358      SPIRIT  OF  NITROUS  ETHER  AND  NITRITE  OF  SODA. 
The  spirit  of  nitrous  ether  met  with  in  commerce  I  have  never 
found  to  yield  any  ether  by  the  chloride  of  calcium  test,  nor  have 
I  ever  heard  of  any  which  did.  It  could  not,  therefore,  contain 
more  than  8  per  cent,  of  ether,  that  being  the  point  at  which  the 
test  will  begin  to  indicate.  In  the  last  process  of  the  London 
College  for  1851  the  gravity  of  the  product  (obtained  by  the 
distillation  of  nitric  acid  with  rectified  spirit)  is  stated  as  below 
that  of  the  spirit  used,  namely  *834,  rectified  spirit  being  *838, 
which  can  only  be  accounted  for  as  an  increase  in  the  percent- 
age of  alcohol  by  the  slow  distillation.  The  amount  of  nitrous 
ether  present  here  must  have  been  very  small.  Such  then  was 
the  position  of  this  manufacture,  as  far  as  regards  officinal  pre- 
paration, up  to  the  time  of  the  issue  of  the  British  Pharmaco- 
poeia.* 
The  original  formula  suggested  by  the  Dublin  Pharmacopoeia 
Committee,  and  handed  to  me,  as  Consulting  Pharmaceutic 
Chemist  to  the  London  and  Edinburgh  Committees,  for  trial, 
was  as  follows  : — "  6  oz.  of  nitrate  of  soda,  200  grs.  of  charcoal 
in  very  fine  powder,  3J  oz.  of  sulphuric  acid,  25  fi.  oz.  of  recti- 
fied spirit.  Mix  the  nitrate  of  soda  with  the  charcoal,  both  in 
fine  powder,  and  deflagrate  the  mixture  in  small  and  successive 
portions  in  a  Hessian  crucible  raised  to  a  low  red  heat.  Then 
increase  the  temperature  to  produce  perfect  liquefaction,  pour 
out  the  salt  on  a  clean  flag,  and  when  cool  reduce  it  to  powder. 
Place  it  in  a  matrass  connected  with  a  condenser,  and  pour  on 
the  spirit  and  acid  previously  mixed.  Distil  over  20  fl.  oz. 
Specific  gravity  -835."  By  experiment,  deflagrating  at  as 
low  a  heat  as  possible,  this  yielded  a  product  having  a  specific 
gravity  '853,  and  giving  by  the  chloride  of  calcium  test  8  mea- 
sures of  ether  per  cent,  separated,  equal,  therefore,  to  16  per 
cent,  really  present,  or  53  per  cent,  of  nitrite  of  soda  in  the  salt 
employed. 
This  formula  was  then  altered  by  the  committees  to  that  which 
now  stands  in  the  Pharmacopoeia,  namely,  5  oz.  nitrite  of  soda, 
4  fl.  oz.  of  sulphuric  acid,  40  fl.  oz.  of  rectified  spirit.    Distil  35 
*  [Note.  The  late  Dr.  Hare  suggested  the  nitrites  of  soda  and  potassa 
in  the  residues  of  the  oxygen  process,  for  making  spt.  of  nitrous  ether. 
See  vol.  xii.,  page  115,  of  this  Journal,  July,  1840. — Editor  Am.  Jour.  Ph.] 
