SPIRITUS  J3THERIS  NITEICI. 
293 
It  makes  use  of  a  salt  that  is  often  difficult  to  obtain  free  from 
chlorides  ;  and  that  is  nearly  insoluble  in  the  menstruum  used, 
thus  postponing  the  reactions  and  rendering  them  somewhat 
variable  and  precarious.  The  reaction  which  produces  an  undue 
proportion  of  aldehyd  in  the  distillate,  and  which  probably  oc- 
curs at  temperatures  about  186°  to  190°  may  very  well  take 
place  in  that  portion  of  the  materials  confined  under  the  cake  in 
contact  with  the  bottom  of  the  retort,  for  it  is  not  uncommon  to 
see  a  violent  boiling  out  from  under  the  cake,  when  the  ebulli- 
tion elsewhere  is  quietly  and  steadily  going  on.  There  is  no 
way  of  securing  uniformity  of  temperature  and  reaction  in  a  re- 
tort of  boiling  liquid  when  a  cake  of  solid  matter  lies  upon  the 
bottom. 
The  process  distils  over  from  one  half  to  three  fourths  of  the 
alcohol  twice  unnecessarily,  for  the  six  pints  first  received  in 
the  etherification,  and  last  received  in  the  rectification,  are  simply 
alcohol.  This  unnecessary  distillation  occupies  half  the  time  of 
the  process,  and  requires  a  larger  apparatus  than  is  commonly 
possessed  by  apothecaries. 
In  making  nitric  acid,  the  materials  used  in  this  process  should 
yield  practically  about  18-J  %  of  an  acid  of  141  s.  g.,  and  upon 
this  the  following  process  is  based;  and  this  process  is  the  best 
substitute  for  the  officinal  one  that  I  have  yet  tried,  and  its  de- 
tails and  results  are  based  upon  an  experience  of  nearly  a  year 
and  a  half : — 
Take  of  Nitric  Acid,    s.  g.  1-408    28  f.§  =  373=2ft>  8-Joz.  Av. 
Alcohol,  «     -835    20  pints. 
Carbonate  of  potassa,  2  §. 
The  apparatus  required  is  the  same  precisely  as  that  for  the 
U.  S.  P.  process,  except  that,  for  double  the  yield,  both  the  retort 
and  receiver  may  be  of  2  pints  less  capacity.  The  receiver  should 
be  marked  at  each  pint  by  a  pencil  on  a  slip  of  paper  pasted 
vertically  on  the  side  of  the  bottle. 
One  gallon  of  the  alcohol  is  introduced  into  the  retort,  the 
acid  slowly  added  to  it,  and  heat  applied  through  the  interven- 
tion of  water,  or  preferably  by  a  steam  jet.  At  178°  the  yellow 
mixture  begins  to  boil;  and  faint  yellow  vapors  appear  in  the  re- 
tort as  brisk  distillation  commences  at  184°,  the  distillate  being 
slightly  yellow  and  ethereal  from  the  beginning. 
