236 
DEODORIZING  INDIA-RUBBER. 
sieve,  which  will  retain  the  prisms  of  nitroprussides  of  sodium, 
and  allow  the  cyanide  of  mercury  to  pass  through.  The  prisms 
may  be  washed  quite  clean  by  allowing  the  cyanide  of  mercury 
to  settle  down  in  the  filtrate,  and  using  the  clear  supernatant 
fluid  for  wTashing.  The  operation,  can  of  course,  be  continued 
as  far  as  it  may  be  deemed  profitable.  If  the  cyanide  of  mer- 
cury is  not  wanted  as  such,  it  can  be  made  to  furnish  hydrocyanic 
acid  and  corrosive  sublimate  for  use  again,  by  boiling  with 
hydrochloric  acid. 
It  may  be  added,  in  conclusion,  that  nitroprussides  react  well 
only  with  monosulphides.  The  more  of  a  persulphide  the  solu- 
tion contains,  and  the  deeper  the  yellow  color,  the  less  distinct 
is  the  reaction.  This  difficulty  can  be  overcome  by  warming  the 
yellow  persulphide  with  sufficient  cyanide  of  potassium  to  decol- 
orize it,  when  the  beautiful  carmine  of  the  monosulphide  will  be 
obtained. — London  Pharm.  Journ.,  February,  1867. 
DEODORIZING  INDIA-RUBBER. 
The  extremely  disagreeable  odor  attaching  to  india-rubber 
manufactures,  and  the  power  possessed  by  them  of  imparting  a 
nauseous  taste  to  liquids  or  other  substances,  has  long  been  a 
difficulty  in  the  way  of  its  use  for  many  purposes  for  which  india- 
rubber  is  peculiarly  adapted.  To  obviate  this  evil  many  expe- 
dients have  been  resorted  to,  but  none  hitherto  with  perfect 
success,  and  this  on  account  of  the  strong  tendency  which  india- 
rubber  has  to  acquire  and  retain  odors.  The  new  process,  invented 
by  Mr.  S.  Bourne,  depends  upon  the  still  greater  affinity  pos- 
sessed by  charcoal,  especially  animal  charcoal,  for  all  kinds  of 
odors,  and  its  great  capacity  for  the  absorption  of  gases.  The 
practical  difficulty  lies  in  so  using  the  charcoal  as  not  to  injuri- 
ously affect  the  articles  with  which  it  may  be  brought  into  con- 
tact, and  this  has  now  been  overcome  by  very  simple  means. 
The  mode  of  application  necessarily  varies  according  to  the 
description  of  articles  which  are  thus  treated.  Generally  speak- 
ing, they  are  laid  in  shelves  or  trays  in  a  hot  chamber,  with  a 
thin  stratum  of  charcoal  beneath  and  on  top,  and  exposed  to  a 
temperature  of  from  120  to  180  degrees  for  from  three  to  six 
