286 
Castilloa  latex  can  be  coagulated  or  agglutinized  also  by  the 
sand  filter,  or  when  placed  in  a vessel  having  a tine  copper  wire 
gauze  at  its  base.  The  watery  fluid  drips  readily  through  this 
without  allowing  the  rubber  globules  to  jiass,  and  when  all  are 
removed  the  rubber  in  paste  can  be  turned  upon  a porous  substance 
to  dry.  With  the  sand  bath,  the  sand  should  be  fine,  clean  and 
w'ell  whetted.  'The  latex  can  then  be  poured  upon  it  after  placing 
w'ire  gauze  on  the  surface.  These  processes,  however,  do  not  com- 
pare in  cleanliness,  nor  can  so  good  rubber  be  made  by  them,  as 
when  the  readily  decomposing  albuminoids  are  washed  away  by 
creaming  process.  The  rubber  produced  is  also  inferior  in  quality. 
There  is  every  reason  to  believe  therefore  that  the  treatment  of 
Castilloa  latex  wdth  Formalin  is  likely  to  become  a highly  suc- 
cessful method  to  adopt  in  the  preparation  of  crude  rubber. 
NATURAL  INDIGO. 
The  following  particulars  respecting  indigo  prospects  are  by  the 
Calcutta  correspondent  of  the  British  Trade  Journat : — 
A great  deal  has  been  written  about  indigo  during  the  last  few’ 
months,  but  the  controversy  can  only  tend  to  convey  to  the  general 
public  an  erroneus  idea.  It  has  been  contended  that  because  the 
Maharajah  of  f)arlangha  turned  his  estates  to  the  cultivation  of 
rhea^  that  indigo  growing  has  been  abandoned  in  East  India;  and 
because  many  consumers  have  adopted  artificial  indigo  as  an  experi- 
ment to  see  how  far  it  can  replace  the  natural  product,  it  is  assumed 
that  chemical  indigo  is  the  more  advantageous  of  the  two,  and  there- 
fore preferred.  The  argument  that  the  high  price  of  indigo  during 
the  last  Calcutta  season  again  alienated  many  regular  partizans  and 
consumers  of  the  natural  product,  causing  them  to  continue  adopt- 
ing synthetic  indigo  can  be  met  in  the  following  manner: — 
In  spite  of  the  energetic  and  zealous  work  of  the  artificial  indigo 
manufacturers,  who  have  lost  no  opportunity  of  puffing  their  article, 
the  worlds  consumption  has  taken  up  all  the  natural  indigo  produced, 
and  the  very  heavy  stocks  which  have  always  existed  have  never 
been  so  low  as  of  late.  If  the  Maharajah  of  Darlangha,  as  many 
other  planters  before  him,  has  seen  that  owing  to  the  low  prices 
prevailing  the  land  can  be  turned  Into  better  accou  it  in  many  other 
ways,  it  shows  nothing  else  but  that  in  the  comparatively  small 
indigo  district  of  lower  Bengal  the  soil  is  not  productive  enough 
for  this  kind  of  culture,  a fact  wdiich  experts  have  know  n for  years. 
Other  districts  continue  to  prosper  satisfactorily,  and  will  go  on  do- 
ing so  if  for  the  next  few  years  better  climatic  conditions  prevail 
than  have  existed  wdth  scarcely  a break  since  1898. 
'The  rate  of  Indian  exchange  has  an  important  influence  on  the 
indigo  trade.  , The  1895  to  1896  harvest  which  wms  an  exception- 
ally good  one,  producing  160,000  maunds — about  40,000  cases  at 
an  exchange  of  i.v.  \d.  per  rupee,  yielded  such  high  rupee  prices 
that  the  planter  w’as  able  to  do  a large  business;  in  i 896  the  ex- 
