508 
Spiritus  ALtheris  Nitrosi. 
Am.  Jour.  Pharm. 
Oct.,  1879. 
Estimation  of  Nitrite  of  Ethyl. — 5  cc.  of  the  spirit  are  added  to  I 
gram  of  pure  potash  (free  from  nitre)  dissolved  in  40  cc.  of  pure  water 
in  a  50  cc.  graduated  flask,  stoppered  and  capped  with  leather,  digest 
in  a  warm  place  at  a  temperature  of  1500  to  200°F.  for  three  hours. 
Allow  the  flask  to  cool  and  then  dilute  with  water  to  50  cc,  shake 
and  then  take  out  with  a  pipette  10  cc,  of  the  liquid  and  run  it  into  a 
platinum  dish,  and  add  to  it  40  cc.  of  water,  evaporate  on  a  water-bath 
to  20  cc.  to  get  rid  of  the  alcohol,  etc.  This  residue  is  now  to  be 
washed  into  a  flask  of  16  ounces  (or  450  cc.)  capacity,  containing  10 
grams  of  zinc  foil  coated  with  copper,  and  the  volume  of  liquid  made 
up  to  about  350  cc.  with  water,  and  connected  with  a  condenser  ;  heat 
is  now  to  be  applied  and  the  distillation  carried  on  as  usual.  Most  of 
the  ammonia  comes  over  in  the  first  100  cc.  of  distillate,  but  it  is 
necessary  to  distill  another  50  cc.  to  ensure  perfect  exhaustion.  The 
ammonia  thus  obtained  is  now  to  be  estimated  with  a  standard  sulphuric 
acid,  1  cc.  equal  to  *ooi  gram  ammonia. 
The  amount  of  NH3  found  is  to  be  multiplied  by  IOOX'824  which 
will  equal  the  total  nitrogen  in  the  spirit;  and  this,  minus  the  nitrogen 
present  in  the  free  nitrous  acid,  when  multiplied  by  5*357  will  give  the 
nitrite  of  ethyl  contained  in  the  spirit. 
Estimation  of  Nitrous  and  Acetic  Acids. — The  amounts  of  these  two 
acids  are  necessary  to  be  known  in  order  to  judge  of  the  quality 
of  the  preparation,  and  for  correctly  estimating  the  nitrite  of 
ethyl.  10  cc.  are  to  be  measured  with  a  pipette  and  run  into  a  plat- 
inum dish,  and  diluted  with  an  equal  volume  of  pure  water,  and  *5  gram 
carbonate  of  potash  added,  and  stirred  until  dissolved  ;  the  solution  is 
then  evaporated  on  a  water-bath  to  dryness.  This  saline  residue  is 
now  to  be  treated  with  5  cc.  of  pure  alcohol  for  the  separation  of  the 
potassium  acetate,  from  the  potassium  nitrite,  and  again  repeated,  and 
the  mixed  solutions  filtered  through  a  very  small  Swedish  filter  ;  this 
filtrate  evaporated  in  a  tared  capsule  to  dryness,  and  rapidly  weighed. 
The  weight  minus  *02i  gram  (the  weight  of  KN02  which  is  dissolved 
by  10  cc.  of  alcohol)  and  the  amount  multiplied  by  *6i22  gives  the 
quantity  of  acetic  acid  present  in  the  spirit. 
The  amount  of  acetic  acid  thus  found,  multiplied  by  '7666  gives 
the  equivalent  of  N02  to  which  it  is  equal,  and  this  product  deducted 
from  the  total  acidity  (previously  determined  alkalimetrically),  leaves 
the  net  amount  of  N02  present. 
