Am  Jour.  Pharm. 
Oct.,  1884. 
Estimation  of  Nicotine. 
499 
Why  it  is  that  all  our  text-books  give  the  composition  of  hydro- 
chloride of  nicotine  as  C10H14N2(HC1)2,  while  the  sulphate,  they  say, 
consists  of  1  equivalent  of  nicotine  and  1  equivalent  of  sulphuric  acid, 
is  difficult  to  understand,  as  the  same  quantity  of  nicotine  which  is 
neutralized  by  49  H2S04  is  also  neutralized  by  36*4  HC1. 
Gmelin  has  the  composition  of  sulphate  of  nicotine,  G20H14N2,HO,SO3 
(old  notation),  and  Husemann  says  that  49  sulphuric  acid  neutralizes 
162  nicotine,  and  both  authors  give  for  the  hydrochloride : 
C10HUN2(HC1)2,  Husemann,  and 
Q>0H14N2,2HC1,  Gmelin. 
Now  for  the  proof  of  my  assertions. 
The  precipitate  obtained  was  collected  on  a  tared  filter,  washed  and 
dried  under  a  bell  glass  above  sulphuric  acid,  and  the  amount  of  Hg 
and  I  in  it  ascertained.  For  this  purpose  a  certain  quantity  of  the 
dried  precipitate  was  placed  in  a  beaker  and  ammonia  water  added  to 
it,  by  which  the  yellowish  precipitate  was  transformed  into  a  fine 
white  powder.  When  the  transformation  was  completed,  freshly  pre- 
pared ammonium  sulphide  was  added,  whereby  the  mercury  was  sepa- 
rated as  HgS. 
After  the  white  precipitate  had  disappeared,  and  was  entirely  decom- 
posed, the  precipitate  of  HgS  was  collected  on  a  tared  filter,  washed, 
dried  and  weighed.  The  liquid  resulting  from  the  precipitate  by 
Am2S  with  the  wash  water  was  heated  on  the  water-bath  until  all  odor 
of  H2S  had  disappeared,  then  slightly  acidulated  with  sulphuric  acid, 
and  AgNOs  added  as  long  as  a  precipitate  was  formed. 
After  the  precipitate  had  subsided,  the  liquid  was  decanted  from  the 
precipitate,  and  filtered  through  a  tared  filter;  to  the  moist  precipitate 
of  Agl  in  the  beaker,  ammonia  water  was  added,  and  macerated  over 
night,  and  the  next  morning  the  Agl  collected  on  the  same  filter, 
thoroughly  washed,  and,  having  become  air  dry,  was  heated  in  a  dry- 
ing oven  at  212°F.  until  the  weight  kept  constant. 
The  ammoniacal  liquid  running  off  from  the  Agl  did  not  become 
turbid  on  addition  of  HNOs,  and  thereby  the  absence  of  chlorine  in 
the  original  precipitate  was  confirmed. 
To  control  the  result  of  examination  of  the  precipitate  by  M.  S., 
the  liquid  obtained  was  also  examined;  the  mercury  was  precipitated 
by  H2S,  and  the  precipitate  of  HgS  washed  and  dried.    The  liquid, 
