﻿1875.] 
  

  

  Theory 
  of 
  Ventilation. 
  

  

  195 
  

  

  the 
  next 
  order. 
  The 
  average 
  rates 
  of 
  progression 
  (including 
  the 
  actual 
  

   excess 
  in 
  No. 
  1) 
  are 
  : 
  — 
  

  

  Temperature. 
  Vapour. 
  Carbonic 
  acid. 
  

  

  3°-42 
  0-345 
  0-2133 
  

  

  Here 
  the 
  amount 
  of 
  vapour 
  is 
  exactly 
  the 
  actual 
  excess 
  in 
  No. 
  1, 
  and 
  the 
  

   amount 
  of 
  carbonic 
  acid 
  somewhat 
  in 
  excess 
  ; 
  the 
  mean, 
  however, 
  be- 
  

   tween 
  this 
  amount 
  and 
  the 
  actual 
  recorded 
  excess 
  in 
  No. 
  1 
  is 
  as 
  

  

  follows 
  : 
  — 
  

  

  Actual 
  excess 
  over 
  outer 
  air 
  in 
  No. 
  1 
  0-1830 
  

  

  Mean 
  of 
  progressive 
  increase, 
  as 
  above 
  0-2133 
  

  

  Sum 
  2)0-3963 
  

  

  Mean 
  0-1982 
  

  

  This 
  is 
  sufficiently 
  close 
  to 
  0-2000 
  to 
  furnish 
  some 
  additional 
  reason 
  

   for 
  adopting 
  this 
  latter 
  number 
  as 
  the 
  limit 
  of 
  respiratory 
  impurity 
  admis- 
  

   sible 
  in 
  good 
  ventilation. 
  

  

  Values 
  of 
  the 
  several 
  series, 
  considered 
  relatively 
  to 
  each 
  other. 
  

  

  The 
  values 
  are 
  important 
  as 
  a 
  guide 
  to 
  the 
  more 
  or 
  less 
  trustworthy 
  

   character 
  of 
  the 
  series. 
  They 
  have 
  been 
  calculated 
  out 
  in 
  three 
  ways 
  : 
  — 
  

  

  1. 
  As 
  the 
  reciprocal 
  of 
  the 
  square 
  of 
  mean 
  error. 
  

  

  2. 
  As 
  the 
  reciprocal 
  of 
  the 
  square 
  of 
  probable 
  error 
  of 
  result. 
  

  

  3. 
  As 
  the 
  ratio 
  between 
  the 
  modulus 
  calculated 
  from 
  the 
  mean 
  error 
  

  

  and 
  the 
  modulus 
  calculated 
  from 
  the 
  error 
  of 
  mean 
  square 
  of 
  a 
  

   single 
  measure. 
  

  

  The 
  following 
  Table 
  gives 
  the 
  values 
  from 
  the 
  first 
  method, 
  viz. 
  as 
  

   reciprocal 
  of 
  the 
  square 
  of 
  mean 
  error 
  : 
  — 
  

  

  No. 
  Temperature. 
  Vapour. 
  Humidity. 
  Carbonic 
  acid. 
  

  

  1 
  0-0821 
  6-1300 
  0-0190 
  122-0000 
  

  

  2 
  0-0625 
  3-1300 
  0*0140 
  34-0000 
  

  

  3 
  0-0403 
  2-6500 
  0-0110 
  21-8000 
  

  

  4 
  0-0543 
  2-7700 
  0-0120 
  17-0000 
  

  

  5 
  0-0664 
  1-3700 
  0-0090 
  14-1000 
  

  

  4&5 
  combined 
  0-0610 
  2-2900 
  0-0010 
  16*5000 
  

  

  and 
  the 
  ratios, 
  taking 
  No. 
  1 
  as 
  1000, 
  are 
  : 
  — 
  

  

  1 
  1000 
  1000 
  1000 
  1000 
  

  

  2 
  760 
  510 
  735 
  277 
  

  

  3 
  492 
  431 
  575 
  178 
  

  

  4 
  662 
  450 
  630 
  139 
  

  

  5 
  810 
  224 
  473 
  115 
  

  

  4 
  & 
  5 
  combined 
  745 
  374 
  526 
  135 
  

  

  