472  Notes  on  New  Zealand  Kauri  Gam.  {A"o™imf"' 
NOTE  ON  NEW  ZEALAND  KAURI  GUM. 
By  M.  M.  Pattison  Muir,  F.R.S.E. 
This  gum  or  resin  exudes  from  a  tree  [pammara  Austfalis)  belong- 
ing to  the  family  of  pines.  It  is  largely  imported  into  this  country 
for  the  purpose  of  making  varnish. 
The  sample  which  I  have  examined  was  sent  to  me  about  two  years 
ago  by  my  brother,  John  M.  Muir.  The  substance  was  in  the  form 
of  a  hard,  brittle,  yellowish-white  mass,  which  could  be  easily  cut  with 
a  knife.  By  rubbing,  the  surface  became  highly  polished,  being  at 
the  same  time  electrically  excited. 
Here  and  there  throughout  the  mass  non-transparent  milky  blotches 
occurred.  The  fracture  was  conchoidal.  Specific  gravity  =  1*042. 
On  treating  the  powdered  gum  with  water,  part  of  it  dissolved,  but 
the  greater  portion  remained  unacted  upon.  This  insoluble  portion 
was  partially  dissolved  by  alcohol,  in  which  solution  the  addition  of 
water  caused  a  white  turbidity. 
About  fifty-two  per  cent,  of  the  original  substance  was  found  to 
be  soluble  in  boiling  alcohol,  while  the  residue  was  almost  entirely 
dissolved  by  digestion  in  ether  at  the  ordinary  temperature. 
The  alcoholic  solution  of  the  gum  showed  a  slightly  acid  reaction  ; 
traces  of  benzoic  and  succinic  acids  were  also  discovered. 
From  these  reactions  "Kauri  gum"  appears  to  be  a  mixture  of 
resins  (probably  more  than  one)  and  true  gum  :  hence  it  may  be 
classed  among  the  gum-resins.  The  following  are  some  of  the  reac- 
tions of  this  substance  with  reagents  : 
1.  Strong  nitric  acid,  aided  by  gentle  warming,  attacks  Kauri  gum 
violently,  the  products  of  the  reaction  being  a  yellowish-white  solid 
mass,  and  a  small  quantity  of  a  reddish  liquid.  The  solid  substance 
is  but  slightly  soluble  in  hot  alcohol  or  in  hot  ether,  the  liquid  gives 
a  yellow  flocculent  precipitate  when  thrown  into  water. 
2.  Concentrated  sulphuric  acid  dissolves  the  gum,  forming  a  clear 
red  liquid,  from  which  a  white  semi-solid  substance  precipitates  on 
the  addition  of  water.  If  heat  be  applied,  sulphuric  acid  partially 
decomposes  the  gum,  at  the  same  time  forming  a  dark-colored  liquid, 
in  which  water  causes  no  precipitate. 
3.  Bromine  and  chlorine  both  attack  Kauri  gum  violently,  dense 
fumes  being  evolved,  the  product  in  the  former  case  being  a  blackish 
mass,  which  dissolves  in  alcohol,  with  formation  of  a  red  liquid.  In 
the  latter  case  carbon  only  remains. 
