OZONE  AND  THE  VOLATILE  OILS, 
509 
2.  Some  paper  was  prepared  with  a  solution  of  iodide  of  potas- 
sium in  starch  water,  and  a  slip  of  it  suspended  in  the  atmosphere 
of  a  nearly  empty  jar  of  rancid  lard.  In  a  short  time  the  iodine 
began  to  be  eliminated,  and  the  paper  ultimately  became  black. 
4.  Another  slip  of  the  prepared  paper  was  inserted  into  a  bottle 
from  which  had  been  emptied  a  small  quantity  of  oil  of  amber;  in 
this  case  also  the  atmosphere  in  the  vessel  blackened  the  paper. 
4.  An  atmosphere  of  oil  of  lemons  and  other  essential  oils  like-1 
wise  decomposed  the  iodide  of  potassium,  and  rendered  the  paper 
black. 
5.  An  eight  ounce  glass  jar,  with  a  thin  stratum  of  water  in  it, 
and  a  few  bits  of  phosphorus  half-covered  with  the  water,  and  a 
strip  of  the  iodized  paper  suspended  in  it,  with  another  slip  of  blue 
litmus  paper  by  its  side,  was  left  with  only  a  glass  plate  over  it, 
until  all  the  white  clouds  of  phosphorus  acid  were  absorbed  by  the 
water  below,  and  the  air  in  the  jar  left  perfectly  clear.  During 
the  formation  of  the  phosphorous  acid  no  change  took  place  in  the 
color  of  the  moistened  litmus  paper,  nor  the  moistened  iodized 
paper.  When,  however,  the  phosphorous  acid  was  absorbed  as 
mentioned,  the  litmus  paper  became  slowly  bleached,  and  the 
iodized  paper  blackened. 
So  indisposed  was  the  ozonized  atmosphere  to  escape,  that  I 
lifted  off  the  glass  plate  and  inserted  a  fresh  strip  of  iodized  paper 
into  the  jar,  and  the  paper  was  instantly  blackened.  I  again  re- 
moved the  lid,  and  lowered  a  bit  of  lighted  candle  into  the  jar  ; 
the  flame  was  immediately  extinguished,  and  every  vestige  of  ig- 
nition in  the  wick  was  gone. 
6.  Neither  the  confined  atmosphere  of  tincture  of  assafetida, 
nor  of  tincture  of  galbanum  affects  the  iodized  paper,  even  after 
thirty  hours  exposure.  The  atmosphere  of  the  gum  resins  them- 
selves produced  no  discoloration  of  the  paper. 
7.  Tincture  of  galbanum,  shaken  up  with  the  indigo  solution, 
readily  bleached  it.  Tincture  of  assdfetida,  unlike  the  tincture  of 
galbanum,  instead  of  making  a  durable  milky  mixture,  speedily 
parted  with  its  gum  resin,  in  such  a  manner  as  to  leave  the  liquid 
almost  entirely  transparent,  but  of  a  pale  blue  color.  Exposure  to 
the  direct  rays  of  sun-light,  for  less  than  one  hour,  wholly  bleached 
the  fluid  and  rendered  it  completely  limpid,  the  precipitated  gum- 
resin  floating  on  the  top  and  adhering  to  the  sides  ol  the  test  tube. 
