﻿CHAMBEELIN— 
  WILLIS 
  591 
  

  

  A 
  mass 
  of 
  gas 
  expelled 
  from 
  the 
  pressure 
  and 
  temperature 
  of 
  the 
  

   sun 
  into 
  the 
  vacuum 
  and 
  cold 
  of 
  space 
  presents 
  dynamical 
  problems 
  

   which 
  divide 
  physicists. 
  Would 
  it 
  assemble 
  in 
  response 
  to 
  its 
  own 
  

   gravitation 
  and 
  form 
  a 
  molten 
  globe? 
  or 
  would 
  it 
  be 
  dispersed 
  by 
  

   the 
  kinetic 
  energy 
  of 
  the 
  gas? 
  Chamberlin 
  and 
  Moulton 
  approached 
  

   the 
  question 
  as 
  a 
  sequel 
  to 
  their 
  investigations 
  of 
  the 
  Laplacian 
  and 
  

   related 
  gaseous 
  assemblages. 
  They 
  had 
  demonstrated 
  the 
  ineffici- 
  

   ency 
  of 
  gravitation 
  and 
  the 
  effectiveness 
  of 
  kinetic 
  dispersion. 
  They 
  

   were 
  forced 
  to 
  recognize 
  that 
  the 
  mass 
  would 
  become 
  a 
  swarm 
  of 
  

   minute 
  solid 
  bodies 
  which 
  would 
  swing 
  into 
  orbits 
  about 
  the 
  sun 
  and 
  

   would 
  thus 
  become 
  " 
  planetesimals." 
  The 
  real 
  problem 
  was 
  to 
  account 
  

   for 
  the 
  fact 
  that 
  the 
  planetesimals 
  had 
  assembled, 
  that 
  each 
  swarm 
  

   had 
  become 
  a 
  planet. 
  

  

  The 
  problem 
  is 
  not 
  one 
  which 
  yields 
  to 
  mathematical 
  analysis 
  unless 
  

   it 
  be 
  stripped 
  of 
  inherent 
  complexities 
  and 
  simplified 
  to 
  suit 
  aa 
  imagi- 
  

   nary 
  case. 
  Chamberlin 
  analyzed 
  it 
  logically. 
  He 
  grasped 
  the 
  com- 
  

   plexity 
  of 
  cyclonic 
  motion 
  in 
  the 
  sun, 
  the 
  compressive 
  action 
  of 
  the 
  

   tidal 
  effect, 
  the 
  dominance 
  of 
  the 
  expulsive 
  force, 
  the 
  drag 
  effect 
  

   upon 
  the 
  bolt, 
  and 
  the 
  consequent 
  resemblance 
  of 
  the 
  mass 
  to 
  a 
  

   rolling 
  cloud. 
  He 
  reasoned 
  the 
  transformation 
  of 
  the 
  billowing 
  bolt 
  

   into 
  the 
  orbital 
  swarm, 
  in 
  consequence 
  of 
  the 
  attraction 
  of 
  the 
  passing 
  

   star, 
  the 
  formation 
  of 
  a 
  heavy 
  core, 
  and 
  the 
  gradual 
  growth 
  of 
  the 
  

   earth 
  by 
  the 
  infall 
  of 
  planetesimals. 
  

  

  He 
  first 
  pubhshed 
  these 
  views 
  in 
  1903-04 
  in 
  reports 
  to 
  the 
  Carnegie 
  

   Institution 
  of 
  Washington 
  on 
  research 
  in 
  fundamental 
  Problems 
  of 
  

   Geology. 
  He 
  embodied 
  them 
  in 
  more 
  popular 
  form 
  in 
  the 
  Origin 
  of 
  

   the 
  Earth, 
  1916. 
  It 
  was 
  characteristic 
  that 
  to 
  the 
  end 
  of 
  his 
  life 
  he 
  

   continued 
  to 
  pursue 
  studies 
  designed 
  to 
  test, 
  modify, 
  or 
  perfect 
  

   theories 
  of 
  the 
  origin 
  of 
  the 
  earth, 
  including 
  the 
  Planetesimal. 
  In 
  1926 
  

   he 
  said 
  concerning 
  the 
  latter 
  : 
  

  

  For 
  25 
  years 
  I 
  have 
  tested 
  every 
  hypothesis 
  of 
  the 
  genesis 
  of 
  the 
  earth 
  of 
  which 
  

   T 
  could 
  learn 
  or 
  which 
  I 
  could 
  conceive. 
  One 
  and 
  one 
  only 
  has 
  withstood 
  every 
  

   critical 
  test. 
  Do 
  you 
  think 
  I 
  am 
  justified 
  in 
  thinking 
  it 
  probably 
  true? 
  

  

  In 
  this 
  attitude 
  of 
  mind 
  he 
  took 
  up 
  the 
  review 
  of 
  his 
  book, 
  the 
  Origin 
  

   of 
  the 
  Earth, 
  when 
  it 
  was 
  to 
  go 
  to 
  its 
  fifth 
  printing. 
  The 
  year 
  was 
  1925 
  ; 
  

   he 
  was 
  82. 
  With 
  the 
  wisdom 
  of 
  a 
  veteran 
  but 
  with 
  the 
  courage 
  of 
  

   youth, 
  he 
  critically 
  revised 
  his 
  earlier 
  postulates 
  — 
  not 
  to 
  prove 
  but 
  to 
  

   test 
  them 
  — 
  and 
  he 
  came 
  upon 
  "a 
  lion 
  in 
  the 
  path." 
  He 
  had 
  met 
  lions 
  

   before, 
  such 
  as 
  the 
  doctrine 
  that 
  the 
  rotation 
  of 
  planets, 
  if 
  they 
  were 
  

   formed 
  from 
  solid 
  accretions, 
  should 
  be 
  backward 
  instead 
  of 
  forward. 
  

   For 
  a 
  long 
  time 
  that 
  lion 
  had 
  barred 
  the 
  way 
  from 
  the 
  field 
  of 
  gaseous 
  

   origins 
  to 
  that 
  of 
  the 
  planetesimals, 
  but 
  he 
  had 
  been 
  shown 
  to 
  present 
  a 
  

   false 
  front. 
  Was 
  this 
  new 
  lion 
  more 
  formidable? 
  

  

  The 
  difficulty 
  lay 
  in 
  the 
  fact 
  that 
  the 
  rotation 
  of 
  a 
  cyclonic 
  bolt 
  must 
  

   be 
  around 
  the 
  axis 
  of 
  the 
  bolt 
  as 
  it 
  left 
  the 
  sun 
  and 
  would 
  therefore 
  be 
  

  

  