Hydrogen  will  speedily  be  given  off  from  the  surface  of  the
aluminium,  and  in  five  or  six  hours  the  whole  of  the  nitrogen  as
nitrates  and  nitrites  will  be  converted  into  ammonia.  Transfer  to
a  small  retort  the  contents  of  the  cylinder,  together  with  the
pumice,  washing  the  whole  apparatus  with  a  little  water  free  from
ammonia.  Distil,  and  estimate  ammonia  in  the  usual  way  with
Nessler  solution.  It  appears  impossible  wholly  to  exclude
ammonia  from  the  re-agents  and  apparatus,  and  therefore  some
blank  experiments  should  bo  made  to  ascertain  the  correction  to  bo
applied  for  this.  This  correction  is  very  small,  and  appears  to  be
nearly  constant

8.    Estimation  of  Nltroaren  as  Nitrates  and  Nitrites  by  the  Indiffo

Process.
Tliis  method  has  been  fully  described  in  §  67.7.
0.    Estimation  of  Nitrates  as  Ammonia  by  the  Copper-sine  Couple.
