ESTIMATION  OF  NITRIC  AND  ACETIC  ACIDS. 
47 
the  wash-water,  has  a  strong  musky  odor.    The  analysis  I.  is  of 
pyroguaiacine  crystallized  from  alcohol ;  II.  is  sublimed  : — 
I.  II. 
Carbon  .    .   78-462  78471      14      78-504  ' 
Hydrogen  .     6-901  7-042        7  6-542 
Oxygen.    .    14-637  14-487        2  14-953 
— Qhem.  Gaz.  Oct.  16,  from  Jour n.fiir  Praht.  Chem.,  Ixii.  p.  291. 
ON  A  METHOD  OF  ANALYSIS  APPLICABLE  TO  THE  QUANTI- 
TATIVE ESTIMATION  OF  NITRIC  AND  ACETIC  ACIDS. 
By  J.  H.  Gladstone,  F.R.S. 
A  good  method  for  estimating  the  amount  of  nitric  acid  pre- 
sent in  its  compounds,  or  in  mixtures  of  salts,  has  long  been  a 
desideratum.  That  which  I  propose  bringing  before  the  notice 
of  the  British  Association  is  one  which  I  have  frequently  made 
use  of ;  and  although  it  does  not  give  rigidly  accurate  results,  I 
have  found  it  sufficiently  exact  for  most  purposes. 
The  process  is  as  follows  : — Place  a  weighed  portion  of  the 
substance  to  be  analysed  in  a  small  tubulated  retort,  and  dissolve 
it  in  a  little  water.  It  will  be  remembered  that  all  neutral 
nitrates  are  soluble  ;  the  few  sub-nitrates  which  are  insoluble  in 
water  should  be  reduced  to  a  very  fine  powder.  Add  to  the 
solution  in  the  retort  a  large  quantity  of  strong  sulphuric  acid, 
very  many  times  more  than  is  requisite  to  effect  the  decomposition 
of  whatever  nitrates  may  be  present.  Attach  to  the  beak  of  the 
retort,  in  such  a  way  as  to  preclude  the  escape  of  any  gas,  a 
receiver  containing  water  and  a  considerable  quantity  of  carbon- 
ate of  baryta.  Heat  the  liquid  in  the  retort  gently  at  first,  but 
more  strongly  towards  the  end  of  the  operation.  The  nitric 
acid  of  course  distils  over,  and  will  be  condensed  wholly  in  the 
receiver,  which,  together  with  the  neck  of  the  retort,  should  be 
kept  cool.  There  it  will  decompose  the  carbonate,  forming 
nitrate  of  baryta,  while  the  liquid  will  be  ever  ready  to  absorb 
or  receive  fresh  increments  of  acid.  The  distillation  should  be 
continued  till  the  sulphuric  acid  itself  rises  in  vapor,  sweeps  down 
the  nitric  acid  which  may  be  adhering  to  the  neck  of  the  retort, 
