June  i,  1893.]  THE  TROPICAL  AGRICULTURIST.  fa 
This  advertisement  of  the  United  Kingdom  Tea 
Company  is  on  a par  with  that  of  all  the  other  great 
firms.  The  tea  trade  is  “ cut”  like  every  other  trade, 
and  the  middleman,  as  can  be  seen  from  the  prices  of 
the  U.  K.  T.  Co.,  is  not  having  that  good  time  that  he 
is  popularly  supposed  to  enjoy.  To  sell  teas  at  9d  and 
lOd,  duty  paid,  is  simply  to  oonduct  business  at  a loss 
which  has  to  be  re-couped  out  of  the  higher  grades, 
and  the  cut-throat  competition,  which  is  a feature  of 
this-end-of-the-century  trading,  must  make  tbe  older 
firms,  like  Peek,  Winoh  & Oo.,  Hanson,  and  others, 
long  for  the  good  old  days  never  to  oome  back  aga:n. 
The  Ceylon  specialist  is  rather  given  to  make  little  of 
Indian  teas.  The  firm  which  attempts  to  send  out  tra- 
vellers to  sell  Ceylon  alone  will  find  out  by  bsrd  experi- 
ence that  the  traveller  wants  to  sell  what  the  trader 
a-k;  for.  He  will  not  long  encounter  being  shown  the 
door  by  being  unable  to  offer  any  other  sort  of  tea 
than  Ceylon  without  objection.  Whilst  the  packet 
trade  was  in  full  swing  he  had  the  whip  hand  of  other 
travellers,  because  he  was  offering  what  every  other 
traveller  was  offering,  with  the  advantage  of  his 
Ceylon  being  plainly  the  genuine  article.  But  the 
packet  trade  is  down  and  blends  are  up,  and  the 
traveller  worth  his  salt  must  have  blends  or  go  to  the 
firm  who  will  do  them. 
What  has  become  of  Ceylon  green  tea.  “In 
self-defence,”  tea  wholesalers  in  London  have  to 
go  back  to  “good  old  China”  for  this  article, 
which  has  a very  strong  hold  abroad  in  many  parts. 
Over  and  over  again  opportunities  of  foreign 
trade  have  been  missed  by  me,  because  I could 
not  supply  what  was  wanted,  viz.,  green  tea. 
Only  this  week  I have  executed  an  order  for  green 
tea  for  Rio  de  Janeiro,  and  would  gladly  have  sent 
Oeylon,  as  it  would  have  saved  a special  label.  Price 
would  not  have  stopped  Oeylon  being  used,  as  a fiue 
tea  was  required  for  which  I paid  Is  5d.  1 should 
imagine  that  it  ought  to  pay  to  produce  green  tea 
to  compete  with  the  China  article.  It  is  useless  to 
say  let  them  drink  black.  I lately  attempted  this 
for  Morocco,  and  to  this  day  I have  not  sent  a pouud 
of  tea  to  that  market,  though  I had  excellent  chances 
of  an  established  trade,  although  I live  in  hupes  of 
doing  so.  Ceylon  first  by  ali  manner  of  means  is 
my  motto  ; but  if  they  won't  have  Oeylon  don’t  throw 
them  up,  but  peg  away  with  what  they  will  take,  and 
eventually  get  the  thin  eeJ  of  the  Oeylon  wedge  in 
and  then  drive  it  home. — A London  Cor.,  local  “Times.” 
ARTIFICIAL  INDIARUBBER. 
One  of  the  most  important  events  in  the  history  of 
chemistry  during  tha  past  year  was  the  discovery  by 
an  English  professor  that  a substance  corresponding 
in  every  respect  to  indiarubber  may  be  produced  from 
oil  of  turpentine.  Dr.  W.  A.  Tilden  began  a series  of 
experiments  last  spring  with  a liquid  hydrocarbon  sub- 
stance, known  to  chemists  as  isoprerie,  a product  of 
the  destructive  distillation  of  indiarubber.  In  1884 
Dr.  Tilden  discovered  that  on  ident'eal  substance  was 
among  the  more  volatile  compounds  obtaine  i by  the 
aotion  of  moderate  heat  upon  oil  of  turpentine  and 
other  vegetable  oils,  snoh  as  rape  seed  oil,  linseed  oil 
and  castor  oil.  Isopr.  ne  is  a very  volatile  liquid, 
boiling  at  a temperature  of  about  36  degrees  Fahrenht  it. 
Chemical  analysis  shows  it  to  be  composed  of  carbon 
and  hydrogen  in  the  proport'oos  from  five  to  tight. 
In  the  course  of  his  experiment;  Dr.  Tilden  found 
that  when  isoprene  is  brought  into  contact  with  strong 
acids,  such  as  aqueous  h drochloric  acid,  for  example, 
it  is  converted  into  a tough  elastic  solid,  which  is,  to 
all  appearanoes,  true  indiarubber. 
