PREPARATION  OF  CHLOROPICRIN. 
133 
preservation  of  all  those  chemicals  particularly  prone  to  deterior- 
ation from  exposure  to  light. 
It  will  perhaps  be  considered  unnecessary  to  advise  that,  (in 
the  absence  of  bottles  of  the  above  description,  all  essential  oils 
should  be  kept  in  a  dark  closet, — as  it  is  only  saying  what  every- 
body knows, — still,  since  everybody  does  not  at  all  times  practise 
what  he  knows  to  be  best,  it  is  earnestly  recommended  to  every 
apothecary,  who  wishes  to  satisfy  himself  or  his  customers,  to  try 
the  expedient,  and  he  will  be  amply  repaid  for  any  trouble  or  in- 
convenience resulting  therefrom. 
Proc.  Amer.  Pharm.  Association,  1863. 
PREPARATION  OF  CHLOROPICRIN. 
By  Samuel  Priestley. 
This  substancce,  which  has  usually  been  prepared  by  distilling 
picric  acid  with  hypochlorite  of  lime,  may  be  prepared  from 
methylic  alchohol  directly — a  fact  which  establishes  beyond  doubt 
the  connection  of  chloropicrin  with  the  methyl  series. 
I  succeeded  in  obtaining  the  substance  in  the  following  man- 
ner : — 
Bleaching  powder  is  introduced  into  a  flask,  with  as  much 
methylalchohol  as  will  form  a  paste.  After  mixing  the  materials, 
the  flask  must  be  placed  in  a  shallow  basin  of  cold  water,  in  order 
to  prevent  the  volatilisation  of  the  spirit  by  the  heat  disengaged. 
When  the  chemical  action  has  subsided,  nitric  acid  is  added 
carefully  and  by  small  portions  at  a  time,  allowing  the  action  to 
subside  each  time,  the  flask  remaining  still  in  the  water. 
The  whole,  when  dissolved,  is  submitted  to  distillation.  Dur- 
ing the  distillation  a  gas  is  evolved,  which  burns  with  a  green 
flame,  and  may  be  collected  over  water.  It  is  probably  chloride 
of  methyl,  but  I  have  not  examined  it  further.  This  product 
which  collects  in  the  receiver  appears  to  be  a  mixture  of  chloro- 
form, chloropicrin  and  wood-spirit.  These  substances  are  after- 
wards separated  by  distillation  ;  the  chloropicrin,  having  a  higher 
boiling  point,  remains  behind. 
In  actual  reaction  it  is  very  probable  that  chloroform  is  first 
