558 
LARIXINIC  ACID. 
When  larixinic  acid  was  treated  with  an  excess  of  aqua  pot. 
ass83  it  very  readily  dissolved,  forming  a  yellowish  solution. 
When  dried  over  sulphuric  acid  in  vacuo,  the  potash  combina- 
tion formed  long  flattish  crystals  having  considerable  lustre,  but 
of  a  reddish-brown  color.  These  crystals,  when  pressed  between 
folds  of  blotting  paper,  to  free  them  from  the  excess  of  potash 
and  recrystallized  in  vacuo,  yielded  crystals  which  were  more 
deeply  colored  than  the  first.  This  potash  combination  is  so 
very  feeble  that  it  is  decomposed  by  carbonic  acid.  It  con- 
tained a  considerable  quantity  of  potash  ;  but  I  have  not  been 
able  to  obtain  it  of  a  constant  composition. 
A  solution  of  larixinic  acid  gives  no  precipitate,  either  with 
lime-water  or  with  saccharate  of  lime.  The  behaviour  of  larix. 
inie  acid  with  baryta  is  extremely  singular  and  characteristic. 
When  a  solution  of  caustic  baryta  is  added  to  a  concentrated 
aqueous  solution  of  larixinic  acid,  the  latter  being  in  excess,  a 
bulky,  semi-transparent,  gelatinous  precipitate  immediately  falls, 
and  if  the  solutions  are  concentrated  fills  the  whole  vessel. 
This  precipitate,  which  considerably  resembles  hydrated  alu- 
mina, is  but  slightly  soluble  in  cold  water,  but  it  dissolves  very 
readily  in  boiling  water,  from  which  it  is  again  deposited  on 
the  cooling  of  the  liquid.  This  baryta  compound  is  readily 
decomposed  by  carbonic  acid.  When  thrown  on  a  filter  and 
washed,  the  air  being  carefully  excluded,  it  was  dried  in  vacuo 
over  sulphuric  acid,  and  was  then  found  to  contain,  as  the  mean 
of  two  experiments,  34-92  per  cent,  of  baryta. 
A  solution  of  larixinic  acid  yields  no  precipitate  with  either 
basic  or  neutral  acetate  of  lead,  neither  is  it  precipitated  by 
nitrate  or  ammonio-nitrate  of  silver ;  but  when  its  solution  in 
the  latter  salt  is  boiled,  the  silver  is  reduced  in  a  pulverulent 
state.  Larixinic  acid  forms  no  precipitate  with  perchloride 
of  platinum,  even  on  the  application  of  heat.  It  does  not 
contain  any  nitrogen.  It  does  not  reduce  oxide  of  copper  when 
tried  by  Trommer's  test.  It  dissolves  in  concentrated  sulphuric 
acid,  but  no  conjugate  combination  is  produced,  as  was  ascer- 
tained by  neutralizing  with  carbonate  of  baryta,  larixinic  acid 
being  obtained  unchanged.  When  larixinic  acid  is  boiled  with 
a  mixture  of  hydrochloric  acid  and  chlorate  of  potassa,  it  is 
decomposed,  but  without  the  formation  of  chloranile.    When  it 
