OZONE  AND  THE  VOLATILE  OILS. 
511 
at  some  distance  from  each  other.  Opposite  these  names  the  re- 
spective liquids  were  applied,  by  letting  a  drop  fall  upon  the  ap- 
propriate spot. 
The  periods  at  which  the  iodine  was  eliminated,  as  determined 
by  the  earliest  discoloration  of  the  paper,  were  as  follows; 
Oil  of  Lemons,  two  seconds. 
Oil  of  Tansey,  half  a  minute. 
Oil  of  Turpentine  and  Juniper,  three-fourths  of  a  minute. 
Oil  of   Wintergreen,  Sassafras,  Bergamot,  and  Anise,  one 
minute. 
Oil  of  Croton,  one  and  a  quarter  minutes. 
Oil  of  Origanum,  tincture  of  Galbanum,  and  Assafetida,  one 
and  a  half  minutes. 
Oil  of  Amber,  Peppermint,  Fennel,  Lavender,  and  Caraway, 
two  minutes. 
Oil  of  Spearmint,  three  minutes. 
Oil  of  Cinnamon,  four  minutes. 
During  this  experiment  an  interesting  result  developed  itself. 
Every  liquid  applied  to  the  paper  produced  so  peculiar  a  shade  of 
brown  as  to  be  quite  characteristic.  Oil  of  cinnamon  yielded  a 
lemon-brown,  with  a  darker  margin  ;  oil  of  fennel  a  uniform 
scorched-paper  brown,  with  no  difference  at  the  margin.  Other 
oils  produced  a  very  dark  brown,  and  some  a  very  pale  brown 
color,  yet  all  differed  from  each  other,  either  by  reflected  or  trans- 
mitted light,  or  in  the  character  of  the  margins.  Tincture  of  gal- 
banum gave  a  pale  violet  tinge  to  the  light  brown  base,  with  a 
much  darker  border ;  tincture  of  assafetida  yielded  a  strikingly 
different  spot  from  this. 
On  a  review  of  the  foregoing  experiments,  it  will  be  perceived 
that,  according  to  experiments  6,  9,  10, 
1.  All  the  odorous  substances  do  not  produce  active  ozonous 
atmospheres.  That 
2.  Oil  of  sassafras  and  oil  of  wintergreen,  which,  according  to 
my  former  communication  already  referred  to,  very  tardily  dis- 
charged the  color  of  sulphindigotic  acid  ;  and,  according  to  experi- 
ment 10  in  the  present  paper,  made  no  impression  upon  the  iodized 
slips,  when  these  were  exposed  to  their  atmospheres,  were  among 
the  most  active  agents  (exp.  11)  in  decomposing  the  iodide,  when 
applied  in  substance  to  the  prepared  paper.  That 
