﻿856 
  Mr. 
  F. 
  Soddy 
  on 
  the 
  

  

  from 
  the 
  straight 
  line. 
  It 
  is 
  doubtful 
  whether 
  the 
  departure 
  

   would 
  be 
  experimentally 
  detectable 
  over 
  this 
  period. 
  This 
  

   shows 
  that 
  the 
  straightness 
  of 
  the 
  experimental 
  curve 
  over 
  

   the 
  period 
  available 
  is 
  no 
  argument 
  against 
  the 
  existence 
  of 
  

  

  n 
  

  

  

  

  

  

  

  

  

  

  Fig. 
  

  

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  7 
  \[ 
  

  

  3 
  1. 
  

  

  3 
  2 
  

  

  o"e 
  

  

  intermediate 
  bodies. 
  On 
  the 
  other 
  hand, 
  the 
  figure 
  at 
  once 
  

   reveals 
  the 
  serious 
  error 
  introduced 
  into 
  the 
  calculated 
  period 
  

   of 
  the 
  parent 
  of 
  radium 
  by 
  the 
  formula 
  used 
  in 
  Section 
  Y. 
  if 
  

   intermediate 
  bodies 
  exist. 
  The 
  true 
  period 
  of 
  this 
  body 
  is 
  

   obtained 
  from 
  the 
  slope 
  of 
  the 
  straight 
  line 
  uppermost 
  in 
  the 
  

   diagram, 
  which 
  represents 
  the 
  rate 
  of 
  production 
  of 
  radium 
  

   if 
  no 
  intermediate 
  bodies 
  intervened. 
  If 
  an 
  intermediate 
  

   body 
  with 
  a 
  period 
  of 
  1 
  year 
  intervened, 
  the 
  period 
  of 
  the 
  

   parent 
  of 
  radium 
  instead 
  of 
  being 
  18,500 
  years 
  as 
  calculated 
  

   in 
  Section 
  V. 
  would 
  really 
  be 
  only 
  0'72 
  times 
  this 
  or 
  13,300 
  

   years. 
  If 
  the 
  period 
  of 
  the 
  intermediate 
  body 
  were 
  4 
  years, 
  

   the 
  true 
  period 
  of 
  the 
  parent 
  of 
  radium 
  would 
  be 
  only 
  0*32 
  

   of 
  the 
  apparent 
  period, 
  or 
  6000 
  years. 
  Yet 
  even 
  a 
  four-year 
  

   period 
  body 
  might 
  exist 
  without 
  producing 
  in 
  the 
  curve 
  a 
  

   departure 
  from 
  the 
  straight 
  line 
  enough 
  to 
  be 
  detected 
  

   experimentally 
  with 
  certainty 
  as 
  far 
  as 
  the 
  measurements 
  

   have 
  ^^Qi 
  gone. 
  

  

  