﻿128 
  C. 
  Barus 
  — 
  Continuity 
  of 
  Solid 
  and 
  Liquid. 
  

  

  vapor 
  baths 
  of 
  thin 
  sheet 
  iron, 
  thickly 
  jacketed 
  with 
  asbestus. 
  

   They 
  were 
  cylindrical 
  in 
  form, 
  20 
  cm 
  high 
  and 
  10 
  cm 
  in 
  diameter. 
  

   Axial 
  tubulures, 
  the 
  upper 
  of 
  which 
  projected 
  outward, 
  the 
  

   lower 
  both 
  inward 
  and 
  outward, 
  allowed 
  the 
  vertical 
  tubular 
  

   piezometer 
  to 
  pass 
  axially 
  through 
  the 
  vapor 
  baths, 
  and 
  suita- 
  

   ble 
  stuffing 
  boxes 
  obviated 
  leakage. 
  Again 
  the 
  upward 
  pro- 
  

   jection 
  of 
  the 
  lower 
  tubulure 
  (both 
  of 
  which 
  fit 
  the 
  piezometer 
  

   snugly), 
  formed 
  an 
  annular 
  trough 
  with 
  the 
  walls 
  of 
  the 
  vapor 
  

   bath, 
  in 
  which 
  a 
  sufficient 
  quantity 
  of 
  the 
  ebullition 
  liquid 
  

   could 
  be 
  placed, 
  and 
  boiled, 
  by 
  aid 
  of 
  the 
  flat 
  spiral 
  burner 
  

   below. 
  The 
  top 
  of 
  the 
  vapor 
  bath 
  was 
  provided 
  with 
  two 
  

   other 
  (lateral) 
  tubulures, 
  one 
  of 
  which 
  served 
  for 
  the 
  perma- 
  

   nent 
  attachment 
  of 
  a 
  vertical 
  condenser, 
  and 
  the 
  other 
  for 
  the 
  

   introduction 
  of 
  a 
  suitable 
  thermometer 
  or 
  thermocouple. 
  

   Here 
  also 
  the 
  quantity 
  of 
  ebullition 
  liquid 
  present, 
  could 
  at 
  

   any 
  time 
  be 
  tested, 
  its 
  amount 
  increased 
  or 
  diminished, 
  and 
  its 
  

   quality 
  directly 
  purified 
  by 
  fractional 
  distillation 
  or 
  otherwise 
  

   (an 
  operation 
  necessary, 
  for 
  instance, 
  when 
  amyl 
  alcohol 
  is 
  

   used). 
  §20. 
  With 
  a 
  good 
  condenser, 
  the 
  boiling 
  may 
  be 
  

   kept 
  up 
  indefinitely, 
  for 
  the 
  condensed 
  vapor 
  falls 
  back 
  into 
  

   the 
  trough 
  below. 
  At 
  temperatures 
  below 
  100°, 
  it 
  is 
  expedi- 
  

   ent 
  to 
  avail 
  oneself 
  of 
  the 
  high 
  latent 
  heat 
  of 
  water* 
  and 
  to 
  

   boil 
  this 
  liquid 
  under 
  diminished 
  pressure. 
  Temporarily 
  attach- 
  

   ing 
  Professor 
  R. 
  II. 
  Richards' 
  jet 
  pump 
  to 
  the 
  end 
  of 
  the 
  con- 
  

   denser, 
  pressure 
  may 
  be 
  reduced 
  at 
  pleasure, 
  and 
  any 
  boiling 
  

   point 
  between 
  50° 
  and 
  100° 
  reached 
  and 
  maintained 
  indefi- 
  

   nitely. 
  For 
  higher 
  temperatures 
  toluol, 
  amyl 
  alcohol, 
  turpen- 
  

   tine, 
  naphthalene, 
  benzoic 
  acid, 
  diphenylamine, 
  phenanthren, 
  

   sulphur, 
  etc., 
  subserve 
  similar 
  purposes 
  more 
  or 
  less 
  thoroughly. 
  

  

  Temperature 
  was 
  measured 
  by 
  a 
  Baudin 
  thermometer 
  of 
  

   known 
  errors, 
  and 
  also 
  computed 
  from 
  the 
  vapor 
  tension 
  of 
  

   steam 
  under 
  known 
  conditions. 
  

  

  5. 
  Pressure. 
  — 
  To 
  obtain 
  pressures 
  as 
  high 
  as 
  2000 
  atm., 
  I 
  

   employed 
  the 
  screw 
  compressor 
  described 
  elsewhere.f 
  I 
  made 
  

   use, 
  however, 
  of 
  a 
  vertical 
  piezometer, 
  identical 
  with 
  the 
  hori- 
  

   zontal 
  form 
  described, 
  except 
  in 
  so 
  far 
  as 
  it 
  could 
  be 
  removed 
  

   from 
  the 
  barrel 
  as 
  a 
  whole. 
  As 
  before, 
  the 
  piezometer 
  is 
  insu- 
  

   lated 
  from 
  the 
  barrel. 
  When 
  in 
  adjustment 
  the 
  former 
  was 
  

   surrounded 
  by 
  the 
  following 
  parts, 
  enumerated 
  from 
  below 
  : 
  

   an 
  insulated 
  guard 
  preventing 
  spilled 
  water, 
  etc., 
  to 
  reach 
  the 
  

   insulation 
  ; 
  the 
  lower 
  cold 
  water 
  jacket, 
  the 
  flat 
  burner, 
  the 
  

   vapor 
  bath, 
  and 
  finally 
  (wherever 
  necessary) 
  an 
  upper 
  cold 
  

   water 
  jacket. 
  Internally 
  the 
  piezometer 
  was 
  filled 
  with 
  thick 
  

   mineral 
  oil.J 
  

  

  * 
  I 
  shall 
  in 
  future 
  experiments 
  also 
  boil 
  water 
  under 
  pressure, 
  

   f 
  Proceed. 
  Am. 
  Acad., 
  xxv, 
  p. 
  93, 
  1890. 
  

   % 
  Phil. 
  Mag., 
  (V), 
  xxxi, 
  p. 
  10, 
  1891. 
  

  

  