306  NEW  PROCESS  FOR  LIQUOR  FERRI  NITRATIS. 
On  digesting  with  ether  and  with  chloroform,  and  evaporating,  a 
pungent,  colorless,  essential  oil  was  left,  though  in  small  quan- 
tity. No  trace  of  a  crystalline  principle  was  obtained  by  this 
process. 
Summary  -From  the  experiments  thus  obtained,  it  may  be 
inferred,  that  the  active  principles  of  capsicum  are :  1st.  A  pe- 
culiar crystallizable  principle,  the  true  capsiein.  2d.  An  essential 
oil,  besides  which  wax  was  obtained  as  a  residuary  product  of 
experiment  first  ;  and  a  peculiar  gum  soluble  in  alcohol  and 
water,  and  precipitable  by  subacetate  of  lead,  as  a  residuum  in 
experiment  second ;  also,  fixed  oil,  which  separated  from  the 
evaporated  ethereal  tincture. 
ON  A  NEW  PROCESS  FOR  MAKING  LIQUOR  FERRI  NITRATIS. 
By  William  Procter,  Jr. 
About  five  years  ago,  (see  vol.  23d,  page  312  of  this  Journal,) 
I  suggested  a  modification  of  the  officinal  formula  for  making 
solution  of  sesqui-nitrate  of  iron,  which  was  afterwards  adopted 
in  the  second  edition  of  the  Pharmacopoeia  of  1851.    This  modi- 
fication consisted  in  the  gradual  addition  of  the  iron  to  the 
nitric  acid  diluted,  so  as  to  insure  its  full  per  oxidation ;  and 
afterwards,  to  convert  any  s%5-nitrate  present  into  fcr-nitrate, 
the  solution  was  heated,  and  NO5  dropped  in,  until  the  proper 
color  of  the  solution  was  attained.    Now,  in  this  process  so  much 
depends  on  the  strength  of  the  nitric  acid,  and  on  the  last  addi- 
tions of  that  acid,  that  in  some  hands  it  has  failed  to  prove  satis- 
factory.   Even  where  a  permanent  solution  has  resulted,  the 
color  varied  from  a  bright  sherry-wine  color  to  that  of  a  full 
reddish-brown.    The  cause  of  the  deposit,  which  occurs  in  the 
officinal  solution  as  formerly  made,  is  a  deficiency  of  nitric  acid  ; 
owing  to  this  deficiency,  the  solution  contains  both  nitrate  of  the 
protoxide  and  sub-nitrate  of  the  sesqui-oxide ;  a  portion  of  this 
sub-nitrate  is  deposited  with  a  portion  of  sub-nitrate  resulting 
from  the  action  of  the  air  on  the  proto-nitrate  with  the  forma- 
tion of  ter-sesquinitrate  and  sub-sesquinitrate.   The  color  of  the 
solution  deepens  in  proportion  to  the  amount  of  sub*nitrate 
