546 
ON  THE  INDIA-RUBBER  OP  THE  AMAZON. 
1854.  Mechanics  threw  aside  their  tools,  sugar-makers  deserted 
their  engenhos,  and  Indians  their  rocas  ;  so  that  sugar,  ram,  and 
even  farinha,  were  not  produced  in  sufficient  quantity  for  the 
consumption  of  the  province,  the  two  former  articles  having  to 
be  imported  from  Maranham  and  Pernambuco,  and  the  last  from 
the  river  Uaupes. 
The  mode  of  obtaining  the  milk  is  almost  universally  by  tap- 
ping. Some  who  began  by  cutting  down  the  trees,  found  that 
in  this  way  they  obtained  much  less  milk  than  by  successive 
tappings  of  the  same  tree,  besides  that  the  work  was  harder,  and 
it  was  necessary  continually  to  shift  their  sphere  of  operations. 
I  am  glad,  therefore,  that  this  killing  of  the  hen  to  get  at'the 
golden  eggs  has  been  abandoned. 
Most  seringueiros  follow  the  old  mode  by  drying  the  milk  by 
smoke,  applied  to  successive  coatings  on  a  mould.  Some  have 
filled  a  small  square  box  with  the  milk,  and  allowed  it  to  coagu- 
late ;  but,  as  the  milk  does  not  become  solid  until  the  end  of  ten 
days  or  more,  and  the  mas3  then  requires  to  be  cut  into  thin 
slices,  and  subjected  to  heavy  pressure  (such  as  it  is  difficult  to 
obtain  here),  in  order  to  free  it  from  the  water  and  air  collected 
in  cells  within  its  substance,  this  mode  is  by  no  means  popular. 
It  is  found  that  the  addition  of  a  small  quantity  of  alum  ac- 
celerates the  coagulation  of  the  milk.  Ammonia  has  a  contrary 
effect,  and  is  accordingly  useful  when  the  milk  is  required  to  be 
kept  some  time  in  a  liquid  state. 
When  the  trees  are  flowering,  nearly  all  the  milk  goes  to  the 
nourishment  of  the  flowers,  and  scarcely  any  can  be  obtained, 
from  the  trunk,  while  if  a  panicle  be  wounded  the  milk  starts 
out  in  large  drops.  It  is  customary  to  leave  the  trees  untouched 
for  a  few  months  in  the  year,  from  the  epoch  of  flowering  until 
the  fruit  has  attained  its  full  size.  About  Para,  the  collection  of 
seringa  seems  limited  to  the  dry  season — June  to  December.  On 
.  the  upper  Rio  Negro,  the  seringa-trees  flower  from  November  to 
the  end  of  January  ;  and  when  I  started  from  San  Carlos  on 
November  23d,  little  milk  was  to  be  obtained. 
The  species  from  which  rubber  is  extracted  on  the  upper  Rio 
Negro  and  lower  Casiquiare  are  two  Siphonia  lutea,  Spruce 
{Joum*  of  Bot.,  vi.,  370),  and  S.  brevifolia,  Spruce  (3139  to 
Bentham) ;  known  respectively  as  the  long-leaved  and  short- 
