﻿Hypothesis, 
  and 
  the 
  Periodic 
  Law. 
  415 
  

  

  lience 
  must 
  be 
  potential, 
  is 
  only 
  one 
  of 
  many 
  similar 
  facts 
  

   pro 
  vino- 
  that 
  this 
  force 
  is 
  very 
  large 
  as 
  theory 
  requires 
  it 
  to 
  be, 
  

   compared 
  with 
  the 
  other 
  molecular 
  forces. 
  Moreover, 
  to 
  call 
  

   Argon 
  monatomic, 
  requires 
  us 
  to 
  explain 
  how 
  a 
  free 
  ion, 
  which 
  

   should 
  possess 
  all 
  the 
  activities 
  of 
  the 
  nascent 
  state, 
  can 
  be 
  as 
  

   chemically 
  inert 
  as 
  Argon 
  has 
  been 
  shown 
  to 
  be. 
  

  

  In 
  view 
  therefore 
  of 
  the 
  fact 
  that 
  the 
  burden 
  of 
  proof 
  is 
  

   upon 
  those 
  attempting 
  to 
  prove 
  monatomicity, 
  it 
  would 
  seem 
  

   safer 
  at 
  present 
  to 
  adopt 
  some 
  such 
  way 
  as 
  this 
  of 
  explaining 
  

   the 
  supposed 
  inconsistency 
  between 
  the 
  specific 
  heat 
  ratio 
  found 
  

   aud 
  the 
  diatomicity 
  of 
  the 
  molecule, 
  and 
  follow 
  the 
  almost 
  per- 
  

   emptory 
  indications 
  of 
  the 
  periodic 
  law 
  by 
  accepting 
  an 
  atomic 
  

   weight 
  of 
  20.* 
  

  

  A 
  very 
  interesting 
  question 
  connected 
  with 
  the 
  discovery 
  of 
  

   Argon, 
  is 
  what 
  will 
  be 
  the 
  effect 
  of 
  these 
  researches 
  upon 
  

   Prout's 
  hypothesis? 
  Is 
  it 
  possible 
  that 
  Argon 
  has 
  been 
  an 
  

   unsuspected 
  cause 
  of 
  error, 
  which 
  when 
  properly 
  allowed 
  for 
  

   will 
  show 
  the 
  ratio 
  of 
  II 
  to 
  O 
  to 
  be 
  almost 
  exactly 
  1 
  to 
  16? 
  

   This 
  would 
  make 
  so 
  many 
  atomic 
  weights 
  even 
  or 
  half 
  multi- 
  

   ples 
  of 
  H 
  as 
  to 
  render 
  probable, 
  what 
  has 
  been 
  often 
  surmised, 
  

   the 
  generation 
  of 
  the 
  elements 
  from 
  a 
  common 
  form 
  of 
  matter 
  

   (Protyle) 
  by 
  the 
  continued 
  addition 
  of 
  some 
  one 
  or 
  more 
  con- 
  

   stant 
  increments 
  of 
  mass. 
  As 
  pointed 
  out 
  by 
  Mendeleeff 
  the 
  

   periodic 
  law 
  does 
  not 
  indicate 
  continuous 
  but 
  abrupt 
  variations 
  

   of 
  weight 
  and 
  properties, 
  from 
  family 
  to 
  family, 
  corresponding 
  

   to 
  the 
  changes 
  iu 
  valency. 
  Some 
  years 
  since 
  I 
  noticed 
  the 
  

   prevalence 
  in 
  the 
  natural 
  series 
  of 
  the 
  elements 
  of 
  a 
  regular 
  

   alternation 
  of 
  intervals 
  of 
  3 
  and 
  1 
  substantially 
  as 
  referred 
  to 
  

   by 
  Dr. 
  Gladstone 
  in 
  a 
  recent 
  issue 
  of 
  Nature. 
  f 
  Thus 
  in 
  round 
  

   numbers 
  and 
  with 
  a 
  few 
  changes 
  we 
  have 
  the 
  following 
  series 
  : 
  

  

  * 
  There 
  is, 
  however, 
  one 
  real 
  difficulty 
  which 
  it 
  may 
  be 
  well 
  to 
  meet 
  as 
  far 
  as 
  

   can 
  be 
  done 
  at 
  present. 
  As 
  the 
  atomic 
  volume 
  is 
  the 
  quotient 
  of 
  specific 
  gravity 
  

   into 
  atomic 
  weight 
  we 
  have 
  these 
  volumes 
  : 
  F=15 
  ? 
  A 
  = 
  1 
  33 
  and 
  Na=23"7, 
  with 
  

   the 
  volumes 
  of 
  the 
  metals 
  of 
  Group 
  VIII 
  varying 
  from 
  6 
  7 
  to 
  9 
  2. 
  Why 
  then 
  

   should 
  not 
  Argon 
  have 
  a 
  volume 
  approximately 
  that 
  of 
  Group 
  YIIT, 
  and 
  since 
  its 
  

   volume 
  is 
  about 
  that 
  of 
  F 
  can 
  we 
  infer 
  close 
  aggregation 
  in 
  the 
  Argon 
  molecule 
  

   in 
  view 
  of 
  the 
  known 
  chemical 
  activity 
  of 
  Fluorine? 
  

  

  We 
  may 
  say 
  in 
  reply 
  that 
  the 
  volumes 
  of 
  Group 
  I 
  are 
  about 
  double 
  those 
  of 
  

   Group 
  VII, 
  although 
  their 
  chemical 
  activities 
  (force 
  of 
  aggregation 
  within 
  the 
  

   molecule) 
  are 
  about 
  equal, 
  thus 
  we 
  have 
  these 
  volumes: 
  F=15,? 
  Na 
  = 
  23*7; 
  

   (3=25-6, 
  K=45-4; 
  Br=269, 
  Rb=56'l; 
  1 
  = 
  25-6, 
  Cs 
  = 
  70-6. 
  Now 
  Argon 
  if 
  tran- 
  

   sitional 
  from 
  F 
  to 
  Na 
  should 
  have 
  its 
  volume 
  a 
  mean 
  value 
  or 
  about 
  195, 
  whereas 
  

   it 
  actually 
  has 
  a 
  volume 
  of 
  13 
  3, 
  the 
  difference 
  indicating 
  the 
  strong 
  force 
  of 
  

   aggregation 
  within 
  the 
  Argon 
  molecule 
  which 
  the 
  theory 
  requires. 
  That 
  is, 
  the 
  

   force 
  of 
  aggregation, 
  weak 
  in 
  F 
  and 
  Na 
  is 
  strong 
  in 
  Argon, 
  and 
  the 
  repulsive 
  force 
  

   in 
  Argon 
  is 
  a 
  mean 
  of 
  that 
  in 
  F 
  and 
  Xa 
  with 
  its 
  value 
  in 
  Na 
  about 
  double 
  that 
  

   in 
  F. 
  

  

  ■f 
  Quite 
  curiously 
  in 
  an 
  article 
  which 
  I 
  prepared 
  on 
  this 
  subject 
  but 
  did 
  not 
  pub- 
  

   lish 
  I 
  almost 
  duplicated 
  Dr. 
  Gladstone's 
  remarks 
  about 
  this 
  relation 
  and 
  its 
  bear- 
  

   ing 
  on 
  the 
  atomic 
  weight 
  of 
  Argon 
  some 
  days 
  before 
  his 
  article 
  was 
  received 
  

   in 
  this 
  country. 
  

  

  