﻿412 
  Mr. 
  L. 
  Vegard 
  : 
  Researches 
  upon 
  

  

  a 
  more 
  or 
  less 
  complicated 
  process 
  going 
  on 
  in 
  the 
  membrane 
  

   and 
  its 
  nearest 
  surroundings 
  ; 
  and 
  it 
  is 
  the 
  principal 
  mea- 
  

   surable 
  property 
  by 
  which 
  the 
  osmosis 
  is 
  able 
  to 
  manifest 
  

   itself. 
  From 
  the 
  definition 
  of 
  the 
  osmotic 
  velocity 
  (§ 
  3, 
  

   equation 
  2 
  a) 
  we 
  see 
  that 
  when 
  the 
  leak 
  is 
  small 
  the 
  apparent 
  

   velocity 
  curve 
  (V) 
  will 
  give 
  the 
  characteristic 
  feature 
  of 
  the 
  

   \ 
  curve. 
  

  

  As 
  stated 
  in 
  equation 
  2 
  b, 
  § 
  3, 
  the 
  velocity 
  depends 
  on 
  the 
  

   three 
  quantities 
  7r, 
  C, 
  and 
  T, 
  and 
  further 
  upon 
  a 
  number 
  of 
  

   quantities 
  characteristic 
  of 
  the 
  membrane. 
  If 
  the 
  quantities 
  

   that 
  are 
  able 
  to 
  influence 
  the 
  osmotic 
  velocity 
  were 
  defined 
  

   quantities 
  that 
  could 
  be 
  given 
  certain 
  values, 
  the 
  function 
  X 
  

   could 
  be 
  found 
  by 
  experiment 
  by 
  finding 
  the 
  influence 
  of 
  

   each 
  property 
  separately. 
  

  

  On 
  account 
  of 
  the 
  nature 
  of 
  the 
  problem 
  we 
  are 
  only 
  able 
  

   to 
  master 
  the 
  quantities 
  w 
  } 
  C, 
  and 
  T, 
  while 
  the 
  others 
  escape 
  

   for 
  the 
  most 
  part 
  our 
  control. 
  To 
  some 
  extent, 
  however, 
  they 
  

   can 
  be 
  altered 
  by 
  using 
  more 
  or 
  less 
  " 
  perfect 
  " 
  membranes. 
  

   And 
  even 
  if 
  these 
  quantities 
  dependent 
  on 
  the 
  membrane 
  and 
  

   mechanism 
  of 
  osmotic 
  flow 
  cannot 
  be 
  given 
  the 
  values 
  desired, 
  

   they 
  will, 
  as 
  we 
  have 
  seen 
  from 
  the 
  experiments, 
  not 
  keep 
  

   constant. 
  They 
  will 
  vary 
  from 
  one 
  experiment 
  to 
  another, 
  

   and 
  even 
  in 
  one 
  and 
  the 
  same 
  experiment 
  the 
  velocity 
  curve 
  

   .shows 
  great 
  changes 
  ; 
  and 
  the 
  study 
  of 
  these 
  variations 
  must 
  

   necessarily 
  be 
  of 
  importance 
  for 
  the 
  study 
  of 
  the 
  osmosis 
  by 
  

   the 
  system 
  under 
  consideration. 
  

  

  And 
  upon 
  the 
  whole, 
  if 
  we 
  wish 
  to 
  make 
  clear 
  the 
  mechanism 
  

   of 
  osmosis, 
  in 
  other 
  words 
  to 
  find 
  the 
  function 
  ^ 
  (§ 
  3 
  eq. 
  2 
  &), 
  

   the 
  study 
  of 
  the 
  velocity 
  must 
  form 
  a 
  necessary 
  part 
  of 
  this 
  

   research. 
  The 
  possible 
  explanation 
  must 
  first 
  of 
  all 
  account 
  

   for 
  the 
  properties 
  of 
  the 
  velocity 
  curves, 
  and 
  especially 
  the 
  

   study 
  of 
  the 
  characteristic 
  point 
  and 
  its 
  motions 
  must 
  be 
  of 
  

   special 
  importance, 
  as 
  giving 
  a 
  good 
  test 
  for 
  the 
  possible 
  

   explanation. 
  

  

  The 
  mode 
  of 
  proceeding 
  for 
  these 
  studies 
  will 
  naturally 
  be 
  

   the 
  following 
  : 
  — 
  

  

  (1) 
  The 
  velocity 
  curve 
  for 
  each 
  system 
  must 
  be 
  deter- 
  

   mined 
  for 
  different 
  concentrations 
  and 
  temperatures. 
  

  

  (2) 
  The 
  variations 
  of 
  the 
  velocity 
  curve 
  due 
  to 
  the 
  

   variations 
  in 
  the 
  properties 
  of 
  the 
  membrane 
  must 
  be 
  

   examined 
  for 
  a 
  number 
  of 
  concentrations 
  and 
  tem- 
  

   peratures. 
  

  

  And 
  we 
  see 
  that 
  from 
  this 
  point 
  of 
  view 
  it 
  will 
  be 
  of 
  great 
  

   importance 
  also 
  to 
  study 
  the 
  properties 
  of 
  the 
  imperfect 
  

   membranes 
  as 
  generally 
  giving 
  rise 
  to 
  the 
  greatest 
  variation. 
  

  

  As 
  long 
  as 
  we 
  have 
  the 
  same 
  cell 
  the 
  changes 
  in 
  the 
  

  

  