﻿with 
  Sodium 
  Peroxide. 
  31 
  

  

  except 
  the 
  rim 
  which 
  is 
  1/4 
  in. 
  The 
  gasket 
  slot 
  in 
  the 
  top 
  is 
  

   5/32 
  in. 
  wide 
  and 
  1/8 
  in. 
  deep. 
  It 
  should 
  fit 
  the 
  top 
  of 
  the 
  

   bomb 
  so 
  that 
  the 
  lead 
  gasket 
  will 
  not 
  flow 
  under 
  pressure. 
  The 
  

   gasket 
  is 
  easily 
  made 
  by 
  placing 
  a 
  disk 
  of 
  lead 
  1/25 
  in. 
  in 
  

   thickness 
  on 
  the 
  bomb 
  and 
  then 
  pressing 
  the 
  top 
  into 
  place 
  by 
  

   means 
  of 
  the 
  screws. 
  There 
  are 
  eight 
  screws 
  5/16 
  in. 
  in 
  diam- 
  

   eter. 
  Four 
  are 
  sufficient 
  except 
  for 
  high 
  pressures. 
  The 
  

   screws 
  should 
  turn 
  easily 
  with 
  the 
  fingers 
  and 
  are 
  best 
  greased 
  

   with 
  tallow. 
  A 
  4 
  in. 
  solid 
  wrench 
  is 
  a 
  convenient 
  one 
  for 
  

   tightening 
  them. 
  The 
  tube 
  o 
  has 
  a 
  length 
  of 
  7 
  1/2 
  in., 
  includ- 
  

   ing 
  the 
  screw 
  ends. 
  The 
  narrow 
  part 
  of 
  it 
  is 
  3/16 
  in. 
  external 
  

   and 
  1/20 
  in. 
  internal 
  diameter. 
  The 
  lower 
  screw 
  joint 
  of 
  b 
  is 
  

   made 
  tight 
  with 
  soft 
  solder, 
  and 
  for 
  the 
  upper 
  one 
  joining 
  the 
  

   valve 
  shown 
  in 
  the 
  fig. 
  3 
  sealing 
  wax 
  answers. 
  The 
  tube 
  c 
  is 
  

   soldered 
  in 
  the 
  tapering 
  hole 
  in 
  the 
  brass 
  top. 
  It 
  is 
  shown 
  full 
  

   size 
  in 
  fig. 
  2. 
  The 
  insulated 
  rod 
  in 
  it 
  has 
  a 
  small 
  short 
  tube 
  

   on 
  the 
  lower 
  end 
  for 
  the 
  plug 
  which 
  fastens 
  the 
  iron 
  wire 
  d 
  of 
  

   fig. 
  1. 
  The 
  upper 
  end 
  of 
  the 
  tube 
  has 
  a 
  glass 
  tube 
  1/2 
  in. 
  in 
  

   length 
  and 
  is 
  packed 
  with 
  dental 
  phosphate 
  cement. 
  The 
  mid- 
  

   dle 
  of 
  the 
  tube 
  is 
  filled 
  with 
  a 
  flexible 
  cement 
  of 
  caoutchouc 
  

   and 
  beeswax, 
  and 
  the 
  rest 
  with 
  phosphate 
  dental 
  cement. 
  To 
  

   prevent 
  the 
  fusion, 
  in 
  case 
  it 
  is 
  thrown 
  against 
  the 
  top 
  of 
  the 
  

   bomb, 
  from 
  closing 
  the 
  hole 
  in 
  the 
  tube 
  5, 
  it 
  is 
  covered 
  by 
  a 
  

   thick 
  disk, 
  £, 
  of 
  pure 
  silver, 
  which 
  is 
  held 
  in 
  place 
  by 
  three 
  fric- 
  

   tion 
  lugs. 
  The 
  ignition 
  wire 
  d 
  should 
  weigh 
  at 
  least 
  20 
  mlg. 
  

   If 
  less 
  is 
  taken 
  it 
  should 
  be 
  weighted 
  with 
  a 
  bit 
  of 
  silver, 
  other- 
  

   wise 
  the 
  oxide 
  formed 
  when 
  the 
  iron 
  burns 
  will 
  not 
  drop 
  off 
  

   into 
  the 
  peroxide 
  mixture. 
  

  

  The 
  sterling 
  silver 
  bomb 
  weighed 
  when 
  made 
  472 
  grams 
  and 
  

   after 
  eight 
  years' 
  use 
  465 
  grams. 
  The 
  loss 
  is 
  due 
  to 
  corrosion, 
  

   especially 
  by 
  sulphur, 
  and 
  to 
  polishing. 
  The 
  total 
  weight 
  of 
  

   the 
  brass 
  work 
  excluding 
  the 
  thick 
  top 
  of 
  the 
  tube 
  o 
  is 
  397 
  

   grams. 
  The 
  lead 
  gasket 
  weighs 
  10 
  grams. 
  The 
  writer 
  has 
  

   two 
  nickel-plated 
  German 
  silver 
  cans 
  for 
  holding 
  the 
  water 
  of 
  

   the 
  calorimeter. 
  The 
  smaller 
  can 
  measures 
  5 
  1/2 
  in. 
  diameter, 
  

   has 
  a 
  depth 
  9 
  1/4 
  in., 
  and 
  weighs 
  50'6 
  grams. 
  The 
  dimen- 
  

   sions 
  of 
  the 
  larger 
  one 
  are 
  6 
  1/2 
  in. 
  and 
  9 
  1/4 
  in., 
  and 
  it 
  weighs 
  

   51*2 
  grams. 
  

  

  The 
  water 
  equivalent 
  of 
  a 
  calorimeter 
  and 
  can 
  may 
  be 
  calcu- 
  

   lated 
  from 
  the 
  specific 
  heats 
  of 
  the 
  metals 
  in 
  it, 
  or 
  may 
  be 
  deter- 
  

   mined 
  by 
  the 
  method 
  of 
  specific 
  heat. 
  By 
  the 
  latter 
  way 
  285 
  

   and 
  281*2 
  grams 
  were 
  obtained 
  for 
  a 
  steel 
  calorimeter 
  and 
  can; 
  

   calculated 
  284*7 
  grams. 
  The 
  specific 
  heat 
  of 
  the 
  metals 
  are 
  

   quite 
  accurately 
  known, 
  hence 
  a 
  calculated 
  hydro-thermal 
  

   equivalent 
  of 
  a 
  calorimeter 
  is 
  likely 
  to 
  be 
  more 
  accurate 
  than 
  

   an 
  experimental 
  one. 
  

  

  * 
  This 
  Journal, 
  xix, 
  425. 
  

  

  