152 
The  Chemistry  of  Gurjun  Balsam. 
f  Am.  Jour.  Pharm. 
\      Mar.,  1880. 
(a)  nitrous  acid,  but  no  nitric  acid  was  found,  whilst  in  (b)  nitric  acid 
was  present  but  no  nitrous  acid  ;  this  is  explained  by  the  fact  that  it 
requires  concentrated  sulpuric  acid  to  combine  with  and  retain  the 
nitrous  acid  ;  and  in  (a)  the  acid  became  concentrated  by  evaporation, 
whilst  in  (b)  it  remained  of  about  the  same  strength,  and  was  unable  to 
retain  the  nitrous  acid. 
Again,  when  the  mixture  was  heated  on  a  water-bath  at  about  95°, 
no  such  changes  occurred. 
As  Winkler  found,  that  on  heating  his  mixture  of  acid  of  6o°B. 
with  nitrogen  tetroxide,  the  latter  was  evolved,  he  presumed  that  it 
existed  as  a  mechanical  mixture  with  the  acid.  This  the  author  denies, 
stating  that  had  Winkler  examined  the  acid  after  boiling,  he  would  have 
found  that  it  contained  nitric  acid,  and  that  the  nitrogen  tetroxide  had 
really  undergone  decomposition  ;  and  further,  that  he  must  have  heated 
it  considerably  above  the  temperature  of  boiling  water,  otherwise  no 
change  would  have  resulted,  and  no  red  fumes  would  have  been  liber- 
ated. 
When  the  amount  of  nitrogen  tetroxide  added  is  in  excess  of  that 
required  to  form  nitrosulphuric  acid,  the  author  is  uncertain  from  ana- 
lysis whether  it  exists  in  the  acid  in  the  form  of  nitrous  acid  or  of 
nitrogen  tetroxide. — Ger.  Chem.  Soc.^  Feb.  1880,  p.  91,  from  D'lngl. 
polyt.  7,  233,  155  to  165. 
CONTRIBUTION  TO   THE    CHEMISTRY    OF  GURJUN 
BALSAM, 
By  Eduard  Hirschsohn,  Mag.  Pharm. 
In  my  work,  "  Contributions  to  the  Chemistry  of  the  more  impor- 
tant Gum  Resins,  Resins  and  Balsams,"^  will  be  found  experiments 
which  were  made  with  a  liquid  sold  as  gurjun  balsam.  The  sample  I 
examined  did  not  solidify  on  heating,  showed  a  slight  fluorescence,  and 
did  not  give  with  nitric  and  sulphuric  acids  the  violet  coloration  men- 
tioned by  Fliickiger."  As  no  sample  of  the  balsam  described  by 
Fllickiger  was  at  my  disposal,  I  was  unable  at  the  time  to  determine 
^"  Archiv  der  Pharinacie,"  vii,  6,  1877. 
-  Fllickiger  proceeded  as  follows:  One  drop  of  the  balsam  is  dissolved  in  twenty- 
drops  of  bisulphide  of  carbon,  and  one  drop  of  a  previously  cooled  mixture  of  con. 
centrated  sulphuric  and  nitric  acids  added  and  the  whole  well  shaken.  "  Jahresbe- 
richt  fiir  Phai macognosie,"  etc.,  1876,  p.  220. 
