﻿72 
  Messrs. 
  McClung 
  and 
  Mcintosh 
  on 
  Absorption 
  of 
  

  

  A 
  deflexion 
  of 
  48'2 
  for 
  Cell 
  II. 
  empty 
  corresponds 
  to 
  a 
  

   deflexion 
  of 
  16*3 
  for 
  the 
  standard. 
  It 
  is 
  reduced 
  to 
  the 
  

   basis 
  15*8 
  for 
  the 
  standard, 
  and 
  can 
  therefore 
  be 
  compared 
  

   with 
  the 
  reading 
  16*6 
  for 
  Cell 
  II. 
  full 
  of 
  water. 
  The 
  per- 
  

   centage 
  absorption 
  of 
  the 
  given 
  thickness 
  of 
  water 
  is 
  thus 
  

   easily 
  obtained. 
  The 
  percentage 
  absorption 
  of 
  any 
  other 
  

   liquid 
  can 
  be 
  obtained 
  in 
  a 
  similar 
  way. 
  By 
  this 
  method 
  of 
  

   taking 
  observations, 
  a 
  considerable 
  number 
  of 
  solutions 
  could 
  

   be 
  compared 
  with 
  one 
  another 
  during 
  the 
  course 
  of 
  a 
  few 
  

   hours. 
  

  

  The 
  percentage 
  of 
  the 
  rays 
  absorbed 
  by 
  the 
  given 
  thickness 
  

   of 
  water 
  kept 
  fairly 
  constant 
  from 
  day 
  to 
  day, 
  except 
  in 
  one 
  

   or 
  two 
  cases. 
  These 
  determinations 
  are 
  shown 
  in 
  Table 
  l. 
  T 
  

   the 
  ones 
  which 
  vary 
  widely 
  from 
  the 
  mean 
  being 
  given 
  also. 
  

  

  Table 
  I. 
  

  

  Electrometer 
  Deflexions 
  per 
  sec. 
  

  

  Percentage 
  

   Absorption. 
  

  

  Cell 
  II. 
  

  

  Cell 
  II. 
  

   with 
  water. 
  

  

  63-4 
  

   47-0 
  

   55-0 
  

   38-9 
  

   35-6 
  

   45-2 
  

   44.7 
  

   496 
  

   95-3 
  

   74-9 
  

   64-7 
  

   77-5 
  

   491 
  

  

  263 
  

   181 
  

   22-6 
  

   15-1 
  

   17-4 
  

   16-7 
  

   16-4 
  

   17-2 
  

   42-6 
  

   31-7 
  

   27-8 
  

   314 
  

   165 
  

  

  58-6 
  

   61*5 
  

   58-9 
  

   61-2 
  

   51-1 
  

   63'1 
  

   66-3 
  

   65-3 
  

   55-3 
  

   57-6 
  

   56-9 
  

   59-5 
  

   66-4 
  

  

  Mean 
  = 
  59*9 
  

  

  The 
  variation 
  is 
  well 
  within 
  the 
  limits 
  of 
  experimental 
  

   error, 
  and 
  the 
  agreement 
  is 
  so 
  close 
  that 
  it 
  indicates 
  that 
  

   the 
  absorptive 
  power 
  of 
  water 
  for 
  the 
  rays 
  at 
  different 
  times 
  

   is 
  practically 
  the 
  same. 
  This 
  agrees 
  with 
  the 
  results 
  found 
  

   by 
  Lord 
  Blythswood 
  and 
  Dr. 
  Marchant, 
  namely, 
  that 
  the 
  per- 
  

   meability 
  of 
  any 
  given 
  substance 
  is 
  the 
  same 
  for 
  rays 
  of 
  

   different 
  intensities. 
  

  

  