﻿On 
  Transpiration 
  from 
  Leaf-Stomata. 
  431 
  

  

  This 
  is 
  not 
  the 
  only 
  passage 
  in 
  the 
  paper 
  under 
  con- 
  

   sideration 
  where 
  an 
  inappropriate 
  conception 
  has 
  led 
  to 
  

   inexact 
  work*". 
  In 
  connexion 
  with 
  his 
  peculiar 
  notion 
  as 
  

   to 
  the 
  nature 
  of 
  an 
  error 
  of 
  observation, 
  the 
  writer 
  appears 
  

   to 
  hold 
  that 
  if 
  the 
  extent 
  of 
  an 
  error 
  varies 
  with 
  the 
  time 
  

   according 
  to 
  the 
  law 
  ?/ 
  = 
  sin£, 
  the 
  frequency 
  of 
  error 
  between 
  

   the 
  extreme 
  values 
  which 
  it 
  can 
  assume 
  is 
  constant 
  f, 
  Not 
  

   so, 
  surely 
  ; 
  the 
  number 
  of 
  errors 
  per 
  unit 
  of 
  time 
  being 
  

   constant, 
  the 
  number 
  of 
  errors 
  per 
  unit 
  of 
  space 
  t 
  is 
  propor- 
  

   tioned 
  to 
  -r 
  , 
  that 
  is 
  to 
  — 
  : 
  . 
  The 
  frequency-curve 
  is 
  

  

  rfjf 
  5 
  vi-p 
  H 
  J 
  

  

  not 
  a 
  straight 
  line 
  but 
  a 
  symmetrical 
  curve 
  of 
  the 
  fourth 
  

   degree 
  with 
  an 
  infinite 
  ordinate 
  at 
  the 
  centre 
  and 
  contact 
  

   with 
  the 
  abscissa 
  at 
  the 
  points 
  distant 
  t 
  from 
  the 
  centre 
  in 
  

   either 
  direction. 
  

  

  In 
  this 
  connexion 
  it 
  is 
  remarked 
  by 
  Dr. 
  Sampson, 
  "it 
  

   seems 
  probable 
  that 
  Laplace 
  and 
  Poisson 
  were 
  on 
  the 
  wrong 
  

   lines/'' 
  To 
  those 
  who 
  have 
  followed 
  the 
  preceding 
  com- 
  

   ments 
  it 
  will 
  seem 
  more 
  probable 
  that 
  Dr. 
  Sampson 
  is 
  on 
  

   the 
  wrong 
  lines. 
  

  

  L. 
  On 
  Transpiration 
  from 
  Leaf-Stomata. 
  

   By 
  Harold 
  Jeffreys, 
  M.A., 
  D.£c.§ 
  

  

  WITH 
  most 
  of 
  Sir 
  Joseph 
  Larmor's 
  note 
  in 
  the 
  April 
  

   Philosophical 
  Magazine 
  I 
  am 
  in 
  agreement. 
  It 
  is 
  

   clear 
  that 
  the 
  amount 
  of 
  water 
  evaporated 
  from 
  the 
  stomata 
  

   of 
  a 
  leaf 
  in 
  a 
  given 
  time 
  must 
  be 
  less 
  than 
  that 
  from 
  the 
  whole 
  

   surface 
  of 
  a 
  wet 
  leaf 
  of 
  the 
  same 
  size 
  ; 
  it 
  must 
  also 
  be 
  less 
  

   than 
  the 
  amount 
  that 
  could 
  be 
  evaporated 
  from 
  all 
  the 
  

   stomata 
  if 
  their 
  total 
  number 
  were 
  the 
  same 
  and 
  all 
  were 
  so 
  

   much 
  separated 
  that 
  they 
  could 
  be 
  treated 
  as 
  isolated. 
  

   Hitherto 
  only 
  the 
  latter 
  criterion 
  has 
  been 
  used 
  to 
  indicate 
  

   the 
  upper 
  limit, 
  and 
  the 
  important 
  question 
  is 
  to 
  decide 
  

   whether 
  the 
  former 
  imposes 
  a 
  further 
  restriction 
  or 
  not. 
  

   When 
  the 
  air 
  is 
  at 
  rest 
  the 
  question 
  is 
  simple, 
  for 
  both 
  limits 
  

  

  * 
  The 
  following- 
  criticism 
  is 
  due 
  to 
  Professor 
  Bowley. 
  

  

  t 
  "For 
  i/=m\t 
  .... 
  the 
  distribution 
  is 
  represented 
  by 
  »?=] 
  for 
  

   — 
  1<£<1 
  and 
  ??=0 
  beyond 
  those 
  limits 
  (fig. 
  3)." 
  Fig-. 
  3 
  and 
  the 
  

   context 
  bear 
  out 
  the 
  interpretation 
  here 
  given. 
  

  

  X 
  The 
  number 
  which 
  multiplied 
  upon 
  A£ 
  a 
  small 
  fraction 
  of 
  (the 
  

   unit 
  of) 
  the 
  abscissa, 
  £ 
  gives 
  the 
  (proportionate) 
  number 
  of 
  observations 
  

   occurring 
  between 
  x 
  and 
  x+A% 
  (or 
  x+±Ax 
  and 
  x— 
  \&Z). 
  

  

  § 
  Communicated 
  by 
  the 
  Author. 
  

  

  