﻿252 
  

  

  Mr. 
  L. 
  Vegard 
  

  

  Researches 
  upon 
  

  

  The 
  volume 
  v 
  was 
  determined 
  by 
  observing 
  the 
  position 
  of 
  

   the 
  mercury 
  column 
  by 
  means 
  of 
  a 
  cathetometer 
  furnished 
  

   with 
  a 
  filament 
  movable 
  by 
  a 
  micrometer-screw 
  reading 
  with 
  

   an 
  accuracy 
  of 
  about 
  1/50 
  mm. 
  It 
  was 
  somewhat 
  more 
  

   difficult, 
  however, 
  to 
  get 
  an 
  exact 
  determination 
  of 
  the 
  other 
  

   end 
  of 
  the 
  air 
  column 
  as 
  the 
  tube, 
  on 
  account 
  of 
  the 
  melting, 
  

   ended 
  in 
  a 
  tip. 
  It 
  is 
  especially 
  at 
  high 
  pressures 
  that 
  an 
  

   exact 
  determination 
  is 
  of 
  importance. 
  The 
  position 
  of 
  the 
  

   lowest 
  point, 
  as 
  well 
  as 
  the 
  point 
  where 
  the 
  diameter 
  began 
  

   to 
  diminish, 
  could 
  be 
  determined 
  with 
  great 
  precision. 
  This 
  

   lowest 
  part 
  had 
  very 
  nearly 
  the 
  form 
  of 
  a 
  cone, 
  and 
  thus 
  the 
  

   position 
  of 
  the 
  end 
  could 
  be 
  found 
  if 
  the 
  tube 
  had 
  been 
  

   throughout 
  cylindrical. 
  Furthermore, 
  I 
  afterwards 
  suc- 
  

   ceeded 
  in 
  calibrating 
  the 
  manometer 
  quite 
  up 
  to 
  the 
  tip. 
  

   The 
  two 
  methods 
  gave 
  results 
  for 
  the 
  end 
  reading 
  differing 
  

   only 
  by 
  1/10 
  mm. 
  In 
  the 
  calculation 
  I 
  have 
  used 
  the 
  

   mean 
  value. 
  

  

  As 
  this 
  error 
  that 
  may 
  arise 
  from 
  the 
  determination 
  of 
  

   the 
  end 
  point 
  when 
  measuring 
  somewhat 
  high 
  pressures 
  is 
  

   predominant, 
  we 
  can 
  conclude 
  that 
  even 
  for 
  pressures 
  up 
  to 
  

   50 
  atmospheres 
  the 
  error 
  in 
  q 
  would 
  not 
  exceed 
  0*2 
  atm., 
  and 
  

   lower 
  pressures 
  could 
  be 
  measured 
  much 
  more 
  accurately. 
  

  

  In 
  the 
  following 
  table 
  is 
  given 
  the 
  volume 
  of 
  air 
  corre- 
  

   sponding 
  to 
  a 
  series 
  of 
  readings 
  at 
  the 
  temperature 
  of 
  15° 
  

   centigrade. 
  All 
  the 
  numbers 
  are 
  derived 
  directly 
  from 
  

   observations. 
  The 
  values 
  of 
  v 
  for 
  intermediate 
  readings 
  

   have 
  been 
  found 
  by 
  interpolation, 
  The 
  volume 
  is 
  expressed 
  

   in 
  an. 
  arbitrary 
  unit, 
  which 
  is 
  the 
  volume 
  of 
  the 
  largest 
  

   mercury 
  column 
  used 
  in 
  the 
  calibration. 
  

  

  Reading. 
  

  

  Volume. 
  

  

  Reading. 
  

  

  Volume. 
  

  

  1*592 
  cm. 
  

  

  02380 
  

  

  60-282 
  cm. 
  

  

  9-9580 
  

  

  3-060 
  „ 
  

  

  0-4761 
  

  

  66-077 
  „ 
  

  

  10-9512 
  

  

  4-520 
  „ 
  

  

  0-7 
  141 
  

  

  72-140 
  „ 
  

  

  119898 
  

  

  5-988 
  „ 
  

  

  0-9522 
  

  

  78-073 
  „ 
  

  

  12-9968 
  

  

  7-439 
  „ 
  

  

  1-1902 
  

  

  83-914 
  „ 
  

  

  13-9952 
  

  

  8-887 
  „ 
  

  

  ] 
  4283 
  

  

  89-712 
  „ 
  

  

  14-9877 
  

  

  10-329 
  „ 
  

  

  1-6663 
  

  

  95-488 
  „ 
  

  

  15-9797 
  

  

  11-763 
  „ 
  

  

  1-9044 
  

  

  101-305 
  „ 
  

  

  16-977* 
  

  

  12160 
  „ 
  

  

  1 
  -9692 
  

  

  107-205 
  „ 
  

  

  17-9783 
  

  

  38306 
  „ 
  

  

  2-9666 
  

  

  112-674 
  „ 
  

  

  18-9030 
  

  

  24-399 
  „ 
  

  

  3-9654 
  

  

  118-114 
  „ 
  

  

  19-8285 
  

  

  30-4*9 
  „ 
  

  

  4 
  9642 
  

  

  123-553 
  „ 
  

  

  20-7-184 
  

  

  36-572 
  „ 
  

  

  5-9639 
  

  

  128-952 
  „ 
  

  

  21-6743 
  

  

  42-601 
  „ 
  

  

  6-9603 
  

  

  134313 
  „ 
  

  

  22-6025 
  

  

  48-535 
  „ 
  

  

  7-9569 
  

  

  139-587 
  „ 
  

  

  25-5290 
  

  

  54-434 
  „ 
  

  

  8-9580 
  

  

  

  

  The 
  temperature 
  of 
  the 
  air 
  when 
  the 
  manometer 
  was 
  closed 
  

   was 
  14°*5 
  C; 
  at 
  other 
  temperatures 
  the 
  volume 
  per 
  length- 
  

  

  