﻿28 
  W. 
  G. 
  Mixter 
  — 
  Color 
  imetry 
  by 
  Combustions 
  

  

  The 
  values 
  for 
  C 
  + 
  20 
  = 
  C0 
  2 
  + 
  94"7, 
  Ti 
  + 
  20 
  = 
  Ti0 
  o 
  crys. 
  

  

  + 
  218*4 
  and 
  3Fe 
  + 
  40 
  = 
  Fe 
  3 
  4 
  (crys.) 
  + 
  265-2 
  were 
  obtained 
  

   by 
  combustion 
  in 
  oxygen. 
  The 
  other 
  values 
  are 
  derived 
  and 
  

   have 
  the 
  mean 
  error 
  of 
  several 
  experiments. 
  Both 
  values 
  for 
  

   C 
  + 
  20 
  are 
  for 
  acetylene 
  carbon. 
  One 
  reason 
  for 
  the 
  higher 
  

   value 
  found 
  in 
  the 
  sodium 
  peroxide 
  method 
  is 
  this 
  : 
  The 
  car- 
  

   bon 
  and 
  peroxide 
  were 
  mixed 
  in 
  a 
  mortar, 
  thus 
  allowing 
  the 
  

   peroxide 
  to 
  absorb 
  a 
  little 
  moisture 
  which 
  added 
  to 
  the 
  heat 
  of 
  

   the 
  fusion. 
  The 
  amorphous 
  Ti0 
  2 
  used 
  in 
  the 
  experiments 
  

   which 
  gave 
  215*6 
  was 
  heated 
  to 
  redness 
  for 
  an 
  hour. 
  Appar- 
  

   ently 
  it 
  has 
  nearly 
  the 
  same 
  heat 
  of 
  formation 
  as 
  the 
  crystalline 
  

   form. 
  The 
  value 
  267*5 
  for 
  3Fe 
  + 
  40 
  is 
  derived 
  from 
  the 
  

   results 
  of 
  fusions 
  of 
  iron, 
  ferrous 
  oxide, 
  ferric 
  oxide 
  and 
  the 
  

   mineral 
  magnetite 
  respectively 
  with 
  sodium 
  peroxide, 
  and 
  265*2 
  

   was 
  the 
  result 
  of 
  burning 
  iron 
  in 
  oxygen. 
  The 
  result 
  for 
  

   2Na 
  + 
  S 
  + 
  40 
  is 
  derived 
  from 
  the 
  heat 
  of 
  the 
  reaction 
  of 
  sul- 
  

   phur 
  with 
  sodium 
  peroxide 
  and 
  the 
  heats 
  of 
  formation 
  of 
  S0 
  3 
  

   and 
  Xa 
  2 
  0. 
  The 
  value 
  451*4 
  for 
  3iSa 
  4- 
  P 
  + 
  40 
  was 
  derived 
  

   in 
  a 
  similar 
  way. 
  452*4, 
  given 
  in 
  the 
  Physikalisch-Chem- 
  

   ische 
  Tabellen 
  is 
  derived 
  from 
  Berthelot's 
  data. 
  

  

  Sodium 
  peroxide 
  absorbs 
  water 
  rapidly 
  from 
  the 
  air 
  and 
  

   hence 
  it 
  should 
  be 
  exposed 
  as 
  little 
  as 
  possible 
  as 
  the 
  hydrated 
  

   peroxide 
  will 
  give 
  more 
  heat 
  with 
  a 
  combustible 
  than 
  the 
  

   anhydrous. 
  One 
  of 
  two 
  samples 
  which 
  gives 
  off 
  the 
  less 
  oxy- 
  

   gen 
  when 
  fused 
  is 
  the 
  better 
  one. 
  The 
  error 
  from 
  water 
  con- 
  

   tent 
  is 
  small 
  in 
  good 
  peroxide 
  especially 
  when 
  carbon, 
  for 
  

   example, 
  is 
  added 
  to 
  make 
  a 
  mixture 
  fuse 
  because 
  the 
  heat 
  

   effect 
  of 
  the 
  carbon 
  has 
  been 
  found 
  for 
  the 
  carbon 
  and 
  perox- 
  

   ide 
  used. 
  The 
  writer 
  has 
  obtained 
  peroxide 
  in 
  pound 
  packages, 
  

   containing 
  according 
  to 
  the 
  seller 
  92 
  to 
  95 
  per 
  cent 
  of 
  Na 
  2 
  2 
  . 
  

   To 
  ensure 
  uniformity 
  in 
  composition 
  four 
  or 
  five 
  pounds 
  are 
  

   mixed 
  thoroughly 
  in 
  a 
  large 
  stoppered 
  jar. 
  Then 
  it 
  is 
  rapidly 
  

   placed 
  in 
  about 
  half 
  pound 
  lots 
  in 
  flasks 
  with 
  necks 
  which 
  are 
  

   narrowed 
  to 
  half 
  an 
  inch, 
  and 
  the 
  necks 
  are 
  drawn 
  off 
  and 
  

   hermetically 
  sealed. 
  The 
  flasks 
  containing 
  peroxide 
  should 
  be 
  

   stored 
  in 
  a 
  metal 
  box 
  as 
  a 
  precaution 
  against 
  Are 
  in 
  case 
  of 
  

   breakage. 
  For 
  convenience 
  in 
  using, 
  the 
  peroxide 
  is 
  put 
  into 
  

   an 
  eight 
  ounce 
  bottle 
  having 
  a 
  smooth, 
  unground 
  neck 
  with 
  a 
  

   smooth 
  red 
  rubber 
  stopper. 
  

  

  Various 
  substances 
  may 
  be 
  added 
  to 
  a 
  peroxide 
  mixture 
  to 
  

   increase 
  the 
  temperature 
  of 
  the 
  fusion. 
  The 
  writer 
  has 
  used 
  

   successively 
  acetylene 
  carbon, 
  sulphur 
  and 
  lampblack. 
  Pure 
  

   rhombohedral 
  sulphur 
  in 
  line 
  powder 
  would 
  appear 
  to 
  be 
  the 
  

   best 
  of 
  the 
  three, 
  but 
  it 
  becomes 
  electrified 
  when 
  shaken 
  in 
  

   the 
  bomb 
  with 
  the 
  other 
  ingredients 
  and 
  sometimes 
  sticks 
  to 
  

   the 
  bomb 
  and 
  is 
  not 
  completely 
  oxidized. 
  Sulphide 
  is 
  formed 
  

   and 
  occasionally 
  free 
  sulphur 
  is 
  left. 
  When 
  the 
  bomb 
  is 
  much 
  

  

  