BEHAVIOUR  OF  BORACIC  TO  TARTARIC  ACID.  241 
ON  THE  BEHAVIOUR  OF  BORACIC  TO  TARTARIC  ACID. 
By  H.  Rose. 
In  the  combinations  of  cream  of  tartar  with  boracic  acid  and 
borax,  the  boracic  acid  is  supposed  to  act  the  part  of  a  base  ; 
several  facts,  however,  are  against  this  view. 
The  solution  of  boracic  acid  in  alcohol  burns  with  a  green 
flame,  owing  to  the  formation  of  borate  of  ethyle  ;  boracic  acid, 
united  with  a  strong  base,  does  not  show  this  green  color,  which 
only  appears  after  the  addition  of  a  strong  acid,  particularly 
sulphuric  acid.  Several  organic  acids,  principally  the  tartaric  , 
act  like  strong  bases,  by  depriving  the  boracic  acid  of  this  pro- 
perty ;  a  considerable  quantity  of  the  organic  acid  however  is 
necessary  ;  a  mixture  of  10  equiv.  tartaric  (C4  H2  05  -f  HO)  to 
1  eq.  boracic  acid,  dissolved  in  alcohol,  burns  without  the  char- 
acteristic green  color,  which  appears  instantly  on  the  ^addition 
of  sulphuric  acid.  Among  the  inorganic  acids,  only  the  phos- 
phoric has  a  somewhat  similar  behaviour,  but  it  requires  a 
larger  proportion  of  it,  and  sulphuric  acid  restores  the  color 
also  in  this  case.  In  a  like  manner  the  addition  of  sulphuric 
acid  is  required  to  the  different  kinds  of  tartarus  boraxatus,  to 
show  the  green  coloration  of  the  flame  peculiar  to  boracic  acid 
burning  with  alcohol. 
All  attempts  to  displace  the  basic  water  of  tartaric  acid  by 
boracic  acid  proved  of  no  avail,  and  therefore  in  order  to  de- 
termine which  of  the  two  acids  in  their  combination  acts  as  a 
base,  a  solution  of  1  eq.  of  boracic  to  10  eq.  of  tartaric  acid 
was  subjected  to  the  action  of  a  Grove's  battery,  consisting  of 
but  2  elements  in  order  to  prevent  the  decomposition  of  tartaric 
acid.  The  poles  were  made  of  strips  of  platina  separated  by  a 
clay  cylinder.  After  several  hours  the  liquid  on  the  poles  was 
examined,  when  that  from  the  positive  pole  on  the  addition  of 
strong  alcohol  burned  with  a  green  flame,  which  was  not  the  case 
with  the  liquid  from  the  negative  pole,  until  after  the  addition 
of  sulphuric  acid.  After  this  result  it  will  be  incorrect  to  con- 
sider the  boracic  acid  the  base  whe'n  combined  with  tartaric  acid. 
Uric  acid  is  of  precisely  the  same  behaviour. 
The  reaction  of  boracic  acid  with  curcuma  paper  has  been! 
16 
