SPIRIT  OF  NITROUS  ETHER  AND  NITRITE  OF  SODA.  359 
fl.  oz.  (seven  times  the  quantity  of  the  nitrite  employed).  Spe- 
cific gravity  -843.  The  preparation  of  the  nitrite  of  soda  was 
made  a  separate  process,  thus — 16  oz.  nitrate  of  soda,  1\  oz.  of 
charcoal  recently  burned,  and  in  fine  powder ;  mix  and  drop  the 
mixture  in  successive  portions  into  a  clay  crucible  heated  to  dull 
redness.  Raise  the  heat  to  liquefy  it,  and  pour  on  to  a  clean 
flagstone.  In  carrying  this  operation  into  practice,  it  was  found 
that  32  fl.  oz.  only  could  be  obtained  by  distillation,  and  that 
it  required  the  addition  of  more  spirit  to  make  up  the  yield 
to  35.  The  specific  gravity,  also,  was  '850,  and  the  percentage 
of  nitrous  ether  below  that  indicated.  In  examining  into  the 
reason  of  this  deficiency,  it  was  found  that  on  the  addition  of 
the  mixed  spirit  and  acid  to  the  salt,  a  crust  of  sulphate  of 
soda,  in  a  comparatively  insoluble  state,  was  formed  on  the  sur- 
face of  the  nitrite  of  soda,  which  enclosed  and  thus  protected  the 
remainder  from  the  action  of  the  acid,  until  a  great  deal  of  the 
spirit  had  distilled  over,  and  that  it  was  hence  some  time  before 
much  nitrous  ether  was  produced.  To  prevent  this  the  nitrite 
was  first  dissolved  in  10  fl.  oz.  of  water  before  the  addition  of 
the  acid  and  spirit,  and  with  this  modification  the  whole  quantity 
directed  can  readily  be  distilled  off. 
A  great  deal  of  difficulty,  I  believe,  has  arisen  in  preparing 
the  nitrite  of  soda  for  this  manufacture,  and  there  can  be  no 
doubt  that  if  great  care  is  not  observed  in  the  process  of  defla- 
grating the  nitrate  of  soda  and  charcoal,  a  considerable  percent- 
age of  carbonate  of  soda  or  even  caustic  soda  is  formed,  with,  of 
course,  an  equivalent  loss  of  nitrite.  The  proportion  of  char- 
coal ordered  is  indeed  rather  above  the  quantity  required,  1-13 
oz.  being  the  calculated  proportion  instead  of  1*25.  One  ounce, 
however,  will  be  found  practically  sufficient.  In  working  on  the 
large  scale,  the  process  of  deflagration  is  also  a  very  tedious  one, 
and  if  the  workman  endeavors  to  expedite  his  operations  by  the 
projection  of  too  large  a  quantity  of  material  at  once  into  the 
heated  vessel,  the  chemical  action  is  increased  to  such  an  extent 
that  he  is  sure  to  destroy  a  great  deal  of  the  nitrite  he  is  endeav- 
oring to  prepare.  As  I  had  obtained  such  good  results  by  con- 
trolling this  operation  within  its  lowest  possible  limits,  it  was 
attempted  next  to  effect  the  partial  deoxidation  of  the  nitrate  of 
