THE  GUMS  AND  RESINS  OF  COMMERCE. 
141 
sinia  dig  deep  trenches  round  the  tree,  and  then  collect  and  sort 
the  pieces  of  gum  which  fall  into  them.  They  are  afterwards 
freed  as  much  as  possible  of  the  earth  that  adheres  to  them  by 
washing  and  stirring.  African  copal  is  obtained  from  a  species 
of  Hymenoea,  and  from  fourteen  to  seventeen  tons  are  imported 
to  Liverpool  from  Sierra  Leone.  New  Zealand  copal  is  the  Kauri 
gum  ;  Brazilian  copal  is  the  produce  of  Tracliylobium  Martia- 
num.  The  imports  of  gum  copal,  which  in  1846  were  549  tons, 
dropped  in  1849  to  200  tons.  From  the  Phillippines  we  imported 
354  of  copal  cwt.  in  1851,  338  cwt.  in  1852;  and  479  cwt.  in  1853 ; 
and  from  Singapore  the  imports  have  lately  been  increasing.  In 
1849  we  received  from  that  entrepot  53  cwt.  ;  in  1850,  40  cwt; 
in  1852,  [218  cwt.;  and'  in  1853,  521  cwt.  The  trade  reports 
also  record  the  import  of  832  cwt.  of  copal  from  New  Zealand 
in  1852,  and  from  those  islands  3217  cwt.  of  gum  not  enume- 
rated, were  received  here  in  1853.  In  commerce,  copal  is  distin- 
guished into  the  hard  and  soft  kinds.  The  chief  varieties  of  the 
former  are — First,  copal  from  Madagascar  (in  large  flat  yellow 
pieces),  which,  when  cold,  is  tasteless  and  odorless,  but  when 
heated  diffuses  an  aromatic  odor :  this  kind  is  rather  rare. 
Secondly,  the  East  India  copal,  the  most  common  commercial 
variety;  it  is  rough  on  the  surface,  bearing  the  impression  of 
sand.  The  best  specimens  are  colorless,  and  in  small  pieces, 
constituting  the  copal  from  Calcutta.  A  third,  but  very  small 
variety,  is  brought  from  the  Brazils  and  south  of  Africa.  We 
receive  all  the  copal  proper  of  commerce  from  India,  whatever 
its  primary  source  may  be.  In  the  Calcutta  variety,  pieces  of 
all  the  others  are  to  be  found ;  nor  is  a  distinction  readily  to  be 
made  between  the  white  copal  of  Calcutta,  and  the  yellow  resin 
of  Bombay ;  the  difference  appears  to  depend  only  on  the  care 
bestowed  on  the  selection  and  purification  of  the  pieces.  The 
various  resins,  from  anime  to  soft  copal,  Indian  and  Madagascar, 
seem  to  form  a  continued  series,  differing  only  in  the  increased 
quantity  of  oxygen  they  contain.  A  curious  variety  of  copal 
is  that  in  the  pebble  form,  rounded  by  the  action  of  the  water, 
of  which  there  are  specimens  on  the  table. 
Copal  is  the  Mexican  generic  name  for  all  resins.  In  the 
collection  of  products  from  Mexico  shown  at  Paris,  there  were 
several  resinous  gums,  of  which  no  particulars,  however,  were 
