420 
PLATINUM  OF  BORNEO. 
olewsky,  as  used  at  the  Mint  of  St.  Petersburg.  The  gold 
having  been  separated  by  boiling  in  diluted  aqua  regia,  the  ore 
is  dissolved  in  a  mixture  of  three  parts  hydrochloric  acid  25° 
B,  and  one  part  nitric  acid  40°  B,  in  the  proportion  of  10  or 
15  parts  acid  to  one  part  of  ore.    The  result  was — 
Platinum,  .  •  .  .  70.21 
Gold,       ....  3.97 
Not  dissolved.         .        f    8'83  being  osmiridium  and 
(  minerals. 
Iron,  copper,  iridium,  os-  C 
mium,  palladium,  &c,  £ 
Iron  and  Copper,     .       I    161  separated  previously  .by 
rjr    7  (    hydrochloric  acid. 
100.00 
It  is  very  remarkable  that  the  platinum  appears  in  small 
circular  or  oval  laminae  like  drops  laminated  or  flattened,  as  if 
struck  by  a  hammer  ;  grains  with  crystalline  facettes  could  sel- 
dom be  distinguished.  I  call  this  very  remarkable,  because  the 
gold  of  the  same  ore  exhibits  the  form  of  pepitas  en  miniature 
or  microscopic  nuggets,  or  irregular  grains  ;  I  saw  some  small 
globules  and  octahedric  crystals.  The  platinum  of  South 
America  has  the  same  appearance. 
In  the  residue,  not  dissolved  in  aqua  regia,  could  be  distin- 
guished, as  stated  by  Fremy,  the  residu  en  grains  being 
the  alloy  of  rhodium,  osmium,  iridium,  and  the  residue  en  pail- 
lettes being  iridium,  ruthenium,  rhodium,  osmium.  The  other 
mineral  constituents  of  this  residue  were  grains  or  small  pebbles 
of  topaz,  hyacinthe,  ruby  (?),  diamond,  quartz,  and  feldspar. 
It  is  unnecessary  to  dwell  upon  the  industrial  uses  of  platinum. 
I  will,  however,  say  a  few  words  upon  the  metals  associated  with 
it,  because  they  hold  out  the  promise  of  many  future  useful  ap- 
plications, since  Deville,  at  Paris,  has  taught  the  method  of 
melting  them.  By  aid  of  his  lamp,  platinum  is  easily  melted. 
At  the  last  Exhibition  in  Paris  we  admired  the  objects  made 
from  molten  platinum  by  Savard,  and  since  then  attempts  have 
been  made  to  employ  it  as  a  plating  for  copper  for  cheap  chemi- 
cal apparatus. 
The  temperature  sufficient  for  melting  300  grammes  (0.3  kilo- 
grammes) of  platina,  melts  90  to  50  grammes  (0.04  to  0.05  kilo- 
grammes) of  rhodium. 
