﻿of 
  various 
  Substances 
  on 
  Solidification. 
  

  

  221 
  

  

  Time. 
  

  

  

  Diameter, 
  

   filled 
  

   shell. 
  

  

  Diameter, 
  

   empty 
  

   shell. 
  

  

  11.30 
  

   12.30 
  

   12.15 
  

   12.55 
  

  

  12.50 
  

   1.20 
  

   1.50 
  

   2.15 
  

   2.45 
  

   3.15 
  

   3.45 
  

   4.15 
  

   4.45 
  

   5.15 
  

   5.45 
  

   6.15 
  

   6.45 
  

   7.15 
  

   7.45 
  

   8.15 
  

  

  Cold 
  

  

  Put 
  in 
  oven-furnace 
  (shell 
  to 
  be 
  filled) 
  

   (empty 
  shell) 
  

  

  After 
  filling 
  with 
  iron, 
  diameter 
  was 
  j 
  

  

  : 
  ■: 
  JJ 
  JJ 
  JJ 
  J 
  J 
  

   33 
  55 
  55 
  53 
  53 
  

   33 
  33 
  35 
  33 
  33 
  

   33 
  33 
  35 
  53 
  33 
  

   JJ 
  JJ» 
  " 
  JJ 
  JJ 
  JJ 
  

   JJ 
  33 
  JJ 
  JJ 
  JJ 
  

   35 
  35 
  33 
  33 
  33 
  

   35 
  55 
  33 
  55 
  55 
  

   33 
  35 
  55 
  55 
  33 
  

   JJ 
  JJ 
  JJ 
  JJ 
  JJ 
  

   33 
  33 
  33 
  33 
  J3 
  

   JJ 
  JJ 
  JJ 
  J» 
  JJ 
  

   JJ 
  JJ 
  JJ 
  JJ 
  JJ 
  

   35 
  55 
  55 
  55 
  33 
  

   g 
  99 
  . 
  JJ 
  JJ 
  JJ 
  JJ 
  

   35 
  53 
  35 
  53 
  33 
  

  

  9-850 
  

  

  10-020 
  

  

  10-030 
  

   10-040 
  

   10-040 
  

   10-020 
  

   10-000 
  

   9-995 
  

   9-980 
  

   9-978 
  

   9-976 
  

   9-975 
  

   9-973 
  

   9-970 
  

   9-968 
  

   9-965 
  

   9-964 
  

   9-964 
  

   9-963 
  

   9-962 
  

   9-960 
  

  

  9-843 
  

  

  9-960 
  

  

  9-955 
  

   9-950 
  

   9-875 
  

   9-865 
  

   9-860 
  

   9-855 
  

   9-854 
  

   9-862 
  

   9-852 
  

   9-851 
  

   9-851 
  

   9-851 
  

   9-851 
  

   9-851 
  

   9-851 
  

   9-851 
  

  

  The 
  object 
  of 
  heating 
  and 
  cooling 
  the 
  empty 
  shell 
  was 
  to 
  ascertain 
  

   what 
  amount, 
  if 
  any, 
  of 
  permanent 
  enlargement 
  it 
  might 
  suffer, 
  it 
  being 
  

   a 
  well-known 
  fact 
  that 
  all 
  solids 
  of 
  revolution 
  of 
  cast 
  iron, 
  and 
  generally 
  

   of 
  all 
  metals 
  of 
  sufficient 
  rigidity, 
  become 
  permanently 
  enlarged 
  by 
  being 
  

   heated 
  red-hot 
  and 
  permitted 
  to 
  cool. 
  This 
  arises 
  from 
  the 
  fact 
  that 
  

   the 
  outer 
  couches 
  of 
  the 
  solid 
  (a 
  sphere 
  for 
  example) 
  are 
  the 
  first 
  heated 
  

   and 
  expanded, 
  and 
  have 
  to 
  draw 
  off 
  more 
  or 
  less 
  from 
  the 
  less-heated 
  

   mass 
  within. 
  Tangential 
  thrusts 
  and 
  radial 
  tensions 
  are 
  thus 
  produced 
  

   in 
  the 
  material 
  of 
  the 
  outer 
  couches 
  which 
  disappear, 
  or 
  even 
  become 
  

   reversed, 
  as 
  the 
  progress 
  of 
  heating 
  reaches 
  the 
  interior 
  of 
  the 
  mass 
  ; 
  but 
  

   in 
  the 
  subsequent 
  cooling 
  the 
  entire 
  train 
  of 
  forces 
  is 
  reversed, 
  the 
  ex- 
  

   terior 
  couches 
  lose 
  heat 
  by 
  dissipation 
  first, 
  and 
  have 
  to 
  accommodate 
  by 
  

   tangential 
  tensions 
  their 
  dimensions 
  to 
  the 
  still 
  hotter 
  interior, 
  the 
  final 
  

   result 
  being 
  that 
  when 
  the 
  whole 
  has 
  cooled 
  the 
  dimensions 
  are 
  greater 
  than 
  

   before 
  the 
  solid 
  was 
  heated. 
  A 
  32-lb. 
  spherical 
  shot, 
  which 
  is 
  rather 
  more 
  

   than 
  6 
  inches 
  in 
  diameter, 
  can 
  be 
  thus 
  permanently 
  increased 
  J-^ 
  of 
  an 
  

   inch 
  in 
  diameter 
  by 
  a 
  single 
  heating. 
  It 
  is 
  obvious 
  that 
  the 
  increase 
  will 
  

   be 
  much 
  less 
  in 
  a 
  spherical 
  shell 
  than 
  in 
  a 
  solid 
  sphere, 
  and 
  the 
  less 
  as 
  

  

  