﻿Chemistry 
  and 
  Physics. 
  425 
  

  

  Berthelot 
  also 
  has 
  observed 
  the 
  formation 
  of 
  this 
  iron-car- 
  

   bonyl 
  compound. 
  If 
  finely 
  divided 
  iron, 
  obtained 
  by 
  reducing 
  

   the 
  precipitated 
  oxide 
  at 
  the 
  lowest 
  possible 
  temperature 
  or 
  by 
  

   igniting 
  the 
  oxalate 
  in 
  hydrogen, 
  be 
  treated 
  at 
  45° 
  with 
  carbon 
  

   monoxide, 
  the 
  escaping 
  gas 
  contains 
  iron 
  and 
  burns 
  with 
  a 
  

   brighter, 
  sometimes 
  whiter, 
  flame 
  than 
  the 
  monoxide 
  itself. 
  

   This 
  flame 
  produces 
  spots 
  on 
  a 
  porcelain 
  surface 
  held 
  in 
  it, 
  these 
  

   spots 
  consisting 
  of 
  iron 
  and 
  its 
  oxide. 
  On 
  passing 
  the 
  gas 
  

   through 
  a 
  heated 
  tube 
  a 
  metallic 
  ring 
  is 
  deposited 
  consisting 
  of 
  

   iron 
  containing 
  carbon. 
  With 
  concentrated 
  hydrochloric 
  acid, 
  

   the 
  gas 
  gives 
  ferrous 
  chloride. 
  On 
  standing 
  over 
  water 
  contain- 
  

   ing 
  air, 
  iron 
  oxide 
  is 
  deposited. 
  The 
  quantity 
  of 
  the 
  iron 
  com- 
  

   pound 
  is 
  very 
  small. 
  Berthelot 
  has 
  also 
  examined 
  nickel-tetra- 
  

   carbonyl 
  and 
  finds 
  that 
  it 
  is 
  permanent 
  and 
  without 
  marked 
  

   dissociation-pressure 
  at 
  ordinary 
  temperatures. 
  When 
  preserved 
  

   under 
  water 
  it 
  is 
  not 
  decomposed 
  if 
  air 
  be 
  absent. 
  When 
  heated 
  

   suddenly 
  to 
  above 
  60° 
  it 
  explodes, 
  producing 
  carbon 
  and 
  carbon 
  

   dioxide 
  besides 
  nickel 
  and 
  the 
  monoxide 
  ; 
  according 
  to 
  the 
  equa- 
  

   tion 
  C 
  4 
  4 
  Xi 
  = 
  (C0 
  2 
  ) 
  2 
  + 
  C 
  2 
  + 
  Xi. 
  It 
  is 
  not 
  soluble 
  in 
  water, 
  dilute 
  

   acids 
  or 
  alkalies 
  or 
  acid 
  cuprous 
  chloride 
  ; 
  though 
  hydrocarbons, 
  

   especially 
  oil 
  of 
  turpentine 
  dissolve 
  it. 
  Mixed 
  with 
  air 
  or 
  oxygen 
  

   it 
  detonates 
  on 
  ignition 
  and 
  sometimes 
  spontaneously 
  as 
  when 
  the 
  

   dry 
  gas 
  mixed 
  with 
  oxygen 
  is 
  agitated 
  over 
  mercury. 
  In 
  pres- 
  

   ence 
  of 
  water, 
  a 
  greenish-white 
  gelatinous 
  precipitate 
  is 
  formed 
  

   which 
  contains 
  nickel, 
  oxygen, 
  water 
  and 
  combined 
  carbon, 
  and 
  

   which 
  deposits 
  carbon 
  on 
  heating. 
  In 
  the 
  liquid 
  state, 
  nickel- 
  

   tetracarbonyl 
  shows 
  similar 
  reactions. 
  Concentrated 
  sulphuric 
  

   acid 
  explodes 
  it, 
  while 
  its 
  vapor 
  when 
  mixed 
  with 
  nitrogen 
  is 
  

   gradually 
  converted 
  by 
  this 
  acid 
  into 
  four 
  times 
  it 
  volume 
  of 
  

   carbon 
  monoxide, 
  the 
  nickel 
  going 
  into 
  solution. 
  Ammonia 
  does 
  

   not 
  act 
  at 
  once 
  on 
  the 
  pure 
  gas, 
  while 
  if 
  oxygen 
  be 
  present 
  white 
  

   fumes 
  appear 
  immediately. 
  Hydrogen 
  sulphide 
  gives 
  a 
  black 
  

   sulphide, 
  hydrogen 
  phosphide 
  a 
  black 
  mirror-like 
  deposit. 
  Nitro- 
  

   gen 
  dioxide 
  when 
  mixed 
  with 
  the 
  liquid 
  or 
  its 
  vapor, 
  produces 
  a 
  

   blue 
  cloud 
  which 
  gradually 
  sinks 
  to 
  the 
  bottom 
  of 
  the 
  vessel 
  ; 
  

   the 
  resulting 
  gaseous 
  mixture 
  containing 
  nitrogen 
  dioxide, 
  car- 
  

   bon 
  monoxide 
  and 
  a 
  new 
  nickel 
  compound. 
  The 
  author 
  calls 
  at- 
  

   tention 
  to 
  the 
  analogy 
  between 
  carbon 
  monoxide 
  and 
  the 
  radicals 
  

   contained 
  in 
  the 
  so-called 
  metallo-organic 
  compounds. 
  — 
  C. 
  B., 
  

   cxii, 
  1343 
  ; 
  Ber. 
  Berl. 
  Chem. 
  Ges., 
  xxiv, 
  Ref. 
  593, 
  July, 
  1891. 
  

  

  G. 
  F. 
  B. 
  

  

  5. 
  On 
  a 
  sensitive 
  Reaction 
  for 
  Tartaric 
  acid. 
  — 
  Mohler 
  has 
  

   observed 
  that 
  when 
  crystals 
  of 
  tartaric 
  acid 
  are 
  thrown 
  on 
  sul- 
  

   phuric 
  acid 
  of 
  66° 
  B., 
  containing 
  one 
  per 
  cent 
  of 
  resorcinal, 
  and 
  

   the 
  whole 
  is 
  heated 
  gradually, 
  a 
  fine 
  red- 
  violet 
  coloration 
  is 
  pro- 
  

   duced 
  when 
  the 
  temperature 
  approaches 
  125°; 
  complete 
  carboni- 
  

   zation 
  taking 
  place 
  at 
  190°. 
  Water 
  destroys 
  the 
  color. 
  The 
  

   coloring 
  matter 
  could 
  not 
  be 
  isolated 
  since 
  it 
  was 
  not 
  soluble 
  in 
  

   ether, 
  amyl 
  alcohol, 
  acetone, 
  chloroform, 
  or 
  benzine. 
  Using 
  other 
  

   phenols, 
  similar 
  colors 
  are 
  produced 
  ; 
  phloroglucinol 
  giving 
  a 
  red 
  

  

  