V 
ACTION  OP  SULPHUR  ON  AMMONIA.  27 
whether  saturated  or  not,  containing  little  or  much  sulphur, 
yields  a  very  intense  coloration  with  nitro-prusside  of  sodium, 
and  contains,  even  if  very  little  sulphur  has  been  used,  princi- 
pally higher  sulphides  of  ammonium  (NH4S5,  and  NH4S7);  for 
it  always  gives  the  reactions  of  the  polysulphides  (see  Am. 
Jour.  Ph.,  1861,  264),  modified  by  the  excess  of  ammonia. 
The  above  saturated  solution  of  sulphur,  rapidly  evaporated 
in  a  water-bath,  leaves  a  yellowish  residue  of  one-fourth  its 
weight.  Water  leaves  sulphur,  and  dissolves  30  to  32  per  ct. 
of  hyposulphite  of  ammonia  3  (NH40,S202)  +  aq.,  the  same 
salt  that  is  precipitated  by  absolute  alcohol  from  the  fresh  so- 
lution. It  differs  from  Rammelsberg's  salt  of  the  same  compo- 
sition* by  being  less  deliquescent,  and  by  precipitating  salts  of 
baryta  only  after  slight  acidulation. 
The  reaction  of  sulphur  on  ammonia  at  100°  C.  is  probably 
as  follows  :  3  (NH3  +  HO)  +  xS  =NH40,S202  +  NH4S5  + 
NH4S7  +  S  (sulphur  in  simple  solution).  It  may  vary  with  the 
concentration  of  the  ammonia  and  the  duration  and  temperature 
of  the  process,  but  the  oxygen  for  forming  S202  is  undoubtedly 
derived  from  the  oxide  of  ammonium.  The  solution  of  sulphur 
is  effected  by  ammonia,  but  may  be  aided  by  the  newly  formed 
compounds.  The  saturated  solution  in  ammonia  of  »885  sp.  gr. 
yields,  by  rapid  evaporation,  7-7  per  cent,  of  its  weight  of  hy- 
posulphite. The  author  suggests  that  this  method  of  preparing 
hyposulphite  might  perhaps  be  profitably  employed  for  techni- 
cal purposes. 
Under  favorable  circumstances,  the  behaviour  of  sulphur  and 
ammonia  to  each  other  is  identical  with  that  of  the  other  hy- 
drated  alkalies  ;  and  the  formation  of  hyposulphite  must  be  ex- 
pected wherever  sulphur  and  ammonia  act  on  each  other.  If 
well  crystallized  3NaS  +  AsS5  -j-  15  aq.  is  decomposed  by 
acetic  acid,  and  the  precipitated  AsS5  carefully  washed,  it  is 
wholly  soluble  in  ammonia,  but  the  solution  soon  separates  sul- 
*  Rammelsberg  obtained  4L5  per  cent.,  Fluckiger  39-07  per  cent.,  of 
Sulphur.  The  formula  3  (NH40,S202)  +  aq.,  requires  41.12  per  cent  S  ; 
2  (NH40,S2O)  +  aq.,  contains  40-77  S  and  NH40,S202  -f  aq,  38-55  S, 
while  Arppe's  anhydrous  salt  NH40,S202  requires  43-24  S.  Fluckiger's 
salt  is,  therefore,  probably  the  monohydrated  hyposulphite  of  ammonia. 
J.  M.  M. 
