58 
FORMATION  OF  KACEMIC  FROM  TARTARIC  ACID. 
ing  chloride  of  calcium  to  the  liquid,  the  racemic  acid  formed  at 
the  expense  of  tartaric  acid  is  precipitated  in  the  form  of  racemate 
of  lime.  If  the  liquid  be  immediately  filtered  to  separate  the  race- 
mate,  a  fresh  crystallization  is  deposited  in  about  twenty-four  hours; 
this  consists  of  pure  inactive  tartrate  of  lime,  from  which  the  inac- 
tive tartaric  acid  maybe  readily  extracted. 
Lastly,  I  have  ascertained  that  the  inactive  tartaric  acid  is  pro- 
duced in  the  preceding  operation  entirely  at  the  expense  of  the 
racemic  acid  already  formed.  This  is  proved  by  the  fact,  that  if 
racemate  of  cinchonine  be  kept  at  a  temperature  of  338°  F.  for 
several  hours,  a  considerable  portion  of  it  is  converted  into  this  in- 
active tartaric  acid. 
We  consequently  now  know  four  tartaric  acids, — dextro-tartar- 
ric  acid  ;  laovo-tartaric  acid;  the  combination  of  both,  or  racemic 
acid  ;  and  the  inactive  acid,  which  deviates  neither  to  the  right  nor 
left,  nor  is  formed  by  the  combination  of  the  dextro-  and  lsevo-tar- 
taric  acids.  There  is  no  doubt  that  this  series  of  four  isomeric  tar- 
taric acids  is  a  type  round  which  a  multitude  of  others  will  range 
hereafter. 
There  is,  however,  a  serious  difficulty  to  be  found  in  the  ulterior 
applications  of  these  new  results.  Thus,  to  pass  from  dextro-tar- 
taric  acid  to  lsevo-tartaric  acid,  it  is  necessary  to  pass  through 
the  racemic  acid,  which  is  a  combination  of  the  two,  and  to  split 
this  combination.  For  this  purpose  I  proposed  the  formation  of 
the  double  salt  of  soda  and  ammonia.  The  crystals  produced  are 
of  two  sorts  ;  these  I  separated  by  hand  according  to  the  charac- 
ter of  their  hemihedric  form.  This  splitting  is  here  accidental. 
It  is  no  doubt  a  very  curious  phenomenon,  for  which  however  we 
see  no  proximate  cause;  besides,  it  is  only  one  racemate  that  pre- 
sents this  faculty  of  splitting;  consequently  a  new  racemic  acid 
might  be  obtained  in  some  other  series  than  the  tartaric  series, 
which  probably  it  might  be  found  impossible  to  resolve,  and  the 
inverse  of  the  product  started  from  to  obtain  it  would  remain  un- 
known. This  was  until  lately  the  state  of  the  question  ;  but  I 
have  recently  found  a  chemical  process,  resting  on  general  princi- 
ples, for  the  resolution  of  racemic  acid.- 
In  a  former  memoir,  I  showed  that  the  absolute  identity  of  the 
physical  and  chemical  properties  of  non-superposable  right  and 
left  bodies  ceased  to  exist  when  the  seproducts  were  placed  in 
