﻿Ske:y, 
  — 
  On 
  ToniUnson's 
  Cohesion 
  Figures. 
  ' 
  491 
  

  

  Secondly, 
  as 
  to 
  the 
  ground 
  of 
  tliese 
  figures, 
  i.e., 
  the 
  part 
  in 
  which 
  these 
  

   annular 
  spaces 
  or 
  markings 
  are 
  set. 
  I 
  found 
  that 
  when 
  a 
  small 
  quantity 
  of 
  

   any 
  oil 
  is 
  gently 
  placed 
  thereon 
  it 
  does 
  not 
  spread 
  to 
  any 
  notable 
  extent, 
  

   but 
  keeps 
  nearly 
  to 
  the 
  drop 
  form 
  ; 
  and 
  it 
  was 
  further 
  manifested 
  to 
  me 
  

   that 
  this 
  part 
  breaks 
  into 
  angular 
  fragments, 
  which 
  are 
  possessed 
  of 
  such 
  

   rigiditj^ 
  that 
  they 
  kee^D 
  to 
  a 
  tabular 
  form 
  no 
  matter 
  how 
  they 
  are 
  dashed 
  

   about. 
  Now, 
  as 
  oils 
  indiscriminately 
  flow 
  over 
  oils, 
  and 
  as 
  none 
  of 
  them 
  

   can 
  indurate 
  to 
  such 
  an 
  extent 
  as 
  would 
  determine 
  angular 
  shapes 
  to 
  their 
  

   fragments, 
  it 
  is 
  clearly 
  demonstrated 
  that 
  this 
  part, 
  i.e., 
  the 
  ground 
  of 
  the 
  

   pattern, 
  is 
  not 
  an 
  oil. 
  

  

  The 
  current 
  idea, 
  then, 
  as 
  to 
  the 
  nature 
  of 
  this 
  part 
  of 
  the 
  figure, 
  being 
  

   fallacious, 
  it 
  is 
  necessary 
  that 
  we 
  should 
  adopt 
  another. 
  

  

  What 
  this 
  ought 
  to 
  be, 
  a 
  full 
  consideration 
  of 
  the 
  case 
  will, 
  I 
  think, 
  

   clearly 
  show. 
  Thus, 
  owing 
  to 
  the 
  great 
  proneness 
  of 
  oils 
  generally 
  to 
  oxidize 
  

   to 
  substances 
  of 
  a 
  resinous 
  nature 
  when 
  exposed 
  to 
  air, 
  it 
  is 
  certain 
  that 
  in 
  

   no 
  instance 
  do 
  we, 
  for 
  the 
  production 
  of 
  these 
  figures, 
  operate 
  with 
  an 
  oil 
  

   that 
  is 
  not, 
  to 
  a 
  small 
  extent, 
  charged 
  with 
  such 
  matters 
  ; 
  and 
  further, 
  it 
  is 
  

   also 
  as 
  certain 
  that 
  the 
  quantity 
  of 
  resinous 
  matter 
  therein 
  must 
  be 
  very 
  

   largely 
  increased 
  by 
  the 
  time 
  that 
  any 
  cohesion 
  figure 
  made 
  with 
  it 
  has 
  

   passed 
  to 
  its 
  final 
  form. 
  It 
  being, 
  therefore, 
  undeniable 
  that 
  resinous 
  

   matter 
  forms 
  one 
  of 
  the 
  principal 
  constituents 
  of 
  the 
  cohesion 
  figure 
  in 
  its 
  

   ultimate 
  condition, 
  the 
  conclusion 
  forces 
  itself 
  upon 
  us 
  that 
  of 
  such 
  matters 
  

   is 
  the 
  material 
  of 
  their 
  ground 
  alone 
  composed. 
  This 
  is 
  really 
  the 
  only 
  

   alternative, 
  as 
  it 
  is 
  one 
  which 
  meets 
  all 
  the 
  requirements 
  of 
  the 
  case. 
  So 
  

   attenuated, 
  indeed, 
  and 
  so 
  exposed 
  are 
  the 
  thinner 
  portions 
  of 
  these 
  figm'es, 
  

   and 
  so 
  rapidly 
  is 
  the 
  kind 
  of 
  change 
  indicated 
  wrought 
  upon 
  oil 
  under 
  these 
  

   conditions, 
  that 
  it 
  is 
  only 
  reasonable 
  to 
  conclude 
  that 
  these 
  portions 
  are 
  

   wholly 
  composed 
  of 
  resin, 
  to 
  the 
  exclusion 
  consequently 
  of 
  any 
  trace 
  of 
  oil. 
  

  

  As 
  being 
  corroborative 
  of 
  the 
  truth 
  of 
  the 
  supposition 
  that 
  the 
  presence 
  

   of 
  resin 
  in 
  the 
  cohesion 
  figures 
  plays 
  an 
  important 
  part 
  in 
  their 
  production, 
  

   I 
  would 
  inform 
  you 
  that 
  the 
  addition 
  of 
  about 
  ten 
  per 
  cent, 
  of 
  resin 
  to 
  a 
  

   good 
  oil 
  very 
  much 
  quickens 
  the 
  production 
  of 
  cohesion 
  figures, 
  and 
  also 
  

   passes 
  them 
  through 
  their 
  various 
  phases 
  to 
  the 
  ultimate 
  figure 
  with 
  a 
  

   speed 
  which 
  is 
  far 
  gi-eater 
  than 
  is 
  to 
  be 
  observed 
  in 
  the 
  case 
  of 
  the 
  oil. 
  

  

  And 
  now 
  I 
  think 
  the 
  foregoing 
  statements 
  of 
  facts 
  and 
  observations 
  may 
  

   be 
  fahiy 
  held 
  to 
  demonstrate 
  — 
  

  

  1st. 
  That 
  the 
  annular 
  spaces 
  or 
  markings 
  of 
  Tomlinson's 
  cohesion 
  

  

  figures 
  are 
  not 
  depressions 
  but 
  protuberances, 
  not 
  holes 
  but 
  hillocks, 
  

  

  and 
  are 
  not 
  composed 
  of 
  water, 
  but 
  of 
  oil. 
  

  

  2nd. 
  That 
  the 
  plane 
  part 
  of 
  these 
  figures 
  the 
  ground 
  as 
  it 
  were 
  of 
  the 
  

  

  pattern, 
  is 
  not 
  oil 
  (as 
  heretofore 
  quiescently 
  allowed), 
  but 
  either 
  a 
  

  

  