250 
ON  KACEMIC  ACID. 
potash,  alum  and  quick  lime,  which  appears  to  facilitate  the  taking 
up  of  the  water  and  starch  by  the  fatty  matter. 
The  cause  of  the  American  lard  appearing  so  white,  is  no 
doubt  the  great  division  of  the  fatty  matter  through  the  inter- 
position of  the  starch,  water,  and  alumina. 
The  quantity  of  alum  should  be  such  that  a  small  excess  should 
remain  to  prevent  the  starch  from  becoming  mildewed,  and  I 
believe  that  the  manufacturer  also  adds  it  for  the  purpose  of 
communicating  to  the  lard  the  property  of  facilitating  the 
raising  and  increasing  the  whiteness  of  the  confectioners'  paste, 
in  which  it  is  employed  largely. 
Royal  Institution,  Manchester,  January  VJth,  1853.* 
ON  RACEMIC  ACID. 
The  doubts  which  hitherto  have  existed  relative  to  the  formation 
of  racemic  acid,  have  at  length  been  completely  removed  by  the 
recent  researches  of  M.  Pasteur. 
It  was  somewhere  about  the  year  1820,  that  M.  Kestner  of 
Thann,  in  the  department  of  Vogdes,  France,  a  manufacturer  of 
tartaric  acid,  first  noticed  the  existence  of  racemic  acid  ;  and  having 
met  with  it  whilst  employing  tartar,  obtained  from  the  grapes 
grown  in  his  department,  he  came  to  the  conclusion  that  it  existed 
ready  formed  in  the  tartar  thus  obtained.  Instead,  however,  of 
this  acid  continuing  to  appear  as  a  regular  product  in  his  manu- 
factory, M.  Kestner  found  that  after  a  few  years  it  ceased  to  ap- 
pear altogether.  During  the  period  in  which  racemic  acid  was 
obtained  by  him  in  the  regular  course  of  his  manufacture,  M. 
Kestner  was  in  the  habit  of  decomposing  his  crude  tartars  by  means 
of  carbonate  of  lime,  using  a  large  excess  of  sulphuric  acid  in  the 
decomposition  of  the  tartrate  of  lime,  and  passing  a  current  of 
chlorine  gas  through  the  tartaric  acid  solution,  for  the  purpose  of 
removing  its  color.  Subsequently,  he  modified  his  process  of 
making  tartaric  acid,  and  was  accustomed  to  decompose  the  tar- 
tar by  caustic  lime,  using  a  slight  excess  only  of  sulphuric  acid  in 
the  decomposition  of  the  tartrate  of  lime,  and  omitting  altogether 
the  bleaching  process. 
It  appears  that  Mr.  White,  of  Glasgow,  also  a  manufacturer  of 
tartaric  acid,  had  noticed  in  his  manufactory  a  product  differing 
