ON  ANGOSTURA  BARK  AND  ITS  ESSENTIAL  OIL. 
421 
The  temperature  sufficient  for  melting  100  to  150  grammes 
(0.10  to  0.15  kilogrammes),  platina  melts  10  grammes  (0.10 
kilogrammes)  iridium,  which  was  considered  as  perfectly  infusi- 
ble. 
The  iridium  is  commonly  alloyed  with  platinum ;  the  latter  is 
then  less  attacked  by  chemical  agents  and  is  much  harder,  but 
can  be  hammered  and  laminated  equally  well.  A  large  propor- 
tion makes  the  platinum  more  brittle. 
During  last  year  M.  Chapuis,  at  Paris,  stated  that  rhodium, 
alloyed  with  platinum,  formed  a  combination  that  could  be 
hammered  and  laminated  without  difficulty,  and  that  this 
combination  had  the  excellent  property  of  not  being  attacked 
by  aqua  regia,  and  thus  the  earnest  wishes  of  the  practical 
chemist  are  satisfied. 
The  American  patent  of  Batchelder  recommends  alloying  iri- 
dium with  copper  for  etching  purposes.  If  this  be  confirmed 
by  experience  there  will  be  a  new  field  opened  for  a  useful  ap- 
plication of  it.  The  use  of  the  iridosmine  for  the  diamond  pens, 
and  of  the  rhodium  for  the  same  purpose,  must  not  be  omitted. 
It  is  said  that  one  ounce  of  rhodium  fetches  in  the  United 
States  from  £2  10s.  to  <£50,  according  to  its  purity. 
I  hope  these  notices  may  serve  to  demonstrate  that  the  plati- 
noid metals,  scarcely  known  to  the  public,  even  by  name,  are 
very  valuable  substances,  requiring  further  investigation  with  a 
view  to  future  useful  employment.  The  residue  of  the  platinum 
ore,  a  few  years  ago  of  a  very  low  value,  scarcely  <£4  per  lb. 
avoirdupois,  has  already  risen  in  price,  and  is  now  saleable  at 
four  or  five  times  that  amount. — Pharm.  Jour,  July,  1858,  from 
Journal  of  the  Society  of  Arts. 
ON  ANGOSTURA  BARK  AND  ITS  ESSENTIAL  OIL.  \ 
By  Dr.  C.  Herzog. 
Saladin  found  in  Angostura  bark  an  indifferent  substance 
which  he  called  cusparine.  The  author  has  in  vain  endeavored 
to  prepare  this  body,  which  is  said  to  be  crystallizable.  The 
author  considers  it  possible  that  the  preparation  was  unsuccess- 
ful in  consequence  of  the  difficulty  of  obtaining  the  solution 
which  contains  it  in  a  colorless  state.    He  found,  however,  that 
