﻿W. 
  P. 
  White 
  — 
  Specific 
  Heat 
  Determination. 
  45 
  

  

  whose 
  very 
  existence 
  was 
  unsuspected 
  for 
  several 
  years 
  

   seems 
  worthy 
  of 
  emphasis. 
  With 
  the 
  air 
  current 
  shut 
  

   off 
  the 
  irregularity 
  increased 
  with 
  temperature. 
  

  

  Day 
  and 
  Sosman, 
  who 
  eliminated 
  the 
  major 
  irregular- 
  

   ity 
  in 
  their 
  furnace 
  by 
  separately 
  adjusted 
  extra 
  coils, 
  

   found 
  that 
  the 
  minor 
  differences 
  were 
  then 
  less 
  at 
  high 
  

   temperatures, 
  as 
  might 
  be 
  expected 
  in 
  view 
  of 
  the 
  

   greater 
  activity 
  of 
  radiation 
  and 
  conduction. 
  

  

  The 
  work 
  done 
  with 
  the 
  platinum-wound 
  furnace 
  was 
  

   greatly 
  facilitated 
  by 
  a 
  temperature 
  regulator. 
  3 
  Several 
  

   hours 
  were 
  usually 
  allowed 
  for 
  the 
  charge 
  to 
  become 
  

   heated 
  with 
  sufficient 
  uniformity; 
  without 
  the 
  regulator 
  

   these 
  would 
  have 
  been 
  occupied 
  by 
  tedious 
  and 
  time- 
  

   wasting 
  hand 
  regulation, 
  with 
  less 
  accurate 
  results. 
  

  

  2. 
  Lead-bath 
  furnace. 
  — 
  The 
  satisfactory 
  measure- 
  

   ment 
  of 
  charge 
  temperature, 
  already 
  reported 
  at 
  700° 
  

   and 
  higher, 
  was 
  obtained 
  by 
  making 
  the 
  most 
  of 
  an 
  only 
  

   moderate 
  uniformity 
  in 
  a 
  simply 
  arranged 
  furnace. 
  At 
  

   lower 
  temperatures 
  a 
  better 
  furnace 
  performance 
  is 
  pos- 
  

   sible. 
  Uniformity 
  to 
  0-1° 
  has 
  been 
  obtained 
  in 
  electric 
  

   furnaces 
  by 
  stirred 
  baths 
  4 
  and 
  also 
  by 
  auxiliary 
  heating 
  

   coils, 
  5 
  but 
  with 
  restrictions 
  on 
  manipulation 
  coming 
  in 
  

   one 
  case 
  from 
  arrangement 
  of 
  the 
  apparatus 
  and 
  in 
  the 
  

   other 
  from 
  the 
  attention 
  required 
  as 
  well. 
  In 
  the 
  lead- 
  

   bath 
  furnace 
  used 
  in 
  this 
  work 
  a 
  combination 
  of 
  the 
  two 
  

   methods 
  gave 
  the 
  assurance 
  of 
  very 
  great 
  uniformity 
  

   without 
  demanding 
  remarkable 
  efficiency 
  either 
  in 
  stir- 
  

   ring 
  or 
  auxiliary 
  coil 
  regulation. 
  The 
  auxiliaries 
  easily 
  

   prevented 
  large 
  temperature 
  differences, 
  and 
  thus 
  the 
  

   stirring 
  was 
  enabled 
  to 
  destroy 
  the 
  lesser 
  irregularities. 
  

  

  Some 
  trouble 
  finally 
  developed 
  with 
  this 
  furnace, 
  which 
  

   is 
  properly 
  chargeable 
  to 
  the 
  fact 
  that 
  the 
  interior 
  of 
  the 
  

   bath 
  was 
  not 
  open 
  to 
  inspection. 
  The 
  cover, 
  originally 
  

   screwed 
  in, 
  had 
  become 
  welded 
  in 
  place. 
  This 
  defect 
  has 
  

   now 
  been 
  remedied 
  by 
  having 
  the 
  cover 
  merely 
  rest 
  in 
  

   place, 
  with 
  its 
  rim 
  dipping 
  into 
  a 
  lead 
  alloy 
  seal. 
  

  

  3. 
  An 
  additional 
  steam 
  heater 
  was 
  made 
  by 
  modify- 
  

   ing 
  an 
  apparatus 
  of 
  Regnault, 
  which 
  is 
  inverted 
  to 
  dis- 
  

   charge 
  the 
  heated 
  body, 
  and 
  loses 
  no 
  water 
  in 
  the 
  opera- 
  

  

  3 
  A 
  description 
  of 
  this 
  regulator 
  is 
  in 
  course 
  of 
  publication. 
  

  

  4 
  A. 
  L. 
  Day 
  and 
  E. 
  B. 
  Sosman, 
  The 
  Nitrogen 
  Thermometer 
  Scale 
  from 
  

   300° 
  to 
  630° 
  with 
  a 
  Direct 
  Determination 
  of 
  the 
  Boiling 
  Point 
  of 
  Sulphur, 
  

   this 
  Journal, 
  33, 
  521, 
  1912. 
  

  

  5 
  John 
  B. 
  Ferguson, 
  Temperature 
  Uniformity 
  in 
  an 
  Electric 
  Furnace, 
  

   Phys. 
  Rev., 
  12, 
  91, 
  1918. 
  

  

  