DISINFECTING  PROPERTIES  OF  CHARCOAL. 
359 
such  as  ammonia,  sulphuretted  hydrogen,  hydrosulphate  of  am- 
monia and  chlorine.  I  have  found  that  air  strongly  impregnated 
with  these  gases,  and  which  could  not  be  respired  for  any  length 
of  time  under  ordinary  circumstances,  may  be  breathed  with 
impunity  when  the  charcoal  respirator  is  worn,  the  odor  of  these 
gases  being  rendered  almost,  if  not  altogether,  imperceptible. 
Any  other  highly  porous  substance,  such  for  instance  as  sponge 
platinum,  or  pounded  pumice-stone,  might  probably  be  found  to 
answer  perfectly  well  for  filling  the  respirator ;  but  I  have  se- 
lected charcoal  as  the  cheapest  and  most  easily  available  material. 
While  the  filtration  of  water  through  charcoal  powder  and  other 
porous  substances  has  been  advantageously  practised  for  many 
centuries,  the  object  in  view  being  to  deprive  the  water  of  nume- 
rous impurities  diffused  through  it,  which  produce  injurious  effects 
on  the  animal  economy,  it  is  certainly  somewhat  remarkable  that 
the  very  obvious  application  of  a  similar  proceeding  to  the  lighter 
fluid  in  which  we  live,  viz.  air,  which  not  unfrequently  contains 
even  more  noxious  impurities  floating  in  it  than  are  usually  present 
in  water,  should  have,  up  to  the  present  time,  been  so  unac- 
countably overlooked. 
In  addition  to  the  precaution  of  wearing  such  a  respirator  as 
that  just  described,  persons  necessitated  to  live  in  especially 
pestiferous  districts  might  have  their  houses  made  as  air-tight  as 
possible,  with  the  exception  of  such  openings  as  are  necessary  to 
maintain  a  proper  amount  of  ventilation.  By  means  of  these 
openings  the  air  could  be  freely  admitted  through  gauze  into 
which  the  requisite  quantity  of  charcoal  had  been  quilted.  The 
doors  of  such  houses  could  also  be  made  double,  and  be  constructed 
of  coarse  cloth,  likewise  containing  a  thin  layer  of  charcoal 
powder.  As  an  additional  precaution,  if  it  were  thought  desirable, 
the  walls,  floors,  and  ceilings  of  houses  in  very  unhealthy  districts 
could  be  easily  lined  with  mattrasses  filled  with  a  couple  of  inches 
of  charcoal  powder.  Were  these  and  similar  precautions  adopted, 
I  confidently  anticipate  that  Europeans  will  be  enabled  to  reside 
with  comparative  impunity  in  some  of  the  hitherto  most  pestilen- 
tial districts  in  the  world.—  Ch em.  Gaz.  April  1854,  from  Jour- 
nal of  the  Society  of  'Arts,  Feb.  24,  1854. 