Specimens  of isopreoe  were  made  from  sever.l  vege- 
table oils  in  the  course  of  Dr.  Tilden’s  work  on  those 
compounds.  He  preserved  several  of  them  and  stowed 
the  bottles  containing  them  away  upon  an  unused  at' elf 
in  his  laboratory.  After  some  months  had  elapsed  he 
was  surprised  at  finding  the  < onteuts  of  the  bottles 
containing  the  substance  derived  from  the  turpentine 
ent  rely  changed  in  appearance.  In  place  of  a limpid, 
coloiloss  liqui  I the  bottles  contained  a dense  syrup,  | 
in  which  were  floating  several  large  masses  of  a solid  ■ 
of  a yellowish  color.  Upon  examination  this  turned  | 
out  to  be  indiarubber.  This  is  the  first  instance  on 
record  of  the  spontaneous  change  of  isoprene  into 
indiarubber.  Accordingto  the  doctor’s  hypothesis  this 
spontaneous  change  can  only  be  accounted  for  by 
supposing  that  a small  quantity  of  acetic  or  forenic 
acid  had  been  produced  by  the  oxidizing  action  of  the 
air,  and  that  the  presenoe  of  this  compound  had  been 
the  mtans  of  transforming  the  rest.  Upon  inserting 
the  ordinary  chemical  test  paper  the  liquid  was  found 
to  be  slightly  acid.  It  yielded  asmall  portion  of  un- 
changed isoprene.  The  artificial  indiarubber  found 
floating  in  the  liquid  upon  analysis  showed  all  the 
constituents  of  natural  rubber.  Like  the  latter  it  con- 
sisted of  two  subs' ances,  one  of  which  was  more 
fo'uble  in  benzine  or  in  carbon  bisulphide  than  the 
other.  A solu'ion  of  the  artificial  rubber  in  benzine 
left  on  evaporation  a residue  which  agreed  in  all 
characteristics  with  the  residum  of  the  best  Para 
rubber  similarly  dissolved  and  evaporated.  The  arti- 
ficial rubber  was  Lund  to  unite  with  natural  rubber  in 
the  same  way  as  two  pieces  of  ordinary  pure  rubber, 
forming  a tough,  elastio  compound. 
Although  die  discovery  is  very  interesting  from  a che- 
mical point  of  view,  it  has  not  as  yet  aDy  commercial 
importance.  It  is  from  such  beginnings  as  these;  how- 
ever, that  cheap  chemical  substitutes  tor  many  natural 
products  have  been  developed.  Few  persons  outside 
of  those  directly  connected  with  rubber  industries 
realize  the  vast  quantities  imported  yearly  into  this 
country.  Last  year  there  were  brought  into  United 
States  ports,  as  shown  by  the  reports  of  tbe  oustoms 
officers,  no  less  than  34,348,000  pounds  of  indiarubber. 
Tbe  industry  has  been  steadily  progressive  since  the 
invention  of  machinery  for  manufacturing  it  into  the 
various  articles  of  every-day  use.  The  wonderful 
growth  of  the  indiarubber  interests  in  this  country 
will  b8  seen  from  the  statistics  oompiled  in  the  tenth 
census. 
Iu  1870  there  were  imported  5,132,000  pounds  at  an 
average  rata  of  $1  per  pound;  in  1880  the  imports 
were  17,835,000  pounds,  at  an  average  price  of  85  cents 
per  pound ; in  1890,  31,949,000  pounds  were  imported, 
at  an  average  price  of  75  cents  per  pound.  The  pre- 
sent price  of  Ind  arubbsr  varies  from  75  cen’s  per 
pound  for  the  Para  rubber  to  45  cents  per  pound  for 
the  cheapest  grade.  It  will  be  seen  that  notwithstand- 
ing the  increase  in  importations  the  price  of  the  raw 
material  remains  at  a comparatively  high  figure.  Many 
experiments  have  been  made  to  find  a Bubstanee  pos- 
sesing  the  same  properties  as  indiarubber,  but  which 
could  be  produced  at  a cheaper  rate. 
Many  of  the  compositions  whioh  have  been  invented 
have  been  well  adapted  for  use  for  certain  purposes  and 
have  beon  used  to  adulterate  the  pure  rubber,  but 
no  substance  has  been  produced  which  could  even 
approach  indiarubber  in  several  of  its  important 
characteristics.  There  has  never  been  a substance 
yet  recommended  as  a substitute  for  rubber  which 
possessed  the  extraordinary  elasticity  which  makes  it 
ind  spensable  in  tbe  manufacture  of  so  many  articles 
of  common  use.  Great  hopes  were  at  one  time  placed 
in  a product  prepared  from  linseed  oil.  It  was  found 
that  a material  could  be  produced  from  it  which  would 
to  a certain  extent  equal  indiarubber  compositions 
in  elasticity  and  toughness.  It  was  argued  that  lin- 
seed  oil  varnish,  when  correctly  prepared,  should  be 
clear,  aDd  dry  in  a few  hours  into  a transparent 
glossy  mars  of  great  tenacity.  By  changing  the 
mode  of  preparing  linseed  oil  varnish  in  so  far  as  to 
boil  the  oil  until  it  became  a very  thiok  fluid  and  spun 
threads,  when  it  was  taken  from  the  boiler,  a mass 
was  ob'ained  which  in  drying  assumed  a character 
resembling  that  of  a thick,  congealed  solution  of  glue. 
Rosin  was  ad  led  to  the  mass  while  hot,  in  a quantity 
depending  up  >n  the  product  designed  to  be  made,  and 
requiring  a greater  or  less  degree  of  elasticity. 
Many  other  recipei  have  been  advocated  at  different 
times  to  make  a product  resembling  caoutchouc  out 
of  linseed  oil  in  combination  with  other  substances, 
but  all  have  failed  to  give  satisfaction,  save  as  adul- 
terants to  pure  rubber. 
J Among  the  best  compounds  in  use  in  rubber  faotories 
: at  present  is  one  made  by  boiling  linsead  oil  to  the 
I consistetcy  of  thick  glue,  Unbleached  shellac  and 
