208  Da  white’s  Experiments 
Hence  it  appears,  that  frefh  fruit  have,  in  com- 
mon with  other  vegetable  matters,  a great  power  in  pol- 
luting the  air,  and  rendering  it  noxious. 
exp.  xv.  In  order  to  find  whether  any  part  of  the 
pernicious  effects  of  vegetables  upon  air  in  the  twelfth 
experiment  might  be  owing  to  their  odorous  particles, 
the  following  experiments  were  made.  In  each,  the 
quantity  of  inclofed  air  was  eight  ounces ; the  time  of 
{landing  together  fixteen  hours. 
1 o grains  of  Mufic  diminifiied  it  from 
'■g  fCamphor, 
Jj  Affa-fcetida, 
O 
2 J Saffron, 
£ Opium, 
K Vol.  Sal.  Ammoniac. 
63  to  62 
63  to  62 
62  to  62 
62  to  62 
60  to  58 
60  to  58 
Mufic  and  camphire  were  feledled  as  examples  of 
effential  oils ; the  firft  of  the  animal,  the  fecond  of  the 
vegetable  clafs.  The  affa-foetida  as  an  inftance  of  the 
foetid  odour;  opium  of  the  narcotic.  Saffron,  from  its 
mode  of  preparation,  is  incapable  of  corruption  whilft 
kept  dry,  and  could  give  nothing  but  pure  odour.  The 
volatile  fait  was  an  example  of  the  volatile  odour. 
Hence  we  find,  that  pure  odour  has  little,  if  any, 
effeil  in  polluting  the  air.  For  where  any  difference 
occurred, 
