OIL  OF  NEROLI.     SALICYLIC  ACID. 
65 
known  to  me  which  affords  direct  proof  of  this  assumption.  By 
the  described  reaction,  very  small  traces  of  sulphuret  of  carbon 
may  be  detected  in  gas  prepared  from  coals.  Two  cubic  feet  of 
purified  coal  gas,  so  completely  freed  from  sulphurretted  hydro- 
gen by  a  watery  solution  of  potash  that  it  ceased  to  react  on  lead 
paper,  were  conducted  slowly  through  an  alcoholic  solution  of 
potash.  A  portion  of  this  solution  somewhat  evaporated,  and, 
added  to  a  boiling  solution  of  nitrate  of  lead,  exhibited  distinctly 
a  black  coloration,  which  could  only  arise  from  a  small  quantity 
of  sulphuret  of  carbon  contained  in  the  gas. — Annals  of  Phar- 
macy from  Annalen  der  Chemie, 
ON  THE  RECTIFICATION  OF  OIL  OF  NEROLI. 
M.,  Donnecy  states  that  the  color  which  oil  of  neroli  rapidly 
acquires  is  due  to  a  molecular  change  in  one  of  the  oils  which 
constitute  it,  and  which,  it  is  well  known,  causes  the  oil  to  assume 
a  brown  color  in  a  very  short  time,  and  a  very  disagreeable  odor, 
which  thus  involves  the  loss  of  a  costly  product. 
Some  experiments  having  demonstrated  the  fixity  of  the  oil 
which  has  undergone  change,  I  distilled  250  grammes  of  neroli 
which  had  been  thus  affected,  and  which  was  five  years  old,  and 
obtained  220  grammes  of  a  perfectly  colorless  essential  oil,  having 
a  fresh  odor  of  neroli,  and  which  remained  unchanged  during  two 
years  in  a  condition  most  favorable  for  the  alteration  of  essential 
oils.— Jour,  de  Pharm.,  Sept.  1853. 
ON  THE  SENSIBILITY  OF  THE  REACTION  OF  SALICYLOUS  AND 
SALICYLIC  ACIDS  ON  THE  SESQUIOXIDE  OF  IRON. 
By  M.  Armand  Dollfus,  of  Mulhausen. 
It  is  well  known  that  salicylous  and  salicylic  acids  cause  a  deep 
violet  color  when  added  to  a  solution  of  sesquioxide  of  iron, 
without  producing  a  precipitate ;  and  that  the  coloration  by  the 
latter  acid  is  a  little  more  beautiful  and  more  intense  than  that 
by  the  salicylous  acid  ;  but  to  this  time  no  accurate  notice  of  the 
sensibility  of  reaction  has  been  taken.    Occupied  in  the  study 
of  the  principal  combinations  of  the  salicylic  series  in  the  labora- 
tory of  Prof.  Buchner,  I  have  found  that  the  reaction  in  ques- 
tion is  more  sensitive  than  that  of  sulphocyanide  of  potassium 
5 
