﻿192 
  Ilolborn 
  and 
  Day 
  — 
  Gas 
  Thermometer 
  at 
  

  

  (nnburned) 
  clay 
  containing 
  organic 
  substances 
  which 
  burned 
  

   when 
  the 
  bulb 
  reached 
  a 
  temperature 
  of 
  1000°, 
  as 
  could 
  be 
  

   readily 
  detected 
  by 
  the 
  odor 
  in 
  the 
  room. 
  The 
  air 
  thermo- 
  

   meter 
  at 
  once 
  began 
  to 
  go 
  up 
  and 
  continued 
  doing 
  so 
  for 
  some 
  

   minutes, 
  though 
  the 
  thermo-element 
  in 
  the 
  oven 
  showed 
  the 
  

   temperature 
  inside 
  to 
  be 
  actually 
  falling. 
  This 
  plainly 
  showed 
  

   that 
  the 
  gases 
  of 
  combustion 
  were 
  penetrating 
  into 
  the 
  bulb 
  in 
  

   spite 
  of 
  an 
  excess 
  of 
  pressure 
  within 
  of 
  a 
  full 
  atmosphere. 
  Fur- 
  

   ther 
  observations 
  were 
  suspended 
  for 
  the 
  time 
  and 
  the 
  oven 
  al- 
  

   lowed 
  to 
  cool, 
  when 
  the 
  ice 
  point 
  was 
  found 
  to 
  have 
  risen 
  4:'46°"°. 
  

   The 
  zero 
  points 
  for 
  the 
  series 
  follow 
  : 
  

  

  Bulb 
  freshly 
  filled 
  296-67"^"^ 
  Hg. 
  

  

  After 
  heating 
  to 
  1085° 
  296*60 
  "' 
  

  

  After 
  standing 
  undisturbed 
  for 
  18 
  days 
  296*66 
  " 
  

  

  After 
  heating 
  as 
  above 
  described 
  301*12 
  " 
  

  

  7. 
  Conclusion. 
  

  

  We 
  have 
  then 
  as 
  a 
  result 
  of 
  the 
  foregoing 
  investigation 
  two 
  

   curves 
  based 
  upon 
  the 
  thermo-elements 
  T^ 
  and 
  T, 
  respec- 
  

   tively. 
  If 
  we 
  compare 
  these 
  we 
  shall 
  obtain 
  the 
  difference 
  

   between 
  the 
  temperature 
  scale 
  measured 
  with 
  porcelain 
  bulbs 
  

   and 
  that 
  secured 
  from 
  the 
  platin-iridium 
  bulb. 
  In 
  Table 
  XI 
  

   this 
  difference 
  A 
  is 
  given 
  in 
  microvolts 
  and 
  in 
  degrees. 
  

  

  

  Table 
  

  

  XL 
  

  

  A 
  

  

  

  

  T.-T: 
  

   Microvolts. 
  

  

  ^ 
  

  

  

  

  Microvolts. 
  

  

  Degrees 
  

  

  500° 
  

  

  93 
  

  

  4 
  

  

  0*4° 
  

  

  550 
  

  

  101 
  

  

  1 
  

  

  0-1 
  

  

  600 
  

  

  107 
  

  

  1 
  

  

  0*1 
  

  

  650 
  

  

  115 
  

  

  1 
  

  

  0-1 
  

  

  700 
  

  

  122 
  

  

  3 
  

  

  0-3 
  

  

  750 
  

  

  130 
  

  

  4 
  

  

  0-4 
  

  

  800 
  

  

  138 
  

  

  8 
  

  

  0-7 
  

  

  850 
  

  

  147 
  

  

  13 
  

  

  1*2 
  

  

  900 
  

  

  156 
  

  

  20 
  

  

  1-8 
  

  

  950 
  

  

  165 
  

  

  28 
  

  

  2-4 
  

  

  1000 
  

  

  174 
  

  

  39 
  

  

  3-3 
  

  

  1050 
  

  

  183 
  

  

  55 
  

  

  4-6 
  

  

  1100 
  

  

  192 
  

  

  77 
  

  

  6-4 
  

  

  1150 
  

  

  201 
  

  

  105 
  

  

  8*5 
  

  

  The 
  difference, 
  as 
  will 
  be 
  seen, 
  always 
  has 
  the 
  same 
  sign, 
  that 
  

   is, 
  the 
  scale 
  founded 
  upon 
  the 
  porcelain 
  values 
  always 
  gives 
  a 
  

   somewhat 
  higher 
  value 
  for 
  the 
  temperature 
  than 
  the 
  other. 
  

   In 
  the 
  lower 
  part 
  of 
  the 
  scale 
  the 
  A 
  chances 
  to 
  be 
  smaller 
  than 
  

  

  