482 
Is  Ozone  a  Concomitant,  etc. 
/Am.  Jouk.  Phakmv 
\     Oct.  1,  1874. 
These  bodies,  which  had  thus  absorbed  known  amounts  of  oxygen, 
were  agitated  after  the  experiment  with  a  mixed  solution  of  potassium 
iodide  and  starch,  when  they  invariably  developed  the  well-known 
blue  coloration  more  or  less  quickly.  It  is  remarkable  that  this 
coloration  does  not  take  place  immediately,  as  one  might  suppose 
would  be  the  case  if  these  bodies  contained  dissolved  ozone. 
On  the  other  hand,  in  the  case  of  the  bergamot  above  givenr 
where  12  c.c.  of  oxygen  had  been  absorbed,  there  was  absolutely 
no  coloration  with  the  potassium  iodide  and  starch  for  some  minutes, 
but  it  then  gradually  became  of  an  opaque  blue.  The  same  remark 
applies  to  the  other  cases  for  the  most  part. 
Evidently,  therefore,  an  agent  now  existed  in  these  oxidized  oilsy 
having  properties  like  those  possessed  by  ozone. 
This  fact  was  confirmed  by  taking  the  various  bodies  and  placing 
them  in  tubes,  together  with  a  solution  of  potassium  iodide,  covering 
the  mouths  of  the  tubes  with  paper,  and  exposing  to  diffused  daylight. 
Ether,  naphtha,  and  turpentine  and  caraway  oils  gave  almost  im- 
mediately a  yellow  line  between  the  two  layers,  showing  either  that 
they  precontained  the  active  agent,  or  quickly  produced  it.  Time- 
was  required  in  all  the  other  cases,  in  all  of  which  affirmative  results- 
were  obtained  and  rendered  very  evident  by  the  addition  of  a  solution 
of  starch.  Confirmation  of  these  results  was  further  obtained  by 
placing  the  substances  in  tubes  heated  to  70°  C.  by  means  of  a  steam- 
bath,  and  spreading  over  the  mouth  of  the  tubes  paper  soaked  in  the 
potassic  iodide  starch  mixture.  But  the  best  results  were  obtained 
by  mixing  in  watch-glasses  the  substance  to  be  tried  and  the  test- 
solution. 
As  the  oils  of  turpentine  and  caraway  were  found  to  give  the  most 
decided  reactions,  most  of  the  subsequent  experiments  were  confined 
to  them.  These  experiments,  which  are  recorded  at  length  in  the 
original  paper,  led  the  author  to  the  conclusion  that  the  active  agent 
produced  in  the  oxidation  of  these  oils,  although  possessing  properties 
similar  in  many  respects  to  ozone,  is  not  ozone  or  peroxide  of 
hydrogen,  but  an  oxidized  principle  derived  from  terpene  (C10H16)^ 
namely,  a  monohydrated  oxide  of  turpentine  (C10H16O'H2O).  The 
evidence  upon  which  this  conclusion  is  based  is  thus  summarized  : 
When  oil  of  turpentine  is  exposed  to  air  or  oxygen,  in  presence  of 
moisture,  it  oxidizes,  producing  an  agent  which  resembles  ozone  and 
peroxide  of  hydrogen,  inasmuch  as  it  gives  a  similar  reaction  with 
