﻿THE 
  

  

  AMERICAN 
  JOURNAL 
  OF 
  SCIENCE 
  

  

  [FOURTH 
  SERIES.] 
  

  

  Art. 
  XYIIL 
  — 
  On 
  the 
  Gas 
  Therinoineter 
  at 
  High 
  Temperattires 
  ; 
  

   by 
  LuDWiG 
  HoLBORN 
  and 
  Arthur 
  L. 
  Day. 
  

  

  [Communication 
  from 
  the 
  Physikaliscli-Technische 
  Reichsanstalt, 
  Charlottenburg, 
  

  

  Germany.] 
  

  

  The 
  high 
  temperature 
  measurements 
  which 
  have 
  been 
  under- 
  

   taken 
  by 
  various 
  observers 
  with 
  the 
  gas 
  thermometer 
  are 
  not 
  

   jet 
  free 
  from 
  considerable 
  disagreements. 
  

  

  Yiolle"^ 
  determined 
  the 
  melting 
  point 
  of 
  gold 
  to 
  be 
  1035° 
  C, 
  

   a 
  value 
  which 
  he 
  afterward 
  increased 
  to 
  10tl:5° 
  ; 
  Barus'sf 
  deter- 
  

   mination 
  for 
  the 
  U. 
  S. 
  Coast 
  and 
  Geological 
  Survey 
  was 
  1092°, 
  

   and 
  one 
  of 
  the 
  authors 
  of 
  this 
  paper 
  has 
  published 
  with 
  W. 
  

   Wien:t 
  the 
  value 
  1072°. 
  

  

  In 
  all 
  three 
  cases 
  the 
  melting 
  point 
  was 
  not 
  directly 
  deter- 
  

   mined 
  with 
  the 
  gas 
  thermometer. 
  Yiolle 
  ascertained 
  first 
  the 
  

   specific 
  heat 
  of 
  platinum 
  with 
  the 
  gas 
  thermometer 
  and 
  then 
  

   by 
  calorimetric 
  methods 
  the 
  melting 
  point 
  of 
  gold, 
  while 
  in 
  

   the 
  last 
  two 
  instances 
  athermo-element 
  was 
  compared 
  with 
  the 
  

   gas 
  thermometer, 
  after 
  which 
  it 
  was 
  used 
  for 
  the 
  actual 
  melting- 
  

   point 
  determination. 
  

  

  ]S"either 
  the 
  indirect 
  method, 
  nor 
  the 
  inherent 
  experimental 
  

   difiiculties 
  which 
  stand 
  in 
  the 
  way 
  of 
  all 
  investigation 
  at 
  high 
  

   temperatures, 
  sufficiently 
  explain 
  the 
  differences 
  mentioned. 
  

   Especially 
  recently, 
  the 
  relative 
  measurement 
  of 
  high 
  tem- 
  

   peratures 
  electrically 
  has 
  become 
  less 
  difficult 
  and 
  more 
  

   accurate, 
  as 
  a 
  consequence 
  of 
  which 
  the 
  variations 
  of 
  the 
  tem- 
  

   perature 
  scales 
  of 
  different 
  observers 
  among 
  themselves 
  is 
  the 
  

   more 
  unpleasantly 
  conspicuous 
  and 
  disturbing. 
  

  

  * 
  Yiolle, 
  C. 
  R 
  , 
  Ixxxix, 
  102, 
  1889. 
  

  

  •(• 
  Barus, 
  Bull. 
  D. 
  S. 
  Geolog. 
  Survey, 
  54, 
  1889: 
  Proc. 
  Am. 
  Acad., 
  xxvii, 
  100, 
  

   1892. 
  

   X 
  Holborn 
  & 
  Wien, 
  Wied. 
  Ana., 
  xlvJi, 
  107, 
  1892, 
  and 
  Ivi, 
  360, 
  1895. 
  

  

  Am. 
  Jour. 
  Sci. 
  — 
  Fourth 
  Series, 
  Vol. 
  YIII, 
  No. 
  45, 
  — 
  September, 
  1899. 
  

   12 
  

  

  