AmNovr;i89ho!rm'}    Iodine  Absorption  of  Essential  Oils.  577 
very  likely  to  be  adulterated  with  turpentine.  Only  once  thus  far 
has  the  writer  found  an  oil  having  a  higher  absorption  in  the 
original  than  this,  and,  as  already  stated,  that  oil  is  still  open  to  ques- 
tion. If  the  oil  exceeds  125  it  is  a  suspect,  and  running  over  185 
may  be  discarded.  With  much  turpentine  present  the  fraction  will 
have  an  absorptive  power  over  225. 
Since  then,  an  oil  examined  by  more  thorough  fractional  distilla- 
tion, taking  one-eighth  of  one-fourth,  the  distillation  being  con- 
ducted in  a  4  oz.  fractional  distillation  flask,  showed  146  and  223. 
Notwithstanding  the  fact  that,  by  the  statement  above,  this  oil  should 
have  been  excluded,  it  was  passed.  If  it  contained  any  turpentine, 
the  amount  was  too  small  to  be  of  any  consequence.  The  high 
number  of  oil  of  cloves  would  indicate  that  iodine  absorption  would 
not  be  of  mucfa  value  in  detecting  turpentine  if  added.  The  ordi- 
nary turpentine  of  commerce  cannot  be  used  as  an  adulterant  to 
any  advantage.  Some  trials  by  the  writer  showed  conclusively  that 
1  in  8  could  be  readily  detected  by  the  nose,  I  in  16  was  not  so 
apparent  and  would  pass,  but  when  one-eighth  was  distilled  in  a 
small  retort,  the  fraction  was  all  terebinthinate  in  odor,  with  only  a 
faint  suggestion  of  cloves.  The  oil  pure,  oil  pure  one-eighth  frac- 
tion and  the  oil  to  which  one-sixteenth  of  its  volume  of  turpentine 
was  added,  showed  iodine,  numbers  (the  time  being  17  hrs.),  as 
follows:  354,  364,  370;  the  indications  so  far  as  iodine  numbers  were 
concerned.  The  same  oil  and  fractions  were  then  tried  with  simple 
chloroformic  iodine;  bearing  in  mind  that  oil  of  cloves  absorbed 
slowly,  while  turpentine  was  highest  in  a  short  period,  only  two 
hours'  digestion  was  allowed.  Results  were  as  follows  :  54  for  pure 
oil,  60  for  the  fraction  and  100  for  the  fraction  containing  turpen- 
tine;  with  oil  of  camphor,  somewhat  similar  results  were  obtained. 
Oil  of  camphor,  one  volume,  was  added  to  seven  volumes  of  the 
same  oil  of  cloves,  as  in  the  preceding.  Its  presence  was  not 
noticeable  by  the  sense  of  smell,  but  in  the  fractions  could  be  dis- 
tinctly noticed  ;  with  Hubl's  solution,  the  iodine  numbers  were  354, 
364,  332.  This  completes  the  writer's  work  to  the  present.  Frac- 
tional distillation  promises  well  in  connection  with  this  line  of  investi- 
gation. It  is  hoped  that  others  will  follow  up  the  subject,  as  it  is  my 
intention  to  collect  data  as  rapidly  as  other  duties  will  permit. 
