92  Testing  of  Balsams,  Resins  and  Gum  Resins.  { Am  Feb.^'i£7arm' 
and,  after  shaking,  phenolphthalein,  the  end  reaction  being  easily 
recognized  by  the  formation  of  a  red  ring  upon  the  surface  of  the 
milky  liquid.  In  some  cases  (copal  and  sandarac)  there  is  a  forma- 
tion of  precipitate  after  the  addition  of  potash  solution,  due  to  the 
potassium  salts  of  the  particular  resin  acids  being  difficultly  soluble  in 
alcohol ;  when  this  occurs  the  addition  of  water  will  redissolve  the 
precipitate. 
The  following  table,  giving  the  results  of  the  examination  of  different 
balsams,  shows  that  a  conclusion  could  be  very  well  drawn  from  num- 
bers obtained  as  to  the  nature  of  a  sample.  For  instance,  an  addition 
of  gurjun  balsam  to  copaiba  balsam  would  very  considerably  lower  the 
acid  number  of  the  latter. 
Balsams. 
Balsamum  Canadense  
Copaivse  Maracaibo. 
Cop.  Mar.  from  Capaifera  nitida. 
Copaivse  Maturin....  
"  Para..  
"  (?)  
Dipterocarpi  (Gurjun  Bals.)  
Mecca  
« 
Peruvianum 
Tolu  
tt  it 
Terebinthin.  comm. 
«  u 
u  Venet. 
Chia..! 
fr.Myroxylon  Peruiferum. 
Styrax  liquid  
4<  Alcohol,  depur. 
1  gm.substance=mff. 
KOH. 
Acid 
No. 
Ether 
No. 
Saponif 
No. 
83 
81-3 
73-75 
76 
787 
77-1 
296 
78-2 
20-0 
19-3 
14*2 
5-8 
45-1 
5P8 
40*4 
189'8 
230-2 
40-8 
199*2 
240-0 
49-4 
181-1 
230-5 
367 
104-9 
141*6 
127-2 
26-7 
1539 
100-6 
587 
1593 
128-7 
124-4 
68-4 
70-3 
47-8 
53-4 
47-6 
31-9 
79-5 
61-0 
76-0 
137.0 
The  important  kinds  of  resins  are  also  distinguishable  from  one 
another  by  considerable  differences  in  the  figures,  as  will  be  seen  from 
the  following  table : 
