  ten 
  grams 
  of 
  magnesium 
  filings, 
  is 
  placed 
  in 
  the 
  long 
  arm 
  of 
  

   a 
  seamless 
  iron 
  tube 
  one 
  meter 
  long 
  and 
  15 
  mm 
  bore, 
  having 
  walls 
  

   three 
  millimeters 
  thick, 
  this 
  tube 
  being 
  bent 
  about 
  15 
  cm 
  from 
  one 
  

   end 
  at 
  an 
  angle 
  of 
  125°. 
  At 
  the 
  bend 
  is 
  placed 
  a 
  loose 
  plug 
  of 
  

   clean 
  steel 
  turnings. 
  The 
  tube 
  is 
  placed 
  in 
  a 
  combustion 
  furnace 
  

   and 
  heated 
  to 
  redness 
  while 
  a 
  current 
  of 
  hydrogen 
  is 
  passed 
  

   through 
  it. 
  The 
  short 
  arm 
  dips 
  beneath 
  the 
  surface 
  of 
  some 
  

   paraffin 
  oil 
  and 
  as 
  the 
  temperature 
  is 
  gradually 
  raised, 
  the 
  

   rapid 
  escape 
  of 
  bubbles 
  indicates 
  that 
  the 
  reaction 
  has 
  begun. 
  

   The 
  heat 
  is 
  then 
  shut 
  off 
  and 
  after 
  hydrogen 
  ceases 
  to 
  be 
  evolved 
  

   from 
  the 
  hydroxide, 
  the 
  temperature 
  is 
  raised 
  to 
  a 
  red 
  heat 
  and 
  

   the 
  metal 
  distils 
  over, 
  14 
  grams 
  being 
  obtained 
  from 
  the 
  20 
  grams 
  

   of 
  hydroxide 
  used. 
  The 
  yield 
  is 
  very 
  pure, 
  the 
  metal 
  having 
  a 
  

   specific 
  gravity 
  of 
  1 
  -5220 
  at 
  15° 
  and 
  a 
  melting 
  point 
  of 
  38'5°. 
  By 
  

   the 
  action 
  of 
  dry 
  oxygen 
  on 
  the 
  metal 
  at 
  the 
  ordinary 
  tempera- 
  

   ture, 
  the 
  dioxide 
  is 
  obtained. 
  Since 
  under 
  these 
  conditions, 
  

   rubidium 
  attacks 
  glass, 
  porcelain, 
  platinum, 
  silver 
  and 
  even 
  

   rubidium 
  chloride, 
  the 
  authors 
  allow 
  .the 
  metal 
  to 
  fall 
  into 
  an 
  

   aluminum 
  dish 
  contained 
  in 
  a 
  small 
  glass 
  flask 
  filled 
  with 
  nitrogen 
  • 
  

   the 
  whole 
  being 
  weighed 
  both 
  before 
  and 
  after 
  the 
  oxidation. 
  

   When 
  a 
  current 
  of 
  oxygen 
  is 
  directed 
  on 
  the 
  metal, 
  it 
  quickly 
  

   melts 
  and 
  even 
  inflames. 
  With 
  normal 
  oxidation 
  the 
  metal 
  pre- 
  

   serves 
  for 
  a 
  time 
  the 
  look 
  of 
  molten 
  gold, 
  then 
  swells 
  and 
  becomes 
  

   black 
  and 
  the 
  absorption 
  ceases. 
  It 
  is 
  renewed 
  however 
  at 
  500°, 
  

   the 
  volume 
  diminishes 
  and 
  a 
  thick 
  black 
  liquid 
  is 
  produced, 
  from 
  

   which 
  on 
  cooling 
  the 
  dioxide 
  crystallizes 
  in 
  dark 
  brown 
  plates. 
  

   No 
  evidence 
  was 
  obtained 
  of 
  any 
  other 
  oxide 
  of 
  rubidium, 
  and 
  

   this 
  one 
  may 
  be 
  highly 
  heated 
  without 
  losing 
  or 
  taking 
  up 
  

   oxygen. 
  Water 
  acts 
  on 
  it 
  violently, 
  producing 
  hydrogen 
  per- 
  

   oxide 
  and 
  rubidium 
  hydroxide, 
  oxygen 
  being 
  evolved. 
  Heated 
  

   in 
  an 
  atmosphere 
  of 
  hydrogen, 
  the 
  dioxide 
  yields 
  the 
  hydroxide, 
  

   water 
  and 
  oxygen 
  in 
  accordance 
  with 
  the 
  equation 
  (Rb0 
  2 
  ) 
  2 
  4- 
  

   (H 
  2 
  ) 
  2 
  =(RbOH) 
  2 
  + 
  H 
  2 
  2 
  .— 
  Ann. 
  Chem. 
  Pharm., 
  ccxciv, 
  55-71, 
  

   November, 
  1896. 
  G. 
  f. 
  b. 
  

  

  6. 
  On 
  the 
  Pyrogenic 
  Reactions 
  of 
  Aliphatic 
  Hydrocarbons. 
  — 
  

   Experiments 
  have 
  been 
  made 
  by 
  Habee 
  on 
  the 
  action 
  of 
  high 
  

   temperatures 
  on 
  aliphatic 
  hydrocarbons, 
  using 
  for 
  the 
  purpose 
  

   hexane, 
  trimethylethylene, 
  acetylene 
  and 
  benzene. 
  By 
  passing 
  a 
  

   current 
  of 
  the 
  gas 
  through 
  a 
  hot 
  tube 
  it 
  was 
  exposed 
  to 
  the 
  high 
  

  

  