﻿OEIG]>^ 
  OF 
  THE 
  EARTH 
  AND 
  ITS 
  CRUST 
  117 
  

  

  Potassium 
  1.6 
  

  

  r 
  

  

  < 
  2.4 
  

  

  Carbon 
  

  

  Iron 
  

  

  Sulphur 
  

  

  Chlorine 
  ^^ 
  

  

  Other 
  elements 
  1 
  

  

  100 
  

  

  Chemical 
  History 
  of 
  the 
  Earth 
  

  

  In 
  whatever 
  manner 
  our 
  earth 
  came 
  into 
  being, 
  every 
  known 
  

   fact 
  indicates 
  that 
  in 
  the 
  beginning 
  it 
  must 
  have 
  been 
  intensely 
  

   heated 
  and 
  in 
  a 
  gaseous 
  condition. 
  In 
  obedience 
  to 
  the 
  laws 
  of 
  

   matter 
  such 
  a 
  mass 
  would 
  constantly 
  lose 
  heat, 
  and 
  with 
  this 
  loss 
  

   of 
  heat 
  would 
  come 
  a 
  gain 
  in 
  density, 
  first 
  at 
  the 
  surface 
  only, 
  but 
  

   gradually 
  progressing 
  toward 
  the 
  center 
  till 
  at 
  that 
  point 
  its 
  con- 
  

   stituent 
  matter 
  had 
  reached 
  at 
  least 
  a 
  fluid 
  condition. 
  This 
  may 
  

   be 
  the 
  present 
  condition 
  of 
  the 
  earth's 
  interior. 
  As 
  an 
  eminent 
  

   chemist 
  has 
  observed, 
  here 
  commences 
  the 
  chemistry 
  of 
  the 
  earth, 
  

   and 
  the 
  probable 
  course 
  of 
  events 
  can 
  best 
  be 
  stated 
  by 
  quoting 
  

   from 
  the 
  words 
  of 
  the 
  late 
  T. 
  Sterry 
  Hunt. 
  As 
  long 
  as 
  the 
  earth's 
  

   component 
  matter 
  remained 
  in 
  a 
  gaseous 
  condition 
  and 
  its 
  tem- 
  

   perature 
  was 
  sufficiently 
  high 
  to 
  prevent 
  the 
  elements 
  from 
  com- 
  

   bining, 
  these 
  elements 
  remained 
  separate, 
  but 
  as 
  the 
  temperature 
  

   was 
  reduced, 
  chemical 
  combinations 
  of 
  these 
  elements 
  became 
  

   possible, 
  and 
  those 
  would 
  be 
  first 
  formed 
  which 
  were 
  stable 
  at 
  the 
  

   higher 
  temperature. 
  The 
  oxides 
  of 
  silicon, 
  aluminum, 
  calcium, 
  

   magnesium 
  and 
  iron 
  w^ere 
  probably 
  among 
  the 
  first 
  substances 
  

   formed. 
  At 
  some 
  early 
  stage 
  of 
  the 
  earth's 
  existence 
  the 
  bases 
  

   alumina, 
  lime, 
  magnesia 
  and 
  oxide 
  of 
  iron 
  were 
  probably 
  all 
  com- 
  

   bined 
  with 
  silica 
  and 
  that 
  which 
  represented 
  the 
  earth's 
  crust 
  

   was 
  a 
  fluid 
  mass 
  similar 
  to 
  a 
  lava. 
  The 
  carbon, 
  chlorine, 
  sulphur 
  

   and 
  water 
  vapor 
  only 
  existed 
  in 
  the 
  primeval 
  atmosphere, 
  which 
  

   must 
  then 
  have 
  been 
  too 
  acid 
  to 
  permit 
  the 
  existence 
  of 
  any 
  form 
  

   of 
  life, 
  as 
  it 
  would 
  probably 
  have 
  destroyed 
  animal 
  or 
  vegetable 
  

  

  a 
  Chemitai 
  and 
  Gt^ologic:!! 
  Essiiys. 
  i)p. 
  37 
  et 
  seq. 
  

  

  