ARTIFICIAL  FORMATION  OF  SALTPETRE.  151 
ON  THE  CONVERSION  OF  THE  NITROGEN  OF  NITROGENOUS 
MATTERS  INTO  NITRATE  OF  POTASH. 
By  MM.  Cloez  and  Guignet. 
The  conversion  is  effected  by  means  of  permanganate  of  pot- 
ash. The  permanganate  employed  was  ascertained  to  contain 
no  nitrate.  Several  grammes  of  crystallized  permanganate  were 
converted  by  sulphurous  acid  into  a  mixture  of  sulphates  of 
manganese  and  potash,  which  contained  no  trace  of  nitrate. 
As  has  already  been  stated,  ammonia  in  excess  reduces  per- 
manganate of  potash  in  the  cold,  and  forms  nitrate  of  potash. 
But  if  an  excess  of  permanganate  be  added  and  the  whole 
boiled,  the  nitrate  itself  is  converted  into  nitrate  of  potash.  In 
this,  as  in  all  the  following  experiments,  the  authors  have  pro- 
duced at  least  1  gramme  of  crystallized  nitre. 
Aniline  immediately  reduces  permanganate  of  potash  with  a 
great  evolution  of  heat.  Carbonate  and  oxalate  of  potash  are 
produced,  but  only  traces  of  nitrate. 
With  quinine,  the  reaction  commences  in  the  cold,  but  is  only 
completed  by  boiling.  It  furnishes  carbonate  and  nitrate  of 
potash,  and  the  potash  salt  of  an  acid  which  appears  to  be  new. 
Cinchonine  is  acted  upon  with  more  difficulty  than  quinine. 
Cyanogen  immediately  reduces  permanganate  of  potash  in 
the  cold.  This  is  also  the  case  with  hydrocyanic  acid  and  cya- 
nide of  potassium.  In  these  three  cases,  nitrate  of  potash  was 
was  readily  obtained. 
The  authors  think  that  the  action  of  permanganate  of  potash 
upon  cyanogen  may  be  employed  in  the  analysis  of  gaseous 
mixtures,  for  example,  to  separate  cyanogen  and  carbonic  acid 
which  has  no  action  on  the  permanganate,  and  this  is  also  the 
case  with  oxide  of  carbon,  protoxide  of  nitrogen,  &c.  Deutox- 
ide  of  nitrogen,  on  the  contrary,  is  absorbed  in  the  cold  and 
forms  nitrate  of  potash. 
Compounds  containing  sulphur  and  cyanogen  furnish  sul- 
phate and  nitrate  of  potash.  This  is  the  case  with  the  body 
called  mlpho- cyanogen  by  some  chemists,  which  is  obtained  by 
the  action  of  chlorine  upon  sulphocyanide  of  potassium. 
Nitroprussiate  of  soda  is  also  oxidized  very  easily,  with  for- 
mation of  nitrate  of  potash.    Ferrocyanide  of  potassium  mere- 
