24 
ACTION  OF  SULPHUR  ON  AMMONIA. 
nard  and  Fourcroy,  a  mixture  of  different  sulphurets.  My  own 
experiments  show  that  no  reaction  takes  place  if  sulphur  is 
heated  in  gaseous  ammonia  merely  to  the  point  of  volatiliza- 
tion. 
Brunner's  statements  are  correct.  At  ordinary  temperature 
no  solution  is  obtained,  but  at  60  to  65°  C.  the  ammonia  water 
is  colored  light  lemon-yellow  and  precipitates,  subsequently,  in 
contact  with  the  air,  a  minute  portion  of  sulphur  in  an  amorphous 
state,  and  too  little  to  be  weighed  from  100  grammes  of  ammonia. 
The  solution  remains  yellow  if  the  air  is  absolutely  excluded, 
but  is  not  colored  by  nitro-prusside  of  sodium,  and  by  plumbate 
of  soda  only  faint  reddish ;  it  contains  no  sulphuret  except  a 
trace,  after  standing  for  several  months  hermetically  sealed.  If 
a  large  quantity  of  such  an  amrnoniacal  solution  of  sulphur  is 
evaporated  to  dryness,  and  the  residue  treated  with  a  little  water, 
the  filtrate  shows  all  the  reactions  of  a  hyposulphite.  Crys- 
tallized hyposulphite  of  ammonia,  dissolved  in  water  and  boiled 
with  sulphur,  yields  no  yellow  solution  ;  the  ammonia  water  must 
therefore  be  capable  to  dissolve  a  little  sulphur  at  and  above 
60°  C.  This  solution  is  altered  in  contact  with  the  air  the 
same  as  solutions  of  a  sulphuret;  sulphur  is  precipitated; 
another  portion  oxidized  to  S202. 
The  ammonia  water  used  in  the  experiments  above  was  pre- 
pared by  the  author,  and  perfectly  pure.  The  flowers  of  sul- 
phur, a  commercial  article,  was  washed  with  much  distilled 
water,  and  the  acid  filtrate  considerably  concentrated,  when  it 
produced,  with  nitrate  of  silver,  at  once  a  purely  white  precipi- 
tate, which  readily  turned  yellowish,  brown,  and  finally  black. 
The  other  usual  reagents  for  hyposulphurous  acid  likewise 
proved  its  presence.  This  observation  is  remarkable,  considering 
the  instability  of  this  acid,  and  proves  the  correctness  of  Hose's 
statement,  that  small  portions  of  it  may  withstand  decomposi- 
tion for  some  time  ;  in  fact,  it  appears  to  keep  unaltered  for 
any  length  of  time  in  commercial  flowers  of  sulphur,  if  it  is  not 
reproduced  in  them.  * 
Another  experiment  indicates  a  greater  stability  of  hyposul- 
phurous acid.  A  mixture  of  finely  divided  cadmium,  sulphuret 
of  cadmium,  and  pure  sulphur,  is  well  agitated  with  absolute 
alcohol  and  sulphurous  acid ;  after  the  removal  of  the  excess  of 
