﻿1875.] 
  

  

  Theory 
  of 
  Ventilation. 
  

  

  199 
  

  

  I 
  think 
  that 
  the 
  general 
  opinion 
  is 
  that 
  Angus 
  Smith's 
  results 
  give 
  too 
  

   low 
  an 
  estimate, 
  and 
  that 
  0*600 
  is 
  really 
  the 
  lowest 
  that 
  can 
  be 
  with 
  

   safety 
  admitted. 
  

  

  The 
  existing 
  Army 
  Eegulations 
  contemplate 
  a 
  delivery 
  of 
  1200 
  cubic 
  

   feet 
  per 
  head 
  per 
  hour 
  in 
  barracks 
  ; 
  but 
  practical 
  inquiry 
  has 
  shown 
  that 
  

   this 
  amount 
  is 
  generally 
  fallen 
  short 
  of. 
  The 
  result 
  is 
  that 
  the 
  life 
  of 
  

   the 
  soldier, 
  at 
  least 
  during 
  his 
  sleeping-hours, 
  is 
  passed 
  in 
  a 
  ~No. 
  3 
  air- 
  

   space, 
  or 
  one 
  in 
  which 
  the 
  organic 
  impurity 
  is 
  decidedly 
  disagreeable 
  to 
  

   the 
  senses. 
  Previous 
  to 
  1858 
  he 
  did 
  not 
  even 
  get 
  this 
  moderate 
  amount 
  

   of 
  air 
  ; 
  so 
  that 
  his 
  life 
  was 
  spent 
  in 
  an 
  air-space 
  in 
  which 
  the 
  organic 
  

   matter 
  was 
  offensive 
  and 
  oppressive 
  to 
  the 
  senses. 
  If 
  we 
  adopt 
  (as 
  proposed 
  

   already) 
  0-2000 
  per 
  1000 
  of 
  C0 
  2 
  as 
  the 
  limit 
  of 
  impurity, 
  then 
  3000 
  cubic 
  

   feet 
  per 
  head 
  per 
  hour 
  is 
  the 
  amount 
  which 
  must 
  be 
  delivered, 
  on 
  the 
  

   supposition 
  that 
  e= 
  0*600, 
  or 
  3525 
  if 
  e= 
  0*705. 
  

  

  We 
  may 
  say, 
  in 
  conclusion, 
  that 
  the 
  experimental 
  data 
  already 
  quoted 
  

   fairly 
  justify 
  the 
  adoption 
  of 
  the 
  following 
  conditions 
  : 
  — 
  

  

  Conditions 
  as 
  the 
  Standard 
  of 
  good 
  Ventilation. 
  

  

  Temperature 
  (dry 
  bulb) 
  63° 
  to 
  65° 
  Fahrenheit, 
  

   (wet 
  bulb) 
  58° 
  to 
  61° 
  

  

  N.B. 
  The 
  temperature 
  should 
  never 
  be 
  very 
  much 
  below 
  60°, 
  but 
  it 
  

   may 
  be 
  found 
  difficult 
  to 
  prevent 
  its 
  rising 
  in 
  hot 
  weather. 
  In 
  any 
  

   case 
  the 
  difference 
  between 
  the 
  two 
  thermometers 
  ought 
  not 
  to 
  be 
  less 
  

   than 
  4°, 
  and 
  ought 
  not 
  to 
  exceed 
  5°. 
  

  

  Vapour 
  ought 
  not 
  to 
  exceed 
  4*7 
  grains 
  per 
  cubic 
  foot 
  at 
  a 
  temperature 
  

   of 
  63 
  F., 
  or 
  5 
  grains 
  at 
  a 
  temperature 
  of 
  65° 
  F. 
  

  

  Humidity 
  (per 
  cent.) 
  ought 
  not 
  to 
  exceed 
  73 
  to 
  75. 
  

  

  Carbonic 
  Acid. 
  Respiratory 
  impurity 
  ought 
  not 
  to 
  exceed 
  0*0002 
  per 
  

   foot, 
  or 
  0*2000 
  per 
  1000 
  volumes. 
  

  

  Taking 
  the 
  mean 
  external 
  air 
  ratio 
  at 
  0*4000 
  per 
  1000, 
  this 
  would 
  

   give 
  a 
  mean 
  internal 
  air 
  ratio 
  of 
  0*6000 
  per 
  1000 
  volumes. 
  

  

  By 
  considering 
  separately 
  the 
  conditions 
  found 
  in 
  barracks 
  and 
  in 
  hos- 
  

   pitals, 
  or 
  among 
  healthy 
  and 
  among 
  sick 
  men, 
  a 
  point 
  of 
  some 
  interest 
  

   and 
  importance 
  seems 
  to 
  be 
  indicated 
  — 
  namely, 
  that 
  more 
  air 
  is 
  required 
  

   for 
  the 
  latter 
  than 
  for 
  the 
  former 
  to 
  keep 
  the 
  air-space 
  pure 
  to 
  the 
  senses. 
  

   This 
  is 
  due 
  either 
  to 
  the 
  greater 
  quantity 
  of 
  organic 
  matter 
  or 
  to 
  a 
  dif- 
  

   ference 
  in 
  its 
  quality 
  and 
  nature. 
  The 
  following 
  results 
  are 
  found 
  from 
  

   the 
  data 
  in 
  the 
  Tables 
  : 
  — 
  

  

  Barracks. 
  Hospitals. 
  

  

  Mean 
  amount 
  of 
  carbonic 
  acid 
  per 
  1000 
  volumes 
  as 
  

  

  respiratory 
  impurity 
  found 
  when 
  the 
  air 
  was 
  noted 
  

  

  as 
  " 
  fresh 
  " 
  &c, 
  the 
  impurity 
  not 
  being 
  appreciable 
  

  

  to 
  the 
  senses 
  0*196 
  0*157 
  

  

  Number 
  of 
  analyses 
  in 
  each 
  group 
  75 
  38 
  

  

  VOL. 
  XXIII. 
  B 
  

  

  