I 
THE  GUMS  AND  RESINS  OF  COMMERCE. 
139 
Wood  Oils. — This  class  of  resinous  oils,  known  in  all  the 
Indian  bazaars  as  gurgun  oils,  is  obtained  by  tapping  certain 
trees  of  the  order  Dipterocarpese  (D.  Icevis,  Hamilton ;  and  D. 
turbinatus,  of  Roxburgh),  and  applying  heat  to  the  incision. 
The  tree  is  a  native  of  Chittagong,  Pegu,  Assam,  the  valley  of 
Kubba,  and  the  jungles  of  the  Malayan  peninsula,  and  grows  to 
a  great  height.  It  is  described  as  having  a  straight  stem,  of 
more  than  forty  feet  to  the  first  branch.  When  not  tapped  too 
soon,  the  base  of  the  trunk  is  often  of  immense  girth,  having  a 
circumference  of  thirteen  feet  and  upwards.  About  the  end  of 
the  dry  season,  that  is,  in  March  and  April,  several  deep  inci- 
sions are  made  with  an  axe  into  the  heart  of  the  wood,  and  a 
good  sized  piece  scooped  out ;  into  these  holes  fire  is  placed,  and 
kept  burning  until  the  oil  begins  to  run,  when  it  is  received  into 
a  bamboo,  and  allowed  to  ooze  slowly  drop  by  drop.  The  aver- 
age produce  is  about  40  gallons  in  each  season.  The  oil  which 
flows  from  the  wound  is  a  mixture  of  balsam  and  volatile  oil,  and 
when  applied  as  a  varnish  to  wood  or  other  substance,  the  oil 
evaporating  deposits  a  hard  and  durable  coat  of  resin. 
These  wood  oils  are  chiefly  used  as  natural  varnishes,  either 
alone  or  in  combination  with  colored  pigments  ;  also  as  a  sub- 
stitute for  tar  in  paying  the  seams  of  shipping,  and  for  preserv- 
ing timber  from  the  attacks  of  white  ants.  They  are  said  also 
to  be  useful  as  an  ingredient  in  lithographic  inks.  This  oil  has 
all  the  medical  properties  of  some  of  the  more  esteemed  balsams. 
From  the  comparatively  imperfect  knowledge  we  possess  of 
the  trees  from  which  these  valuable  substances  are  derived,  the 
oils  generally  receive  the  names  of  the  localities  from  which  they 
are  imported — hence  there  are  wood  oils  from  Canara,  and  the 
Madras  Presidency,  Malacca,  Pegu,  Moulmein,  and  Rangoon, 
Singapore,  Tinnevelly  and  China.  The  last  named  deserves 
notice,  as  being  one  of  the  substances  of  which  the  well-known 
and  much  prized  Chinese  lacquer  is  made.  It  is  used  in  Singa- 
pore for  painting  the  beams  and  wood-work  of  native  houses, 
and  may  also  be  mixed  with  paint  when  not  exposed  to  the  sun. 
Dammer  is  the  eastern  name  for  a  kind  of  indurated  pitch  or 
turpentine  exuding  spontaneously  from  various  trees  indigenous 
to  most  of  the  Indian  islands.  The  principal  species  are  Dam- 
mara  Australis  (Don),  the  Kauri  tree  of  New  Zealand,  and  D. 
