﻿1875.] 
  

  

  Theory 
  of 
  Ventilation. 
  

  

  191 
  

  

  thus 
  obtained 
  shown 
  as 
  another 
  means 
  of 
  estimating 
  the 
  value 
  of 
  the 
  

   series. 
  

  

  Analyses 
  of 
  the 
  different 
  Orders. 
  

  

  No. 
  1 
  (see 
  Table 
  No. 
  1)*. 
  — 
  " 
  Fresh 
  " 
  &c. 
  : 
  a 
  condition 
  of 
  atmosphere 
  

   not 
  sensibly 
  different 
  from 
  the 
  external 
  air. 
  

  

  1. 
  Temperature. 
  — 
  The 
  experiments 
  were 
  made 
  during 
  both 
  winter 
  and 
  

   summer, 
  so 
  that 
  there 
  is 
  a 
  good 
  deal 
  of 
  variation 
  in 
  the 
  external 
  tempe- 
  

   rature, 
  and 
  the 
  mean 
  is 
  some 
  degrees 
  above 
  the 
  mean 
  annual 
  temperature 
  

   of 
  this 
  country 
  (southern 
  part 
  of 
  it), 
  viz. 
  57°'47. 
  The 
  mean 
  in 
  the 
  inha- 
  

   bited 
  air-spaces 
  is 
  62°* 
  85, 
  or 
  5°*38 
  higher. 
  This 
  is 
  a 
  moderate 
  difference, 
  

   and 
  shows 
  a 
  good 
  average 
  temperature 
  for 
  dwelling-rooms. 
  The 
  maxi- 
  

   mum 
  range 
  is 
  10° 
  (57°*89 
  to 
  67°'81), 
  calculated 
  from 
  the 
  error 
  of 
  mean 
  

   square, 
  the 
  actual 
  extremes 
  being 
  77° 
  and 
  53°. 
  

  

  2. 
  Vapour 
  and 
  Humidity. 
  — 
  As 
  the 
  external 
  temperature 
  varied 
  con- 
  

   siderably, 
  so 
  also 
  did 
  the 
  amount 
  of 
  vapour, 
  the 
  mean 
  being 
  4*285, 
  equal 
  

   to 
  about 
  80 
  per 
  cent, 
  of 
  humidity. 
  The 
  internal 
  observations 
  showed 
  a 
  

   mean 
  of 
  4*629, 
  or 
  73 
  per 
  cent, 
  of 
  humidity, 
  being 
  an 
  excess 
  of 
  vapour 
  of 
  

   0*344 
  of 
  a 
  grain, 
  and 
  a 
  lowering 
  of 
  relative 
  humidity 
  equal 
  to 
  7 
  per 
  cent. 
  

  

  3. 
  Carbonic 
  Acid,. 
  — 
  The 
  mean 
  external 
  carbonic 
  acid 
  was 
  0*4168, 
  a 
  

   little 
  above 
  the 
  usual 
  amount. 
  The 
  mean 
  in 
  the 
  inhabited 
  air-spaces 
  was 
  

   0*5998, 
  or 
  an 
  excess 
  of 
  0*1830, 
  the 
  mean 
  error 
  being 
  0*0910. 
  The 
  pro- 
  

   bable 
  error 
  of 
  a 
  single 
  observation 
  is 
  0*0831, 
  so 
  that 
  the 
  truth 
  would 
  lie 
  

   between 
  0*2661 
  and 
  0*0999 
  ; 
  whilst 
  the 
  probable 
  error 
  of 
  the 
  result 
  is 
  

   only 
  0*0078, 
  the 
  range 
  being 
  between 
  0*1908 
  and 
  0*1752 
  ; 
  we 
  are 
  there- 
  

   fore 
  entitled 
  to 
  say 
  that 
  the 
  limit 
  of 
  impurity, 
  imperceptible 
  to 
  the 
  sense 
  

   of 
  smell, 
  lies 
  at 
  or 
  within 
  0*2000 
  volume 
  of 
  C0 
  2 
  per 
  1000 
  as 
  a 
  mean. 
  

   From 
  these 
  data, 
  then, 
  we 
  may 
  lay 
  down 
  as 
  conditions 
  of 
  good 
  ventilation 
  

   the 
  following 
  : 
  — 
  

  

  Temperature 
  about 
  63° 
  Fahrenheit. 
  

   Vapour 
  shall 
  not 
  exceed 
  4*7 
  grains 
  per 
  cubic 
  foot. 
  

   Carbonic 
  acid 
  shall 
  not 
  exceed 
  the 
  amount 
  in 
  the 
  outer 
  air 
  by 
  more 
  

   than 
  0*2000 
  per 
  1000 
  volumes. 
  

  

  No. 
  2 
  (see 
  Table 
  No. 
  2).—" 
  Eather 
  close 
  " 
  &c. 
  : 
  a 
  condition 
  of 
  atmo- 
  

   sphere 
  in 
  which 
  the 
  organic 
  matter 
  begins 
  to 
  be 
  appreciated 
  by 
  

   the 
  senses. 
  

  

  1. 
  Temperature. 
  — 
  In 
  this 
  series 
  the 
  external 
  temperature 
  (although 
  

   still 
  above 
  the 
  mean 
  temperature 
  of 
  this 
  climate) 
  was 
  rather 
  lower 
  than 
  

   in 
  the 
  previous 
  one, 
  viz. 
  54°* 
  85, 
  whilst 
  the 
  internal 
  observations 
  gave 
  a 
  

   mean 
  of 
  62°*85 
  (the 
  same 
  as 
  in 
  No. 
  1), 
  or 
  a 
  difference 
  of 
  8°. 
  

  

  2. 
  Vapour 
  and 
  Humidity. 
  — 
  Although 
  the 
  temperature 
  was 
  the 
  same 
  as 
  

   in 
  No. 
  1, 
  the 
  amount 
  of 
  vapour 
  in 
  the 
  inhabited 
  air-spaces 
  was 
  greater, 
  

  

  * 
  It 
  has 
  not 
  been 
  thought 
  necessary 
  to 
  publish 
  Tables 
  1-5, 
  but 
  they 
  are 
  preserved 
  in 
  

   the 
  Archives 
  of 
  the 
  Society. 
  

  

  