﻿468 
  Scientific 
  Intelligence. 
  

  

  much 
  below 
  their 
  melting 
  points. 
  In 
  his 
  experiments, 
  the 
  metals- 
  

   were 
  in 
  the 
  form 
  of 
  cylinders 
  with 
  perfectly 
  plane 
  ends, 
  placed 
  

   end 
  to 
  end 
  in 
  an 
  iron 
  holder, 
  and 
  forced 
  together 
  by 
  means 
  of 
  a 
  

   screw, 
  while 
  heated 
  in 
  an 
  air 
  bath 
  or 
  in 
  a 
  bath 
  of 
  an 
  indifferent 
  

   gas. 
  The 
  metals 
  used 
  were 
  aluminum, 
  bismuth, 
  cadmium, 
  cop- 
  

   per, 
  tin, 
  gold, 
  lead, 
  zinc, 
  antimony 
  and 
  platinum. 
  In 
  the 
  earlier 
  

   experiments 
  both 
  cylinders 
  were 
  of 
  the 
  same 
  metal, 
  and 
  the 
  tem- 
  

   perature 
  was 
  kept 
  at 
  from 
  200° 
  to 
  400° 
  for 
  from 
  four 
  to 
  eight 
  

   hours. 
  It 
  was 
  then 
  found 
  that, 
  with 
  the 
  exception 
  of 
  the 
  plati- 
  

   num 
  and 
  antimony, 
  the 
  cylinders 
  had 
  alloyed 
  so 
  perfectly 
  that 
  

   when 
  one 
  end 
  was 
  fixed 
  in 
  a 
  lathe 
  the 
  entire 
  cylinder 
  could 
  be 
  

   turned, 
  and 
  when 
  broken 
  in 
  a 
  vise 
  the 
  fracture 
  was 
  not 
  through 
  

   the 
  line 
  of 
  separation. 
  When 
  different 
  metals 
  were 
  employed, 
  as 
  

   copper 
  or 
  lead 
  with 
  certain 
  others, 
  an 
  alloy 
  of 
  a 
  considerable 
  

   thickness 
  was 
  produced, 
  I8 
  mm 
  in 
  the 
  case 
  of 
  zinc 
  and 
  copper 
  and 
  

   15 
  mm 
  in 
  that 
  of 
  cadmium 
  and 
  copper. 
  When 
  lead 
  and 
  tin 
  were 
  

   used 
  a 
  cavity 
  was 
  made 
  at 
  one 
  end 
  of 
  the 
  cylinder 
  and 
  filled 
  with 
  

   mica, 
  in 
  order 
  that 
  contact 
  should 
  take 
  place 
  only 
  at 
  the 
  edge. 
  

   The 
  alloy 
  formed 
  had 
  a 
  thickness 
  of 
  15 
  mm 
  , 
  nine 
  millimeters 
  being 
  

   in 
  the 
  tin 
  and 
  six 
  in 
  the 
  lead. 
  With 
  cylinders 
  of 
  copper 
  and 
  

   zinc 
  having 
  a 
  central 
  cavity 
  at 
  the 
  ends 
  in 
  contact, 
  the 
  surface 
  of 
  

   the 
  copper 
  next 
  to 
  the 
  cavity 
  was 
  colored 
  yellow, 
  resembling 
  the 
  

   alloy 
  formed 
  when 
  copper 
  is 
  exposed 
  to 
  zinc 
  vapor. 
  The 
  author 
  

   explains 
  these 
  results 
  upon 
  the 
  assumption 
  that 
  the 
  molecules 
  of 
  

   solids, 
  like 
  those 
  of 
  fluids, 
  have 
  not 
  all 
  the 
  same 
  velocity. 
  — 
  Zeit. 
  

   physikal. 
  Chem., 
  xv, 
  65, 
  September 
  1894. 
  g. 
  f. 
  b. 
  

  

  3. 
  On 
  the 
  Light 
  emitted 
  during 
  Crystallization. 
  — 
  The 
  emission 
  

   of 
  light 
  during 
  the 
  crystallization 
  of 
  certain 
  salts 
  has 
  been 
  exam- 
  

   ined 
  by 
  Bandrowsej, 
  who 
  considers 
  it 
  to 
  be 
  in 
  all 
  probability 
  

   electrical 
  and 
  to 
  be 
  due 
  to 
  the 
  union 
  of 
  electrified 
  ions. 
  If 
  this 
  

   is 
  the 
  case 
  it 
  should 
  be 
  most 
  decided 
  in 
  the 
  sudden 
  crystallization 
  

   of 
  strongly 
  dissociated 
  compounds. 
  He 
  suggests 
  the 
  iollowing 
  

   experiments 
  in 
  proof 
  of 
  this, 
  which 
  are 
  suitable 
  also 
  for 
  the 
  lec- 
  

   ture 
  table. 
  A 
  glass 
  cylinder 
  is 
  half 
  filled 
  with 
  a 
  warm 
  saturated 
  

   solution 
  of 
  sodium 
  chloride 
  and 
  into 
  it 
  is 
  poured 
  an 
  equal 
  volume 
  

   of 
  hydrochloric 
  acid 
  of 
  specific 
  gravity 
  1*12, 
  the 
  whole 
  being 
  

   mixed 
  by 
  means 
  of 
  a 
  glass 
  rod. 
  A 
  bluish 
  green 
  light 
  fills 
  the 
  

   entire 
  cylinder. 
  The 
  experiment 
  may 
  be 
  modified 
  by 
  pouring 
  in 
  

   the 
  two 
  liquids 
  separately 
  and 
  carefully 
  and 
  then 
  strongly 
  shak- 
  

   ing 
  the 
  cylinder. 
  A 
  flash 
  of 
  light 
  occurs. 
  In 
  place 
  of 
  the 
  acid, 
  

   alcohol 
  may 
  be 
  used 
  and 
  the 
  results 
  may 
  be 
  obtained 
  with 
  potas- 
  

   sium 
  bromide 
  or 
  chloride 
  in 
  place 
  of 
  the 
  sodium 
  salts. 
  When 
  

   potassium 
  chloride 
  was 
  used 
  with 
  alcohol 
  the 
  effect 
  was 
  very 
  

   marked, 
  the 
  light 
  being 
  stronger 
  and 
  greener 
  than 
  that 
  given 
  by 
  

   sodium 
  chloride. 
  — 
  Zeit. 
  physikal. 
  Chem., 
  xv, 
  323, 
  November, 
  1894. 
  

  

  G. 
  F. 
  B. 
  

  

  4. 
  On 
  the 
  Two-fold 
  Spectra 
  of 
  Oxygen. 
  — 
  In 
  a 
  paper 
  to 
  the 
  

   Royal 
  Society, 
  Baly 
  has 
  sought 
  to 
  account 
  for 
  the 
  two-fold 
  

   spectra 
  of 
  oxygen. 
  These 
  spectra 
  are 
  of 
  a 
  different 
  nature 
  ; 
  they 
  

   behave 
  differently 
  and 
  there 
  are 
  reasons 
  why 
  in 
  all 
  probability 
  

  

  