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  ^^^^ 
  NEW 
  YORK 
  STATE 
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  ^^^^^^^H 
  

  

  Thermoelectric 
  pyrometer. 
  Le 
  Cliatelier's 
  thermoelectric 
  pyrome- 
  

   ter 
  depends 
  on 
  the 
  measurement 
  of 
  a 
  current 
  generated 
  by 
  

   the 
  heating 
  of 
  a 
  thermopile. 
  The 
  latter 
  consists 
  of 
  two 
  wires, 
  one 
  

   of 
  platinum 
  and 
  the 
  other 
  an 
  alloy 
  90^ 
  platinum 
  and 
  10^ 
  rhodium, 
  

   twisted 
  together 
  at 
  their 
  free 
  ends 
  for 
  a 
  distance 
  of 
  about 
  an 
  inch, 
  

   while 
  the 
  next 
  foot 
  or 
  two 
  of 
  their 
  length 
  is 
  inclosed 
  in 
  a 
  fire 
  clay 
  

   tube, 
  so 
  that 
  when 
  the 
  couple 
  is 
  inserted 
  in 
  the 
  furnace 
  only 
  the 
  

   end 
  which 
  is 
  held 
  near 
  the 
  body 
  whose 
  temperature 
  is 
  to 
  be 
  meas- 
  

   ured 
  will 
  receive 
  the 
  full 
  force 
  of 
  the 
  heat. 
  The 
  two 
  wires 
  con- 
  

   nect 
  with 
  a 
  galvanometer, 
  the 
  deflection 
  of 
  whose 
  needle 
  measures 
  

   the 
  temperature 
  at 
  the 
  point 
  where 
  the 
  free 
  end 
  of 
  the 
  wire 
  couple 
  

   is 
  applied. 
  As 
  at 
  present 
  put 
  on 
  the 
  market, 
  the 
  thermoelectric 
  

   pyrometer 
  costs 
  about 
  $180, 
  and 
  the 
  price, 
  together 
  with 
  the 
  deli- 
  

   cacy 
  of 
  the 
  galvanometer, 
  has 
  tended 
  to 
  restrict 
  its 
  use. 
  There 
  is 
  

   no 
  reason 
  however 
  why 
  one 
  should 
  not 
  be 
  made 
  and 
  put 
  on 
  the 
  

   market 
  for 
  a 
  much 
  lower 
  price. 
  It 
  is 
  not 
  necessary 
  that 
  the 
  record- 
  

   ing 
  instrument 
  shall 
  be 
  in 
  the 
  immediate 
  vicinity 
  of 
  the 
  kiln; 
  it 
  

   may 
  be 
  kept 
  in 
  another 
  room 
  where 
  it 
  is 
  safe 
  from 
  dust 
  and 
  rough 
  

   handling, 
  and 
  the 
  wires 
  can 
  extend 
  from 
  there 
  to 
  the 
  kiln. 
  This 
  

   pyrometer 
  is 
  considered 
  to 
  be 
  accurate 
  to 
  within 
  10° 
  F. 
  

  

  Soger 
  cones 
  are 
  very 
  useful 
  for 
  determining 
  the 
  completion 
  of 
  

   firing, 
  but 
  the 
  thermoelectric 
  pyrometer 
  serves 
  as 
  a 
  guide 
  during 
  

   the 
  burning 
  operation, 
  indicating 
  whether 
  the 
  temperature 
  is 
  rising 
  

   slowly 
  or 
  quickly, 
  and 
  whether 
  steadily 
  or 
  unevenly. 
  

  

  If 
  careful 
  records 
  are 
  kept 
  of 
  these 
  facts 
  during 
  the 
  firing 
  of 
  a 
  

   kiln, 
  and 
  the 
  results 
  obtained 
  compared, 
  we 
  are 
  enabled 
  to 
  collect 
  

   valuable 
  data 
  concerning 
  the 
  conditions 
  necessary. 
  

  

  A 
  crude 
  means 
  of 
  judging 
  temperature 
  is 
  to 
  observe 
  the 
  color 
  

   of 
  the 
  fire 
  as 
  shown 
  by 
  the 
  following 
  table, 
  which 
  gives 
  the 
  color 
  

   of 
  a 
  body 
  when 
  heated 
  to 
  different 
  degrees, 
  thus: 
  

  

  Just 
  glowing 
  in 
  the 
  dark 
  977° 
  F. 
  

  

  Dark 
  red 
  1252° 
  F, 
  

  

  Cherry 
  red 
  1666° 
  F. 
  

  

  Bright 
  cherry 
  red 
  1832° 
  F. 
  

  

  