﻿Osmosis 
  and 
  Osmotic 
  Pressure. 
  

  

  399 
  

  

  The 
  water 
  in 
  the 
  cell 
  being 
  insufficient 
  for 
  filling 
  the 
  tnbe 
  

   had 
  to 
  be 
  diluted. 
  

  

  6*5 
  cm. 
  3 
  water 
  from 
  the 
  cell 
  + 
  15 
  cm. 
  3 
  water 
  gave 
  an 
  angle 
  

   of 
  polarization 
  of 
  10'. 
  

  

  As 
  1 
  mm. 
  3 
  corresponds 
  to 
  5 
  mm. 
  in 
  the 
  capillary 
  we 
  get 
  

  

  / 
  7r 
  = 
  2 
  , 
  5 
  mm. 
  per 
  hour 
  ; 
  and 
  

  

  g 
  t 
  = 
  2'0 
  gr./l.= 
  cone, 
  of 
  water 
  in 
  exp, 
  la. 
  

  

  g 
  = 
  3'8 
  „ 
  = 
  „ 
  ,, 
  lb. 
  

  

  We 
  have 
  no 
  observations 
  for 
  the 
  velocity 
  of 
  osmotic 
  flow 
  

   for 
  this 
  experiment 
  ; 
  but, 
  as 
  will 
  be 
  seen 
  later, 
  we 
  have 
  

   observations 
  for 
  the 
  same 
  cell 
  for 
  other 
  concentrations. 
  From 
  

   these 
  we 
  get 
  

  

  2- 
  

  

  \dir)w'' 
  

  

  395 
  atria. 
  

   32-83 
  „ 
  

  

  21 
  

   16 
  

  

  If 
  we 
  take 
  the 
  mean 
  value 
  we 
  get 
  

   A7r=0-13atm. 
  

  

  Experiment 
  2. 
  

  

  Apparatus 
  put 
  up 
  Nov. 
  11. 
  

  

  Resistance 
  of 
  the 
  membrane 
  400,000 
  ohms 
  at 
  1°*6 
  C, 
  

  

  G= 
  302-8 
  gr./l. 
  at 
  ll°-8 
  C. 
  

  

  Date. 
  

  

  to. 
  

  

  t 
  m 
  . 
  

  

  a. 
  

  

  h 
  m 
  

  

  

  

  

  jS 
  t 
  ov.21, 
  8 
  15 
  p.m. 
  

  

  1005 
  

  

  10-55 
  

  

  8*3 
  cm. 
  

  

  „ 
  22,11 
  10 
  a.m. 
  

  

  975 
  

  

  10-20 
  

  

  6-25 
  „ 
  

  

  „ 
  22, 
  6 
  45 
  p.m. 
  

  

  9-82 
  

  

  10-20 
  

  

  6-107 
  ., 
  

  

  „ 
  23, 
  2 
  15 
  „ 
  

  

  9-88 
  

  

  10-39 
  

  

  5-667 
  ., 
  

  

  n 
  23, 
  6 
  30 
  „ 
  

  

  9-90 
  

  

  1037 
  

  

  5-657 
  „ 
  

  

  „ 
  24, 
  10 
  50 
  a.m. 
  

  

  9-45 
  

  

  9-70 
  

  

  5660 
  „ 
  

  

  „ 
  24, 
  6 
  p.m. 
  

  

  9-25 
  

  

  9-50 
  

  

  5-645 
  „ 
  

  

  The 
  considerable 
  time 
  required 
  for 
  the 
  osmosis 
  to 
  reach 
  

   the 
  maximum 
  pressure 
  is 
  due 
  to 
  the 
  fact 
  that 
  in 
  putting 
  up 
  

   the 
  apparatus 
  some 
  air 
  was 
  left 
  in 
  the 
  osmometer, 
  and 
  the 
  

   space 
  occupied 
  by 
  the 
  air 
  had 
  first 
  to 
  be 
  filled 
  before 
  the 
  

   pressure 
  could 
  increase 
  considerably. 
  When 
  first 
  attention 
  

   is 
  directed 
  to 
  this 
  point 
  it 
  is, 
  however, 
  easy 
  to 
  prevent 
  any 
  

   air-bubbles 
  being 
  left 
  in 
  the 
  osmometer. 
  

  

  