﻿Y2 
  Scientific 
  Intelligence. 
  

  

  SCIENTIFIC 
  INTELLIGENCE. 
  

  

  I. 
  Chemistry 
  and 
  Physics. 
  

  

  1. 
  On 
  the 
  Peroxides. 
  — 
  Some 
  further 
  results 
  have 
  been 
  pub- 
  

   lished 
  by 
  Melikoff 
  and 
  Pissarjewsky 
  in 
  their 
  investigations 
  on 
  

   peroxides. 
  They 
  have 
  shown 
  that 
  acid 
  peroxides 
  may 
  form 
  salts 
  

   with 
  alkali 
  peroxides. 
  The 
  resulting 
  soluble 
  salts, 
  such 
  for 
  

   example 
  as 
  the 
  sodium 
  and 
  lithium 
  salts 
  of 
  peruranic 
  acids, 
  when 
  

   treated 
  with 
  aluminum 
  hydrate 
  are 
  converted 
  into 
  the 
  free 
  acid 
  

   and 
  hydrogen 
  peroxide. 
  The 
  insoluble 
  salts, 
  such 
  as 
  the 
  barium 
  

   salt 
  of 
  peruranic 
  acid, 
  when 
  treated 
  with 
  carbon 
  dioxide, 
  act 
  like 
  

   barium 
  peroxide; 
  barium 
  carbonate, 
  hydro_o;en 
  peroxide, 
  and 
  peru- 
  

   ranic 
  acid 
  being 
  formed. 
  Acid 
  peroxides 
  RO^ 
  have 
  been 
  obtained 
  

   from 
  elements 
  belonging 
  to 
  six 
  groups. 
  The 
  stability 
  of 
  the 
  salts 
  

   formed 
  by 
  them 
  with 
  alkali 
  peroxides 
  decreases 
  with 
  the 
  atomic 
  

   mass 
  of 
  the 
  element 
  forming 
  the 
  acid 
  peroxide. 
  With 
  metallic 
  

   peroxides, 
  strongly 
  acid 
  peroxides 
  do 
  not 
  form 
  salts 
  but 
  decom- 
  

   pose 
  them, 
  forming 
  hydrogen 
  peroxide. 
  They 
  assign 
  to 
  the 
  

   peroxy-acids 
  and 
  the 
  metallic 
  peroxides 
  the 
  constitution 
  HO 
  — 
  OH 
  

   analogous 
  to 
  that 
  of 
  hydrogen 
  peroxide, 
  as 
  they 
  behave 
  similarly 
  

   with 
  certain 
  reagents. 
  They 
  yield 
  hydrogen 
  peroxide 
  on 
  treat- 
  

   ment 
  with 
  dilute 
  sulphuric 
  acid, 
  but 
  if 
  the 
  acid 
  is 
  concentrated 
  

   many 
  of 
  them 
  yield 
  ozone. 
  Water 
  decomposes 
  the 
  peroxy-acids 
  

   as 
  it 
  does 
  the 
  peroxides; 
  sodium 
  perborate 
  for 
  example 
  being 
  

   partially 
  decomposed 
  into 
  sodium 
  metaborate 
  and 
  hydrogen 
  per- 
  

   oxide. 
  The 
  peroxy-acids 
  also 
  behave 
  like 
  the 
  metallic 
  peroxides 
  

   when 
  treated 
  with 
  manganese 
  peroxide, 
  oxygen 
  being 
  evolved 
  

   rapidly 
  in 
  the 
  case 
  of 
  soluble 
  salts 
  and 
  slowly 
  in 
  the 
  case 
  of 
  insol- 
  

   uble 
  ones 
  ; 
  the 
  peroxy-acids 
  oxidize 
  alkalis, 
  easily 
  converting 
  them 
  

   into 
  peroxides. 
  — 
  Zeitschr. 
  Aiiorg. 
  Cliem.^ 
  xviii, 
  59-65, 
  1898. 
  

  

  G. 
  F. 
  B. 
  

  

  2. 
  On 
  the 
  Preparation 
  of 
  Iron 
  Silicide. 
  — 
  The 
  fact 
  has 
  been 
  

   observed 
  by 
  Lebeau 
  that 
  copper 
  silicide 
  in 
  the 
  melted 
  state 
  dis- 
  

   solves 
  iron 
  silicide 
  very 
  readily. 
  And 
  upon 
  this 
  he 
  has 
  based 
  a 
  

   method 
  of 
  preparing 
  the 
  latter 
  compound. 
  Commercial 
  copper 
  

   silicide, 
  coarsely 
  pulverized, 
  is 
  mixed 
  with 
  ten 
  per 
  cent 
  of 
  iron 
  

   filings, 
  the 
  mixture 
  is 
  placed 
  in 
  a 
  carbon 
  crucible 
  and 
  this 
  is 
  

   inserted 
  in 
  an 
  electric 
  furnace 
  supplied 
  with 
  a 
  current 
  of 
  950 
  

   amperes 
  at 
  a 
  pressure 
  of 
  45 
  volts, 
  for 
  from 
  four 
  to 
  five 
  minutes. 
  

   A 
  button 
  is 
  thus 
  obtained, 
  white 
  in 
  color 
  and 
  having 
  a 
  crystalline 
  

   fracture. 
  It 
  is 
  coarsely 
  pulverized 
  and 
  treated 
  with 
  diluted 
  

   nitric 
  acid, 
  the 
  temperature 
  being 
  raised 
  toward 
  the 
  end. 
  The 
  

   copper 
  silicide 
  is 
  dissolved 
  and 
  crystals 
  of 
  iron 
  silicide 
  remain 
  

   surrounded 
  by 
  gelatinous 
  silica. 
  To 
  remove 
  this, 
  the 
  crystals 
  

   after 
  washing 
  are 
  heated 
  with 
  a 
  solution 
  of 
  caustic 
  soda. 
  Repe- 
  

   tition 
  of 
  the 
  treatment 
  with 
  nitric 
  acid 
  and 
  with 
  soda 
  gives 
  the 
  

   iron 
  silicide 
  pure. 
  It 
  has 
  the 
  composition 
  SiFe, 
  thus 
  differing 
  

   from 
  the 
  silicide 
  SiFe, 
  prepared 
  by 
  Moissan 
  by 
  the 
  direct 
  union 
  

  

  