448 
Folyhydiic  Alcohols  and  Borax. 
(  Am.  Jour.  Pharm. 
X      Sept.,  1883. 
detailed  inquiry  into  this  same  reaction.  This  inquiry  is  still  in  pro- 
gress, but  I  learn  that  some  of  the  results  are  similar  to  those  described  in 
this  paper.  It  will  be  convenient  here  to  recapitulate  the  principal 
work  which  has  been  done  upon  this  subject. 
In  1877,  lies  {Chem.  News,  xxxv,  204)  recorded  the  fact  that  a 
mixture  of  borax  with  glycerin  imparts  a  green  color  to  the  flame,  and 
proposed  to  utilize  this  fact  as  a  test  for  borates. 
In  1878,  D.  Klein  {Bull.  Soc.  Chim.,  xxix,  195)  showed  that  when 
certain  polyhydric  alcohols  are  added  to  a  solution  of  borax  an  acid 
reaction  is  the  result ;  this  was  observed  with  glycerol  (glycerin),  man- 
nitol  (mannite),  erytlirol  (erythrite),  levulose,  dextrose,  a-galactose  and 
/^-galactose.  A  special  study  was  made  of  the  reaction  in  which  man- 
nitol  is  involved,  and  published  in  the  same  year  (Bull.  Soc.  Chim.y 
xxix,  357).  Klein  found  that  when  half  a  molecular  weight  of  borax 
is  dissolved  in  water  and  added  to  one  molecular  weight  of  mannitol, 
also  in  aqueous  solution,  the  resulting  liquid  is  neutral ;  but  when  the 
quantity  of  borax  added  was  less  than  this  quantity,  the  liquid  is  acid. 
From  the  neutral  liquid  a  compound  was  obtained  of  one  molecule  of 
borax  with  one  molecule  of  mannitol.  From  the  acid  liquid,  after 
fractional  precipitation  with  alcohol  of  different  degrees  of  strength,  a 
residue  was  obtained  which  was  very  acid,  and  was  supposed  to  be  a 
compound  of  mannitol  with  boric  acid,  but  was  not  further  examined. 
By  heating  together  mannitol  and  boric  acid  to  150°  C.  for  seven  or 
eight  hours,  treating  the  resulting  substance  with  water  and  barium 
carbonate,  and  subsequently  purifying  by  precipitation  with  alcohol,  a 
substance  was  obtained  which  Klein  calls  barium  biboromannitate 
2  BO3 
This  was  decomposed  by  sulphuric  acid,  yielding  a  compound  which 
crystallized  into  needles,  but  did  not  receive  further  investigation. 
The  results  of  Klein's  work  which  bears  upon  the  present  question 
amounted  to  showing  that  when  mannitol  is  added  to  an  aqueous  solu- 
tion of  borax  two  compounds  are  formed  depending  upon  the  amount 
of  mannitol  present.  If  the  borax  be  in  excess,  a  compound  of  borax 
and  mannitol,  molecule  for  molecule,  results ;  if  the  mannitol  is  in 
excess,  a  compound  with  boric  acid  is  formed,  the  exact  composition 
and  properties  of  which  were  not  determined,  analogy  leading  to  the 
supposition  that  it  was  a  conjugate  acid. 
In  the  same  year,  Senier  and  Lowe  {Pharm.  Journ.,  [3],  viii. 
