﻿Hypothesis, 
  and 
  the 
  Periodic 
  Law. 
  413 
  

  

  molecules 
  are 
  free 
  ions, 
  and 
  what 
  other 
  instance 
  have 
  we 
  of 
  a 
  

   chemically 
  inert 
  free 
  ion 
  ? 
  Which 
  of 
  the 
  two 
  horns 
  shall 
  we 
  

   choose 
  ? 
  The 
  nascent 
  state 
  is 
  par 
  excellence 
  the 
  state 
  of 
  maxi- 
  

   mum 
  tendency 
  towards 
  chemical 
  combination, 
  and 
  finds 
  its 
  best 
  

   explanation 
  in 
  the 
  idea 
  that 
  the 
  free 
  and 
  unincumbered 
  ion 
  is 
  

   exceptionally 
  prone 
  to 
  combination 
  with 
  the 
  first 
  partner 
  it 
  

   finds, 
  but 
  what 
  have 
  we 
  about 
  Argon, 
  if 
  monatomic, 
  which 
  

   in 
  the 
  slightest 
  degree 
  reminds 
  us 
  of 
  the 
  nascent 
  state 
  ? 
  Is 
  

   not 
  its 
  great 
  inertness 
  just 
  what 
  we 
  would 
  not 
  expect 
  a 
  free 
  

   ion 
  to 
  possess? 
  Which 
  is 
  the 
  more 
  unique, 
  a 
  diatomic 
  gas 
  

   without 
  rotational 
  energy 
  or 
  a 
  free 
  ion 
  devoid 
  of 
  chemical 
  

   affinity 
  1 
  

  

  On 
  the 
  whole, 
  therefore, 
  it 
  seems 
  a 
  fair 
  conclusion 
  as 
  to 
  

   Groups 
  III, 
  IV 
  and 
  VIII 
  that 
  the 
  force 
  binding 
  the 
  atoms 
  

   together 
  in 
  the 
  molecule 
  is 
  great, 
  therefore 
  their 
  atomic 
  volume 
  

   is 
  small, 
  likewise 
  the 
  distance 
  between 
  the 
  atoms 
  in 
  the 
  mole- 
  

   cule, 
  their 
  tendency 
  to 
  combine 
  directly 
  with 
  other 
  elements, 
  

   and 
  their 
  tendency 
  as 
  diatomic 
  gases 
  to 
  acquire 
  internal 
  rota- 
  

   tion 
  ; 
  hence 
  the 
  large 
  quantities 
  of 
  heat 
  required 
  for 
  their 
  dis- 
  

   sociation, 
  and 
  evolved 
  when 
  they 
  are 
  dissociated 
  by 
  solution 
  

   in 
  water 
  or 
  combine 
  with 
  other 
  elements. 
  

  

  The 
  theory 
  on 
  which 
  these 
  conclusions 
  rest 
  (which 
  conclu- 
  

   sions 
  accord 
  with 
  the 
  facts 
  found) 
  accords 
  also 
  with 
  fact 
  in 
  that 
  

   the 
  resultant 
  force 
  causing 
  the 
  elements 
  to 
  combine 
  in 
  the 
  free 
  

   state 
  to 
  form 
  a 
  binary 
  compound 
  is 
  not 
  identical 
  with 
  that 
  

   holding 
  the 
  atoms 
  together 
  after 
  combination, 
  which 
  thing 
  has 
  

   proved 
  a 
  stumbling 
  block 
  to 
  more 
  than 
  one 
  theory 
  of 
  affinity, 
  

   for 
  certain 
  forces 
  may 
  come 
  into 
  play 
  to 
  facilitate 
  or 
  restrain 
  

   combination, 
  as 
  for 
  instance 
  the 
  force 
  required 
  to 
  dissociate 
  the 
  

   two 
  component 
  atoms, 
  which 
  are 
  no 
  longer 
  factors 
  in 
  the 
  prob- 
  

   lem 
  after 
  combination 
  has 
  occurred. 
  The 
  stability 
  of 
  the 
  ele- 
  

   mentary 
  molecule, 
  the 
  tendency 
  to 
  combine 
  with 
  other 
  elements, 
  

   and 
  the 
  stability 
  of 
  the 
  compound, 
  will 
  in 
  each 
  case 
  depend 
  not 
  

   on 
  single 
  forces, 
  but 
  will 
  be 
  determined 
  by 
  the 
  magnitude 
  of 
  the 
  

   resultant 
  of 
  many 
  forces, 
  changing 
  in 
  various 
  ways 
  and 
  with 
  

   varying 
  conditions 
  just 
  as 
  we 
  find 
  actually 
  occurs 
  in 
  nature, 
  as 
  

   for 
  instance 
  in 
  cases 
  of 
  reversed 
  chemical 
  action 
  and 
  many 
  

   others 
  which 
  will 
  occur 
  to 
  the 
  mind 
  at 
  once. 
  

  

  We 
  may 
  then 
  briefly 
  sum 
  up 
  the 
  matter 
  as 
  follows 
  : 
  The 
  

   Periodic 
  law 
  places 
  Argon 
  if 
  an 
  element 
  betw 
  r 
  een 
  F 
  and 
  Na 
  

   with 
  an 
  atomic 
  weight 
  of 
  20; 
  which 
  law 
  has 
  been 
  confirmed 
  

   by 
  such 
  a 
  mass 
  of 
  evidence 
  that 
  any 
  reasonable 
  hypothesis 
  

   should 
  be 
  adopted 
  rather 
  than 
  a 
  theory 
  inconsistent 
  therewith. 
  

  

  While 
  Argon 
  may 
  yet 
  prove 
  to 
  be 
  an 
  allotropic 
  form 
  of 
  nitro- 
  

   gen, 
  yet 
  the 
  specific 
  heat 
  ratio 
  of 
  1*66 
  is 
  apparently 
  even 
  less 
  con- 
  

   sistent 
  with 
  a 
  triatomic 
  than 
  a 
  diatomic 
  molecule, 
  so 
  that 
  in 
  

   either 
  case 
  it 
  is 
  in 
  order 
  to 
  show 
  that 
  such 
  a 
  ratio 
  does 
  not 
  

  

  