386 
Tlie  chemical  composition  of  a 
CKU.KS  Scott  to  be  as  follows: — 
India  Rubber 
Albumen 
Re  SI  ns 
KssentiaLoils 
Sugar  .. 
Mineral  matter 
WMter  . . . 
latex  has  been  stated  by  Las- 
37-13  percent. 
271 
3M4 
'braces. 
4-17 
’-3  M 
5^*32 
In  the  main  this  may  be  accepted  as  not  far  from  the  truth,  but 
different  lalices  shew  variations  in  (he  amounts  of  the  various  con- 
stituents and'  the  same  tree  will  produce  a latex  of  different  pro- 
portional composition  at  different  times  and  the  proportios  of  the 
('onstituents  will  vary  with  tiie  depth  and  nature  of  the  incisions 
made  in  the  tree.  Ibiis  is  only  what  would  be  expected  when 
it  is  remembered  that  tissues  other  than  the  laticiferous  are  cut 
through  during  the  process  of  tapping  and  the  cells  of  each 
contribute  their  contents  to  make  up  the  sum  total  of  the  mixture 
collected.  Analyses  shewing  these  variations  are  being  made  and 
will  be  published  as  soon  as  completed. 
The  constituents  of  the  latex  may  be  arranged  into  two  groups 
as  follows: — 
(1)  Rubber,  Resins,  Albuminous  matter,  Mineral  matter. 
This  group  makes  up  the  globules  which  can  be 
microscopically  observed  in  the  latex  and  separated 
on  filtration. 
(2)  Water  with  Albumenous  matter,  Sugar,  and  Mineral 
matter,  in  solution. 
This  group  constitutes  the  liquid  separated  in  a pure  state  from 
the  latex  by  filtration.  To  separate,  in  group  i,  the  rubber  from 
the  other  constituents  appears  at  present  to  be  a practical  impossi- 
bility on  a commercial  scale  : the  task  therefore  left  for  the  rubber 
grower  is  to  separate  group  i from  group  2 as  perfectly  as  may  be. 
If  this  were  done  the  resulting  substance  would  represent  the 
purest  and  best  possible  rubber  that  could  be  prepared  on  the  large 
scale  from  the  latex,  and  'as  such  it  ought  to  command  the  best 
price.  As  long  however,  as  rubber  is  bought  and  sold  by  the 
appearance,  smell,  and  strength,  as  they  appeal  to  the  rubber 
brokers,  there  is  no  guarantee  that  the  best  price  will  be  given  for 
the  chemically  pure  product. 
I propose  now  to  consider  briefly  the  chemical  characteristics  of 
each  of  the  constituents  of  the  latex  in  turn,  and  then  to  discuss 
the  processes  that  now  are  adopted  for  the  coagulation  and  pre- 
paration of  the  rubber. 
lNf3iA  Rubber. 
Dealing  first  with  the  India  Rubber  itself,  'fhis  substance  in 
elementary  composition  is  a compound  of  carbon  and  hydrogen 
and  belongs  to  the  class  of  bodies  known  as  terpenes.  It  mav  bo 
