490  Silphium  Laciniatum,  Rosin  Weed.  {^^oct\8si^^^^ 
bon  probably  identical  in  composition  with  oil  of  turpentine.  The 
sodium  was  left  in  contact  with  the  oil  for  several  days  without 
perceptibly  changing  its  odor^  but  the  oil  assumed  a  light  yellowish 
color. 
The  watery  liquid  left  in  the  retort  on  the  distillation  of  the  vola- 
tile oil  contained  sugar^  and  yielded  after  some  time  a  brownish  pre- 
cipitate with  ferric  chloride  and  white  precipitates  with  caustic  alka- 
lies and  with  the  lead  acetates. 
The  residue  left  in  the  retort,  after  complete  exhaustion  with  water 
was  a  brownish-white  mass,  having  an  odor  while  warm  very  much 
like  that  of  copaiba.    It  was  t^ompletely  soluble  in  chloroform,  while 
carbon  disulphide  dissolved  97*1  per  cent.,  ether  78'4  per  cent.,  ben- 
zin  7 2' 7  per  cent,  and  alcohol  (90  per  cent.)  5*40  per  cent,  of  it. 
The  portion  soluble  in  alcohol,  after  spontaneous  evaporation,  wa.s 
obtained  in  the  form  of  a  yellowish  extract.  It  was  wholly  soluble 
in  chloroform,  almost  entirely  soluble  in  carbon  disulphide,  benzin 
and  ether,  which  solutions  by  evaporation  left  residues  of  the  same 
amorphous  character. 
The  part  insoluble  in  alcohol  is  whitish,  tasteless,  falls  to  powder 
when  rubbed  between  the  fingers,  and  is  wholly  soluble  in  chloroform 
and  carbon  disulphide,  and  only  partly  soluble  in  benzin  and  ether,, 
and  upon  the  evaporation  of  the  liquids  was  again  obtained  as  an 
amorphous  powder. 
A  portion  of  the  resinous  residue  from  the  retort  was  soluble  in 
potassa  and  in  ammonia,  and  reprecipitated  by  acids,  and  consists  pro- 
bably of  a  resinous  acid. 
Some  of  the  residue  was  fused  with  caustic  potash,  the  fused  mas& 
extracted  with  water,  filtered,  acidulated  with  sulphuric  acid,  the  solu- 
tion concentrated  and  the  sulphate  of  potassium  for  the  most  part  sep- 
arated by  crystallization  ;  the  filtrate  was  then  well  shaken  with  ether, 
the  ether  separated  and  allowed  to  evaporate  spontaneously,  when  a 
whitish  residue  was  left.  This  tested  with  ferric  chloride  did  not 
change  color,  showing  that  there  was  no  protocatechuic  acid  formed  by 
this  treatment. 
The  oleoresin  which  is  gathered  by  children  for  chewing  gum  resem- 
bles mastich  very  much  in  appearance,  but  is  much  less  soluble  in 
alcohol,  and  its  constituents  seem  to  be  more  nearly  allied  to  those  of 
Chian  turpentine. 
The  only  part  of  the  plant  generally  used  is  the  leaves,  and  a  fluid 
